Diseases

Travel Medicine Information

Cholera

Cholera is an infection caused by bacteria (Vibrio cholerae) that look like curved rods when viewed under the microscope. The bacteria attach to the lining of the intestines and secrete a toxin. The cholera toxin can causes the cells in the intestines to pour out life-threatening amounts of fluid. The excess water loss can lead to watery diarrhea, so severe that it is difficult to keep the body hydrated. The term "rice water" is often used to describe this diarrhea because of the appearance of small white flecks of mucus in liquid. Cholera spreads when human waste contaminates water and food. Because it takes high numbers of bacteria to cause infection, the contamination usually has to be quite significant. For example, in areas of poor sanitation, cholera can be spread when the drinking water supply is contaminated by feces from people who are sick. Cholera is most common in areas that have poor sanitation, with faulty sewage systems or contaminated drinking water. Asia, Africa, and Latin America have been affected for several decades. Cholera can be prevented by using proper sanitation and sewage treatment. Boiling, filtering, or chlorinating water can help to prevent the spread of cholera. Treatment is mainly oral rehydration with simple electrolyte solutions. There is no vaccine for cholera that is approved in the United States. Following food and water precautions is the first line of defense (see "What is safe to eat and drink while traveling?"). Cholera is very rare in recreational travelers, but travelers providing humanitarian aid to underdeveloped areas, or areas were sanitation and water supply is disrupted by disaster, should be aware of the risk of cholera. Basic knowledge of hand hygiene, infection control measures, and correct sanitation procedures can avoid inadvertent spread of infections and keep aid workers healthy and able to help.

Hepatitis A

Hepatitis A is caused by a virus that infects the liver. People get sick two to six weeks after they get the virus. Symptoms include nausea, yellowing of the skin and eyes (jaundice), dark urine, pale stools, loss of appetite, and fatigue. The symptoms take two to six months to completely resolve. Unlike some other hepatitis viruses, hepatitis A does not cause chronic liver disease. In other words, once the person gets better, he or she is completely cured. Some infected people (especially children) are asymptomatic, meaning that they do not develop symptoms. Hepatitis A is spread when human waste is mistakenly ingested. Even a small amount can cause disease, such as might occur by shaking hands with someone with contaminated hands and then touching the mouth. Food preparers have transmitted disease by mistakenly contaminating food. It is also possible to get hepatitis A through sexual contact or contaminated needles or blood. Hepatitis A occurs throughout the world but is more common in developing countries. There is an effective vaccine that is quite good at preventing hepatitis A. If you are traveling to a developing country, your doctor will probably recommend vaccination. In a few cases, if you will be traveling before the vaccine has time to take effect, your doctor might recommend a more temporary measure called gamma globulin instead of or in addition to the vaccine. Remember to follow food and water precautions (see "What is safe to eat and drink while traveling?"). The vaccine also requires a second dose six to 12 months later for full protection (or two or three more doses if combined with hepatitis B vaccine), so you will to follow up with your doctor after coming home. However, hepatitis A vaccine is protective for at least 25 years.

Malaria

Malaria is an infection caused by a protozoan that enters red blood cells and multiplies until the cells burst open. The broken cells release the young protozoa into the bloodstream where they infect more red blood cells. This release of young protozoa causes high fevers that can last for several hours, as well as anemia due to the destruction of red cells. The fever of malaria often comes and goes, coinciding with when the infected red cells burst open. With some types of malaria, the protozoa can hide in the liver and cause episodes of fever over many years. In serious cases, malaria can cause the kidneys to shut down, can infect the brain (cerebral malaria), or cause death. Malaria is spread to people by mosquitoes. The mosquitoes bite between dusk and dawn. Malaria occurs in many tropical areas and a few areas that have a milder climate. Travelers to sub-Saharan Africa, South America, and Asia may be at risk for the disease. Some countries in Central America and the Caribbean also have malaria. Not every area of a country will be affected. The people who have lived all their lives in the area with malaria typically have some immunity, but travelers are at much higher risk for severe infection, especially with some types of malaria. Malaria is serious enough to see a doctor about possible preventive medication if your itinerary suggests you might be exposed. The CDC has a web page that tells where malaria occurs (http://wwwn.cdc.gov/travel/). Many public-health departments and some private travel clinics provide pre-travel evaluations. CDC also offers a "Find a Clinic" web page to help you find one (http://wwwnc.cdc.gov/travel/page/find-clinic). The American Society for Tropical Medicine and Hygiene also has a list of clinics that specialize in travel medicine (http://www.astmh.org/source/ClinicalDirectory/).You should visit these clinics at least four to six weeks before you travel in case you need vaccines, but especially with malaria it is better to go later than not at all to avoid traveling unprotected. Malaria can be prevented by avoiding mosquito bites (see "What can I do to avoid insect bites?") and by taking preventive medications. Travelers who will be exposed to malaria should take medications starting before travel to the area and continuing for a time after they leave the area. Several different medicines are available. Some are taken only once a week, and others are taken daily. In some countries, malaria has become resistant to older medicines. Your physician or travel clinic will choose which medicine to use based on what countries you are visiting. Some medicines must be started two weeks before departure, so you should plan to go to the doctor or travel clinic well in advance. It is very important to take every last dose of preventive medication that may be prescribed to take after you return home, especially with types of malaria that hide in the liver and can return months later.

