Current Status Of Malaria Vaccinology Essay -- essays research papers

Current Status of Malaria Vaccinology In order to assess the current status of malaria vaccinology one must first take an overview of the whole of the whole disease. One must understand the disease and its enormity on a global basis. Malaria is a protozoan disease of which over 150 million cases are reported per annum. In tropical Africa alone more than 1 million children under the age of fourteen die each year from Malaria. From these figures it is easy to see that eradication 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 effect humans, but can also infect a variety of hosts ranging from reptiles to monkeys. It is therefore necessary to look at all the aspects in order to assess the possibility of a vaccine. The disease has a long and complex life cycle which creates problems for immunologists. The vector for Malaria is the Anophels Mosquito in which the life cycle of Malaria both begins and ends. The parasitic protozoan enters the bloodstream via the bite of an infected female mosquito. During her feeding she transmits a small amount of anticoagulant and haploid sporozoites along with saliva. The sporozoites head directly for the hepatic cells of the liver where they multiply by asexual fission to produce merozoites. These merozoites can now travel one of two paths. They can go to infect more hepatic liver cells or they can attach to and penetrate erytherocytes. When inside the erythrocytes the plasmodium enlarges into uninucleated cells called trophozites The nucleus of this newly formed cell then divides asexually to produce a schizont, which has 6-24 nuclei. Now the multinucleated schizont then divides to produce mononucleated merozoites . Eventually the erythrocytes reaches lysis and as result the merozoites enter the bloodstream and infect more erythrocytes. This cycle repeats itself every 48-72 hours (depending on the species of plasmodium involved in the original infection) The sudden release of merozoites toxins and erythrocytes debris is what causes the fever and chills associated with Malaria. Of course the disease must be able to transmit itself for survival. This is done at the erythrocytic stage of the life cycle. Occasionally merozoites differentiate into macrogametocytes and microgametocyt... ...ereas the prevailing wisdom required T cells as well in order to achieve protective immunity. Sceptics also pounced on the elaborate and painstaking process of elimination Patarroyo used to find the right peptides. He took 22 "immunologically interesting" proteins from the malaria parrasite, which he identified using antibodies from people immune to malaria, and injected these antigens into monkeys and eventually found four that provided some immunity to malaria. He then sequenced these four antigens and reconstructed dozens of short fragments of them. Again using monkeys (more than a thousand) he tested these peptides individually and in combination until he hit on what he considered to be the jackpot vaccine. But the WHO a 31% rate to be in the grey area and so there is still no decision on its use. In conclusion it is obvious that malaria is proving a difficult disease to establish an effective and cheap vaccine for in that some tests and inconclusive and others while they seem to work do not reach a high enough standard. But having said that I hope that a viable vaccine will present itself in the near future (with a little help from the scientific world of course).