Current Status Of Malaria Vaccinology Essay -- essays research papers

Current Status of Malaria VaccinologyIn order to assess the on-going status of malaria vaccinology one must first takean overview of the whole of the whole ailment. One must belowstand the diseaseand its enormity on a world(a) basis.Malaria is a protozoan disease of which over 150 million cases are reported perannum. In tropical Africa alone more than 1 million children under the age of quaternteen die each year from Malaria. From these figures it is easy to see thateradication of this disease is of the utmost importance.The disease is caused by one of four species of plasmodium These four are P.falciparium, P .malariae, P .vivax and P .ovale. Malaria does not only effecthumans, but can also infect a variety of hosts ranging from reptiles to monkeys.It is therefrom necessary to look at all the aspects in order to assess thepossibility of a vaccine.The disease has a long and complex life cycle which creates problems forimmunologists. The vector for Malaria is the Anophels Mosqu ito in which the lifecycle of Malaria both begins and ends. The parasitic protozoan enters the blood stream via the bite of an infected female mosquito. During her feeding shetransmits a small fare of anticoagulant and haploid sporozoites along withsaliva. The sporozoites head directly for the hepatic cells of the liver wherethey multiply by asexual fission to produce merozoites. These merozoites can now trip up one of two paths. They can go to infect more hepatic liver cells or theycan attach to and penetrate erytherocytes. When inside the erythrocytes theplasmodium enlarges into uninucleated cells called trophozites The nub ofthis newly formed cell then divides asexually to produce a schizont, which has6-24 nuclei.Now the multinucleated schizont then divides to produce mononucleated merozoites. Eventually the erythrocytes reaches lysis and as result the merozoites enterthe bloodstream and infect more erythrocytes. This cycle repeats itself every48-72 hours (depending on the spec ies of plasmodium involved in the originalinfection) The sudden release of merozoites toxins and erythrocytes debris iswhat causes the fever and chills associated with Malaria.Of course the disease must be able to transmit itself for survival. This is doneat the erythrocytic stage of the life cycle. Occasionally merozoitesdifferentiate into macrogametocytes and microgametocyt... ...ereas the prevailing wisdom required T cells aswell in order to achieve protective immunity.Sceptics also pounced on the elaborate and painstaking process of eliminationPatarroyo used to find the right peptides. He took 22 "immunologicallyinteresting" proteins from the malaria parrasite, which he identified usingantibodies from people immune to malaria, and injected these antigens intomonkeys and eventually found four that provided some immunity to malaria. Hethen sequenced these four antigens and reconstructed dozens of short fragmentsof them. Again using monkeys (more than a thousand) he tested these peptidesindividually and in combination until he hit on what he considered to be thejackpot vaccine. But the WHO a 31% rate to be in the grey area and so there isstill no decisiveness on its use.In conclusion it is obvious that malaria is proving a difficult disease toestablish an effective and cheap vaccine for in that some tests and inconclusiveand others darn they seem to work do not reach a high enough standard. Buthaving said that I hope that a viable vaccine will present itself in the nearfuture (with a little help from the scientific world of course).