Immunizations
Required Vaccinations
Yellow Fever
This viral infection is transmitted by the day-time biting Aëdes aegypti mosquito typically found in urban, suburban, and rural areas.
A Yellow Fever vaccination certificate is required on arrival from all countries.
Note: A vaccination certificate is required for children over one year of age.
Recommended Vaccinations
Routine Immunizations
Your trip is a good occasion for a reminder to keep your routine immunizations updated; more than 80% of adults in developed countries have not maintained their immunization status. The following vaccinations are recommended for your protection and to prevent the spread of infectious diseases.
Tetanus-Diphtheria, Poliomyelitis, Measles, Mumps, Rubella should be reviewed and updated if necessary.
Seasonal influenza vaccine is recommended for children, persons over the age of 50, and those of any age suffering from chronic heart disease, emphysema, asthma, renal disorders, immuno-suppressive disorders, and organ transplant recipients. Note: Flu seasonal patterns are opposite in the southern and northern hemispheres. If the flu vaccine is not available at the time of departure, contact your doctor or travel health clinic regarding influenza anti-viral protection.
Pneumococcal vaccine is recommended for persons over the age of 65 and persons of any age suffering from cardiovascular disease, diabetes, renal disorders, liver diseases, sickle cell disease, asplenia, or immuno-suppressive disorders.
Hepatitis A
The Hepatitis A virus is primarily transmitted through contaminated water and food or by the fecal-oral route, and may cause severe liver damage. Prevention includes good personal hygiene, ensuring safe water supply, eating well cooked foods, and peeling your own fruits.
Vaccination is recommended for all travellers over one year of age. The vaccine is often combined with Hepatitis B and affords excellent long-term protection for both viral diseases.
Typhoid Fever
This intestinal infection, caused by Salmonella typhi bacteria, is transmitted from person to person primarily through ingestion of contaminated food and water in areas with poor sanitary and hygienic conditions. Prevention includes good personal hygiene such as washing your hands frequently, ensuring safe water supply, eating well cooked foods, and peeling your own fruits. Vaccination is also recommended for travellers' protection.
Selective Vaccinations
Cholera
Cholera is an acute gastro-intestinal infection caused by vibrio cholerae bacteria. Risk of infection to travellers is low and vaccination is advised only for medical and rescue personnel working in endemic areas.
The best protection is to avoid potentially contaminated water and food. See IAMAT's 24 World Climate and Food Safety Charts describing the sanitary condition of water, dairy products, and food in 1440 cities. Meticulous food and water hygiene are essential when travelling in endemic areas.
Persons living and working in inadequate sanitary conditions and those with impaired defence mechanisms (deficient production of gastric acid due to surgery for duodenal or gastric ulcers), persons on antacid therapy, and users of cannabis (smoking marijuana reduces acid secretion of the stomach) are more susceptible to cholera infection. The World Health Organization announced in 1991 that Cholera vaccination certificates are no longer required by any country or territory.
Hepatitis B
The Hepatitis B virus is transmitted through infected blood products, sexual intercourse, or infected items such as needles or razor blades, and may cause severe liver damage.
Vaccination is recommended for persons on working assignments in the health care field (dentists, physicians, nurses, laboratory technicians), or for those working in close contact with the local population (teachers, aid workers, missionaries), or persons foreseeing sexual relations with locals. This vaccine is often combined with the Hepatitis A vaccine and affords excellent long-term protection for both viral diseases.
The recommendations for vaccinations outlined above are intended as guidelines only. Your immunization needs depend on your health status, previous immunizations received, and your travel itinerary. Seek further advice from your doctor or travel health clinic.
Disease Risks
MALARIA
Infection is spread by the night-time - dusk to dawn - biting female Anopheles mosquito.
Malaria risk is present throughout the country, including urban areas, risk present at all altitudes.
