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Major infectious diseases

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This entry lists major infectious diseases likely to be encountered in countries where the risk of such diseases is assessed to be very high as compared to the United States. These infectious diseases represent risks to US Government personnel traveling to the specified country for a period of less than three years. The degree of risk is assessed by considering the foreign nature of these infectious diseases, their severity, and the probability of being affected by the diseases present. The diseases listed do not necessarily represent the total disease burden experienced by the local population.
The risk to an individual traveler varies considerably by the specific location, visit duration, type of activities, type of accommodations, time of year, and other factors. Consultation with a travel medicine physician is needed to evaluate individual risk and recommend appropriate preventive measures such as vaccines.
Diseases are organized into the following six exposure categories shown in italics and listed in typical descending order of risk. Note: The sequence of exposure categories listed in individual country entries may vary according to local conditions.

food or waterborne diseases acquired through eating or drinking:
Hepatitis A - viral disease that interferes with the functioning of the liver; spread through consumption of food or water contaminated with fecal matter, principally in areas of poor sanitation; victims exhibit fever, jaundice, and diarrhea; 15% of victims will experience prolonged symptoms over 6-9 months; vaccine available.
Hepatitis E - water-borne viral disease that interferes with the functioning of the liver; most commonly spread through fecal contamination of drinking water; victims exhibit jaundice, fatigue, abdominal pain, and dark colored urine.
Typhoid fever - bacterial disease spread through contact with food or water contaminated by fecal matter or sewage; victims exhibit sustained high fevers; left untreated, mortality rates can reach 20%.

