Travel Medicine (cont.)

Cholera is an infection caused by bacteria (Vibrio cholerae) that look like curved rods when viewed under the microscope. The bacteria attach to the inside of the intestines and secrete a toxin. The cholera toxin can cause the cells in the intestines to pour out large amounts of fluid. In severe cases, the excess water loss leads to massive amounts of watery diarrhea that can contain cells from the body and bacteria. 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. Cholera can be prevented by using proper sanitation and sewage treatment. Boiling, filtering, or chlorinating water can help to prevent the spread of cholera. There is no vaccine for cholera that is approved in the United States. Fortunately, cholera is very rare in travelers.

There are several diseases of concern for travelers for which there is no vaccine or medicine to prevent infection. Among these are some viral infections, sexually transmitted diseases, and parasitic infections.

Many viral infections can be spread by biting insects such as ticks or mosquitoes. These include serious infections like hemorrhagic fever, a viral infection that causes high fever and bleeding. Another virus causes Chikungunya fever, which is common in Africa and Asia. Spread by mosquitoes, Chikungunya fever causes high fever and severe joint pain and usually lasts for days or weeks. Another viral illness is dengue fever, which occurs throughout the world in tropical areas. Symptoms of dengue fever are high fever, headache, and occasionally bleeding (hemorrhage). The key to reducing the risk of getting these infections is to follow insect precautions (see section on insect precautions).

Sexually transmitted diseases can be acquired anywhere in the world. The only sure way to prevent disease is to abstain from sexual intercourse. Use of condoms will reduce risk. HPV vaccines now available will reduce the risk of acquiring infection with the human papillomavirus virus that causes genital warts and cervical cancer.

Parasites occur in most areas of the world but are especially common in tropical and subtropical regions. Some are spread by eating contaminated food (see food and water precautions), while others are spread by direct contact with infected water or soil. Most travelers do not get parasitic infections, but those who are going into rural areas of developing countries should ask their doctors about parasites they might encounter.

Infectious-disease outbreaks occur periodically and officials may recommend additional precautions. Examples have included outbreaks of bovine spongiform encephalitis (mad cow disease) or severe acute respiratory syndrome (SARS). Travelers should check the CDC web site to obtain health and risk information specific to their destination country.

Source: MedicineNet.com
http://www.medicinenet.com/travel_medicine/article.htm