High risk months for Malaria are: January - December
Malaria transmission vector(s): A. gambiae
Incidence of Plasmodium falciparum Malaria: > 85%
Of the four species of human malaria parasites, Plasmodium falciparum is the most dangerous. The remaining percentage represents vivax group infections (benign forms of malaria caused by Plasmodium vivax, Plasmodium ovale and Plasmodium malariae.)
Areas with drug resistant Malaria: P. falciparum malaria is resistant to chloroquine. Resistance is present in all malarious areas.
Suppressive Medication Guide:
For details on anti-malarial drug side-effects, dosages for children and pregnant women, medications used around the world, and comprehensive protection measures, see: How to Protect Yourself Against Malaria (pdf)
SCHISTOSOMIASIS
Infection is transmitted by snails living in fresh water such as lakes, rivers, streams and ponds in the Caribbean, South America, Africa, and Southeast Asia.
Schistosomiasis risk is present in the country - since research data is still fragmentary, the extent of the infection cannot be determined; the whole country should be considered infected.
Infection with S. haematobium was introduced on the island of São Tomé by workers from the African continent during the construction of major irrigation projects. The infection seems to be localized around the capital São Tomé, but the extent of the infection has not been determined. The snail intermediate host has not been identified.
There is a risk of Schistosomiasis caused by: Schistosoma haematobium, Schistosoma intercalatum
The main intermediate host snail is: See text for intermediate snail host.
Prevention Guidelines:
OTHER DISEASES OF INTEREST TO TRAVELLERS
Hepatitis C
The Hepatitis C virus is transmitted from person to person through unscreeened blood transfusions, blood products, contaminated needles and instruments used for tattooing and body piercing. Travellers are at risk of infection in countries where the blood supply is not adequately screened and a transfusion is required after an accident. Avoid body piercing and tattooing. The virus may also be transmitted sexually.
Hepatitis C is endemic in this country.
Hepatitis E
Hepatitis E is caused by infection with the hepatitis E virus. It is transmitted mainly through contaminated water or food by the fecal-oral route. It is common in countries with low standards of sanitation. Prevention includes good personal hygiene, ensuring water supply is safe, and following food safety measures (eating food well-cooked and hot, peeling your own fruits, etc...).
Intestinal Parasites
Food-transmitted parasitic infections can be prevented by washing salads and/or vegetables or thoroughly cooking food to destroy infective eggs. Travellers should avoid raw or undercooked food that may be contaminated. Soil-transmitted infections may be avoided by not walking barefoot and not touching soil with bare hands.
Amoebiasis (amoebic dysentery) is a parasitic infection causing intestinal disease. Transmission occurs by eating food that is contaminated with feces from an infected person or drinking water containing amoebic cysts. Transmission also occurs sexually by fecal/oral contact. Infection rates are highest in areas where sanitation is poor.
Ancylostomiasis (hookworm, Necator americanus) is an intestinal parasite of humans. It causes mild diarrhea and abdominal pain. Humans can become infected by direct contact with contaminated soil, generally through walking barefoot, or accidentally swallowing contaminated soil. Do not walk barefoot or touch soil with bare hands where hookworm is common or where there may be fecal contamination of soil. Common in tropical and subtropical regions.
Angiostrongyliasis (roundworm) is a parasitic infection found mainly among people who eat snails, prawns, crabs, vegetables, contaminated by the mucous of infected slugs, land snails or aquatic snails.
Ascariasis (roundworm, Ascaris lumbricoides) is an intestinal helminthic disease. The primary route of infection is ingestion of eggs from contaminated soil or vegetables.
Trichuriasis (whipworm, Trichuris trichuria, Trichuris vulpis) is an intestinal parasite of humans, primarily affecting children. They may become infected if they ingest soil contaminated with whipworm eggs. Some outbreaks have been traced to contaminated vegetables (due to presumed soil contamination). Most commonly found in countries with warm, humid climates.
No data available but presumed to occur in São Tomé and Príncipe.
Sexually Transmitted Infections
Avoid unprotected sexual contact. If you are going to have sex with a stranger, use latex or polyurethane condoms consistently and correctly. Bring your own condoms from home.
