Carole Tracey MSc, DipHE, RGN, RM.
Practice Nurse, The Health Centre, University of East Anglia, Norwich
Malaria kills, yet decades ago doctors were confident that it could be beaten and control measures were beginning to be very effective, with medicines working well. Now the picture is very different and malaria is re-emerging as a very serious disease.
Malaria is a protozoal disease transmitted by the female anopheline mosquito; it is caused by parasitic protozoa of the genus Plasmodium, which infects human and insect hosts alternately. There are about 420 different species of anopheline mosquito, of which 70 are able to transmit the parasite (Stürchler, 2000).
When advising parents on malaria prevention it is important to have some understanding of the basic natural history and epidemiology of the disease, including the life cycle of the parasite within the mosquito and human. This goes some way to helping convince people of the life-threatening nature of this disease and to make clear why bite avoidance measures and compliance with appropriate chemoprophylaxis is so vital.
The classic symptoms of malaria are fever, malaise, headache and myalgia, but malaria may mimic other diseases such as typhoid - the symptoms of P. falciparum malaria are notoriously atypical and therefore difficult to diagnose.
Diagnosis is by microscopic examination of blood on thick and thin slides. Blood should be taken when the patient has a fever if possible and it is important to realise that a single negative test is not diagnostic and further sets should be taken at four- to six-hourly intervals. Patients with a strong suspicion of malaria, particularly P. falciparum should start treatment with quinine, even if the blood films are negative (CATMAT, 2000).
The latest UK guidelines issued in 2001 (Bradley and Bannister, 2001) identify four principles of malaria prevention that should receive attention from travel advisers, travellers and parents (Box 1).
Knowing what does not work is as important as knowing what does. Acoustic devices that produce ultrasound waves have been shown to be ineffective in repelling mosquitoes (Mark et al, 2002), as have light traps, which are successful at electrocuting flies and other insects, but not mosquitoes.
Travel advisers should always recommend against taking small children and infants to areas of substantial transmission of chloroquine-resistant P. falciparum (Box 3), such as certain regions of Africa, South America, Oceania and Asia (CATMAT, 2000).
The WHO advises that parents do not take babies and small children to areas with chloroquine-resistant P. falciparum. If travel is unavoidable, the child must be carefully protected against mosquito bites and given appropriate chemoprophylaxis.
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