EXAMINATION OF INCIDENCE OF MALARIA INFESTATION CAUSED BY DIFFERENT SPECIES OF PLASMODIUM

1.0 THE BACKGROUND INFORMATION
Malaria is a febrile illness caused by a protozoan of the germs plasmodium present public health problem and cause suffering and premature death in tropical and subtropical countries, because of htier ample rainfall; and long periods, of warmth which favour both mosquito breeding and human infection (Adams and Magraitt 1980,),
In many endemic area, malaria increases and difficult to control because of the resistance of the parasite to antimalaria drings and the failure of vector control measures: At present, about two billion population live in malarious zone. Every year, 200-300 million people are due to the disease. Most of the victims are children under five (5) and pregnant women in areas of stable malaria (intence malaria) transmission. Malaria also poses a risk to travellers, tarists and immigrants and exotic cases of malaria are
There are four species of Plasmodium which infects humans. although infection is generally cases occur in the USA and other countries which are otherwise free of malaria transmission. Falciparum, and Plasmodium vivaz, which are found throughout malaria belt. Plasmodium malaria is widely distributed but less common Plasmodium Ovale is rare but it tends to replace P. Viax in west Africa where it has been linked with Lack of Duffy blood group by (John Murray, 1880).
The life cycle of the malaria (Plasmodium protozoa) includes of the malaria (plasmodium protozoa)includes three basic stages. The first stage occurs in the mosgintos body (Exogenous stage). The second and the third stages take place in a persons body (exogenous stage) the first stage begins where the mosginto bites Samoan who has malaria. Plasmodium enter the insects body and reproduce in its stomach. The protozoan young tin their way into the mosguito saliva. The second stage occurs after the mosquito bites another person. Plasmodia.
During the third stage, each plasmodium invades a red blood cell, where it multiples again. The infected blood cells eventually rapture and release large numbers of plasmodia, which invades additional red blood cells. This invasism, multiplying and cell rupture by, the parasites continues, causing the periodic attacks of fever that are typical of malaria. An attack occurs each time the red blood cells rupture. Some plasmodia develop further in human blood and are able to reproduce in a mosquitoes body. They enter the insects body when the mosquito bites a person their life cycle begins again.

Figure: THE LIFE CYCLE OF THEMALARIA PARASITE

Human malaria can be transmitted only by female anopheline mosquitoes. In addition to transmitting malaria, anophelines also transmits filariasis and some viral disease, but other mosquitos are more important as vectors of the two latter infections. The Anopheless belong to the order of Diptera, sub-order Nematocera, family culicidae sub-family culicinae and tribe Anophelim in the zoological classification.. within the tribe Anophelin, the germs anopheles has several sub-genera. (Ketchum 1984).
There are about 400 species of Anophelese mosquitoes throughout the world, but only some 60 species are vectors of malaria under natural conditions: of these some 30 species are of major importance. Natural susceptibility or resistance of Anapheles to infection with a defined species of malaria parasite is largely unexplained though it is certainly related to biochemical processes in the body of the mosquito and to its nutritional requirements. Among the main factors determining whether a particular species of Abophelese is an important vector, the frequency of its feeding on man (in preference to animals) is of particular relevance. The other factors are the mean longevity of the local population of an anpheline species and its density in relation to man. Thus, a particular species of Anopheles may be an important vector in one area of the world and of no importance in another area. Although Anopheles mosquitoes are most frequently seen in tropical or subtropical regions, they are found in termperate climates. They life expertance of the mosquito depends on enviroenmntal conditions.
The external morphology of both female and male anophels provides the main criteria for recognising both the genus and the species of these mosquito. The successive stages of growth and metamorphosis of the mosquito are the egg, lava, pupa and finally the adult or imigo.
In general, malaria is yound in regions lying roughly between latitute 60N and 400 of the equator. The impart of malaria on any population depends upon its epidemilogical pattern. Nigeira has endemic and stable malaria (Meneudez, 1995).