Lecture 12: Malaria

What are the four species of Plasmodium recognized as etiologic agents of malaria?

Plasmodium vivax, P. ovale, P. malariae, and P. falciparum (most serious)

What type of organism causes malaria?

A protozoa

What are the two stages of the malaria life cycle?

Asexual and sexual stages

Which mosquito species is primarily responsible for transmitting malaria?

Anopheles mosquitoes

Describe the initial step in the malaria life cycle.

An infected mosquito bites a human, and the organism enters the blood.

What happens after the malaria organism invades liver cells?

It undergoes several stages of development and asexual divisions.

What is the incubation period for the pre-erythrocyte stage of malaria?

6 days (asymptomatic)

What are common clinical signs of uncomplicated malaria?

Fever, chills, vomiting, and diarrhea

What severe symptoms can occur in young children with malaria?

Prostration, respiratory distress, severe anemia, and occasionally CNS effects (cerebral malaria)

What is the primary method for diagnosing malaria?

Visualization of the organism in red blood cells (rbc's)

What is a newer method for malaria diagnosis?

Immunochromatographic methods

What is the main target of most anti-malarial treatments?

The asexual erythrocyte stage of the organism

What is the significance of artemisinin in malaria treatment?

It acts fast and kills asexual blood stage parasites and gametocytes.

What challenges exist in developing new malaria drugs and vaccines?

Cost, delivery methods, safety concerns, and difficulty in growing the organism in vitro.

What is the focus of malaria control efforts?

Controlling the vector (mosquitoes)

What type of vaccine targets the pre-erythrocyte stage of malaria?

Vaccines being tested to block the parasite at this stage.

What is a potential benefit of a vaccine against the sexual stage of malaria?

It could reduce transmission if deployed widely.

What was a significant historical effort to eradicate malaria?

Initial efforts in the 1960s failed due to resistance against anti-malarial drugs and DDT.

Which populations are especially at risk for malaria?

Young children and pregnant women

What is the estimated number of malaria cases per year?

500 million cases/year with 1-2 million deaths

What are the geographical areas currently most affected by malaria?

Africa, Asia, and Latin America

What is the typical duration of the symptomatic erythrocyte stage of malaria?

48-72 hours