Meningitis and encephalitis

There are several causes of meningitis, an infection of the lining and fluid around the brain and spinal cord. Encephalitis means that the brain tissue itself is also infected. There are serious types of meningitis and encephalitis that are associated with travel and can be prevented. Meningococcal meningitis is one of the most serious types associated with travel to certain areas. The cause is a bacterium called Neisseria meningitidis. The disease can be quite severe or even fatal. The infection is spread from person to person by close contact through coughing or sneezing or other respiratory means. Meningococcal meningitis occurs at low rates throughout the world, including the United States. However, some countries have high rates of disease and pose a special risk to travelers. This includes many countries in the "meningitis belt" of sub-Saharan Africa. Saudi Arabia has experienced outbreaks when pilgrims travel to religious sites. There are two effective vaccines to prevent meningitis. The choice of vaccine depends on the age of the patient. The vaccines are synthetic (meaning that they do not contain live infectious agents). They should not be given to people who have previously had a neurological illness called Guillain-Barre syndrome. Meningitis immunizations are now routinely recommended for adolescents and college freshmen in the United States. It is also recommended for travelers who are going to areas that have high rates of infection. Vaccination is required for pilgrims to religious sites in Saudi Arabia, and proof of vaccination (preferably an International Certificate of Vaccination) will be required at the border. The vaccination is effective for three to five years (depending on which of the two vaccines is given), after which revaccination may be recommended for travelers who travel to areas with high rates of infection. There are several kinds of viral encephalitis that occur in various areas of the world, such as Japanese encephalitis virus, which are spread by mosquito bites. They are fortunately rare, and most viral encephalitis is prevented by avoiding mosquito bites (see the section on insect precautions). Japanese encephalitis virus is preventable by vaccine, and a doctor or travel clinic can advise if you will need it. Meningitis and encephalitis caused by parasites (amoebae) is also a concern for travelers. Harmless amoebae are common in freshwater and plumbing all over the world. Naegleria fowleri prefers hot springs, lakes, rivers, or any warm freshwater that is untreated for human use; it may grow in pipes and hot water tanks of homes and buildings as chlorine dissipates. If affected water with enough Naegleria is inhaled, it may cause severe meningoencephalitis; death occurs in 97%-99% of cases. This type of meningitis is hard to diagnose, children are often affected, and effective treatment is still being studied. Prevention is very easy. If bathing in hot springs or bodies of fresh water with unknown chlorination during hot seasons, keep the head above water, hold the nose shut, or use nose clips. Avoid getting bath or hose water up the nose. If you rinse your sinuses, or practice religious nasal cleansing, tap water is safe if boiled for at least one minute and left to cool. Other options include using chemical disinfectants, filters with an absolute pore size 1 micron or less, and distilled or sterile water. Drinking affected water cannot transmit Naegleria, and it cannot live in saltwater.

