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 only for travellers coming from, or in transit through, infected countries. The vaccination requirement is imposed by this country for protection against the introduction of Yellow Fever since the vector Aëdes aegypti is present in its territory.
The following countries are considered infected:
AFRICA - Angola, Benin, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Republic of the Congo, Democratic Republic of the Congo, Côte d'Ivoire, Equatorial Guinea, Ethiopia, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Liberia, Mali, Mauritania, Niger, Nigeria, Rwanda, São Tomé and Príncipe, Senegal, Sierra Leone, Somalia, Sudan, Tanzania, Togo, Uganda.
AMERICAS - Argentina, Bolivia, Brazil, Colombia, Ecuador, Guyana, French Guiana, Panama, Paraguay, Peru, Suriname, Trinidad and Tobago, Venezuela.
Note: A vaccination certificate is required for children over one year of age.
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, Pertussis, Measles, Mumps, Rubella, Poliomyelitis should be reviewed and updated if necessary. Note: Many of these vaccine preventable illnesses are making a resurgence due to non-vaccination, incomplete vaccination, and waning immunity. It is important to keep your routine immunization up-to-date.
Seasonal influenza vaccination is recommended for all travellers over 6 months of age, especially for children, pregnant women, persons over 65, and those with chronic health conditions such as asthma, diabetes, lung disease, heart disease, immune-suppressive disorders, and organ transplant recipients. Note: In the northern hemisphere the flu season typically runs from November to April and from April to October in the southern hemisphere. 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.
The Hepatitis A virus (HAV) is primarily transmitted from person to person via the fecal-oral route and through contaminated water and food - such as shellfish, and uncooked vegetables or fruit prepared by infected food handlers.
The virus is present worldwide, but the level of prevalence depends on local sanitary conditions. HAV circulates widely in populations living in areas with poor hygiene infrastructure. In these areas, persons usually acquire the virus during childhood when the illness is asymptomatic (but still infective to others) or mild, and end up developing full immunity. Large outbreaks in these countries are rare. In contrast, a large number of non-immune persons are found in highly industrialized countries where community wide outbreaks can occur when proper food handling or good sanitation practices are not maintained including in daycare centres, prisons, or mass gatherings.
In many cases, the infection is asymptomatic (persons do not exhibit symptoms). Those with symptoms will usually get ill between 15 to 50 days after becoming infected. Symptoms include malaise, sudden onset of fever, nausea, abdominal pain, and jaundice after a few days. The illness can range from mild to severe lasting from one to two weeks or for several months. Severe cases can be fatal especially in older persons. Most infections are asymptomatic in children under six years of age, but infants and children can continue to shed the virus for up to six months after being infected, spreading the infection to others. Many countries are now including vaccination against Hepatitis A in their childhood vaccination schedules.
Prevention: Practice good personal hygiene, including washing your hands frequently and thoroughly, drink boiled or bottled water, eat well cooked foods, and peel your own fruits.
All non-immune persons, especially travellers, should be vaccinated. Two vaccines are available for persons over one year of age. Two doses are needed for full protection (the second dose is given 6 to 12 months after the first dose (HAVRIX) or 6 to 18 months after the first dose (VAQTA). TWINRIX is a vaccine against Hepatitis A and Hepatitis B. It is available for persons over 18 years of age. Three doses are needed for full protection. The second dose is given 1 month after the first, and the third 6 months later. For an accelerated schedule four doses are needed at 0, 7, 21, 31 days and the last dose 12 months later.
The Hepatitis B virus (HBV) 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.
Outdoor air pollution (a mix of chemicals, particulate matter, and biological materials that react with each other) contributes to breathing problems, chronic diseases, increased hospitalization, and premature mortality. Cities and rural areas around the world are affected by air pollution.
No matter where you travel, you will not be able to escape air pollution. Exposure and concentration of pollutants can affect your health. When planning your trip, consider your health status, age, destination, length of trip and season to help you mitigate the effects of air pollution.