Some countries have entry restrictions for travellers with HIV / AIDS. See The Global Database on HIV Related Travel Restrictions for details on this country.
Traveller's Diarrhea
Diarrhea is the most common cause of illness during travel. The source of illness is the ingestion of contaminated food or water, person-to-person transmission, or recreational exposure to water bodies. The infective agents can be bacteria, viruses, protozoa or toxins found in food. Good personal hygiene practices (including frequent and thorough hand washing), proper food handling, and water purification are the most effective methods to prevent infection.
Consult your doctor for the best treatment options tailored to your needs, including taking prescription medication on your trip in case you suffer from diarrhea. Travellers with chronic conditions are more susceptible to infections and should consider taking preventive medication.
See our Guide to Healthy Travel for prevention and treatment tips.
Tuberculosis
Tuberculosis is transmitted from person to person through inhalation of airborne infectious respiratory droplets. Travellers who have only casual contact with infected persons are at low risk.
However, travellers visiting friends and relatives (especially young children) in developing countries, persons on working assignments in the health care field (dentists, physicians, nurses, laboratory technicians), long-term travellers and those who have close and prolonged contact with the local population (teachers, missionaries, Peace Corps volunteers) are at risk. Travellers at risk should have a pre-departure TB skin test and be re-tested after leaving the country.
Tuberculosis is endemic in São Tomé and Príncipe.
DISEASES PRESENT - LOW RISK TO TRAVELLERS
Dracunculiasis / Guinea Worm Disease
Dracunculiasis or Guinea Worm Disease, is caused by the parasite Dracunculus medinensis. The disease affects poor communities in remote parts of Africa that do not have safe drinking water. There is no treatment for Guinea Worm Disease. Removal of the worm as it emerges from the infected person's skin is curative or surgical removal by a trained doctor.
Anyone who drinks standing pond water contaminated by persons with Guinea Worm Disease is at risk for infection. People who live in villages where the infection is common are at greatest risk.
Echinococcosis
Echinococcosis is a potentially fatal parasitic disease that affecting wildlife, commercial livestock and humans. Humans become infected by accidentally swallowing the eggs of the E. multilocularis tapeworm. Humans can be exposed to these eggs by directly ingesting food contaminated with stool from infected foxes or coyotes. This might include grass, herbs, greens or berries collected from fields. Humans may also be contaminated by petting infected cats or dogs. These pets may shed the tapeworm eggs in their stool and their fur may be contaminated.
Basic hygiene practices such as thoroughly cooking food and vigorous hand washing before meals can prevent the infective eggs entering the human digestive tract.
Endemic Flea-Borne Typhus
Endemic typhus (murine typhus) is caused by the bacteria Rickettsia typhi and is transmitted by fleas that infest rats, especially during exposure in rat-infested premises, such as warehouses, stores, and grain elevators. Flea-infested rats can be found throughout the year in humid tropical environments, especially in harbour or riverine environments. In temperate regions, they are most common during the warm summer months.
Limiting exposure to vectors or animal reservoirs remains the best means for reducing the risk of disease. Risk for travellers is low. Persons who are occupationally exposed to rats ( naturalists, geologists, agricultural workers) should avoid vector-infested habitats, use repellents and wear protective clothing.
Filariasis
Lymphatic Filariasis is a parasitic disease caused by nematodes Wucheria bancrofti and Brugia malayi. The parasites are transmitted to humans through the bite of an infected mosquitoes (Aedes, Anopheles, Culex and Mansonia mosquitoes can be vectors) and develop into adult worms in the lymphatic vessels, causing severe damage and swelling (lymphoedema).
Short-term travellers to endemic areas are at low risk but should take preventive measures against mosquito bites. Travellers visiting endemic areas for longer periods of time and who are exposed to infected mosquitoes can become infected. Prevention measures include applying a DEET-containing repellent to exposed skin, applying permethrin spray or solution to clothing and gear and sleeping under bednets.
Tungiasis
Tungiasis is a skin infestation of the Tunga penetrans flea found in tropical parts of Africa. Tungiasis affects persons walking barefoot or lying in infested sand or soil.
