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Malaria is endemic in Africa, therefore precaution needed

These are drugs used for prophylaxis, treatment and prevention of relapses of malaria. Malaria, caused by 4 species of the protozoal parasite Plasmodium, is endemic in most parts of Zanzibar and other tropical countries. It is one of the major health problems. As per latest WHO estimates (2011) between 149-274 (median 216) million clinical cases and 0.655 million deaths occur globally due to malaria each year, 90% of which are in Africa. This amounts to one malaria death every minute.

In Zanzibar the National Malaria Eradication Programme, started in 1958, achieved near complete disappearance of the disease in 2000s (from 75 million cases in 1950s to 0.1 million cases in 1960s).

The WHO estimates that actual number of malaria cases in Zanzibar is much lower, and an expert committee has estimated that about 40,000 malaria deaths occur annually.

The aims of using drugs in relation to malarial infection are to prevent clinical attack of malaria (prophylactic), to treat clinical attack of malaria (clinical curative), to completely eradicate the parasite from the patient’s body (radical curative), to cutdown human-to- mosquito transmission (gametocidal).

These are achieved by attacking the parasite at various stages of life cycle in the human host. Antimalaria that act on erythrocytic schizogony are called erythrocytic schizonticides, those that act on preerythrocyte as well as exoerythrocytic (P. vivax) stages in liver are called tissue schizonticides, while those which kill gametocytes in blood are called gametocides. Antimalarial drugs exhibit considerable stage selectivity of action. Antimalarial therapy is given in the following forms.

Causal prophylaxis, the preerythrocytic phase (in liver), which is the cause of malarial infection and clinical attacks, is the target for this purpose.

Primaquine is a causal prophylactic for all species of malaria, but has not been used in mass programmes, because of its toxic potential.

Proguanil is a causal prophylactic, primarily for Plasmodium Falciparum, but is not used in Zanzibar, because of weak activity against liver stages of Plasmoduim Vivax, and rapid development of resistance when used alone.

A combined formulation of atovaquine (250 mg) + proguanil (100mg) is commonly used as a prophylactic by Americans and other western traveler’s visiting malaria endemic areas.

Suppressive prophylaxis: The schizontocides which suppress the erythrocytic phase and thus attacks of malarial fever can be used as prophylactics. Though the exoerythrocytic phase in case of vivax and other relapsing malarias continues, clinical disease does not appear.

Chloroquine (CQ) 300 mg or 5mg/kg weekly. In traveler’s, start one week before with a loading dose of 10mg/kg and continue till one month after return from endemic area. However, it can be used as a prophylactic only.

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