vector-borne diseases acquired through the bite of an infected arthropod:
Malaria - caused by single-cell parasitic protozoa Plasmodium; transmitted to humans via the bite of the female Anopheles mosquito; parasites multiply in the liver attacking red blood cells resulting in cycles of fever, chills, and sweats accompanied by anemia; death due to damage to vital organs and interruption of blood supply to the brain; endemic in 85, mostly tropical, countries with 95% of cases and the majority of 0.4-0.6 million estimated annual deaths occurring in sub-Saharan Africa (six countries – Nigeria, the Democratic Republic of the Congo, Uganda, Mozambique, Angola and Burkina Faso – accounted for just over half of all malaria deaths globally in 2020).
Dengue fever - mosquito-borne (Aedes aegypti) viral disease associated with urban environments; manifests as sudden onset of fever and severe headache; occasionally produces shock and hemorrhage leading to death in 5% of cases.
Yellow fever - mosquito-borne (in urban areas Aedes aegypti) viral disease associated with urban environments; severity ranges from influenza-like symptoms to severe hepatitis and hemorrhagic fever; occurs only in tropical South America and sub-Saharan Africa, where most cases are reported; fatality rate is less than 20%.
Japanese Encephalitis - mosquito-borne (Culex tritaeniorhynchus) viral disease associated with rural areas in Asia; acute encephalitis can progress to paralysis, coma, and death; fatality rates 30%.
African Trypanosomiasis - caused by the parasitic protozoa Trypanosoma; transmitted to humans via the bite of bloodsucking tsetse flies; infection leads to malaise and irregular fevers and, in advanced cases when the parasites invade the central nervous system, coma and death; endemic in 36 countries of sub-Saharan Africa; cattle and wild animals act as reservoir hosts for the parasites.
Cutaneous Leishmaniasis - caused by the parasitic protozoa leishmania; transmitted to humans via the bite of sandflies; results in skin lesions that may become chronic; endemic in 88 countries; 90% of cases occur in Iran, Afghanistan, Syria, Saudi Arabia, Brazil, and Peru; wild and domesticated animals as well as humans can act as reservoirs of infection.
Plague - bacterial disease transmitted by fleas normally associated with rats; person-to-person airborne transmission also possible; recent plague epidemics occurred in areas of Asia, Africa, and South America associated with rural areas or small towns and villages; manifests as fever, headache, and painfully swollen lymph nodes; disease progresses rapidly and without antibiotic treatment leads to pneumonic form with a death rate in excess of 50%.
Crimean-Congo hemorrhagic fever - tick-borne viral disease; infection may also result from exposure to infected animal blood or tissue; geographic distribution includes Africa, Asia, the Middle East, and Eastern Europe; sudden onset of fever, headache, and muscle aches followed by hemorrhaging in the bowels, urine, nose, and gums; mortality rate is approximately 30%.
Rift Valley fever - viral disease affecting domesticated animals and humans; transmission is by mosquito and other biting insects; infection may also occur through handling of infected meat or contact with blood; geographic distribution includes eastern and southern Africa where cattle and sheep are raised; symptoms are generally mild with fever and some liver abnormalities, but the disease may progress to hemorrhagic fever, encephalitis, or ocular disease; fatality rates are low at about 1% of cases.
Chikungunya - mosquito-borne (Aedes aegypti) viral disease associated with urban environments, similar to Dengue Fever; characterized by sudden onset of fever, rash, and severe joint pain usually lasting 3-7 days, some cases result in persistent arthritis.
Severe fever with thrombocytopenia syndrome (SFTS) - a tick-borne viral (phlebovirus) hemorrhagic fever; infection can spread through contact with infected wild and domesticated animals, including household pets; human-to-human transmission is also possible through direct contact with infected blood or bodily secretions; disease is characterized by rapid-onset of acute fever, vomiting, diarrhea, thrombocytopenia (low platelet count), low white cell count, bleeding tendency, and multiple organ failure; mortality rate is between 10-40%; there is no vaccine or treatment for the disease
Bartonellosis (Oroya fever) – a parasitic bacterial (Bartonella bacilliformis) infection transmitted by bites from infected sand flies (genus Lutzomyia); also known as Carrion’s disease; the bacteria is limited to the Andes Mountains of western South America at an elevation of 915-3,050 m (3,000 to 10,000 ft.) and chiefly in  Peru (where most cases are reported), Colombia, and Ecuador; Oroya fever is the acute phase of the disease and characterized by fever, headache, muscle aches, abdominal pain, and severe anemia may occur; complications can occur in up to 70% of patients with Oroya fever, including secondary infections and cardiopulmonary complications such as heart failure, pericardial effusion, pulmonary edema, and cardiogenic shock; infection with B. bacilliformis requires antibiotic treatment
Hantaviral hemorrhagic fever with renal syndrome (HFRS), also known as Korean hemorrhagic fever - hantaviruses are carried and transmitted by rodents through exposure to aerosolized urine, droppings, or saliva of infected rodents or after exposure to dust from their nests; transmission may also occur when infected urine or other materials are directly introduced into broken skin or onto the mucous membranes of the eyes, nose, or mouth; human-to-human transmission is rare; the most serious disease is caused by the Hantaan or Seoul  viruses; symptoms of HFRS usually develop within 1 to 2 weeks after exposure to infectious material but, in rare cases, may take up to 8 weeks to develop; initial symptoms begin suddenly and include intense headaches, back and abdominal pain, fever, chills, nausea, and blurred vision; later symptoms can include low blood pressure, acute shock, vascular leakage, and acute kidney failure, which can cause severe fluid overload; fatality ranges from 5-15% for the most serious cases of HFRS caused by Hantaan virus; there is no cure for HFRS, treatment involves supportive therapy including renal dialysis; vaccines are available

water-contact diseases acquired through swimming or wading in freshwater lakes, streams, and rivers:
Leptospirosis - bacterial disease that affects animals and humans; infection occurs through contact with water, food, or soil contaminated by animal urine; symptoms include high fever, severe headache, vomiting, jaundice, and diarrhea; untreated, the disease can result in kidney damage, liver failure, meningitis, or respiratory distress; fatality rates are low but left untreated recovery can take months.
Schistosomiasis - caused by parasitic trematode flatworm Schistosoma; fresh water snails act as intermediate host and release larval form of parasite that penetrates the skin of people exposed to contaminated water; worms mature and reproduce in the blood vessels, liver, kidneys, and intestines releasing eggs, which become trapped in tissues triggering an immune response; may manifest as either urinary or intestinal disease resulting in decreased work or learning capacity; mortality, while generally low, may occur in advanced cases usually due to bladder cancer; endemic in 74 developing countries with 80% of infected people living in sub-Saharan Africa; humans act as the reservoir for this parasite.

