PREVENTING MOSQUITO-BORNE DISEASES

[Malaria, Yellow Fever, Dengue Hemorrhagic Fever, and Japanese Encephalitis]

Diseases carried by mosquitoes are important hazards of the tropics. Prevention is essential. We will discuss your individual exposure at your travel visit with us, but you might want to read the CDC publication about "malaria and travelers" before this visit.

Immunization

There is no immunization for malaria, nor for dengue fever. But happily there are vaccines for Yellow Fever and Japanese Encephalitis. Both of these vaccines are available at Bayside offices.

Mechanical measures for mosquito avoidance

For all four of these diseases: don’t get bit and you won’t get hit! Here are measures to use to avoid being bitten:

• Avoid going outside at sunrise and sunset, the times when mosquitoes feed most actively. When you do go out, wear long sleeves and long pants, and protect other areas of open skin.
• Use screens or mosquito nets at night and other times if practical
• Use air-conditioning, which makes mosquitoes too cold to fly
• Make liberal use of the mosquito repellent DEET (N, N-diethyl-toluamide). DEET should be a minimum of 30% strength for international travel. "Deep Woods OFF" is the strongest available at ordinary stores, but stronger is available at REI Co-op or on the internet. This should be applied liberally to exposed areas every 4 to 6 hours.
• You may want to pre-treat your clothes with insect repellent by soaking them in a permethrin solution, and then air-drying with the insecticide on them. Clothes treated in this way can effectively repel bugs up to 10 launderings. There is a commercially available clothing line known as "Bug Off" that is pre-treated in this manner for travel.

Preventing Malaria: The Use of Anti-malarials

For malaria prevention, it is mandatory that you use anti-malarial medications if you are traveling to an area where you might be exposed to malaria-carrying mosquitoes. There are choices to be made; the anti-malarials all have advantages and disadvantages, and are used in different circumstances and in different regions. We will discuss the choices with you at your visit. Unfortunately, none of these preventives are 100% effective.

• Chloroquine

Chloroquine is only effective in Central America above the Panama Canal, and in Egypt. It is taken once per week, from one week before travel to 4 weeks after travel. Chloroquine is generally well-tolerated, but it can cause fatigue and GI upset (stomach aches, diarrhea).

• Mefloquine, also known as Larium

Mefloquine is useful in most parts of the world. It is taken once per week, starting one week before travel and continuing for four weeks after travel. Mefloquine is a terrific malaria preventive medicine, but there are some rare but serious side effects that need to be considered. The most common side effects include GI upset, fatigue, irritability. More rare but more disturbing side effects include vivid dreams or nightmares, depression, and balance difficulties. (Some SCUBA guides recommend against Mefloquine, but this is not a common side effect.) Even more serious side effects are possible – they include psychological problems, such as severe depression, or psychotic break. Although this possible adverse reaction has gotten the most press coverage, it is estimated that only one in 35,000 people would get this reaction. We do not recommend this medication if you have a history of psychiatric illness or are on psychiatric medications. Otherwise, it can be a very good choice.

• Atovaquone-Proguanil, also known as Malarone

Malarone is also useful in most parts of the world. It is taken as a daily pill. Side effects are mild, and include GI upset and headaches. Malarone is about twice the price as Mefloquin. Except for the price, it can be an excellent choice.

• Doxycycline

Doxycycline is a formulation of the familiar antibiotic tetracycline. It is an effective antimalarial in every part of the world, taken as a daily pill. There are a few side-effects that limit its use as an antimalarial, but they are generally not severe. Side effects can include: increased incidence of yeast infections in women, and increased sun-sensitivity, including exaggerated sunburn, or rash or itching with sun exposure. Doxycycline cannot be taken by women who are pregnant, or are not taking precautions against pregnancy. It is very inexpensive. The dose of Doxycycline is a single 100 mg pill at bedtime beginning a day or two prior to entering the endemic area and finishing 4 weeks after leaving the area.

Preventing Yellow Fever

Yellow Fever is caused by a virus carried by mosquitoes. It is found in the Amazon jungle areas of South America and jungle areas of Africa.

A single injection of the Yellow Fever vaccine is good for 10 years. Reactions to the vaccine are generally few and mild, with 2-5% of recipients reporting mild headaches, muscle aches and fevers up to a week after the injection.

You must receive the vaccine at a "designated vaccination center" (Bayside qualifies), and receive a Yellow Card with an official "stamp," that you must carry with your passport, to be shown upon request on arrival in countries that require proof of immunization.

Preventing Japanese Encephalitis

Travelers rarely need to be protected from Japanese Encephalitis. Only those who are to be living for prolonged times in the rural areas where JE is endemic need to be immunized. If you will need this vaccine, we will have to special-order it for you.