What is a malarial parasite?
| The malarial parasite lives as a parasite in
mosquitos. |
The malarial parasite, Plasmodium, is a very small, single-cell
blood organism, or 'protozoan'.
It lives as a parasite in other organisms, namely man monkeys
and mosquitoes. The parasite is the cause of the tropical disease
malaria.
The Plasmodium parasite is dependent on a single species of
mosquito, Anopheles, which is the only species capable of serving as host for
it.
What are the different stages of the parasite's life cycle?
This small single-cell organism has three to four different forms. Each form is specialised in living in a certain place.
The gametocyte is the form that infects the mosquito and reproduces itself, as if it were both sexes. When the mosquito has sucked blood containing gametocytes, these pass into the salivary glands of the mosquito, where they develop into a new form, the sporozoite. The infection can then move on.
The sporozoite can be passed on to man when the mosquito bites, injecting its saliva into the tiny blood vessels. The sporozoite travels with the blood to the liver and enters the liver cells. In the liver some of the sporozoites divide (tachysporozoites) and become thousands of merozoites.
The merozoites are released from the liver to the blood where they are taken up by the red blood corpuscles. Some of these turn into ring-formed trophozoites that split again to form schizonts.
Schizonts burst the red blood corpuscles at a certain moment, releasing the merozoites. This release coincides with the violent rises in temperature during the attacks seen in many cases of malaria.
The trophozoites that are left over during division can, in the course of the next day, develop into the sexual form, the gametocyte, which can be taken up by a blood-sucking mosquito and start another cycle.
The incubation period (time from infection to development of the disease) is usually from 7 to 30 days (shorter periods with the deadliest form of flaciparum).
Plasmodium ovale and Plasmodium vivax can produce a dormant form, a hypnozoite, that can cause relapses of the disease months and even years after the original disease (relapsing malaria) because it's dormant in the liver cells.
This is why it's important after these infections to be treated with primaquine to kill the liver stages. (Primaquine cannot be used by people with a condition called G6PD-deficiency.)
According to news making the rounds from the office of The Director
General, National Space Research and Development Agency NARSDA, Dr.
Seidu Mohammed said that Nigerian will witness a partial or total solar
eclipse on Sunday, November 3.
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