Antonio Gordon, MD, Ph.D.

The number of travelers continues to increase. In the Miami International Airport alone, more than one million passengers pass in any one day. The risk of transmission of certain diseases exists. Furthermore, the risk the traveler is exposed when he or she visits certain geographical areas is dangerously real. Recently, we saw a patient with Dengue Hemorrhagic Fever here in Northwest Miami-Dade County. The illness had been transmitted to this young man in the Island of Hispanola. Supportive care was sufficient to allow this patient to survive and tell the story.

All diseases which are transmitted hematogenously through the insect or arthropod vectors are not preventable through vaccination. For example, Dengue is not a disease for which a vaccine is in use currently.

Prevention in these cases must take the form of avoidance of contact with the vector, in this case the Aedes aegypti mosquito. Two diseases which are viral illnesses transmitted through the mosquito are yellow fever and Japanese Encephalitis virus disease. Both of these illnesses can be prevented through the use of effective vaccination. Japanese Encephalitis (JE) is distributed throughout Asia. It is indeed the world's most common arboviral encephalitic disease. A vaccine has been available for many years but in the past decade adverse reactions have been reported. In one case, a military person collapsed after receiving the JE vaccine. However, it was noted that the individual involved used steroids for muscle building. Therefore, exactly what was the cause of the collapse was not really known. The current recommendation is for the JE vaccine to be given with other vaccines and for the subject to avoid known allergens and alcohol in the period immediately after the JE vaccination. Avoiding mosquitos needs further attention. The three widely recognized methods to avoid mosquitos are: To avoid the area where mosquitos are known to be prevalent, using repellents on the skin or garments, and using pyrethroids insecticides on garments and mosquito nets. Care must be exercised in the prevention of toxic reactions particular in the children and pregnant women on exposure to large or relatively large doses of pyrethroids.

In general, the traveler should follow these guidelines at the time of traveling:

1. Update immunization against tetanus, diphtheria, poliomyelitis, hepatitis B for all ages.

2. For the youngsters, check status of measles and rubella vaccination.

3. For persons who suffer chronic illnesses, diabetes, lung or heart disease, provide updated influenza vaccination.

4. For anyone traveling to Africa and the Amazonian forest, provide yellow fever vaccination.

5. For anyone traveling to Arabia including Mecca, provide meningococcal vaccine A and C.

6. For any person traveling to countries with uncertain hygiene, provide typhoid vaccine, hepatitis A, and cholera vaccination.

7. Japanese Encephalitis vaccine needs to be offered to anyone traveling to rural areas of Asia in the monsoon season.

8. Tickborne Encephalitis vaccine needs to be offered to any person traveling to Central Europe from May to September.

9.If traveling to any area where malaria is prevalent, chemoprophylaxis must be taken appropriately depending on the prevalence of sensitivity of the plasmodia in that region.

For travelers to the Island of Cuba in this year of 1999, we recommend the use of typhoid vaccine and hepatitis A vaccination if the traveler has not demonstrated immunity against these disorders.

Further information may be obtained in:

Marchoud, B et al. Ann Med Interne 1998, 149:332-9

Neogi DK, et al. J. Commun Dis. 1998, 30: 113-6