Short term symptoms of exposure to air pollution include itchy eyes, nose and throat, wheezing, coughing, shortness of breath, chest pain, headaches, nausea, and upper respiratory infections (bronchitis and pneumonia). It also exacerbates asthma and emphysema. Long term effects include lung cancer, cardiovascular disease, chronic respiratory illness, and developing allergies. Air pollution is also associated with heart attacks and strokes.
Prevention: Comply with air pollution advisories (ask around and observe what locals are doing) and avoid strenuous activity. If you have asthma or chronic obstructive pulmonary disease (COPD), carry an inhaler, antibiotic, and oral steroid (consult your doctor to see what is best for you). It is recommended that older travellers get a physical exam that includes a stress and lung capacity test prior to departure. Newborns and young children should minimize exposure as much as possible or consider not travelling to areas with poor air quality. Ask your medical practitioner if a face mask is advisable for you.
>> For city and country air pollution levels, see the World Health Organization.
Dengue is a viral infection caused by four types of viruses (DENV) belonging to the Flavivirdae family. The viruses are transmitted through the bite of infected Aëdes aegypti and Aëdes albopictus female mosquitoes that feed both indoors and outdoors during the daytime (from dawn to dusk). Dengue is present in tropical and subtropical areas of Central America, South America, Africa, Asia, and Oceania. It's found predominantly in urban and suburban settings and higher rates of transmission occur during rainy seasons.
All travellers are at risk during epidemics. Long-term travellers and aid or missionary workers going to areas where Dengue is endemic are at higher risk.
In some cases, Dengue infection is asymptomatic (persons do not exhibit symptoms). Those with symptoms get ill between 4 to 7 days after the bite. The infection is characterized by flu-like symptoms which include a sudden high fever coming in separate waves, pain behind the eyes, muscle, joint, and bone pain, severe headache, and a skin rash characterized by bright red spots.
The illness may progress to Dengue Hemorrhagic Fever (DHF). Symptoms include severe abdominal pain, vomiting, diarrhea, convulsions, bruising, and uncontrolled bleeding. High fever can last from 2 to 7 days. Complications can lead to circulatory system failure and shock, and can be fatal. Exposure to one type of Dengue virus does not provide immunity to the other three types. Contracting Dengue more than once increases the risk of developing Dengue Hemorrhagic Fever.
Prevention: Travellers should take measures to prevent mosquito bites during the daytime. Insect-bite prevention measures include applying a DEET-containing repellent to exposed skin, applying permethrin spray (or solution) to clothing and gear, wearing long sleeves and pants, getting rid of water containers around dwellings and ensuring that door and window screens work properly. There is currently no preventive medication or vaccine against Dengue.
Sporadic cases and outbreaks are reported.
Tuberculosis (TB) is an airbone bacterial infection caused by Mycobacterium tuberculosis. TB can be acquired by breathing contaminated air droplets coughed or sneezed by a person nearby who has active Tuberculosis. Humans can also get ill with TB by ingesting unpasteurized milk products contaminated with Mycobacterium bovis, also known as Bovine Tuberculosis.
Tuberculosis occurs worldwide and commonly spreads in cramped, overcrowded conditions. The most common form of the infection is pulmonary TB which affects the lungs. In some cases, the bacteria can also attack the lymphatic system, central nervous system, urogenital area, joints, and bones.
The risk for travellers is low. There is no evidence that pulmonary TB is more easily transmitted in airplanes or other forms of public transportation. However, travellers with immuno-compromised systems, long-term travellers, and those visiting friends and relatives in areas where Tuberculosis is endemic are at greater risk. Humanitarian and healthcare personnel working in communities with active TB are also at increased risk. Persons with active TB should not travel.
Tuberculosis treatment involves taking antibiotics for a minimum of 6 months. Drug-resistant TB is a major concern as an increasing number of people are no longer able to be treated with previously effective drugs. Due to misuse of antibiotic therapies, patients can develop multi-drug resistant Tuberculosis (MDR TB). When a second line of antibiotics fail to cure the multi-drug resistant infection, it is known as extensively drug-resistant Tuberculosis (XDR TB).
