Lecture 13+14 Malaria

Question 1

Cause of malaria

Answer 1

Five species of protozoan parasites Plasmodium and transmitted by mosquitos of the genus Anopheles, part of the Anopheline subfamily

Only females bite!

Question 2

Parasite development in humans

Answer 2

1. Sporozoites: injected through the bite and saliva - infect liver cells –> schizonts –> burst open
2. Merozoites: infect RBCs –> burst open, can lead to anemia

Question 3

Parasite development in mosquito gut

Answer 3

Microgametoxyte and macrogametocyte fuse in stomach –> zygote –> ookinete –> oocyst –> sporozoites –> burst open and some enter the salivary glands

Question 4

Pathogenesis of malaria

Answer 4

Cyclical fever related to waves of malaria parasites invading the RBCs, multiplying and bursting out of them –> fever, anaemia and signals of onset

Question 5

Mosquito vector - reproduction number

Answer 5

R > 1: disease will spread
R < 1: disease will decline and die out eventually

–> EIR: number of infective bites per person per night

Question 6

Controlling malaria

Answer 6

Human landing collections (golden standard), CDC light traps, outdoor odour-bated traps, window entry/exit traps, larval sampling
–> Provide information about seasonality of malaria transmission

Parasite surveillance: fever, microscopy (golden standard), RDT, PCR

Question 7

Drugs/vaccines against malaria

Answer 7

Resistance is spreading and drugs are getting less effective.

• ACT from Artemisia annua

Vaccines: target the Plasmodium. Mosquirix only one, but not fully protective.

Question 8

Vector control

Answer 8

Insecticides (resistance spreads) and bed nets (current strategies, removal of breeding sites, biological control of adults/larvae, sterile insect technique, odour-baited traps, transgenic mosquitos