Malaria

Definition: Malaria is mainly caused due to four distinct species of malarial parasite:

  1. Plasmodium vivax
  2. Plasmodium falciparum
  3. Plasmodium malariae
  4. Plasmodium ovale

Epidemiology

Malaria epidemiology is a complex product of variable patterns of transmission of disease that rely primarily on an intricate relationship between host, agent, and environment. The degree of malaria endemicity in a region essentially determines the strength of the relationship between the variables.

Around 300-500 million malaria cases are estimated to occur worldwide every year. The transmission of malaria is deeply influenced by deforestation, migration, and changes in agricultural practices. In several nations, urban malaria is becoming a growing epidemic. There have been epidemics in North India, Srilanka, South-East Asia, Madagascar, and Brazil.

Plasmodium vivax has the world’s largest geographic distribution and causes a tone of debilitating diseases. Around 60 percent of infections are attributed to P. vivax in India. Often common, Plasmodium falciparum results in the most serious infections and is responsible for almost all malarial-related deaths. Forty percent of all infections are caused by P. falciparum. Plasmodium malaria has small distribution and is said to account for less than 1% of India’s infections.

A very rare human parasite, often restricted to tropical Africa, is Plasmodium ovale. The patient may become infected with one, two, or even more malarial parasite species in highly endemic areas. In India, 4-8% is caused by mixed infections. The incidence of malaria varies from village to village, city to city, and even within a town. It is possible to split the malaria problem into agricultural, urban, and tribal malaria. Rural malaria accounts for 47.4%, 42% for the Tribal Belt, and 10.6% for urban malaria.

(a) Urban Malaria: The major vector is Anopheles stephensi in India but due to the expansion of urban areas in the peripheral zones, other vectors can also play a significant role in transmission. Other vector species may include A. culicifacies in the urban locality. It is aggravated by rapid urbanization, construction of buildings, and movement of labor and water storage facility.

(b) Rural malaria: Generally, Anopheles culicifacies are mainly involved in transmission in India. The seasonal transmission area is generally open terrain, agricultural plains of the country with sparse natural vegetation.

(c) Tribal malaria: The general vector involved in the transmission is P. falciparum. In India, about 50 percent of cases are contributed from various states such as; Andhra Pradesh, Madhya Pradesh, Chhattisgarh, Maharashtra, Rajasthan, Orissa, Gujarat, Bihar, and North-Eastern states having about 44 million populations. The mobile population involved in forest-related activity is at high risk.

Agents/Factors

  • Malaria is caused by four distinct species of plasmodium. These are P. Vivax, P. falciparum, P. malariae and P. ovale.
  • In India, 70% of cases occur due to Plasmodium vivax.
  • The female mosquito anopheles bite an infected individual and gametocytes are ingested within the mosquito body, there is a sexual cycle that leads to the development of the parasite in 10-20 days (extrinsic incubation period) under favorable conditions from gametocyte to sporozoite level. When this infected mosquito bites a human, the sporozoites are injected. Sporozoites undergo an asexual cycle of four stages.
  • Man is the reservoir of an agent of malaria. The person is a reservoir of infection if he has both the sexes of gametocyte Le., micro and macrogametocyte in blood and is mature to undergo development in the mosquito.
  • The communicability of malaria depends upon the maturation, viability of gametocytes, which should be insufficient density to infect the mosquito.

Host Factors

  • Malaria affects all ages and both sexes, but due to more outdoor activities, males are at higher risk for acquiring malaria.
  • Pregnant women are at risk and can have premature labor or abortion or intrauterine death due to infection of malaria in pregnancy.
  • Immunity in humans is acquired after several years from repeated exposure.

Environmental Factors

Rainfall, temperature (The optimal temperature in the insect vector required for the development of parasites is 20 to 30°C), the humidity of 60% is required for the life span of mosquitoes, irrigation channels, garden pools, stagnant water.

Incubation Period

It depends on the type of species.

