Estimating the level of malaria transmission in Nairobi amongst the paediatric age group

Abstract

AIM or STUDY: To estimate the level oftransmission or malaria in Nairobi by using the malaria parasite rate ill children, presenting with fever or history or fever. Nairobi is classified as 'malaria-free' but anecdotal reports have suggested that malaria transmission was occurring in Nairobi. PERIOD OF STUDY: November 17,1998 - January 18,1999. STUDY SITE: All government health centers offering curative services in Nairobi METHODOLOGY: This was a cross sectional study. 1481 children, aged 0-13 years, presenting to the study health facilities with rever (temperature t 37.5 degrees centigrade) or history or fever were recruited. Unaccompanied children were excluded. The parent or guardian was interviewed using standard questionnaire that collected information on age, sex, tribe, residence, travels and blood transfusions. Blood smell'S ['m malaria parasites were made and slide reading was done by two independent malaria slide readers at the Walter Reed Projects in Nairobi and Kisumu. Children with non-travel outside Nairobi in the three months pr or to the interview were considered to have acquired malaria in Nairobi if the blood smear results were positive. Children with no history of travel outside Nairobi in their lifetime provided stronger evidence for malaria transmission in Nairobi. RESULTS: The overall prevalence or malaria was 11.2%. Fi Itv-six (33.7%) or' (he 1()() cases of malaria were seen in children with no history oftravel ill the past three months. Thirty one (18.7%) of the malaria eases were seen in children with no travel in the j1,lsl one-year. Twenty-three (13.9°A,) of the malaria eases were seen ill children with IlO history or travel ill their lifetime. The parasite rates calculated using children with nontravel in the previous three months, one-year and life time was 6.2%, 4.8% and 4.4% respectively. There was a strong association between travel outside Nairobi in the previous three months and malaria. The risk ratio being 3.02 for an outcome of positive malaria slides ifthere was (ravel in the past three months. Age differences were noted in the parasite rates lor children with no travel in the P:lst three months with peak prevalence in the 5-10 years age group (13.2%). No statistically signific.uu differences were noted in the parasite rates {or the different divisions of Nairobi lor children with non- travel in the past three months, past year or lifetime. Certain divisions, however showed higher prevalence ofmularin compared to others e.g. Kibera (9.5%) Dagoretti (8.2%) and Central division (0%). CONCLUSION AND RECOMMENDATION: There is evidence for hypocndcmic rialaria transmission in Nairobi with possible differences in transmission for tile different Divisions in Nairobi. There is need Cor malaria survey in Nairobi to include entomological survey to quantify malaria transmission and plan mnlaria control efforts .