Essay on Malaria: A Comprehensive Guide to Malaria:- 1. Introduction to Malaria 2. Types of Malaria and Human Species of Plasmodium 3. Symptoms and Phases 4. Control 5. Anti-Malaria Campaign in India.
Essay on Malaria: Intro, Types, Symptoms
- Introduction to Malaria
- Types of Malaria and Human Species of Plasmodium
- Symptoms and Phases of Malaria
- Control of Malaria
- Anti-Malaria Campaign
Essay # 1. Introduction to Malaria:
Malaria (= Ague) is a widely known human disease. It is caused by infection with a pathogenic protozoan parasite of blood, the Plasmodium. Four species of Plasmodium,viz., P. vivax, P. falciparum. P. malariae and P. ovale, are so far known to infect human beings, causing different types of malaria. Female Anopheles mosquitoes transmit Plasmodium from person to person, thus serving as carrier or vector hosts.
Malaria is one of the most common diseases of mankind. It is more common in tropical and subtropical countries, especially in Africa and Asia, where millions are infected. It is responsible for the death and reduced resistance in large number of persons every year, the heaviest toll being the children under 4 years of age.
Due to WHO and NMEP (National Malaria Eradication Programme) of India, the malaria was effectively reduced but party owing to socio-economic factors and partly because of unexpected proliferation of DDT- resistant mosquitoes and drug-resistant parasites, the attempts to eradicate the infection have failed and the malaria is again on increase.
About 60 species of Plasmodium are known to cause malaria in reptiles, birds and mammals. According to Jahn, there are 4 species in man, 4 in monkeys, 15 in birds, 13 in reptiles, and one or more in buffalo, antelope, squirrels, bats and frogs.
Malarial parasites are found widely spread from 45°S to 63° N latitudes. Their endemic home is in the tropical zone, but they also occur in many temperate countries. Species infecting the migratory birds are spread all over the world. Some avian malarial parasites are confined to cold regions only. Species infecting reptiles have a localized distribution.
Essay # 2. Types of Malaria and Human Species of Plasmodium:
The following distinct types of human malaria are recognized, based on the period of reoccurrence of fever. They are also caused by four different species of plasmodium:
1. Benign Tertian or Vivax:
It is caused by P. vivax. Fever recurs after every 48 hours. Plasmodium vivax has a wide distribution in tropical and temperate zones. Incubation period is 10 days. Ring shaped trophozoite is half to one third the size of the erythrocyte.
Schizont fills the enlarged erythrocyte and has yellowish brown haemozoin. Enlarged erythrocyte has Schuffner’s dots. In the blood the schizont forms 12 to 24 merozoites, gametes fill the enlarged erythrocytes. It causes benign tertian malaria fever every 48 hours.
2. Malignant Tertian:
It is due to P. falciparum. Fever recurs every second or third day, i.e. after 36 to 48 hours. P. falciparum is very common in tropics. Incubation period is ten days. Ring shaped trophozoite one sixth to one fifth of the erythrocyte often there are two trophozoites in one corpuscle. Schizont is two third to three fourth of erythrocyte which is not enlarged. Haemozoin is black.
Erythrocytes are not enlarged. They may even shrink and become greenish. They have no Schuffner’s dots. In blood the schizent forms eight to thirty six merozoites which are not seen in peripheral circulation. Gametocytes are crecentric occupying one side of the erythrocyte. It causes malignant tertian malaria fever almost continuously or from twenty four to forty eight hours.
It is caused by P. malariae. The fever recurs every fourth day that is after 72 hours. It may last to 40 years or more in untreated persons. P. malariae is found in tropical and temperate zones. Incubation period is twenty seven to thirty seven days. Ring shaped trophozoite is one third to one half the size of the erythrocyte schizont fills the erythrocyte which is not enlarged.
Haemozoin is dark brown. Erythrocyte has no Schuffner’s dots. In blood the schizont forms six to twelve merozoites. Gametocytes are found. They fill the erythrocyte which is not enlarged. It causes quartan malaria fever even 72 hours.
4. Ovale or Mild Tertian:
It is caused by P. ovale. The fever recurs third day or after 48 hours. It is not greatly harmful and is mainly confined to tropical Africa.
5. Relapse Malaria:
Exoerythrocytic cycles continue uninterrupted in P. vivax. P. ovale and P. malariae even after the disease is completely cured. Merozoites of these cycles can anytime attack RBCs and cause a relapse of malaria.
Essay # 3. Symptoms and Phases of Malaria:
Malarial attack is preceded by headache, nausea and muscular pain.
Total period of malarial attack is of 6-10 hours and can be divided into 3 stages:
(a) Cold stage characterized by chilling and shivering.
