Female Anopheles carrying infected blood.
Picture: http://science.nationalgeographic.com/science/photos/malaria/#/anopheles-mosquito_816_600x450.jpg
Malaria Enters the Human Body
Once an infected mosquito, carrying Plasmodium, bites a human, the parasites enter the human bloodstream through the mosquito’s saliva. This begins the exoerythrocytic cycle of the infection. The parasites (specifically called sporozoites) travel to the human liver and within a short duration, are able to asexually reproduce, multiply, and produce merozoites. This can occur from 5-16 days. The merozoites are then able to exit the liver and enter the bloodstream again. This begins the erthrocytic phase of the infection.
The merozoites rupture their host cells and then attack the red blood cells. in 1-3 days, the merozoites can multiply further in their new environment. The parasite has access to infect more and more red blood cells. This is usually when the onset of symptoms occur. The immune system is unable to impede the malaria parasites because the parasites safety reside within liver and red blood cells (both of which the immune system do not attack).
Source: http://www.niaid.nih.gov/topics/malaria/pages/lifecycle.aspx
Picture: http://science.nationalgeographic.com/science/photos/malaria/#/malaria-parasites_1059_600x450.jpg:
“The Life Cycle of Malaria Parasite in the Mosquito”
Source: http://www.youtube.com/watch?v=RqRuSwZey_U
Climates of Africa that Effect Malaria Transmission
Rainfall spurs the growth of Anopheles mosquitoes and the maturation phase of larvae to adult can take as little as 9-12 days in a tropical climate.
When the mosquito is an adult, it relies on temperatures that has sufficient humidity, warmth and precipitation for survival. The mosquito thrives on subtropical and tropical climates with lower altitude. For the mosquito to successfully be able to infect a human, it needs to stay alive for 9-21 days after a consuming a blood meal with an infected human in order for the Plasmodium parasite to complete the infection process within the mosquito.
The mosquito primarily infects humans at dusk and dawn, but mostly during the night (which is why mosquito nets are such an important prevention method).
Source: http://www.cdc.gov/malaria/about/biology/ecology.html
Picture: http://science.nationalgeographic.com/science/photos/malaria/#/wooden-huts_1299_600x450.jpg
Symptoms of Malaria
Symptoms can range from very mild to extremely severe.
Different variations of the parasite produce varying severity of symptoms. The four variations are:
- Plasmodium falciparum (most severe)
- Plasmodium vivax
- Plasmodium ovale
- Plasmodium malariae
The incubation phase of the infection is usually around 7-30 days. Symptoms are produced during the erthrocytic cycle, when the parasites have begun infecting red blood cells. The initial symptoms are fever, vomiting, chills, and headache. Because of the genericness of these symptoms, the malaria infection may not be distinguishable. Malaria should be treated within the first 24 hours of the onset of symptoms. If not treater right away, it can result in death of the infected victim.
In adults, malaria can infect a multitude of organs in the body. If treated successfully, subsequent infections can occur.
Picture: http://en.wikipedia.org/wiki/Malaria
Malaria occurs after parasites are able to infect a female Anopheles mosquito and then subsequently a human host. These parasites are known as Plasmodium parasites, and there are four known Plasmodium species. In order for an infection to occur, there needs to be a human and a vector (mosquito).
The process of transmission from the mosquito to the human is known as anterior station transfer. A female Anopheles first bites into an infected human host for their blood meal. The Plasmodium parasite, specifically in the gametocyte phase, will infect the mosquito after multiplying in the mosquito’s gut and traveling to the salivary glands. Once in the saliva, the mosquito can transmit malaria to a human.
Sources: http://www.cdc.gov/malaria/about/biology/
Picture: http://www.emro.who.int/rbm/aboutmalaria-quickoverview.htm