Polio

Polio is a viral illness that can lead to severe neuromuscular problems. Polio is spread from person to person. Infected oral secretions and feces can cause disease. Many people have no symptoms, but some have neurological problems such as weakness and paralysis. Symptoms are especially severe if they involve the breathing muscles. Some people are left with permanent neurological disabilities such as paralysis of limbs or breathing muscles. Thanks to a global public-health campaign, many countries no longer have polio. A few countries in Africa, South Asia, Southeast Asia, and the Middle East still have outbreaks. The list of infected countries is constantly changing, as some countries successfully eliminate the infection and others become reinfected. If there is international spread from a country within 12 months, the World Health Organization (WHO) may declare a public-health emergency and issue updated vaccine requirements for travelers staying in those countries longer than four weeks. Proof of vaccination on an International Certificate of Vaccination or Prophylaxis may be required before leaving. Check the CDC web site (http://cdc.gov/travel) for an update to see if your itinerary includes any of these countries. The inactivated polio vaccine is recommended if the traveler is going to an area where polio is still occurring. Unless special circumstances arise as above, a single lifetime booster dose in adulthood is sufficient if the traveler has received the usual vaccine series in childhood. If the traveler has not been fully vaccinated in the past (has not received all doses at recommended times), more doses may be needed.

Travel health insurance & medical evacuation insurance

Most health insurance policies have very limited coverage outside the home country, and your portion of the cost may be much more than it would be at home. Some may not cover travel-related care at all, or not cover emergencies related to high-risk activities. You may also be more comfortable with familiar health care in familiar surroundings, and being seriously ill away from home and family may can add an unanticipated and heavy financial burden, as well as psychological stress. Furthermore, most care will require up front cash or credit payment or not accept health insurance. If you have a chronic disease, immune deficiency, or are pregnant in the third trimester, it may be especially beneficial, but anyone traveling outside the continental U.S. may wish to consider purchasing short-term travel health or medical evacuation insurance. This type of coverage is usually inexpensive compared to the cost of an unexpected health emergency. Most out of country health emergencies are related to motor-vehicle accidents and trauma, rather than health issues. The U.S. Department of State can provide information on health care and medical emergencies when traveling abroad (http://www. travel.state.gov).

Travel safety and health alerts

Keep current on travel warnings and alerts related to crime, civil unrest, or terrorism by checking with the U.S. State Department for current travel alerts and warnings (http://travel.state.gov/content/passports/english/alertswarnings.html). Enrolling in the Smart Traveler Enrollment Program (STEP) with the U.S. Bureau of Consular Affairs Register your itinerary and contact information with the U.S. Consulate office at your destination (https://step.state.gov/step/).

Traveler's diarrhea

Traveler's diarrhea is the most common medical complaint in travelers, occurring in up to 50% of travelers to developing countries. It occurs when infectious organisms are inadvertently ingested by travelers, resulting in one to five days of loose stools. The stools are often watery and may be accompanied by abdominal cramps. Although not fatal, traveler's diarrhea can cause dehydration, vomiting, low-grade fever, and discomfort to the point that some travelers have to change their itineraries. It is important to note that traveler's diarrhea is not associated with bloody stools, severe abdominal pain, or high fever. These symptoms are suggestive of more serious conditions and should prompt medical attention. Traveler's diarrhea is spread when bacteria or other infectious agents such as viruses are ingested. Traveler's diarrhea is most often spread through contaminated food or water, or by putting contaminated hands in the mouth. Even small amounts of contamination can cause infection. Although bacteria are the most common cause of traveler's diarrhea, there have been outbreaks of diarrhea on cruise ships caused by viruses known as noroviruses. Noroviruses spread readily from person to person. Travelers can get diarrhea in most areas of the world, but some countries pose a higher risk. High-risk areas include most of Asia, the Middle East, Africa, and Central and South America. Risk is increased if the traveler is adventurous with his or her diet, eats foods from street vendors, or travels to areas off the usual tourist routes. Protective measures may help prevent or shorten the duration of traveler's diarrhea. All travelers should wash their hands often and understand basic food and water precautions (see "What is safe to eat and drink while traveling?"). However, it has been shown that even well-informed travelers often choose to eat foods that pose an increased risk of traveler's diarrhea. Therefore, travelers at risk should carry in their first-aid kit an antimotility agent such as loperamide (Imodium; Kaopectate II; Imodium A-D; Maalox Anti-Diarrheal Caplets; Pepto Diarrhea Cont) and start taking it if they get symptoms. Bismuth subsalicylate (Pepto-Bismol) is also helpful. Because bacteria are developing resistance to many antibiotics, many older antibiotics do not work, and those prescribed currently may not be effective in the future. Antibiotics also have risks of their own and do not protect against viruses or parasites; therefore, routine prophylactic antibiotics are not recommended for most travelers. However, many physicians recommend that travelers carry along an antibiotic to take in case they get diarrhea. Fluoroquinolones, such as ciprofloxacin, levofloxacin, ofloxacin, or norfloxacin, are the most commonly prescribed antibiotic; azithromycin (Zithromax, Zmax) or rifaximin (Xifaxan) are alternatives. If an antimotility agent (a drug that reduces gastrointestinal motility) and an antibiotic are started at the first sign of diarrhea, symptoms may be shortened to only a few hours instead of a few days. Physicians might prescribe daily antibiotics or daily bismuth subsalicylate to prevent diarrhea in people who are immunosuppressed, or when the purpose of a trip would be severely impacted if it were interrupted by diarrhea. This is not needed for most travelers, and bismuth subsalicylate may cause adverse effects in doses required for protection. Pregnant women and children need special advice because many of these drugs are not appropriate for them. Affected people should stay well hydrated with beverages that are sealed, treated with chlorine, boiled, or are otherwise known to be purified; in most cases, commercial sports drinks are adequate, but very sugary drinks can worsen diarrhea. If antibiotics are prescribed, fill the prescription before travel; if you must buy drugs during a trip to an area of the world with few drug regulations, avoid counterfeits by using a licensed pharmacy, asking the pharmacist about the ingredients, and checking the packaging for poor print quality or odd appearance; drugs should be in the manufacturer's original packaging if at all possible.