(b) Hot stage characterized by high fever (106°F), faster respiration and heart beat etc.
(c) Sweating stage and temperature goes down to normal.
After the malarial attack, the patient feels weak, exhausted and anaemic. The malaria may secondarily cause enlargement of spleen and liver.
In a typical malaria infection, mild symptoms appear early, even during incubation period. These include nausea, loss of appetite, constipation, and sometimes insomnia (= sleeplessness). Mouth often feels dry. Tongue may be thickly coated. Headache, muscular pain and aches in joints develop, and there may be mild sensations of chill.
It is the actual (clinical) attack of malaria which initially begins after a few earliest erythrocytic cycles, but is, then, repeated after every cycle. Obviously, paroxysm results due to sufficient accumulation of haemozoin and other toxins in blood.
Duration of paroxysm varies from person to person and includes three stages:
(i) Rigor Stage:
In this, the patient experiences a terrible chill and shivering, rapid pulse and breathing, severe headache, nausea and vomiting.
(ii) Febrile Stage:
Shivering subsides in about an hour or so and the body temperature rises to 104° to 105°F.
(iii) Defervescent Stage:
After a few hours, profuse sweating starts, temperature of body steadily drops and, apart from exhaustion and weakness, the patient feels healthy again.
A gradual recovery from malaria may be due to effective immunity developed by the patient.
Essay # 4. Control of Malaria:
The fight for eradication of malaria is practically worldwide. In India, the prevention and control of malaria is treated as a national problem and the anti-malaria department of the government deals with it. The war waged on the material parasite in fought by attacking it simultaneously on three major fronts.
In other words, all the control measures fall under the following three categories:
1. Elimination or destruction of vector, i.e., anopheles mosquito.
2. Prophylaxis, i.e., prevention of infection.
3. Therapy, i.e., treatment of infection in the patient.
1. Destruction of Mosquito:
This is being done in three ways:
a. Mass killing of adult mosquitoes in residential areas by spraying DDT, or Flit, or by burning sulphur-pyrethrum and Tarcamphor,
b. Constructing proper drainage for dirty water to prevent its stagnation, became mosquitoes lay eggs in water,
c. Destroying eggs and larvae of mosquitoes in such ponds, lakes, etc., cannot be drained off. This is done by periodic cleaning, oil-spraying and introducing insectivorous predators like ducks, fishes (e.g. mosquitofish— Gambusia affinis, trouts, minnows, stickle-backs, etc.) and some insectivorous plants like Utricularia, Drosera, etc.
2. Prophylaxis or Prevention of Infection:
(a) Wire-gauzing of doors, windows etc. to check entry of the mosquitoes.
(b) Use of insect-repellents to prevent mosquito-bite.
(c) Sleeping under mosquito-nets.
(d) Killing of mosquito-larvae by filling small sized ditches etc. with soil; or sprinkling kerosene oil on large sized water body; or introducing larvicidal fishes (e.g., Gamhusia, minnows, trout’s, Sticklebacks), birds (ducks) and plants (e.g., Utricularia) etc.
(e) Killing of adult mosquitoes by spraying insecticides like D.D.T. (Dichlorodiphenyl- trichloroethane), and B.H.C. (Benzene Hexa-Chloride).
Protection of healthy persons in malarious areas from being infected can be done through the use of insect repellents, nets, gloves and by screening the sleeping quarters.
(i) Defence against Mosquito Bites:
The mosquitoes can be prevented from biting by adopting various protective measures. The houses should be built on high grounds having good drainage and away from vegetation and marshy places. In the mosquito-infected areas, the horses should be made mosquito-proof by adequate screening all the doors, windows and ventilators, etc. Light-coloured clothing may also deter some species.
Mosquito nets should be used, especially during night, to keep away the mosquitoes. The cloth of mosquito net must not contain less than 100 holes in one square inch. The exposed parts of the body may be protected by the use of veils, gloves and boots, etc., or by the application of repellents, such as anti-mosquito creams (e.g., Odomos), mustard oil, and dimethyl phthalate or dimethyl carbate, etc. Application of repellents to the skin confuses the mosquito’s sensors and thus prevents it from biting.
(ii) Use of Prophylactic Drugs:
Healthy person’s inhabiting malarious regions should take small regular doses of prevention medicines as a precaution against infection through mosquito bites. A casual prophylactic drug which may kill the sporozoites before they may develop further in the body is unknown at present. However certain anti-malaria drugs, such as Quinine, Paludrine, Daraprim and Chloroquin, if taken in small daily or weekly does may prove satisfactory.