Food and Water Safety
All local water should be considered contaminated. All tap water used for drinking, brushing teeth, and making ice cubes should be boiled (bringing water to a good rolling boil is sufficient). Good brands of bottled water are available; check cap seal and ensure that the bottle is uncapped in your presence.
Milk should be boiled before consumption because of possible improper refrigeration during distribution. Powdered and evaporated milk are available and safe. Butter should not be used as a table food. Cream, ice cream, and whipped cream should not be consumed. Cheese, unless cured, is best avoided. Yoghurt is safe only if it is known to be made from pasteurized milk.
All meat, poultry, and fish must be well cooked and served while hot. Pork is best avoided; vegetables should be well cooked and served hot. Salads are best avoided. Fruits with intact skins should be peeled by you just prior to consumption. Avoid raw and undercooked eggs, and dishes prepared with raw eggs (steak tartar, mayonnaise, and dressings). Avoid cold buffets, uncured cheeses, custards, and any frozen desserts.
First rate hotels and restaurants serve purified drinking water and reliable food. However, the hazard is left to your judgement.
Gastro-intestinal infections are the most common illnesses affecting travellers and can occur in any country you are visiting. Proper food handling, drinking purified water, and maintaining good personal hygiene are key to prevention. Below is a summary of the agents causing gastro-intestinal illnesses.
Bacterial Contamination
It is estimated that about 85% of traveller’s diarrhea is caused by bacteria of which the following are the most important agents:
Enterotoxigenic Escherichia coli (ETEC) and Enteroaggregative Escherichia coli (EAEC) account for most cases of traveller’s diarrhea associated with contaminated food and water world wide. They are the cause of large outbreaks in developed countries when food and water sanitation have not been properly maintained. Symptoms include watery stools, abdominal cramps, and possible vomiting lasting three to seven days.
Campylobacter jejuni is more prevalent in developing countries and is associated with contaminated water, undercooked food, and unpasteurized milk. Symptoms include diarrhea, abdominal cramps, and fever lasting from two to ten days.
Salmonella enteritidis is associated with contaminated eggs, poultry, milk, fruits, and uncooked vegetables. Symptoms include diarrhea, vomiting, abdominal cramps, and fever lasting from four to seven days. Infected persons can become asymptomatic carriers and shed the bacteria for years, becoming the source of infection for others through poor hygiene practices.
Shigellosis is a human infection caused by one of four species and transmitted by fecal-oral route due to unsanitary conditions, contaminated food and water, and overcrowded living conditions. Symptoms include diarrhea, abdominal cramps, fever, and may cause bloody diarrhea and mucous lasting four to seven days.
Vibrio cholera is associated with contaminated water, raw and undercooked seafood. Cholera infection in travellers is rare; symptoms include watery diarrhea and vomiting lasting three to seven days, but can lead to severe dehydration and death in undernourished persons. Vibrio parahaemolyticus is also related to the consumption of raw and undercooked seafood. Vibrio vulnificus is associated with contaminated shellfish and raw oysters in particular, and has caused septicemia in persons with liver disorders.
Viral Contamination
Gastro-intestinal infections caused by viruses account for about 5%. The main agents are Norovirus, associated with outbreaks at large gatherings and on cruise ships, and Rotavirus, which is more prevalent in developing countries. Symptoms include vomiting, diarrhea, fever, and myalgia lasting 12 to 60 hours.
Protozoal Contamination
Gastro-intestinal infections with protozoa account for about 10% of traveller’s diarrhea, but may cause prolonged illnesses (lasting weeks) and cause serious complications if not diagnosed in a timely manner.
Giardia lamblia (Giardiasis) and Entamoeba hystolytica (Amebiasis) are the most important agents in this category and both infections are acquired through contaminated food and water, as well as person to person transmission due to poor hygiene practices. Cryptosporidium and Cyclospora cayetanensis are implicated with contaminated food, water, and fresh produce (berries).
