Malaria Prevention

Question 1

Malaria Prevention - Risk Assessment Components (3 parts)?

Answer 1

1. Person - VFR, extremes of age, pregnancy, immunosuppressed, co-morbidities
2. Place - Sub-Saharan Africa, areas of deforestation, rural vs urban, accommodation type
3. Time - longer term travellers, seasonality

Question 2

Malaria Prevention - Insect Repellant Options?

Answer 2

1. DEET - reapply q6-8h, 50%, >2 mo of age, ok for preg and breastfeeding
2. Icaridin - 20%, >6 mo of age, q4-6h
3. IR3535 - use highest strength, >2 mo of age, q6-8h, not helpful for Anopheles

Question 3

Malaria Prevention - Chemoprophylaxis options in Chloroquine-sensitive region?

Answer 3

1st line –> Chloroquine
2nd line –> Hydroxychloroquine

Both taken once weekly starting 1 week before travel to area, during exposure, and 4 weeks after leaving malaria-endemic region.

3rd line –> Atovaquone-proguanil, doxycycline, mefloquine

Question 4

Malaria Prevention - Chemoprophylaxis options in Chloroquine-resistant regions?

Answer 4

Drugs of choice: Atovaquone-proguanil, doxycycline or mefloquine
2nd line: primaquine daily

-If mefloquine resistance, use either of other two

Question 5

Malaria Prevention - Chloroquine-sensitive regions?

Answer 5

Haiti, Dominican Republic, Central America north of the Panama Canal, parts of Mexico, parts of South America, north Africa, parts of Middle East, and west/central China

Question 6

Malaria Prevention - Chloroquine-resistant regions?

Answer 6

Most of sub-Saharan Africa, South America, Oceania and Asia

-Some mefloquine resistance in border areas of Thailand, Myanmar, Laos and Cambodia, and southern Vietnam

-Now almost worldwide however

Question 7

Malaria Prevention - Atovaquone-proguanil chemoprophylaxis dosing?

Answer 7

Malarone
-Daily
-Start 1 day before until 7d after

Considerations: DDI, renal dosing (avoid if eGFR <30), needs fatty meal (milky drink), cannot crush
Pregnancy/BF: ok in 2nd trimester, data in 1st trimester
Side effects: neuro, GI, hair loss

Question 8

Malaria Prevention - Doxycycline chemoprophylaxis dosing?

Answer 8

-Daily
-1 day before until 4 weeks after

Considerations: DDI
Pregnancy/BF: up until 15 wks, no BF and no for children?
Side effects: gastritis, teratogen, bones/teeth, photosensitivity

Question 9

Malaria Prevention - Mefloquine chemoprophylaxis dosing?

Answer 9

-Weekly
-3 weeks before until 4 weeks after

Considerations: DDI, psych hx (don’t give), can crush, epilepsy issues, anticoag issues
Pregnancy/BF: ok
Side effects: neuro psych (dreams, insomnia, anxiety, depression)

-Many people discontinue due to side effects, 95% of ADRs by 3rd dose

Question 10

Malaria Prevention - Tafenoquine chemoprophylaxis dosing?

Answer 10

-Monthly for 6 months vs weekly?
-Unclear access in Canada

Question 11

Malaria Prevention - Pregnancy Risks?

Answer 11

-Increased risk of severe malaria
-Placental sequestration (can delay diagnosis)
-Congenital malaria (rare but more common with vivax)

Question 12

Malaria Risks - Pregnancy Prophylaxis

Answer 12

-Chloroquine/Proguanil –> ok in all trimesters, folic acid with proguanil but resistance
-Mefloquine - all trimesters
-Doxycycline - under special circumstances <15 weeks + 4 weeks on return
-Atov/Prog - data sparse, take folic acid for duration

Question 13

Malaria Prevention - Proph for Epilepsy?

Answer 13

• Doxy YES
• Atov/Prog YES
• Chloroquine NO
• Mefloquine NO

Question 14

Malaria Prevention - Children Chemoproph?

Answer 14

-Mefloquine easiest - >5kg, weekly
-Atov/Prog - >5kg with milk/yogurt daily
-Doxy >12 years old

Question 15

Malaria Prevention - Chemoproph in renal disease?

Answer 15

• Atov/Prog - avoid if eGFR <30 (can do dose reductions if needed)
• Mefloquine - ok in severe disease
  -Doxycycline - ok in severe disease

Question 16

Malaria Prevention - Chemoproph in liver disease?

Answer 16

• All drugs metabolized by liver

Severe disease:
- Doxy YES
-Malarone ??
-Mefloquine NO

Mod to mild disease:
-Can use all three

Question 17

Malaria Prevention - Chemoproph in G6PD deficiency

Answer 17

All but Primaquine ok

Question 18

Artemisinin resistant areas?

Answer 18

-Rwanda
-Uganda
-Horn of Africa

Question 19

What are the approved malaria vaccines?

Answer 19

1. RTS,S/ASO1E - Mosquirix
   -26% reduction in severe malaria
   -30.1% reduction in first malaria episode
2. R21/Matrix M

Question 20

What are the 5 threats to vector control for malaria?

Answer 20

1. Vector resistance to insecticides
2. Invasive vectors (A stephensi)
3. Climate change
4. Funding challenges
5. Diminished access, use and durability of insecticidal nets

Question 21

What are 4 means of vector resistance to insecticides?

Answer 21

1. Metabolic resistance
2. Behavioural resistance
3. Cuticular resistance/reduced penetration (thickened cuticle)
4. Target site modifications (Kdr, Ace1r)

Question 22

What are 2 new means of vector control?

Answer 22

1. Dual ITNs - nets (pyrethroids + new insecticides)
2. New IRS insecticides (new modes of action)
   -Broflaniline WP - Vectron T500 pre-qualified by WHO

Question 23

What are the two approved methods by WHO for vector control? What are the supplemental interventions suggested?

Answer 23

1. Long-lasting insecticidal nets
2. Indoor residual spraying

Supplemental: larviciding + house screening