Malaria
Malaria of a person is a disease or illness that is caused by the parasites of Plasmodium genus in blood or tissues.
Malaria is a generic term routinely used to refer to protozoa of the Plasmodium family usually in the combined form malaria parasites. Malaria transmission is a phrase using this broad definition malaria parasites are transmitted but malaria disease is not. Infection by the parasites of any stage in any area of the human body means infection of malarial, which may or may not be caused by disease. Malaria is a public health issue that impacts a population and encompasses the collective effects of the disease in the entire population.
Plasmodium malaria is a major killer in the tropics. Immunity to infection is slowly acquired despite repeated exposure to the parasite in malaria endemic parts of the world. Protection can be provided by immunity to various stages in the life cycle of the parasite. We will then discuss recent advances in the dissection of protective versus pathogenic immune mechanisms with particular emphasis on newly elucidated immune escape mechanisms and subsequently summarize some recent advances in the development of malaria vaccines. Among the approximately 400 Anopheles species worldwide around 60 species are malaria vectors in field studies 30 of which are of primary importance.
Infection parasites are eukaryotic unicellular organisms of the genus Plasmodium. Over 100 species of Plasmodium infect many animal species like reptiles birds and other mammals. Still under natural conditions only four species of parasite infect humans Plasmodium falciparum Plasmodium vivax Plasmodium ovale and Plasmodium malariae. They are morphologically and immunologically different from each other in their geographical range in their relapse pattern and in drug susceptibility. P. falciparum is responsible for severe potentially fatal malaria and is the leading cause of death due to malaria in African children. The most uncommon of the parasites of malaria is P. which exists only in West Africa, and P.
Malaria is found all over the world but also with comparitively low incidence. P. vivax is the geographically most prevalent malaria parasite but is never lethal to the infected. Whereas both P. falciparum and P. vivax can cause excessive blood loss, mild anemia is the rule in P. vivax infection but severe anemia in malaria caused by P. falciparum is a major killer in Africa. In addition, in the case of P. falciparum, the infected erythrocytes are able to block small blood vessels and if this occurs in the brain, cerebral malaria results, a complication that is typically fatal, particularly in African infants.
P. ovale and P. vivax both have latent liver stages known as hypnozoites that can linger in this organ for weeks to many years prior to a new cycle of pre erythrocytic schizogony, resulting in recurrences of malaria infection. Long-term blood stage infections are also caused by P. malariae under specific conditions, which, if left untreated, will persist asymptomatically in the human host for periods of time extending into several decades.
Strategies of Control
Malaria control is so multifaceted that it cannot be tackled with one strategy, and any effort to do the same is risky. It is necessary to adapt the strategy to the current ecological and epidemiological situation. For example, definitions of the four dominant patterns of epidemiology are founded upon indicators which are measurable in the community. Of importance, the population’s immune status and the pattern of malaria to be encountered will vary in these four scenarios as well as influencing the control strategy. Thus, these will be determined by the current transmission patterns and will be directed to the following: mortality control transmission control and eradication.
Mortality control
The most prominent effect of malaria in any population is that of the death of human beings. To ensure that an individual does not die from the disease, there has to be proper treatment. Control of mortality strategy entails detection of presumptive cases, identifying parasite-positive cases, and giving effective treatment. This type of strategy has minimal influence on malaria morbidity and has little or no influence on overall disease transmission. In holoendemic areas of infection, it contributes a significant population burden to morbidity.
Control of mortality is the central focus of the present Global Malaria Control Strategy. Because it is based on chemotherapy, no special program is needed nor do there need to be countrywide strategies and formation of local priorities. Some method of record keeping and some means of getting the drugs of choice into the peripheral clinics are the only things needed. Training is limited and may also include local commercial stores for antimalaria medication.
It is a useful stopgap method to deal with epidemics of malaria when emergencies are evoked. During crisis situations like extreme flooding or epidemic outbreaks it is the preferred strategy because the equipment can be mobilized easily and rapidly. The key issue is that chemotherapy by itself is not a method of managing malaria and is not viable in the long run. There are good evidence to suggest that medicines taken from unskilled hands are often unsuitable and ineffective and can encourage drug resistance among parasites.
Control of transmission
Malaria is viewed as a key contributor to morbidity and mortality by the malaria transmission control strategy. It is a highly debilitating disease which has a very high cost to the communities. The children are anemic and unable to focus at school, and society in general is compromised. While appropriate treatment is one aspect of the transmission control plan, vector control is also an important played and have correctly used all these components together with some impact on both the morbidity and mortality of malaria.
It works against the majority of epidemiological scenarios and is a fine control plan for a sustained attack on the malaria problem. It is adaptable to the use of insecticide treated bed nets and indoor sprays with insecticide. It can be used in specific circumstances where malaria is a local priority or on a large scale as part of a large-scale intervention program. Control of transmission requires coordination and the development of strategic plans for intervening against malaria.
Treatment of malaria
Diagnosis of malaria
Malaria is an ancient disease and has been a major source of human suffering for over three thousand years. In the period 1500 to 800 BC it was described the autumn fevers as King of Diseases and enlargement of spleen incriminating that during that period malaria existed in India. Malaria antigen was identified from the skin and lung tissue of Egyptian mummies in 3200 and 1340 BC. The Chinese medical treatise Nei Ching explains tertian and quartan fevers and other manifestations of malaria.
Severe and complicated malaria
Complicated malaria are almost always caused by infection with P falciparum. The other species cause only fever disease. Severe and complicated malaria are clinical emergencies since mortality is high.
Intravenous use of antimalarial drugs is recommended therapy for severe malaria. Parenteral artesunate was superior to quinine for treatment of severe malaria in both children and adults. In a second systematic review artemether and arteether the artemisinin derivatives, were equivalent to quinine for cerebral malaria in children. Supportive therapy is utilized in the management of severe malaria and should be done in a critical care unit. It entails control of high temperature and the accompanying seizures. It also entails observation of poor effort to breathe low blood sugar and low blood potassium.
Artemisinin derivatives also have the same or better efficacy as quinolones in avoiding death in complicated or advanced malaria. Quinine loading dose shortens the duration taken by fever and improves clearance of parasites from the body. No efficacy difference is present when intrarectal quinine is compared with intravenous or intramuscular quinine for uncomplicated/complicated falciparum malaria. There is no evidence for intramuscular arteether in the treatment of severe malaria. Rectal artesunate pre-treatment before hospital transfer may reduce child mortality from severe malaria. In children with malaria and concomitant hypoglycaemia, sublingual glucose seems to produce better increases in blood glucose after 20 minutes than oral intake on the basis of very limited evidence.