aerosolized dust or soil-contact disease acquired through inhalation of aerosols contaminated with rodent urine:
Lassa fever - viral disease carried by rats of the genus Mastomys; endemic in portions of West Africa; infection occurs through direct contact with or consumption of food contaminated by rodent urine or fecal matter containing virus particles; fatality rate can reach 50% in epidemic outbreaks.

respiratory disease acquired through close contact with an infectious person:
Meningococcal meningitis - bacterial disease causing an inflammation of the lining of the brain and spinal cord; one of the most important bacterial pathogens is Neisseria meningitidis because of its potential to cause epidemics; symptoms include stiff neck, high fever, headaches, and vomiting; bacteria are transmitted from person to person by respiratory droplets and facilitated by close and prolonged contact resulting from crowded living conditions, often with a seasonal distribution; death occurs in 5-15% of cases, typically within 24-48 hours of onset of symptoms; highest burden of meningococcal disease occurs in the hyperendemic region of sub-Saharan Africa known as the "Meningitis Belt" which stretches from Senegal east to Ethiopia.

animal-contact disease acquired through direct contact with local animals:
Rabies - viral disease of mammals usually transmitted through the bite of an infected animal, most commonly dogs; virus affects the central nervous system causing brain alteration and death; symptoms initially are non-specific fever and headache progressing to neurological symptoms; death occurs within days of the onset of symptoms.

Afghanistan

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever (2024)

vectorborne diseases: Crimea-Congo hemorrhagic fever

note: Afghanistan is one of two countries with endemic wild polio virus (the other is Pakistan) and considered high risk for international spread of the disease; before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the US Centers for Disease Control and Prevention (CDC) recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Algeria

note: on 23 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Algeria is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Angola

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, typhoid fever

vectorborne diseases: dengue fever, malaria

water contact diseases: schistosomiasis

animal contact diseases: rabies

Bangladesh

degree of risk: high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A and E, and typhoid fever

vectorborne diseases: dengue fever and malaria are high risks in some locations

water contact diseases: leptospirosis

animal contact diseases: rabies

Benin

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever, malaria, sexually transmitted diseases: hepatitis B (2024)

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Benin is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Bolivia

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea and hepatitis A

vectorborne diseases: dengue fever, malaria, sexually transmitted diseases: hepatitis B (2024)

Botswana

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, sexually transmitted diseases: HIV/AIDS (2024)

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Botswana is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Brazil

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea and hepatitis A

vectorborne diseases: dengue fever, malaria, sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

Burkina Faso

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever, malaria, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Burkina Faso is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Burma

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever, malaria, Japanese encephalitis, and sexually transmitted diseases: hepatitis B (2024)

animal contact diseases: rabies

Burundi

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria and dengue fever

water contact diseases: schistosomiasis

animal contact diseases: rabies

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Burundi is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Cambodia

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever, Japanese encephalitis, and malaria

animal contact diseases: Rabies

Cameroon

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Cameroon is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Central African Republic

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A and E, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: HIV/AIDS, hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; the Central African Republic is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Chad

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A and E, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Chad is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

China

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: Crimean-Congo hemorrhagic fever, dengue fever, Japanese encephalitis, severe fever thrombocytopenia syndrome (SFTS)

soil contact diseases: hantaviral hemorrhagic fever with renal syndrome (HFRS)

Colombia

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea

vectorborne diseases: dengue fever, malaria, and sexually transmitted diseases: hepatitis B (2024)

Congo, Democratic Republic of the

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and trypanosomiasis-gambiense (African sleeping sickness)

water contact diseases: schistosomiasis

animal contact diseases: rabies

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; the Democratic Republic of the Congo is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Congo, Republic of the

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria and dengue fever

water contact diseases: schistosomiasis

animal contact diseases: rabies

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; the Republic of the Congo is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Costa Rica

