Semi-immune individuals, such as the patient described by Allan and Tahir (April 2006 JRSM1), present a diagnostic challenge in UK emergency departments due to the relatively uncommon presentation of malaria in these settings. The patient probably had recrudescent Plasmodium falciparum infection, caused by persistence of blood forms of P. falciparum in small numbers between attacks. Though exposed to infection in her country, the authors did not state if she had clinical infection prior to leaving, if it was treated, or if she took prophylactic medication before or after arriving in the UK.
Widespread anti-malarial drug resistance in Africa makes the possibility of recrudescent infection more significant.
The Health Protection Agency guidelines would thus provide the greatest sensitivity and specificity for diagnosing malaria.1 Thrombocytopenia which is a relatively common presentation of malaria in Nigerians and other Africans in western countries,2,3 may be a vital clue to the diagnosis in busy emergency departments.
Competing interests ATA is a Nigerian, and a senior house officer in Accident & Emergency medicine on the GPVTS of the Kent, Sussex, and Surrey postgraduate deanery.
References
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