14- Malaria

Question 1

most cases of malaria are due to

Answer 1

plasmodium falciparum

Question 2

vector of malaria

Answer 2

female anopheles

Question 3

highest to lowest mosquitoes for malaria

Answer 3

P falciparum
P vivax
P malariae
P knowlesi

Question 4

entomologic inoculation rates

Answer 4

the number of infectious female anopheline bites per person per year - used to indicate transmission rates
EIR<10/year is low
EIR 10-49 is intermediate
EIR>50 is high transmission area
Higher the EIR the greater burden of malaria (Esp on kids). Constant year round infection is termed stable transmission (EIR>50 areas) in such areas most malaria infections in long term resident adults are asymptomatic. Note that in areas where transmission is low, highly seasonal, or focal, full protective immunity is not acquired, and symptomatic dx occurs at all ages

Question 5

control vs elimination vs eradication of malaria

Answer 5

control: reduction of disease incidence and prevalence to levels that dont pose a threat to public health
elimination: is reduction to zero transmission in humans
eradication: global elimiation of human disease

Question 6

methods of vector control

Answer 6

insecticide treated nets, household insecticide residual spraying, larval control, genetic control methods

Question 7

inoculated sporocytes for malaria go to

Answer 7

the liver within one to 2 hours, then pts are asymptomatic for 12-35 days, until the erythrocytic stage of the parasite cycle

Question 8

erythocytic stage of the parasite life cycle in malaria

Answer 8

release of merozoites from infected red cells when the rupture causes fever etc

Question 9

the classic malaria attack lasts 6-10 hours and includes

Answer 9

cold stage (shivering)
hot stage (fever, headaches, vomiting, seizures in babies)
sweating stage (sweats, return to normal temp, tiredness)
NOTE THAT THIS IS RARELY OBSERVED AND PPL JUST GET NORMAL BUG SYMPTOMS

Question 10

malaria paroxysm

Answer 10

are associated with release of merozoite

Question 11

dx of malaria

Answer 11

microscopy: thin and thick malaria smear (thick shows parasites, and thin shows species and parasitemia
or use a Rapid diagnostic test
PCR

Question 12

TX of malaria depends on

Answer 12

depends on infecting plasmodium species, clinical status of pt, expected drug susceptibility, previous use of antimalarias(including those for chemoprophylaxis)

Question 13

Endemicity is defined by

Answer 13

terms of parasitemia rates:
Hypoendemic: <10%
Mesoendemic: 11-50%
Hyperendemic: 51-74%
Holoendemic: >75%
- In holo/hyper endemic areas (africa) ppl are bitten more than once a day, and are infected repeatedly, here morbidity and mortality due to malaria in childhood is high

Question 14

T/F intermittent preventive tx is useful for reducing risk of malaria among indv at high risk (pregnant women)

Answer 14

T

Question 15

T/F the efficacy of mosquito repellents against malaria are variable depending on the transmitting mosquito vector

Answer 15

T
Mass drug administration may be a useful tool in regions where
elimination of falciparum malaria is a feasible goal. An effective drug, rapid
diagnostics, and sensitive monitoring system for adverse events are
required for such an intervention

Question 16

T/F SX of malaria vary with parasite species, epidemiolgy, immunity and age

Answer 16

T
• In areas where malaria is highly endemic, groups at highest risk include
young children (6 to 59 months), who can develop severe illness, HIV
infected people and pregnant women, who are at risk for anemia and
delivering low birthweight newborns.
• In areas where malaria is transmitted throughout the year, older
children and adults develop partial immunity after repeated infections
and are at relatively low risk for severe disease.

Question 17

Which plasmodium species cannot cause relapse and why

Answer 17

P falicparum
P malariae
Bc they do not have a dormant hypnozoite phase

Question 18

T/F • Early in the course of malaria infection, febrile paroxysms occur at
irregular intervals each day. The temperature of nonimmune
individuals and children may rise above 40ºC and may occur in
conjunction with tachycardia and/or delirium. Febrile convulsions may
occur among children in the setting of malaria due to any species.

Answer 18

T
• Febrile paroxysms may occur:
- Every other day for P. vivax, P. ovale, and P. falciparum
- Every third day for P. malariae.
Paroxysms occurring at regular intervals are more common in the
setting of infection due to P. vivax or P. ovale than P. falciparum. With
improvements in early diagnosis and treatment, this traditional
description of cyclic fever is seen infrequently.

Question 19

Manifestations of severe malaria

Answer 19

• cerebral malaria (abnormal behavior, imparement of consciousness, seizures, coma)
• Anemia (due to hemolysis)
• Hemoglobinuria
• ARDS
• Abnormalities in blood coagulation
• Low BP due to CV collapse
• AKI
• Hyperparasitemia (>5% of RBC are infected)
• Metabolic acidosis (with hypoglycemia)
• Hypoglycemia (can occur post tx with quinine)

Question 20

Why is it important to know the infecting plasmodium species before starting tx for malaria

Answer 20

• P falciparum and P knowlesi infection can rapidly progress to severe illness/death
• P vivax and P ovale need tx for hypnozoites
• P falciparum and P vivax have different drug resistance patterns in the world
• P falciparum and P knowlesi need urgent initiation of tx

Question 21

tx to eradicate hyponozoites in which 2 malaria species?

Are there side effects?

Answer 21

P vivax
P ovale
Use tafenoquine or primaquine phosphate
Note that both can cuase hemolytic anemia in pts with G6PD def

Question 22

Severe malaria should be treated with

Answer 22

IV artesunate