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea

vectorborne diseases: dengue fever

Cote d'Ivoire

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Côte d'Ivoire is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Croatia

degree of risk: intermediate (2023)

vectorborne diseases: tickborne encephalitis

Cuba

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea and hepatitis A

vectorborne diseases: dengue fever

Djibouti

degree of risk: high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever, and sexually transmitted diseases: hepatitis B (2024)

Dominican Republic

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever

Ecuador

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever and malaria

Egypt

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

El Salvador

degree of risk: high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea

vectorborne diseases: dengue fever

Equatorial Guinea

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

animal contact diseases: rabies

Eritrea

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria and dengue fever

Estonia

degree of risk: intermediate (2020)

vectorborne diseases: tickborne encephalitis

Eswatini

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: sexually transmitted diseases: HIV/ADIS, hepatitis B (2024)

water contact diseases: schistosomiasis

Ethiopia

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria and dengue fever

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

Gabon

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

Gambia, The

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

Gaza Strip

note: on 21 March 2022, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Asia; the Gaza Strip is currently considered a high risk to travelers for polio; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Ghana

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Ghana is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Guatemala

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever and malaria

Guinea

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

aerosolized dust or soil contact diseases: Lassa fever

note:  on 20 September 2023, the Centers for Disease Control and Prevention updated a Travel Health Alert for a diphtheria outbreak in several states in Guinea; vaccination against diphtheria is essential to protect against disease; if you are traveling to an affected area, you should be up to date with your diphtheria vaccines; before travel, discuss the need for a booster dose with your healthcare professional; diphtheria is a serious infection caused by strains of Corynebacterium diphtheriae bacteria that make a toxin from which people get very sick; diphtheria bacteria spread from person to person through respiratory droplets like from coughing or sneezing; people can also get sick from touching open sores or ulcers of people sick with diphtheria (see attached map)

Guinea-Bissau

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

Guyana

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever and malaria

Haiti

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever and malaria

Honduras

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever

Hungary

degree of risk: intermediate (2016)

vectorborne diseases: tickborne encephalitis (2016)

India

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A and E, and typhoid fever

vectorborne diseases: dengue fever, Crimean-Congo hemorrhagic fever, Japanese encephalitis, and malaria

water contact diseases: leptospirosis

animal contact diseases: rabies

Indonesia

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever, malaria, and sexually transmitted diseases: hepatitis B (2024)

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Southeast Asia; Indonesia is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Iran

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea

vectorborne diseases: Crimean-Congo hemorrhagic fever

Iraq

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

Israel

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Asia; Israel is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Kenya

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, Rift Valley fever, and sexually transmitted diseases: HIV/AIDS (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Asia; Israel is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Laos

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever, malaria, and sexually transmitted diseases: hepatitis B (2024)

Latvia

degree of risk: intermediate (2023)

vectorborne diseases: tickborne encephalitis

Lesotho

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

Liberia

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

aerosolized dust or soil contact diseases: Lassa fever

Lithuania

degree of risk: intermediate (2023)

vectorborne diseases: tickborne encephalitis

Madagascar

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria and dengue fever

water contact diseases: schistosomiasis

animal contact diseases: rabies

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Madagascar is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Malawi

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: HIV/AIDS (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Malawi is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Malaysia

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea

vectorborne diseases: dengue fever

water contact diseases: leptospirosis

Mali

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

aerosolized dust or soil contact diseases: Lassa fever

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Mali is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Mauritania

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

Mexico

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea and hepatitis A

vectorborne diseases: dengue fever

Montenegro

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea

vectorborne diseases: Crimean-Congo hemorrhagic fever

Mozambique

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: HIV/AIDS (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Mozambique is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Namibia

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, and sexually transmitted diseases: HIV/AIDS (2024)

water contact diseases: schistosomiasis

Nepal

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A and E, and typhoid fever

vectorborne diseases: Japanese encephalitis, malaria, and dengue fever

Nicaragua

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever and malaria

Niger

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Niger is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Nigeria

