12. Malaria

Question 1

agent

Answer 1

Malaria Parasites

P. falciparum: Causes most severe disease and responsible for most deaths; shorter incubation period.

P. vivax: Most prevalent malaria parasite

Question 2

At Risk Populations

Answer 2

Young children who have not yet developed immunity

Pregnant women whose immunity is lowered due to pregnancy

Travelers or migrants coming from areas with low or no malaria transmission and lack immunity

Question 3

Severe Malaria

Answer 3

Caused by P. falciparum; occurs when infections include one or more of a number of severe complications:

Severe malaria is a medical emergency requiring urgent treatment

Question 4

clinical feature (incubation, symptom)

Answer 4

7-30 days (part of life cycle in vector, part in human)

Can result in a wide range of symptoms from asymptomatic or mild symptoms to severe disease and death

Question 5

Vector

Answer 5

only the genus Anopheles

Great variation exists among different species

• Feed indoors or outdoors (or both)
• Rest (after feeding) indoor or outdoors
• Preferred source for blood meal
• Preferred breeding environment
• Insecticide resistance

Question 6

diagnosis

Answer 6

In endemic areas: based on symptoms and travel history

Definitive diagnosis requires demonstration of malaria parasites in red blood cells.

“Gold standard” technique is microscopic examination, but is skill-intensive.

Malaria Rapid Diagnostic Tests (RDT) is an alternative. fast and not skill-demanding.

Question 7

Treatment

Answer 7

very complicated!

combination of drugs, ASAP.

Determination of best treatment is based upon

• Plasmodium species
• Geographic area and associated drug resistance
• Clinical status of the patient
• Comorbidity
• Pregnancy status

Question 8

Sickle cell trait

Answer 8

potential protection.

Question 9

Acquired immunity

Answer 9

After repeated attacks of malaria, a person may develop a partial protective immunity

“Semi-immune” individuals can still be infected by malaria parasites, but may not develop severe disease, or may not experience symptoms at all

Question 10

Malaria Control

Answer 10

Insecticide Treated Bed Nets (protect community)

Intermittent Preventive Treatment (aim at high-risk pop)

Indoor Residual Spraying (does not prevent being bitten, but transmission to another person)

Larval Control (difficult to determine where/when breeding occurs)