AN OVERVIEW ON MALARIA IN SUB-SAHARAN WITH SPECIAL REFERENCE TO TANZANIA

Document Type : Original Article

Authors

1 Military Medical Academy, Egypt.

2 Tanzania People’s Defence Forces.

3 Department of Parasitology, Faculty of Medicine, Ain Shams University, Cairo 11566, Egypt.

Abstract

Malaria is Anopheles-borne protozoan disease of worldwide distribution. Infection may result in a wide variety of symptoms, ranging from absent or very mild symptoms to severe disease and even death. Malaria can be categorized as uncomplicated or severe. It is a curable disease if diagnosed and treated promptly and correctly. All the clinical symptoms associated with malaria are caused by the asexual erythrocytic or blood stage parasites. When the parasite develops in
the erythrocyte, numerous known and unknown waste substances such as hemozoin pigment and other toxic factors accumulate in the infected red blood cell. These are dumped into the bloodstream when the infected cells lyse and release invasive merozoites. The hemozoin and other toxic factors such as glucose phosphate isomerase (GPI) stimulate macrophages and other cells to produce cytokines and other soluble factors which act to produce fever and rigors and probably influence other severe pathophysiology associated with malaria. After infective bite by Anopheles-vector, a period of time (incubation period) goes by before the first symptoms appear. Incubation period in most cases varies from 7 to 30 days. The shorter periods are most frequently with P. falciparum and the longer ones with P. malariae. Antimalarial drugs taken for prophylaxis by travelers can delay the appearance of malaria symptoms by weeks or months, long after the traveler has left the malaria-endemic area. This can happen particularly with P. vivax and P. ovale, both of which can produce dormant liver stage parasites; the liver stages may reactivate and cause disease months after the infective mosquito bite. Besides, malaria-co-infection with HIV/AIDS and others is another serious issue.

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