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

aerosolized dust or soil contact diseases: Lassa fever

note 1: on 4 May 2022, the Centers for Disease Control and Prevention issued a Travel Health Notice for a Yellow Fever outbreak in Nigeria; a large, ongoing outbreak of yellow fever in Nigeria began in September 2017; the outbreak is now spread throughout the country with the Nigerian Ministry of Health reporting cases of the disease in multiple states (Bauchi, Benue, Delta, Ebonyi, and Enugu); the CDC recommends travelers going to Nigeria should receive vaccination against yellow fever at least 10 days before travel and should take steps to prevent mosquito bites while there; those never vaccinated against yellow fever should avoid travel to Nigeria during the outbreak (see attached map)

note 2: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Nigeria is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

note 3: on 20 September 2023, the Centers for Disease Control and Prevention updated a Travel Health Alert for a diphtheria outbreak in several states in Nigeria; vaccination against diphtheria is essential to protect against disease; if you are traveling to an affected area, you should be up to date with your diphtheria vaccines; before travel, discuss the need for a booster dose with your healthcare professional; diphtheria is a serious infection caused by strains of Corynebacterium diphtheriae bacteria that make a toxin from which people get very sick; diphtheria bacteria spread from person to person through respiratory droplets like from coughing or sneezing; people can also get sick from touching open sores or ulcers of people sick with diphtheria (see attached map)

Pakistan

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A and E, and typhoid fever

vectorborne diseases: dengue fever, malaria, and Crimean-Congo hemorrhagic fever

animal contact diseases: rabies

note: Pakistan is one of two countries with endemic wild polio virus (the other is Afghanistan) and considered high risk for international spread of the disease; before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the US Centers for Disease Control and Prevention (CDC) recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Panama

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea

vectorborne diseases: dengue fever

Papua New Guinea

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever, malaria, and sexually transmitted diseases: hepatitis B (2024)

Paraguay

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever

Peru

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever, malaria, Bartonellosis (Oroya fever), and sexually transmitted diseases: hepatitis B (2024)

Philippines

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever and malaria

water contact diseases: leptospirosis

Poland

degree of risk: intermediate (2023)

vectorborne diseases: tickborne encephalitis

Russia

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea

vectorborne diseases: Crimean-Congo hemorrhagic fever, tickborne encephalitis

Rwanda

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: HIV/AIDS (2024)

animal contact diseases: rabies

Sao Tome and Principe

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

Senegal

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

Serbia

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea

Sierra Leone

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue feve, and sexually transmitted diseases: hepatitis Br (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

aerosolized dust or soil contact diseases: Lassa fever

Somalia

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A and E, and typhoid fever

vectorborne diseases: dengue fever, malaria, Rift Valley fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Somalia is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

South Africa

degree of risk: intermediate (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: sexually transmitted diseases:  HIV/AIDS, hepatitis B (2024)

water contact diseases: schistosomiasis

South Sudan

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A and E, and typhoid fever

vectorborne diseases: malaria, dengue fever, Trypanosomiasis-Gambiense (African sleeping sickness)

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

Sri Lanka

degree of risk: intermediate (2023)

vectorborne diseases: dengue fever

water contact diseases: leptospirosis

animal contact diseases: rabies

Sudan

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A and E, and typhoid fever

vectorborne diseases: malaria, dengue fever, Rift Valley fever, and sexually transmitted diseases: HIV/AIDS, hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Sudan is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Suriname

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria

Tajikistan

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

Tanzania

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, Rift Valley fever, and sexually transmitted diseases: HIV/AIDS, hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

Thailand

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea

vectorborne diseases: dengue fever, Japanese encephalitis, and malaria

Timor-Leste

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever and malaria

Togo

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

respiratory diseases: meningococcal meningitis

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Togo is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Uganda

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A and E, and typhoid fever

vectorborne diseases: malaria, dengue fever, and Trypanosomiasis-Gambiense (African sleeping sickness), and sexually transmitted diseases: HIV/AIDS (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

United Kingdom

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued an updated Travel Alert for polio in Europe; the United Kingdom is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Venezuela

