Presumptive diagnosis of malaria in infants in an endemic area

422 OF TXE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE (1993) 87, 422 TRANSACTIONS

Presumptive diagnosis of malaria infants in an endemic area

in

A. Sowunmi and J. A. Akindele Departments of Pharmacology and Therapeutics and Paediatrics, University of Ibadan, Ibadan, Nigeria

Malaria is one of the 5 leading causesof morbidity and mortality in Nigerian children (NIGERIA, 1983). In that country, at all health care levels, emphasis has been placed on the prevention and treatment of a number of common communicable and non-communicable diseases including malaria. Accordingly, at the primary health care level, health workers have been trained to give treatment for uncomplicated fevers suspected to be malaria without a parasitological diagnosis. In order to assessthe efficacy of this practice, we prospectively studied over 2 years (1989-1991) a group of infants reporting at the University College Hospital, Ibadan, Nigeria, for whom a clinical diagnosis of malaria was made by the attending general physician. Although other clinical signs (for example, splenomegaly) were taken into account in the diagnosis of malaria, all pyrexia of undetermined origin was initially treated as malaria. Parasitological confirmation of the clinical diagnosis in the infants was by examination of peripheral blood films obtained from a finger or heel prick. Blood films were Giemsa-stained and 200 high-power fields were examined before a film was declared negative. Parasitaemiain positive thick blood films was assessedby counting the number of asexual forms against 1000leucocytes. During the period, 1345 infants were examined. Plasmodium falciparum was the predominant speciesin 97%, 2% were mixed P. falciparum and P. malariae, and 1% were pure P. malariae infections. Parasite rates were 15% in the O-3 months old infants, 33% in those aged 4-6 months, 27.5% in those aged 7-9 months and 33.2% in those aged 10-11 months. Parasite density in infected infants was generally low: 4149% of parasite-positive infants had a parasite density 250 000 asexual forms/FL) was uncommon in the O-3 months old children (2.3%), and this increased with increasing age (5.8, 11.3 and 9.3% in the children aged 4-6, 7-9, and 10-l 1 months respectively). The parasite rate was significantly higher in the wet season(May-October) than in the dry season (November-April): 265/695 (38.1%) vs. 1471650 (22.6%), P
JFiliMJjASONil Month. Figure. Monthly distribution of number of infants with fever and malaria parasitaemia(hatched portion of bars only).

nosesin the older infants were wrong. Since self-medication with antimalarial drugs is not uncommon before hospital presentation (30-40% of the older infants had positive Dill-Glazko urine tests for 4-aminoquinolines), it is possible that, in a small number of the older infants, the parasite rate recorded in the present study might have been higher if no antimalarial drug had been administered. In such cases, in the absence of parasitological confirmation of the clinical diagnosis, administration of more antimalarial drugs by the attending physician or health worker may be expected to lead to increased toxicity.

Since,

as a whole,

the presumptive

diagnosis

was

likely to be correct in only 30% of all the children, this underlines the need to reappraise the clinical diagnosis of malaria in infants who are not responding to presumptive malaria treatment early. Failure to do this may lead to increasedmorbidity or mortality in such infants. References Hendrickse, R. G., Hassan, A. H., Olumide, L. 0. & Akinkunmi, A. (1971). Malaria in early childhood. An investigation of five hundred seriously ill children in whom a diagnosis of malaria was made on admission to the University College Hospital, Ibadan. Annals of Tropical Medicine and Parasitology, 65, l-20. Nigeria (1983). Federal Ministry of Health Report. Lagos, Nige-ria.

Received 26 February 1992; revised 7 September 1992; accepted for publication I7 September 1992