Symptoms of malaria
Malaria symptoms can occur from seven days after arriving in a risk area, up to a year (or longer) after being bitten. Anyone showing a combination of the following symptoms up to a year (and especially within three months) after travel to an endemic region should be referred to their GP for assessment:
- Fever, myalgia, chills and sweating.
- Cough, headache.
- Nausea, vomiting, diarrhoea.
- Seizures and loss of consciousness with severe illness from falciparum malaria.
- Babies and children may have difficulty sitting or standing and can develop respiratory problems.
Bite avoidance measures
No chemoprophylaxis regimen is 100% effective at preventing malaria, so in all cases travellers should be given advice on bite avoidance measures. In some cases this advice alone is sufficient, in others chemoprophylaxis will also be required. The following advice should be given:
- Anopheles mosquitos tend to bite between dusk and dawn. In Africa biting peaks just after midnight and in South America and South East Asia the highest risk is in the evening. So, protection at night is essential.
- Wear long-sleeved clothing and socks when outside between dusk and dawn to minimise accessibility to skin. Cotton clothing can be sprayed with DEET insecticide.
- An insecticide-treated net should be used around the bed at night if sleeping outdoors or in un-screened accommodation. Mosquito nets must be free of tears and should be tucked in under the mattress.
- Insecticides in the form of heated ‘mats’ and sprays should be used in rooms at night. Smoke coils can be used but are less effective and are not recommended for indoor use.
- Effective insect repellents should be used on the skin. ACMP strongly recommends the use of DEET (N,N-diethyl-m-toluamide) in strengths over 20%. Duration of protection is one to three hours for 20%, up to six hours for 30% and up to twelve hours for 50% DEET. There is no further increase beyond the 50% concentration.
- DEET can be used on clothing although its duration of action is reduced. Care should be taken with artificial fibres and plastics which can degrade in contact with DEET.
- DEET is suitable for everyone over two months of age including pregnant and breast-feeding women (note that this may be outside of some manufacturer’s recommended use).
- Icaridin is reported to have a repellent effect equivalent to DEET. ACMP recommends icaridin preparations of at least 20%.
- Travellers who show interest or request information should be strongly advised to avoid reliance on herbal, homoeopathic or alternative means of preventing insect bites.