  • Plasmodium vivax: 8-17 days.
  • Plasmodium falciparum: 9-14 days.
  • Plasmodium malariae: 18-40 days.
  • Plasmodium ovale: 16-18 days.

Mode of Transmission

  • Vector transmission (Anopheles mosquito) infected person to healthy.
  • Direct transmission (Blood transfusion needle injury).
  • Congenital (Mother to new born).
Malaria Transmission cycle

Symptoms of Malaria

  • Fever (39°C-41°C) with chills and rigors
  • Headache
  • Vomiting
  • Tachycardia
  • Sweating Nausea
  • An attack of malaria has three stages: Cold stage, hot stage and sweating stage.
Symptoms of Malaria

Laboratory Diagnosis

A blood smear is checked for the malarial parasite. Two types of blood films are prepared, Le. thin film and thick film.

Prevention and Control of Malaria

To reduce morbidity and mortality, malaria prevention and control are required. Health guides and multi-purpose staff need to be professionally qualified to recognize and manage malaria cases and if possible, refer to hospitals.

(1) Diagnosis and Treatment: As laboratory diagnosis is not immediately possible, cases should be identified based on clinical manifestations. Later on, the laboratory diagnosis confirms the diagnosis. Presumptive care is offered for the care of suspected and clinical cases of malaria according to the drug policy for malaria under the National Anti-malaria Program and radical treatment is given in the table below (Table 1 and 2):

Table 1: Presumptive and Radical Treatment in Adults

Presumptive and Radical Treatment in Adults

Note: The dosage of chloroquine phosphate is 10 mg/kg of body weight, except 5 mg/kg of body weight on the 3rd day of presumptive treatment in high-risk areas.

Table 2: AgeWise Treatment of Malaria in Low-Risk Areas.

AgeWise Treatment of Malaria in Low-Risk Areas.

If the case of malaria has been complicated and the patient’s condition is serious, then Preventive Medicins the case needs to be hospitalized, then 5% Dextrose saline is given to quinine by I.V. drip. The added dosage of quinine is 10 mg/kg of body weight. It should be initiated orally as soon as the patient can take it orally. The needed therapy is for 7 days. 

(2) Chemoprophylaxis: Chemoprophylaxis develops drug resistance, so it is not reliable, but still some experts feel that it is useful. As a prophylaxis treatment, Tab chloroquine 300 mg B.D twice a week is given.

(3) Mass Drug Administration: Mass drug administration is recommended in a highly endemic area.

(4) Mosquito Control Measures: All the measures given in prevention and control of arthropod-borne diseases are recommended such as:

  • Anti Larval Measures: Anti larval measures include the use of larvicides on the standing water.
  • Anti-Adult-Measures: Residual spraying of D.D.T, Malathion, Fenitrothion is an effective measure to kill the adult mosquitoes and Application of pesticides in the form of fog or mist.

(5) Protection against Mosquito: Man should protect himself against mosquitoes by use of mosquito repellants, protective clothing, nets, and coils, etc.

(6) Reduction in Mosquito Breeding Sites: The method by which, the mosquito sites are reduced, can be adopted to prevent morbidity due to malaria. These methods include; proper drainage system, management of water level, cleaning of water coolers, keeping the area clean in and around the house, and free from stagnant water.

(7) Health Education: Health education is one of the important measures by which the community can be educated regarding the preventive methods to be used against malaria, with the use of mass media, group education, or individual education methods.

(8) Integrated Approach: An integrated approach including bioenvironmental and personal protection measures should be used to achieve a reduction in malarial health problems.

(9) Role of National Anti-Malaria Programme: The National Anti-Malaria Programme also plays a major role in malaria control and prevention. To achieve the defined targets, the strategies are planned and approved.

  • Metabolic Diseases are a cluster of conditions that occur together, increasing the risk of heart disease, stroke, and type-II Diabetes mellitus. These conditions include; increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol and triglycerides level.
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