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea and hepatitis A

vectorborne diseases: dengue fever and malaria

Vietnam

degree of risk: very high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever, malaria, Japanese encephalitis, and sexually transmitted diseases: hepatitis B (2024)

note: On 20 September 2023, the CDC issued a travel notice for an outbreak of diphtheria in several provinces in Vietnam (see attached map); vaccination against diphtheria is essential to protect against disease; if you are traveling to an affected area, you should be up to date with your diphtheria vaccines; Diphtheria is a serious infection caused by strains of bacteria called Corynebacterium diphtheriae that make a toxin; Diphtheria bacteria spread from person to person, usually through respiratory droplets, like from coughing or sneezing

West Bank

note: on 31 August 2022, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Asia; the West Bank is currently considered a high risk to travelers for polio; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

World

food or waterborne diseases: Typhoid fever - An estimated 26 million cases of typhoid fever and 5 million cases of paratyphoid fever occur worldwide each year, causing 215,000 deaths. High-risk regions for typhoid and paratyphoid fever include Africa and Southeast Asia; lower-risk regions include East Asia, South America, and the Caribbean. Typhoid fever is a life-threatening illness caused by Salmonella Typhi bacteria. Paratyphoid fever is a life-threatening illness caused by Salmonella Paratyphi bacteria. The bacteria that cause typhoid fever are most often spread through contaminated food and water and person to person contact. Symptoms of typhoid fever include high fever, weakness, stomach pain, headache, constipation or diarrhea, cough, and loss of appetite. Typhoid fever can be fatal without appropriate antibiotic treatment. CDC recommends that all travelers (even short-term travelers) to affected areas be vaccinated against typhoid fever before travel.

vectorborne diseases: Malaria - In 2020, an estimated 627,000 people died of malaria—most were young children in sub-Saharan Africa. Nearly half the world’s population lives in areas at risk of malaria transmission in 87 countries and territories (see attached map). In 2020, malaria caused an estimated 241 million clinical episodes, and 627,000 deaths. An estimated 95% of deaths in 2020 were in the WHO African Region. The predominant parasite species is Plasmodium falciparum, which is the species that is most likely to cause severe malaria and death. Where malaria is found depends mainly on climatic factors such as temperature, humidity, and rainfall. Malaria is transmitted in tropical and subtropical areas, where Anopheles mosquitoes can survive and multiply, and malaria parasites can complete their growth cycle in the mosquitoes (“extrinsic incubation period”). Temperature is particularly critical. For example, at temperatures below 20°C (68°F), Plasmodium falciparum (which causes severe malaria) cannot complete its growth cycle in the Anopheles mosquito, and thus cannot be transmitted.
African Trypanosomiasis - also known as “sleeping sickness”, is caused by microscopic parasites of the species Trypanosoma brucei. It is transmitted by the tsetse fly (Glossina species), which is found only in sub-Saharan Africa. Two morphologically indistinguishable subspecies of the parasite cause distinct disease patterns in humans: T. b. gambiense causes a slowly progressing African trypanosomiasis in western and central Africa and T. b. rhodesiense causes a more acute African trypanosomiasis in eastern and southern Africa. Control efforts have reduced the number of annual cases and for the first time in 50 years, the number of reported cases fell under 10,000 in 2009. In 2017–2018, fewer than 2000 cases were reported to WHO. The number of cases continue to drop and in 2020, fewer than 700 combined cases were reported to WHO; over 85% caused by T. b. gambiense and around 15% caused by T. b. rhodesiense. Sleeping sickness is curable with medication but is fatal if left untreated.
Dengue fever - Dengue viruses are spread to people through the bite of an infected Aedes species (Ae. aegypti or Ae. albopictus) mosquito. Almost half of the world’s population, about 4 billion people, live in areas with a risk of dengue. Dengue is often a leading cause of illness in areas with risk. Each year, up to 400 million people get infected with dengue. Approximately 100 million people get sick from infection, and 40,000 die from severe dengue. Dengue has emerged as a worldwide problem since the 1960s. The disease is common in many popular tourist destinations in the Caribbean (including Puerto Rico), Central and South America, Southeast Asia, and the Pacific Islands (see attached regional maps). In the United States, local cases and limited spread of dengue does occur periodically in some states with hot, humid climates and Aedes mosquitoes.

