W9 Malaria Flashcards
What is Malaria?
- Potentially serious Plasmodia sp. parasitic infection
- Transmitted by bite of infected mosquito (vector)
Malaria and travel from UK
Who are at risk? (1)
Who are at high risk?(4)
- Around 1,500 cases of malaria are reported annually in travellers returning to or arriving in the UK – eight or fewer deaths each year in UK since 2006
- All travellers visiting areas where malaria occurs are at risk
- Most at risk are migrants to the UK who were born in malaria risk areas and return to visit friends and relatives in their country of birth
- Others at higher risk include:
- Pregnant women
- Those with no spleen
- Children
- Elderly
Different Plasmodia, different outcomes
- P. falciparum
- Causes the most severe disease because of micorvascular effects
- Only species likely to be fatal in healthy patients
- Can cause death within days of symptom onset
- P. vivax, P. ovale, P. malariae, and P. knowlesi
- Typically do not compromise vital organs
- Mortality rare and mostly due to splenic rupture or uncontrolled hyperparasitaemia in asplenic patients
Travellers to malarious regions
What does ABCD stand for?
- A wareness of risk
- B ite avoidance
- C hemoprophylaxis
- D iagnosis
Malaria life cycle
- Bite prevention acts at the start of the cycle
- “Causal” prophylaxis acts on the parasite in
the liver - “Suppressive” prophylaxis acts on the parasite in the RBCs
Symptoms of malaria:
Headache (Central)
Fever (Systemic)
Fatigue, Pain (Muscular)
Pain (Back)
Chills, Sweating (Skin)
Dry cough (Respiratory)
Enlargement (Spleen)
N & V (Stomach)
Clinical signs and symptoms of malaria:
Fever, sweats or chills
Malaise (vague discomfort)
Myalgia
Diarrhoea
Cough
Level of risk of exposure to malaria and what affects it:
- Number of bites: higher = increased risk
- Temperature, altitude and season: usually 20-30C, lower than 2,000m, often worse in the rainy season
- Rural versus urban location: higher in rural areas
- Type of accommodation: well-sealed, air-conditioned rooms reduce risk
- Patterns of activity: being outdoors between dusk and dawn when Anopheles mosquitoes bite
- Length of stay: longer stays = increased risk
Bite prevention:
What are the most likely bite times?
- Effective bite prevention should be the first line of defence against malarial infection
- Bite times vary between mosquito species, but mostly dusk till dawn
- Africa: most bites around midnight so protection overnight particularly important
- South America and South East Asia: higher risk in evening before retiring indoors.
What Repellent is 1st line for malaria?
Not reccomended for..?
50% DEET (N,N-Diethyl-meta-toluamide)
* Can damage plastics!
* Follow re-application instructions carefully
* Ensure do not come into contact with eyes or mouth
* Only use on exposed areas of skin
* Not recommended for infants below the age of 2 months
* Benefit outweighs risk in pregnancy
What are some other less common Repellents ? (4)
- Eucalyptus citriodora oil, hydrated, cyclized (eucalyptus citriodora): provides protection for several hours
- Icaridin (Picaridin): protection equivalent to 20% DEET
- 3-ethlyaminopropionate: shorter duration of action than DEET
- Oil of citronella: short-lived protection, not recommended
Other ways to prevent bites (3)
- Insecticides: permethrin and other synthetic pyrethroids are used to
kill resting mosquitoes in a room - Nets: all travellers to malaria-endemic areas should sleep under an
insecticide-treated mosquito net – efficacy estimated at 50% - Clothing: Within the limits of practicality, cover up with loose-fitting
clothing, long sleeves, long trousers and socks if out of doors after
sunset, to minimise accessibility to skin for biting mosquitoe
Things that don’t work
- Herbal remedies: none proven
- Homeopathy: none proven
- Buzzers: “completely ineffective”
- Vit B1: not effective
- Vit B12: not effective
- Garlic: not effective
- Yeast extract: no evidence
- Tea tree oil: not effective
- Bath oils/emollients: none have evidence
- Alcohol: not effective
ABCD:
C= Chemoprophylaxis
- Drug choice needs to be appropriate for destination
- Use NaTHNaC, MIMS, BNF to find what needs to be used
- Need to consult at least 2-3 weeks before travel ideally
- Protection not absolute
- Causal prophylaxis: liver stage – need to be continued for 7 days post-exposure
- Suppressive prophylaxis: RBC stage – need to take for 4 weeks post-exposure
What drugs are used to treat malaria? (5)
Mefloquine (weekly)
Doxycycline (daily)
Proguanil and atovaquone (daily) [P]
Proguanil (daily) [P]
Chloroquine (weekly) [P]
