WEEK 4: MALARIA Flashcards
Malaria is a parasitic disease caused by Plasmodium parasites.
Name the vector for plasmodium parasites.
Female anopheles mosquito
Malaria is caused by several species of the Plasmodium parasite.
State the 5 species of plasmodium.
Which one is most deadly?
. The most common species that infect humans include:
*Plasmodium falciparum,
*Plasmodium vivax
*Plasmodium ovale
*Plasmodium malariae
*Plasmodium knowlesi
Plasmodium falciparum is the most deadly.
How is malaria transmitted?
Malaria is primarily transmitted through the bite of female Anopheles mosquitoes. When an infected mosquito bites a person, it injects the malaria parasite into the person’s bloodstream.
Use of shared and infected syringes.
Organ transplantation.
Transfusion.
From an infected mother to her baby during birth.
Why is the female anopheles’ mosquito the one able to transmit malaria?
Only female mosquitoes of this genus feed on blood, and the parasite that causes malaria spends part of its life cycle in the blood.
State symptoms of malaria.
Malaria symptoms typically include fever, chills, sweating, and flu-like symptoms.
Severe forms of the disease can lead to complications such as severe anemia, organ failure, and, in the case of Plasmodium falciparum, cerebral malaria.
Describe the geographic distribution of malaria.
Malaria is prevalent in many parts of Africa, Asia, and South America. The risk of malaria transmission varies with climate, local vector mosquito species, and other factors.
Outline prevention methods of malaria.
Malaria can be prevented through several strategies, including the use of insecticide-treated bed nets, indoor residual spraying, and chemoprophylaxis (taking antimalarial medications when in endemic areas). Vaccines such as the RTS,S/AS01 (Mosquirix) have been developed to offer partial protection against Plasmodium falciparum.
The Plasmodium parasite has a complex life cycle that involves both the mosquito vector and the human host.
Describe the life cycle of plasmodium in the Human body.
- Gametocyte Stage:
When a female Anopheles mosquito feeds on an infected human, it ingests the merozoites, which enter the mosquito’s midgut.
In the midgut, some merozoites develop into male and female gametocytes (sexual forms of the parasite).
These gametocytes are taken up by the mosquito along with a blood meal.
- Mosquito Midgut:
In the mosquito’s midgut, male and female gametocytes mature into gametes (microgametes and macrogametes, respectively).
- Fertilization (Syngamy):
The male and female gametes fuse, resulting in a zygote.
The zygote undergoes meiosis, giving rise to sporozoites.
- Sporozoite Stage (Salivary Glands):
The sporozoites migrate to the mosquito’s salivary glands, ready for transmission to a new human host.
Describe the life cycle of plasmodium in the Human body.
- Sporozoite Stage (Liver Phase):
*Sporozoites travel to the liver and enter hepatocytes (liver cells).
*Inside hepatocytes, sporozoites multiply asexually to form thousands of merozoites.
*This liver phase is asymptomatic and typically lasts about 5-16 days, depending on the Plasmodium species.
- Merozoite Stage (Blood Phase):
*Merozoites are released from hepatocytes and enter the bloodstream.
*Merozoites invade red blood cells (erythrocytes).
Inside red blood cells, the merozoites develop into trophozoites, which feed on hemoglobin and multiply by schizogony.
*Eventually, the red blood cell bursts, releasing more merozoites into the bloodstream and causing the characteristic periodic fever and chills associated with malaria.
Name the toxin release during the rupture of red blood cells in malaria that causes chills.
The rupture of red blood cells by the malaria parasite releases a toxin called hemozoin which causes the patient to experience a condition known as the chills.