Prevention: Avoid exposure to people known to who have active Tuberculosis and only consume pasteurized milk products. Travellers at higher risk should have a pre-departure tuberculin skin test (TST) and be re-tested upon their return home. Those at increased risk should also consult their healthcare provider to determine if the Bacillus Calmette-Guérin (BCG) vaccine is recommended.
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.
Lymphatic Filariasis, also known as Elephantiasis, is a parasitic infection caused by the Wuchereria bancrofti, Brugia malayi, and Brugia timori nematode worms transmitted to humans through the bite of infected Aedes, Culex, Anopheles, and Mansonia mosquitoes. The disease, which is found in Africa, Central and South America, South Asia, and the Pacific Islands, targets the body's lymphatic system. The infective microscopic larvae (microfilariae) develop in the vector mosquitoes and are injected into humans through a blood meal. In the human host, they reproduce and mature over a period of one year and live in the body for approximately 4 to 6 years. The larvae hatched in humans are ingested by feeding mosquitoes who pass the infection on to another person, continuing the infectious cycle.
Long term travellers visiting endemic areas are at risk. Persons on long term work assignments like humanitarian workers, missionaries, and military personnel are also at risk of contracting Lymphatic Filariasis.
The infection is typically characterized by extreme swelling of limbs or genitals. The majority of cases are asymptomatic (persons do not exhibit symptoms) although the worms can damage kidneys and lymph nodes over a long period of time without a person showing external symptoms. A severe infection, which may not show up for years, causes swelling in the genitals, breasts, arms and legs and may progress to lung disease. Treatment includes taking the anthelmintic drugs diethylcarbamazine (DEC) and albendazole.
Prevention: Travellers should take precautions against mosquito bites by wearing light coloured clothing, using DEET-containing repellent on exposed skin, applying a permethrin spray (or solution) to clothing and gear, and sleeping under a permethrin-treated bed net. There is no preventive medication or vaccine against Lymphatic Filariasis.
>> For Lymphatic Filariasis images, life cycle, and distribution maps, see Infection Landscapes.
Drinking water is chlorinated and has no ill effect on the local population. However, some strains of E. coli (naturally occurring bacteria found in your gastro-intestinal system) may be present in very small concentrations in the local water supply. Some local strains are different than those that you may be used to, and may cause diarrhea in travellers since immunity is not developed as a result of short-term exposure. Using bottled water for the first few weeks will help you adjust and decrease the chance of traveller's diarrhea.
Milk is pasteurized and safe to drink. Butter, cheese, yoghurt, and ice cream are safe.
Local meat, poultry, seafood, vegetables, and fruits are safe to eat.
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.
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.
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.
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.
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.
Travel is enjoyable, but there is no doubt that it can be stressful. Even if you don't have a prior history of mental illness, travel stress, mood changes, anxiety and other mental health concerns can unexpectedly affect you and potentially disrupt your trip. Studies show that psychiatric emergencies are the leading cause for air evacuations along with injuries and cardiovascular disease.
Your mental and physical health prior to, and during, a trip determines how well you will cope with travel stress. Consider the following:
Mental illness is an under recognized public health concern and travellers often have difficulty accessing adequate emergency psychiatric care abroad. While some countries are leading the way in mental healthcare and treatment, 30% of countries do not have a budget dedicated to mental health and 64% do not have any mental health legislation or it's outdated.
Accessibility to a psychiatrist varies from more than 10 per 100,000 to fewer than 1 per 300,000 people. Almost 70% of psychiatric beds are in mental hospitals rather than general hospitals or in integrated community care facilities.*
Persons with mental health concerns have the additional burden of dealing with stigma ? negative attitudes and behaviour towards their illness. Prejudice and discrimination towards mental illness may determine the type of medical care you will receive abroad.
* World Health Organization: Mental Health, Human Rights and Legislation Framework.
April 25, 2013
Do you know if your travel destination country has malaria? If so, would you take medication to prevent a malaria infection?
March 28, 2013
Do you understand how your immune system works to protect you from disease? Do you know how vaccines work?
February 28, 2013
Guest post by Dr. Erik McLaughlin