INF2 - A. MALARIA-COVERED

Question 1

where is malaria mainly found

Answer 1

tropical regions
- Africa and Asia
- central and south America
- Haiti and Dominican Republic
- Middle East
- some pacific islands

not found in UK (only returning travellers)

Question 2

what factors affect travellers’ exposure to malaria

Answer 2

• high humidity and 20-30 degrees Celsius
• transmission doesn’t occur where temp is below 16 degrees Celsius isotherm
• parasite maturation in mosquito can’t take place >2000m above sea level
• seasonal rainfall increases mosquito breeding (monsoons)
• rural location (swampy)
• backpackers: cheap accommodation, open windows
• outdoors between dusk and dawn when Anopheles mosquitos bite

Question 3

prophylaxis of malaria

Answer 3

ABCD
- Awareness of risk: are you at risk: where, what, how long
- Bite prevention: insect repellent, cover arms and legs, insecticide-treated mosquito net, inside between dusk and dawn
- Check if need malaria prevention tablets
- Diagnosis: immediate medical advice if develop malaria symptoms, up to a year after travelling

Consult a HC professional if going somewhere where malaria is a risk

Question 4

how to prevent getting bitten

Answer 4

• air conditioning and screening on doors and windows
• close windows and doors
• sleep under an intact mosquito net treated with insecticide
• long lasting impregnated nets
• insect repellent on skin and when sleeping. Need at least 50% DEET
• loose-fitting trousers and long sleeves: esp at night when they prefer to feed
• homeopathic remedies don’t offer any protection

Question 5

what are the 2 types of chemoprophylaxis

Answer 5

1. casual prophylaxis
   - targets liver stage
   - takes 7 days to develop (liver stage)
   - continue for 7 days after leaving malarious zone
2. suppressive prophylaxis
   - targets erythrocytic stage
   - continue for 4 weeks after leaving malarious zone

no prophylactic drugs for hypnozoites - P. oval and P. vivax

Question 6

Atovaquone plus proguanil (Malarone) chemoprophylaxis (POM)

Answer 6

• 1st choice
• prevents development of liver schizonts (casual)
• take 1-2 days before entering malarial zone, when there and for a week after leave
• 1 tablet every day
• works on erythrocytic stages so used for treatment aswell
• 90% efficacy against P. falciparum and also against P. vivax
• side effects: headache, GI upset, skin rash, mouth ulcers
• NOT taken by pregnant or breastfeeding women or those with severe kidney problems
• more expensive
• licensing: 12 weeks

Question 7

Mefloquine (Larium) prophylaxis (POM)

Answer 7

• a quinoline
• suppressive?
• take a week before, when there for 4 weeks after leave
• one tablet weekly
• 90% efficacy against P. falciparum
• NOT for those with epilepsy, seizures, depression, mental health problems, if close relative has these, severe heart or liver problem
• side effects: dizziness, headache, sleep disturbances, psychiatric reactions (anxiety, depression, panic attacks, hallucinations)
• 3-week trial recommended
• licensing: 12 months

Question 8

doxycycline (vibramycin-D) prophylaxis (POM)

Answer 8

• suppressive: prevents development of erythrocytic stages
• take a week before, when there for 4 weeks after leave
• 1 tablet every day
• NOT taken by pregnant or breastfeeding women, under 12 (risk of permanent tooth discolouration), sensitive to tetracycline antibiotics or people with liver problems, on warfarin
• side effects: sunburn due to light sensitivity, stomach upset, heartburn, thrush
• take with food, standing or sitting

Question 9

chloroquine and proguanil prophylaxis (P)

Answer 9

• 2 separate tablets
• chloroquine: once weekly, proguanil: everyday
• suppressive
• take a week before, when there for 4 weeks after leave
• rarely used as largely ineffective against P. falciparum
• india and Sri Lanka: P. falciparum less common
• same side effects as mefloquine

Question 10

what is the most common cause of malaria

Answer 10

P. falciparum, where chloroquine-resistant P. falciparum is endemic

Question 11

what is the incubation period for P. falciparum, vivax, oval

Answer 11

8-12 days

Question 12

what is the incubation period for P. malariae

Answer 12

18 days - 6 weeks

Question 13

prodromal symptoms

Answer 13

headache
muscular aches and pains
malaise
nausea
vomiting
- 2nd week after exposure
- incubation period can be delayed for months

Question 14

what can confirm diagnosis

Answer 14

• history of travel to an endemic area
• typical paroxysmal episode of chills and fever
• thrombocytopenia
• jaundice
• +ve identification of parasites in blood (blood film)

Question 15

what are the 3 stages of malarial febrile paroxysms

Answer 15

1. cold stage: marked vasoconstriction
   - lasts 30-60 minutes
   - intensely cold and shivering
   - temp rises rapidly - 41 degrees Celsius
   - can have seizures
2. hot stage:
   - lasts for 2-6 hours
   - intensely hot
   - delirium esp if dehydrated
3. sweating stage:
   - bedclothes drenched
   - fatigued and exhausted
   - sleeps

*fever every other day with P vivax and ovale
*P. falciparum - develops in RBCs, RBCs develop knobs and stick to endothelium - organ damage to kidneys, liver, brain, GI tract
*severe fever and prodrome has no pattern

need to be in intensive care
paracetamol
fluids
oxygen
treatment

Question 16

how does cerebral malaria and blackwater fever occur

Answer 16

• not treated promptly enough
• > 2% RBCs infected

Question 17

symptoms of cerebral malaria

Answer 17

• increase in body temp
• rapid deterioration in consciousness
• convulsions
• coma and death

Question 18

symptoms of blackwater fever

Answer 18

• dark brown urine from intravascular haemolysis
• only P. falciparum
• acute renal failure so dialysis needed
• splenic rupture
• jaundice
• diarrhoea
• severe anaemia
• hypoglycaemia
• acidosis
• pulmonary oedema
• if pregnant: high maternal mortality and and increased risk of LBW and infant mortality

Question 19

what is tropical splenomegaly syndrome

Answer 19

• inflamed spleen
• where malaria is hyper endemic

Question 20

treatment for severe falciparum malaria (IV)

Answer 20

• UK, artesunate or quinine dihydrochloride infusion

IV artesunate not licensed in UK, so has to be given on a named-patient basis but quinine is 2nd choice as not as well-tolerated or effective

use unlicensed artesunate if quinine unsuccessful, quinine resistance (for named patient and specially imported)

• haemodialysis, response support, glucose, blood transfusions, BZDs in children

Question 21

treatment for uncomplicated falciparum malaria (ORAL)

Answer 21

1. artemisinin combo therapy: artemether-lumefantrin or dihydroartemisinin-piperaquine for 3 days
2. oral atovaquone-proguanil for 3 days
3. oral quinine plus doxycycline for 7 days

Question 22

treatment for non-falciparum malaria (vivax/ovale)

Answer 22

oral chloroquine or artemether-lumefantrin 3 days then primaquine 14 days

Question 23

what are the emergency treatments

Answer 23

Malarone
artemether with lumefantrine = Riamet
quinine with doxycycline

Question 24

determinants of malaria

Answer 24

• host: SCD, no Duffy blood factor - more resistant to malaria
• parasite: falciparum is more virulent and resistant
• tropical warms areas, heavy rainfall, high humidity, still water
• swamp draining, air conditioning etc

Question 25

burden of malaria

Answer 25

- anaemia and LBW babies - malaise, fatigue for life - neurological defects for children that survive cerebral malaria - persistent language deficits, epilepsy, decreased life expectancy

Question 26

what is the malaria initiative

Answer 26

Roll back malaria initiative (global partnership)