Overview of the Fatal Disease Malaria

Causes of Malaria

Figure 1. Diagrams Illustrating the Temperature Charts of Typical Cases of Teritan (Upper Left), Quartan (Lower), and Estivo-Autumnal (Upper Right) Malaria

Malaria is caused by a protozoan parasite, three of which impact people in the United States: Plasmodium vivax (tertian malaria), Plasmodium malariae (quartan malaria), and Plasmodium falciparum (estivo-autumnal malaria). All three varieties are quite similar, not just in appearance but also in habits and developmental cycles. They differ mostly in the frequency with which spores form within human erythrocytes. Thus, each species of plasmodium has a varied period necessary to complete the asexual cycle and generates a variable quantity of spores at maturity.

Hosts and Mosquitos

Figure 2. Cross Section of Anopheles Female Mosquito Illustrating the Anatomy of the Transmitter of Malaria

The female mosquito transmits malaria because the male mosquito does not feed from blood. These mosquitoes are most active in the late evenings and spend the day sleeping and hiding. Because they cannot fly extremely high, they are frequently seen in fewer numbers in elevated residences.

The mosquitos are adaptable: the mosquito Neocellia stephensi, for example, is by far the most hazardous vector of malaria illness in Bombay. It breeds most commonly in cisterns, fountains, masonry, and other tanks, tubs, barrels, tin pots, and other modest water collections, as well as open water pools. Larvae have been discovered in wells of clean water used on a regular basis, as well as in the deep reservoir of clear water on Malabar Hill. This mosquito can reproduce in both saline and brackish water.

The Incubation Period and its Symptoms

Figure 3. Distribution of the short and long incubation periods of P. vivax malaria cases, 2001-2010

Malaria incubation periods range from five to thirty days, depending on the kind of malaria and the individual's condition. Prodromal symptoms are generally mild and consist of malaise and headache when present. Clinically, the onset is typically sudden and is marked by the development of the regular cyclic paroxysms of malaria.

The paroxysms are divided into three stages:

1. The characteristics of the first, or cold, stage include chilly feelings that evolve to a noticeable rigidity. The patient is chilly and frequently requires many blankets to keep warm. The surface temperature is modest, while rectal temperatures are high. Headaches and backaches are severe, and nausea and vomiting may occur. This stage may continue from twenty to sixty minutes, following which the second or hot stage is introduced.

2. When the chilly sensation fades, the skin becomes dry, heated, and flushed, and the surface temperature rises to 105 or 106 degrees F, or even higher in some cases. Thirst is great, and the first-stage headache and backache may be more severe. In certain situations, the patient may become cognitively confused, delirious, or comatose. The heated stage lasts between one and six hours and is followed by a sweating stage.

3. The temperature begins to drop quickly, followed by heavy sweat. The patient's fever may drop below normal, and after two to three hours, he or she begins to feel better and generally falls asleep for several hours.

Discovery of the Transmission of Malaria

1. Sir Ronald Ross

Figure 4. Portrait of Sir Ronald Ross

Although Ross was a mathematician, poet, and student of tropical medicine, his pivotal discovery in malaria transmission looks to be the most important accomplishment of his life. Ross recognized the significance of malaria after serving in the British military service in India for 14 years. Sir Patrick Manson presented the malarial parasite to Ross in 1894, emphasizing the mosquito's possible involvement in disease transmission. After Ross returned to India in 1895, he began researching mosquito-malaria interactions in Secunderabad. The process that led to success is depicted in the figure below:

Figure 5. Events that Culminated in Sir Ronald Ross' Success

Ross remained focused on malaria transmission for the remainder of his life, specializing in management. He traveled to Africa, Spain, Greece, and the Far East for field research and was an advocate for malaria prevention through mosquito reduction. However, he failed to persuade the government to launch control campaigns. During his career, he worked as a malaria expert for the War Office, and for the Ministry of Pensions. In 1926, he was appointed Director-in-Chief of the Ross Institute for Research in Tropical Medicine at Putney Heath.

2. Dr. Albert Freeman Africanus King

Figure 6. Portrait of Sir Ronald Ross

Dr. King’s theory was substantially developed, and his whole presentation was written early in 1882 and was read before the Philosophical Society of Washington on February 10, 1882, under the title "The Prevention of Malarial Disease Illustrating, Among Other Things, the Conservative Function of Ague."

The summary of Dr. King's paper is the following:

1. The malarial season correlates to the mosquito breeding season.
2. Malaria-infested areas are ideal for mosquito breeding.
3. Malaria and mosquito protection are provided in similar settings.
4. Exposure to night air exposes you to mosquitoes.
5. The impact of the profession: Soldiers, tramps, and fishermen are highly vulnerable to malaria and are especially vulnerable to mosquitoes at night.
6. Turning up the soil or excavating in formerly healthy regions is frequently followed by malaria, but this turning up of the soil allows water to accumulate, and so mosquitoes to proliferate.
7. Malaria and mosquito numbers both rise in late summer and early fall.

His system included all that was done in Italy for many years after Ross's scientific breakthrough and resulted in lowering the percentage of malaria on the Roman Campagna from 74 to 14. Surprisingly, despite the fascination with the subject, it was greeted with such little interest and has since been ignored.