Malaria

If you are traveling to almost any tropical country these days it is likely you will need to protect yourself against malaria. This is a disease which was supposed to have been eradicated by now but instead is on the increase. Resistant forms of malaria have now spread to most of the tropical world.

Malaria is a disease spread by the bite of an Anopheles mosquito. These mosquitoes are more common in open, rural areas and usually bite at night. The parasite is injected by the bite and travels within seconds to the liver where it is protected against the body’s defense mechanisms (and most drugs.)  It goes through some reproductive stages and then emerges to invade the red blood corpuscles. These are soon destroyed by the parasites, leading to anemia and clogging up small blood vessels. Even if the body manages to destroy these parasites a new batch is forming in the liver, soon to be released to start the process all over again. Even weeks after a bout of malaria is successfully treated the parasites which have been hiding in the liver may emerge again. Only the treatment of the liver stages with special drugs or the prolonged taking of prophylactic drugs will forestall this.

There are four types of malaria--Vivax, Ovale, Malariae and Falciparum. The first two are most likely to cause delayed relapses but least apt to be fatal. Falciparum malaria, often known as malignant malaria, is the one that is most apt to be fatal and is rapidly becoming resistant to many forms of drug therapy.

At this time malaria is most common in moist, tropical countries but as drug resistance increases it is spreading to other, less typical parts of the world. The rise in air travel also is causing the disease to crop up in unlikely locations such as Switzerland and California.

The illness of malaria usually begins seven to thirty days after exposure. It starts out as a flu-like syndrome with headache, body aches and a general feeling of unwellness. It soon progresses to include abdominal pain, nausea, vomiting and sometimes diarrhea. The classic symptom is a fever, usually accompanied by body-shaking chills and in an increasingly predictable pattern. Untreated, it can rapidly progress to liver and kidney failure, coma, shock and death.

The diagnosis is typically made by special blood stains which should be performed by people specifically trained in what to look for. If the symptoms persist and the blood stains are negative they should be repeated--OFTEN. Other common travel-related diseases which may mimic malaria to some degree are dengue fever, typhoid, hepatitis and brucellosis.

Treatment is typically with chloroquine, mefloquine or a related drug. As drug resistance increases so does the need to use more powerful drugs, often in combinations. These drugs are often difficult to get and have serious side effects and should be administered by someone experienced in their use such as an Infectious Disease or Travel Medicine specialist.

Malaria is one of the most dreaded diseases during pregnancy, both for its frequency and its severity.  Studies have shown a preference of Anopheles mosquitoes for pregnant women.  Whether this is due to the fact that in pregnancy you exhale more carbon dioxide or increased body surface temperature is a matter of conjecture.  But the fact remains that  a pregnant woman is more apt to get malaria than is her non-pregnant counterpart.

And her illness will likely be more severe.  The number of parasites in the blood reaches much higher levels and results in an increased likelihood of cerebral malaria, anemia, low blood glucose levels and a relapse after usual treatment.  Red blood corpuscles may “sludge” in the placenta and cause premature labor or separation of the placenta. 

A baby born to a mother with malaria is more apt to be of low birth weight and to suffer from dehydration, seizures, bleeding disorders and rupture of the spleen.

A pregnant woman must, therefore, take careful precautions against malaria.  She should use mosquito nets and be sure that windows have screens.  She should avoid mosquito breeding areas, wear long sleeves and long pants in the cool of the day, and use insecticides and insect repellents (discussed in separate chapters). 

Preventive medicines are also discussed in a separate chapter.  Expert opinion, however, is that treatment of a pregnant woman with malaria is complicated enough to require an intensive care unit and the attendance of a specialist in infectious or tropical diseases.