by Dr. Rajiv Narula
Among the many diseases transmitted by mosquitoes, malaria is one of the most dreaded, and yet preventable, causes of mortality among travelers. The geographic distribution of malaria covers most tropical regions and some warm temperate regions of the world. Risk of malarial transmission decreases above 4,500 feet, however in hotter climates, it may occur at heights above 9,000 feet. Last summer there was a big outbreak in Kissi, Kenya - altitude 6,000 feet.
Malaria is transmitted by the bite of the female Anopheles mosquito that injects the malaria parasite into the blood. These usually bite between dusk and dawn. Early symptoms are flu, fever, chills, muscle aches, headaches and sometimes vomiting and diarrhea Severe cases can rapidly progress to mental confusion, liver and kidney failure, convulsions, coma and death.
Making an early diagnosis is crucial to a successful outcome. You may have any of these symptoms from one week to several months after possible exposure to the mosquito. The period between the bite and the onset of illness is usually seven to 21 days but can be several months.
There are four species of malaria which can infect humans and cause illness, however only Falciparum Malaria can be life threatening; it can be treated effectively in its early stages. Yearly about 300-500 million people contact malaria, out of that 2-3 million will die! One million people die yearly in Africa alone, the second biggest killer on the continent after AIDS, according to the United Nations.
Travelers can protect themselves by avoiding mosquito bites by minimizing outdoor activities at night, wearing proper clothing, taking the correct anti-malarial medications, using repellents such as DEET and permetherine and mosquito nets. You cannot reduce the risk to absolute zero, but using this three-layer strategy will reduce the odds significantly.
The choice of anti-malarials is of paramount importance, as picking the correct one depends on the patient’s medical history- allergies, health status and itinerary. Studies done in Canada and Europe have shown that only between 11-27% of travelers were given the correct recommendations for protection.. This shows the importance of getting these recommendations from a reliable source. Vaccines for prevention are being developed and will hopefully be available in a few years. Until then, try not to make yourselves feeding grounds for mosquitoes.