water contact diseases: Schistosomaisis - also known as bilharzia, is a disease caused by parasitic worms. In terms of impact this disease is second only to malaria as the most devastating parasitic disease (see attached map).  Schistosomiasis is considered one of the neglected tropical diseases (NTDs). The parasites that cause schistosomiasis live in certain types of freshwater snails. The infectious form of the parasite, known as cercariae, emerge from the snail into the water. You can become infected when your skin comes in contact with contaminated freshwater. Most human infections are caused by Schistosoma mansoni, S. haematobium, or S. japonicum. Freshwater becomes contaminated by Schistosoma eggs when infected people urinate or defecate in the water. The eggs hatch, and if certain types of freshwater snails are present in the water, the parasites develop and multiply inside the snails. The parasite leaves the snail and enters the water where it can survive for about 48 hours. Schistosoma parasites can penetrate the skin of persons who are wading, swimming, bathing, or washing in contaminated water.

respiratory diseases: Meningococcal meningitis - Meningococcal disease occurs worldwide, with the highest incidence of disease found in the ‘meningitis belt’ of sub-Saharan Africa (see attached map). In this region, major epidemics occur every 5 to 12 years with attack rates reaching 1,000 cases per 100,000 population. Bacteria called Neisseria meningitidis cause meningococcal disease. About 1 in 10 people have these bacteria in the back of their nose and throat without being ill. This is called being ‘a carrier.’ Sometimes the bacteria invade the body and cause certain illnesses, which are known as meningococcal disease. Other regions of the world experience lower overall rates of disease and occasional outbreaks. Annual attack rates in these regions averages around 0.3 to 3 per 100,000 population. Risk factors for meningococcal disease outbreaks in Africa are not fully understood. However, the following characteristics create favorable conditions for meningococcal disease epidemics: Dry and dusty conditions during the dry season between December to June, Immunological susceptibility of the population, Travel and large population displacements, Crowded living conditions

note 1: widespread ongoing transmission of a respiratory illness caused by the novel coronavirus (COVID-19) is occurring globally; older adults and people of any age with serious chronic medical conditions are at increased risk for severe disease; as of 23 August 2023, 769,806,130 confirmed cases of COVID-19 and 6,955,497 deaths had been reported to the World Health Organization; as of 23 August 2023, 70.5% of the World population had received at least one dose of COVID-19 vaccine

note 2: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for some international destinations (see attached map) currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Yemen

degree of risk: high (2023)

food or waterborne diseases: bacterial diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: dengue fever, malaria, and sexually transmitted diseases: hepatitis B (2024)

water contact diseases: schistosomiasis

note: on 31 August 2022, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Asia; Yemen is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Zambia

degree of risk: very high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: HIV/AIDS (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies

note: on 31 August 2023, the US Centers for Disease Control and Prevention (CDC) issued a Travel Alert for polio in Africa; Zambia is currently considered a high risk to travelers for circulating vaccine-derived polioviruses (cVDPV); vaccine-derived poliovirus (VDPV) is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus; this means it can be spread more easily to people who are unvaccinated against polio and who come in contact with the stool or respiratory secretions, such as from a sneeze, of an “infected” person who received oral polio vaccine; the CDC recommends that before any international travel, anyone unvaccinated, incompletely vaccinated, or with an unknown polio vaccination status should complete the routine polio vaccine series; before travel to any high-risk destination, the CDC recommends that adults who previously completed the full, routine polio vaccine series receive a single, lifetime booster dose of polio vaccine

Zimbabwe

degree of risk: high (2023)

food or waterborne diseases: bacterial and protozoal diarrhea, hepatitis A, and typhoid fever

vectorborne diseases: malaria, dengue fever, and sexually transmitted diseases: HIV/AIDS (2024)

water contact diseases: schistosomiasis

animal contact diseases: rabies