Long term travellers

Most recommendations are applicable only to non-immune travellers visiting malarious areas for up to one month, which includes most travellers. Long-term travellers intending to stay in malarious areas should follow the recommendations of their home doctor for at least the first 1-3 months of residence, after which they should seek advice from local health -care practitioners familiar with the management of malaria in non-immune foreigners.

The risk of serious side-effects associated with taking long-term prophylactic chloroquine and proguanil is low. However, twice-yearly screening for the detection of early retinal changes should be performed in anyone who has taken 300 mg of chloroquine weekly for over five years and requires further prophylaxis (screen after three years if daily doses of 100 mg have been taken). If changes are observed, an alternative drug should be prescribed.

Data indicate no increased risk of serious side-effects with long-term use of mefloquine. The risk of serious side-effects from prolonged use of doxycycline is not yet known. Mefloquine and doxycycline should be reserved for those at greatest risk of infection.

Frequent travellers

Some travellers, such as members of aircraft crews, make frequent short stops in endemic areas over a prolonged period of time. Such travellers may eventually choose to reserve chemoprophylaxis for high-risk areas only. However, they should maintain rigorous self-protection against mosquito bites and be prepared for an attack of malaria: they should always carry a course of antimalarials for stand-by emergency treatment, seek immediate medical care in case of fever, and take self-treatment if prompt medical help is not available.