The growth of international travel puts us at risk of new infections
Disease such as hepatitis A, dengue and yellow fever have no treatments available
Travelers should get vaccinated, wear repellents, and avoid contaminated water
Vital Signs is a monthly program bringing viewers health stories from around the world.
As globalization continues to grow and dominate our trade, economy and lifestyles, the associated ease of access to remote regions of the world is reflected in our travels.
Increasing numbers of destinations worldwide have opened their arms to international travelers, but as you venture on your own travels, whether for business or pleasure, which infectious diseases could you be exposed to?
Locations: Caribbean, Central and South America, Western Pacific Islands, North Australia, South and South-East Asia, West and Sub-Saharan Africa.
This mosquito-spread virus can be found in many parts of the world and with no treatment or vaccine available yet, your only protection is to cover up and use insect repellent to keep the mosquitoes at bay. This species of mosquito, Aedes aegypti, bites throughout the day. Symptoms can take up to two weeks to develop and are flu-like, including fever, headache, nausea, vomiting and pain in the eyes, muscles and joints, and generally last for one week.
There are four different serotypes of the dengue virus, all of which are now found globally and whilst infection with one can give you immunity to that type in the future, infection with a second, third of fourth serotype can lead to more severe illness than the first exposure – such as Dengue hemorrhagic fever.
Locations: Africa, the Middle-East, and some parts of South America, the Caribbean and South-East Asia.
Freshwater snails carry the schistosoma parasitic worm that causes this disease – also known as bilharzia. The snails release the worms’ larvae into contaminated freshwater rivers, lakes, ponds or wetlands, which then penetrate through skin, such as the soles of your feet.
According to the World Health Organization (WHO), the worm is endemic in 52 counties where water is contaminated with the feces of people infected with the worm, which contains parasitic eggs. Symptoms can take up to two months to develop and whilst some people never develop symptoms, others experience fever, chills, cough, and muscle aches within two months of infection. The extent of symptoms depends on the amount of parasite you have inside your body.
You can evade infection by avoiding swimming in freshwater and by heating water if needed for bathing. There is no vaccine available, but there is an effective and fast-acting treatment: The drug praziquantil will kill parasites within one to two days of treatment.
Locations: Africa, Central and South America, parts of the Caribbean, Asia, and the South Pacific.
Malaria is a parasitic disease spread by the bite of the female Anopheles mosquito. Symptoms include high fevers, shaking chills and flu-like illness, and if untreated malaria can progress to severe illness and even death. The WHO estimates there were 207 million cases of malaria in 2012.
No licensed malaria vaccine exists but preventative anti-malaria drugs are available and recommended for people traveling to endemic regions. A range of options is available, from weekly to daily pills. Wearing long clothing, regular use of repellants and sleeping in air-conditioned rooms or under insecticide-treated bed nets can help avoid bites. But if despite all this you still get infected, an effective treatment is available.
Locations: Tropical regions of Africa and South America.
The Aedes aegypti mosquitoes continue to wreak their havoc with the yellow fever virus, which can cause fever, chills, headache, backache and muscle aches. About 15% of people infected develop serious illness that can lead to bleeding, shock, organ failure and sometimes death. Some people become jaundiced, which is where the “yellow” comes from. The WHO estimates there are 200,000 cases of yellow fever each year, with 90% of them occurring in Africa.
As there is no treatment, the main method of protection is from a vaccine, which travelers need to receive at least 30 days before travel to get lifelong protection against the virus. If you are a seasoned traveler you will be familiar with the need to prove your vaccination with the yellow card provided after your injection, as countries with the disease, as well as those harboring this mosquito species, aim to prevent the disease spreading or entering their population. If traveling to remote locations, it might be wise to keep that card firmly inside your passport.
Locations: Africa, Asia, Eastern Europe
A third of the world’s population is thought to be infected with tuberculosis (TB), which is the second greatest infectious cause of death globally (after HIV/AIDS). TB can occur in a “latent” state where people carry the bacteria without developing the disease itself. TB occurs in nearly every country but infections are more concentrated in developing countries, particularly in Asia, Africa and Eastern Europe.