(iii) Reduction of Susceptibility to Infection:
The chances of infection can be greatly minimized by maintaining proper health. It can be achieved by getting proper nourishment, by avoiding exposure to bad conditions and by following regularly in life.
3. Therapy of Treatment of Malaria:
A number of anti-malarial drugs are available e.g., quinine (extracted from the bark of Cinchona tree), chloroquin, paludrine, atabrine, daraprim etc. Most effective drug is daraprim which kills the parasitic stages present in both liver cells and RBCs of blood. Latest anti-malarial drug is mefloquin.
Plasmodium does not produce antibodies or antitoxins in human blood like germs of other infectious diseases, such as cholera and smallpox. Therefore, treatment of malaria by inoculations or vaccinations is out of question. In allopathy, various synthetic drugs such as Quinine, Arabrin, Camoquin, Chloroquin, Mepacrine (Atebrin), Paludrine, Plasmoquine, Resochin, Pamaquine and Pentaquine, etc., are used as suppressants of various stages of the parasites.
None of these present day anti-malaria drugs is perfect in itself, so that they are used only to supplement the action of the traditional malaricidal drug or Quinine, which is a natural alkaloid extracted from the bark of the cinchona tree grown in Java, Peru, Sri Lanka and India.
Quinine was used effectively for as long as 300 years to cure malaria. But, during World War II, Japan got control over the major quinine-producing areas in the East Indies. Scarcity of quinine led to the production of various synthetic drugs.
The schizonts of the erythrocytic phase are mainly responsible for all clinical symptoms of malaria. Therefore, malaria can be most effectively treated by means of a schizonticide or schizont-killer. The schizonts are rapidly killed by Quinine but the gametocytes are resistant and persist even after recovery from fever, so that the patient still remains infective to mosquitoes.
The pre-and exo-erythrocytic stages of the parasite remain immune to the resistance of the host or to the therapeutic action of any anti-material drug. Little or no damage occurs to the host’s tissues during these phase and haemozoin pigments are absent. Moreover, in case of P. vivax and P. malariae, the parasite may continue to live for years without causing clinical symptoms, in the liver cells serving a reservoir.
From this reservoir, the parasite may re-infect the blood and cause a malaria relapse, whenever the immunity of the resistance of the host has fallen down. Such relapses may occur repeatedly for at least two years in case of P. vivax, and for several years in case of P. malariae.
Essay # 5. Anti-Malaria Campaign in India:
About two decades ago, malaria was the most widespread disease in India. In 1952, the disease afflicted some seventy five million Indians every year, killing nearly eighty thousands. In 1952, the Ministry of Health of the Government of India launched a nationwide malaria eradication campaign, with the assistance of the World Health Organization (WHO).
Regular spraying of malaria infested areas with DDT and other insecticides and mass distribution of chlroroquin, an anti-malaria drug, almost eradicated malaria and brought it under control. In 1964, only one lakh persons suffered from malaria, none of whom died. But in recent years, malaria has come back with a vengeance, not only in India but in many other developing countries.
In 1975 alone twenty nine million people suffered from malaria, and 45 of them died in India. There have been several reasons responsible for the resurgence of malaria. The Indo-Pakistan War of 1965, which disrupted the procurement and distribution of insecticides, caused the initial setback to the anti-malaria campaign. Besides, the mosquitoes have learnt to avoid DDT-sprayed walls.
In one village of Assam, the malaria parasite (Plasmodium) has shown resistance to traditional anti-malaria drugs, like chloroquin. According to a WHO prediction, there shall be twelve million malaria cases in India by 1980, four lakh of them fatal. Then, there is the problem of environmental pollution due to excessive use of insecticides.
Hence chemical control of mosquitoes is becoming increasingly difficult. Other methods of fighting malaria are now being studied. The Vector Control Research Centre (VCRC) in Pondicherry, one of the research units under the Indian Council of Medical Research (ICMR) has discovered a species of water bug (fam. Notonectidae) which feeds on the eggs and larvae of mosquitoes.
Scientists have also identified a fungus in the paddy fields that kills the mosquito larvae. Four species of fish have been found as the largest consumers of mosquito larvae. Two of them are “guppy” and “gambusia”. Experiments are being conducted for genetic control of mosquitoes in consultation with Prof. Hannes Laven of West Germany, who found that certain strains of mosquitoes when crossed cannot breed.
In addition to biological and genetic control of mosquitoes, and water-management to flush out mosquito larvae from their breeding grounds, the ICMR is also trying, “the immunological approach”.
It means using methods which will make the body immune to the malaria parasites. The National Institute of Communicable Diseases (NICD) in Delhi, and the Post-graduate Institute of Medical Education and Research in Chandigarh are busy in developing vaccines to immunize people against Malaria.