Typhoid fever

Typhoid fever is an infection caused by a bacterium called Salmonella typhi. Most people who get sick develop a headache, a very high fever (up to 103 F or 104 F), and fatigue. Nausea, abdominal pain, diarrhea, or constipation may also occur. The disease spreads when infected human waste contaminates food or water or is otherwise ingested. Some people are able to carry the bacteria inside their body for a very long time ("carriers"), even after symptoms have disappeared. Carriers can get it again or spread it to other people. People who get sick may be given antibiotics by their doctor. In addition to the antibiotics, people should make sure they always wash their hands after toileting and before cooking, so that they don't spread the disease to anyone else. Some occupations require proof that you no longer carry any typhoid bacteria before you may go back to work; a doctor may perform several cultures of your stool before clearing you for work. Typhoid fever occurs in many areas around the world, especially Asia, Africa, and South America. A vaccine is available to reduce the risk of getting typhoid, and it lasts several years. Ask a doctor or local public-health department about typhoid vaccination before you travel. Food and water precautions (see "What is safe to eat and drink while traveling?") also reduce the risk of disease. The saying "Boil it, cook it, peel it, or forget it!" helps you remember how to prevent becoming sick with typhoid fever (and many other infections) while traveling.

Yellow fever

Yellow fever virus is a rare cause of illness in U.S. travelers, but it can be serious, and some countries require proof of vaccination before border entry. It is caused by a virus that attacks the liver. Symptoms start within three to five days of infection. In many people, the disease is mild and goes away. About 15% of people will develop severe disease with liver failure, and up to half will die. Yellow fever is spread by the bite of a mosquito. Yellow fever occurs in areas of sub-Saharan Africa, Central America, and South America. Not all countries in these areas have yellow fever. Even within a country, some areas may have yellow fever while others do not. There is a very effective vaccine available to prevent yellow fever. It contains a live virus that has been modified ("attenuated") to make it safer. Vaccine side effects are usually mild. Rarely (a few cases per million doses), the vaccine virus can spread and cause severe disease. Infants under 6 months old, and people with weak immune systems (for example, people with certain chronic diseases, and some people with HIV infection or cancer) should not receive the live vaccine. These people should consult with a doctor before traveling to an area where yellow fever occurs. For people 60 or over and pregnant or breastfeeding women, a doctor should carefully review the risks and benefits of the vaccine. Vaccination is generally recommended for travelers who will be exposed to yellow fever with the above exceptions. The vaccine may be required for entry into some countries. Check the CDC web site to see if vaccination is required for your trip. If you get vaccinated, you should receive an International Certificate of Vaccination, signed and validated with the center's stamp where the vaccine was given. If you cannot be vaccinated, a medical waiver can be given. Take the certificate and any waivers with you on your trip. You may need it to enter your destination country or get back home. This certificate is valid for 10 years, and some countries are starting to accept it as valid for life. Yellow fever vaccine is only given at authorized U.S. yellow fever vaccine clinics, so you will need to check well in advance. CDC can help you find a place to get yellow fever vaccine (http://wwwnc.cdc.gov/travel/yellow-fever-vaccination-clinics-search.aspx). The first line of defense against illness transmitted by insects is prevention of bites (see "What can I do to avoid insect bites?").