What is Malaria

WHAT IS MALARIA?

What is Malaria and what are its Symptoms (Part B)

Malaria is a mosquito borne disease caused by a parasite called Plasmodium. Human malaria is carried out by a species of mosquito of the Anopheles genus (often referred as "malaria vector"). They are the female mosquitoes that bite from dusk to dawn and the only that transmit malaria.

Malaria parasite gets inside a human body once he/she has been bitten by an infected mosquito, if the mosquito have been infected through a previous blood meal taken (If its host was infected) This is where the life cycle of Plasmodium Falciparum begins.

The Plasmodium takes three life cycles in a human body;

Ø  The Gametocytes

Ø  The Sporozoites, and

Ø Merozoites

Gametocytes is where the mosquito get infected, inside the mosquito gut the haploids gamets busts to form a diploid zygot, which undergoes a process of multiple division called Sporogony in which many Sporozoites are produced. After a period of time following the infection, common symptoms of malaria will occur. Such symptoms include;

Ø  Profuse sweating

Ø Headache

Ø  Nausea

Ø Vomiting

Ø Diarrhea

Ø  Anemia

Ø  Muscle Pain

Ø  Convulsion

Ø  Coma or Blood Stool

The Plasmodium parasite that causes malaria is a single-celled parasite that multiplies in red blood cells of humans as well as in the mosquito intestine.

There are over 100 species of plasmodium, but only five species are known to infect humans which include;

Ø Plasmodium falciparum

Ø Plasmodium ovale

Ø Plasmodium vivax

Ø Plasmodium malariae

Ø Plasmodium knowlesi

The disease is preventable, treatable and curable. If left untreated, those with malaria may develop severe complications which disrupts blood supply to the vital organs of the body and sometimes leads to death.

Although presently there is no vaccination against malaria parasite, timely treatment of the disease is usually very successful. Early detection of malaria symptoms and getting treatment as early as possible always saves life.   

Mainly in countries that have been stricken by malaria like Kenya, Plasmodium falciparum and Plasmodium vivax are the most common parasites. Plasmodium falciparum being the most deadliest and most common malarial parasite.

Factors that contribute to Malaria Transmission (Part C)

In Sub Saharan Africa, species of mosquitoes of the anopheles genus Anopheles Gambiae and Anopheles Funestus mosquito species are the main primary vectors of Plasmodium falciparum malaria.

The largest number of malaria transmission in Kenya and other part of Africa where the disease is prevalent, the patterns of vector changes significantly due to several aspects, and this is sometimes influenced by compositions of vectors, Mosquitoes competence, latent statistical data and ecofactors.

Normally high intensity of malaria transmission occur where both Anopheles gambiae sensu lato and Anopheles funestus are present, as they tend to exploit different breeding habitats and peak at different times, thereby prolonging the transmission period. Mainly during the wet season Anopheles gambiae are the most abundant, while Anopheles funestus are predominant at the end of the rains and beginning of the dry season.  

The environment also plays a bigger role in determining the intensity of transmission. In many parts of the world, transmission of malaria is seasonal - highest during and just after the rainy season, mainly when rainfall is heavy, temperatures are high, and the air is humid.

Another factor that plays a major role is the altitude, limiting malaria in the tropical highlands by negatively influencing the development of vector species. In the Kenyan highlands, research shows high densities of An. gambiae mosquitoes in a town 1,650 m above sea level and still more at altitudes higher than 2,000 m.

Other factors contributing to the spread of malaria are the natural and human associated activities that create fertile vector’s breeding grounds. The main key determinants of malaria transmission factors includes;

Ø  Swampy areas, rivers and lakes which provides suitable breeding grounds for mosquitoes

Ø  Agriculture in both urbanized, and rural areas. Normally this is when watering the plants and during wet seasons, the soil tends to collect stagnant water that provides an optimal condition for mosquito’s to breed.

Other potential vector breeding sites are;

Ø Streams, Dams and Ponds   

Ø Tree holes and Seepages

Ø Drains/gutters, springs and Ditches  

Ø Domestic plastic containers due to improper waste disposal and Water tanks/reservoirs

Ø Construction sites and Swimming pools

Ø Canal, Foundations and unsecured water tanks

Ø Car Tyres, Pipes and Bathtubs

 

There are several other factors that influence the intensity of malaria in Kenya, although stagnant water provides excellent aquatic conditions for mosquitoes to breed.  

Plasmodium parasite which is more endemic in the tropical areas, is transmitted through a bite of an Anopheles mosquito, her saliva often causes an irritating rash that is a serious nuisance. The vector breeds in water, but then all different species of anopheles have their own different, unique and specific preferences that will allow them to breed more rapidly and efficiently. For instance, some prefer shallow collections of water such as water collected on domestic plastic containers, swimming pools, water tanks, Seasonal swamps, ponds with shallow depth, or agricultural fields.

Globally 300 to 500 million cases of malaria are recorded yearly, with more than 440,000 deaths from Anopheles mosquito. The transmission of malaria is more intense during and just after the rainy season, when rainfall is heavy, temperatures are high, and the air is humid, the mosquito lifespan is longer, and also the parasite has time to become completely developed in the mosquito. Although in some parts of the world malaria transmission is only seasonal.

Immunity on human to malaria increases with age, for adults in populations that are at high risk for malaria infection, many of them earn partial immunity after being exposed to the parasite for years, which does not offer complete protection from the disease but does provide some immunity. This is the reason why malaria mainly affects small children in endemic regions. Although in low-risk regions where little to now immunity is formed, everyone is at an equal risk.