This airborne disease is spread from person to person and infects mainly your lungs but can spread to other parts of the body.
There is a vaccination available but its protection in adults is limited. Its greatest protection is in young children yet to be exposed to the TB bacteria. Symptoms include a prolonged cough, weakness, tiredness, weight loss and night sweats. If diagnosed, TB is treatable and curable with an extensive course of antibiotics. However, drug-resistant forms of the disease have emerged globally.
Locations: Highest risk in Indian subcontinent, North Africa and the Middle East, sub-Saharan Africa and South America.
This is a collective term for diarrhea caused by a range of bacteria, viruses or protozoa.
Transmission is generally through consuming contaminated food or water and though symptoms are usually mild, infections can ruin a vacation or business trip, causing dehydration, weakness and general inconvenience from numerous trips to the bathroom. It can be avoided by sticking to bottled water, making wise food choices and regularly washing your hands, as your immune system simply isn’t ready for those new, exotic micro-organisms.
Location: Guinea, Liberia, Sierra Leone, Nigeria, DR Congo, (Senegal has had an isolated case).
As of March 2014 this once remote and easily contained disease has gained international recognition. To date the current outbreak of Ebola Viral Disease (EVD) has reached five countries and those traveling to affected regions are advised to be aware of the symptoms, which include fever, rash, diarrhea, vomiting and red eyes. Alongside these symptoms, internal and external bleeding are also signs of the disease, which spreads from person to person by contact with infected body fluids, such as saliva, semen or blood. Small outbreaks continue to occur in the Democratic Republic of Congo.
Ebola has no licensed vaccine or treatment and has fatality rates of up to 90% in infected people – but the virus requires very close contact with body fluids to be transmitted and is easily avoided with regular hand-washing and protective clothing – and avoiding contact with bodily fluids.
Locations: Africa, Asia, the Caribbean and Central and South America. Highest risk in South Asia.
This bacterial disease is spread by contaminated food and water and the resulting fever can be life threatening. Symptoms begin as high fevers, weakness, stomach pains, headache, and loss of appetite. Travelers should get vaccinated before travel but as the vaccine only protects 50%-80% of recipients it’s wise to be careful about your choice of food and drink.
As with travelers’ diarrhea, stick to bottled water and avoid unpeeled fruit and vegetables, street food (as delicious as it may look) and ice in drinks. Typhoid fever can be treated with antibiotics but drug-resistant bacteria have begun to emerge so perhaps avoid that cucumber in your salad or that icy cocktail in the sunshine.
Locations: North America, Europe, Asia.
Lyme disease is mainly found in the northeastern, north central, and Pacific coastal regions of North America. It is caused by bacteria which spread through the bites of infected black leg ticks.
Symptoms include fever, headache, fatigue, and a characteristic skin rash called erythema migrans. If untreated the infection will spread to the joints, heart and nervous system. So when wandering through the wilderness be sure to protect yourself with insect repellant. But as infected ticks need to be attached for 36-48 hours or more before the Lyme disease bacterium can be transmitted, effective spotting and removal of ticks from your body will also prevent you from getting infected.
If caught early the disease is treatable with antibiotics.
Location: Most of the developing world.
The Hepatitis virus has many forms (A, B, C and D) but Hepatitis A is the one most travelers should be aware of as it spreads through contaminated water and uncooked food. The disease is closely linked to unsafe water, inadequate sanitation and poor personal hygiene and is one of the most frequent causes of foodborne infection.
There is a safe and effective vaccine available against the virus, which most travelers are advised to have, but again, wise food and drink choices are recommended to avoid the resulting liver disease and potentially severe illness. Symptoms include fever, malaise, loss of appetite, diarrhea, nausea, abdominal discomfort, dark-colored urine and jaundice. WHO estimates show 1.4 million cases of Hepatitis A each year. There is no treatment for the disease other than rehydration and supportive treatment for the weeks or months of recovery time required.