Toxins Causing Food Poisoning
Clostridium perfringens is the most important agent causing food poisoning in developed countries. The spores of the bacterium germinate on cooked food that is cooled and stored at room temperature over a prolonged period of time. After ingestion, the spores produce an enterotoxin in the small intestine causing abdominal pain, diarrhea, and vomiting. Foods implicated are meats and poultry.
Staphylococcus aureus enterotoxins are spread by unsanitary practices of infected persons. The foods implicated are custards, creamy desserts, meats, and salads.
Clostridium botulinum bacteria produce a very potent toxin. It is associated with improperly canned food, lightly preserved vegetables, salted fish, and meats. Symptoms include nausea, vomiting, and neurological symptoms such as blurred and double vision, paralysis of respiratory and motor muscles that may progress rapidly.
Seafood Poisoning
Fish and shellfish can be contaminated with the toxins produced by marine micro-organisms called dinoflagellates found in all oceans, especially in coral reef areas. Larger fish have usually more toxins accumulated in the skin, musculature, and organs, as these toxins are passed up through the food chain. The toxins are not destroyed through cooking, smoking, or freezing, they are odorless and tasteless, and do not alter the appearance of the fish.
Ciguatera Fish poisoning is the most common illness in this category. The most affected fish are amberjack, barracuda, grouper, kahala, parrotfish, sea bass, red snapper, surgeon fish, ulua. Symptoms usually appear within a few hours but can be delayed for a day or more and include nausea, vomiting diarrhea, muscle pain, itchiness, dizziness and temperature reversal (hot feels cold and cold feels hot). Symptoms can last for months. Persons who had a previous episode of ciguatera fish poisoning should avoid a second exposure as symptoms will be more severe. Prevention: Avoid large fish (more than 2.5 to 3 kilos [6 lbs]) or fillet of large fish, avoid head, roe, intestines and liver where the toxin is more concentrated.
Scombroid poisoning is the result of improper handling and refrigeration of fish containing high levels of natural occurring histidine (amino acid in protein). Contamination with bacteria will convert histidine to histamine-causing symptoms similar to allergic reactions, which occur very rapidly and include headache, abdominal cramps, diarrhea, itching, flushed face, and paralysis may occur. Scombroid poisoning occurs worldwide and affects fish from the Scombridae family: yellow tuna, mackerel, skipjack, and bonito. It can also affect other species such as herring, bluefish, sardine, anchovy, amberjack, and mahi-mahi. Prevention: Proper handling and immediate refrigeration of catch.
Shellfish poisoning is associated with the algal blooms (red tides) occurring in temperate and tropical areas. Shellfish – oysters, clams, cockles, mussels, crabs, lobsters – filter or ingest toxins produced by dinoflagellates micro-organisms. Each different toxin produces characteristic symptoms:
- Symptoms of diarrheic shellfish poisoning occur about 30 minutes to hours after ingestion and include nausea, vomiting, and diarrhea. Recovery occurs within two to three days.
- Symptoms of neurotoxic shellfish poisoning appear rapidly after ingestion and include tingling of mouth, arms and legs, stomach upset, and severe muscle pain. Recovery occurs within two to three days.
- Symptoms of paralytic shellfish poisoning appear rapidly after ingestion and include nausea, numbness of face arms and legs, headache, loss of coordination and dizziness, in severe cases respiratory failure and paralysis may lead to death.
- Symptoms of amnesic shellfish poisoning occur within 24 hours of ingestion and include vomiting, diarrhea, and disorientation. Permanent short-term memory loss has been observed, and in severe cases seizures, paralysis, and death may occur. Persons with kidney disease are especially vulnerable.
Puffer Fish poisoning (Fugu) is caused by a tetrodotoxin accumulating mainly in the liver, intestines and ovaries of puffer fish, ocean sunfish, globe fish, and porcupine fish. Symptoms appear between six and 20 hours and include profuse sweating, salivation, headache, hypothermia, and neurological symptoms of paralysis and respiratory failure. The mortality rate is very high.
