Diagnostic Accuracy of Fever and Fraction of Fevers Attributable to Malaria among Under-fives under Reduced Malaria Infection Prevalence in Bagamoyo District, Tanzania Donath S Tarimo 1* , Edward O Lyimo 2 and Candida Moshiro 1 1 Medical Statistician, Department of Epidemiology & Biostatistics School of Public Health & Social Sciences, Muhimbili University of Health & Allied Sciences, United Republic of Tanzania 2 Medical Parasitologist, Department of Parasitology/Medical Entomology School of Public Health & Social Sciences, Muhimbili University of Health & Allied Sciences, United Republic of Tanzania 3 Epidemiologist, Lugalo General Military Hospital Tanzania Peoples Defence Forces (TPDF), United Republic of Tanzania * Corresponding author: Donath S Tarimo, Medical Parasitologist, Department of Parasitology/Medical Entomology School of Public Health & Social Sciences, Muhimbili University of Health & Allied Sciences, United Republic of Tanzania, Tel: +255 578 528; E-mail: dontarimo@gmail.com Received date: April 04, 2014; Accepted date: June 3, 2014; Published date: June 10, 2014 Copyright: ©2014 Tarimo DS, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract A decline in malaria transmission is evident in malaria endemic areas of sub-Saharan Africa and is likely to reduce the proportion of fevers due to malaria. Fever has been used as a predictor of malaria, however, the proportion of fevers due to malaria vary with prevalence such that low malaria infection prevalence might alter the accuracy of fever as a marker of malaria. This study examined the diagnostic accuracy and proportion of fevers attributable to malaria among under-fives in a cross-sectional survey carried out in Bagamoyo district, Tanzania from April–May 2012 during peak malaria transmission. Consecutive under-fives with and without history of fever were recruited; for each, fever was measured by digital thermometer, and two Giemsa stained thick and thin blood films taken for parasite count and species identification. Accuracy of fever for prediction of malaria was assessed by performance indices, microscopy as gold standard. Proportion of fevers attributable to malaria was computed by the odds ratio technique at 0.05 significance level.{Formatting Citation} Only 98 out of 925 (10.6%) under-fives had parasitaemia. Among under-fives with a history of fever, the fraction attributable to malaria was 71.4% [95%CI: 54.8–81.9]; in those with measured fever ≥ 37.5˚C, the fraction was 74.3% [95%CI: 61.8–82.7]. In bivariate and multivariate analyses, at 1001-10000 parasites/µl the attributable fraction was 66%, and 93% for parasitaemia>10000/µl. Fever was more likely to be due to malaria among infants<12 months than subsequent months. Despite the recorded decline in malaria infection prevalence, fever is highly likely to be due to malaria among under-fives with fever and malaria infection in peripheral blood. This observation highlights the need to scale up and maintain parasitological confirmation of malaria; and to look for other causes of fever. Keywords: Under-fives; Fever; Malaria; Diagnostic accuracy; Attributable proportion; Tanzania Background For decades fever has been the entry point for the management of malaria in African children in endemic settings. Prior to the adoption of Artemisisnin based combination therapy (ACTs), presumptive treatment of all fevers with antimalarial drugs was the approach for the management of malaria across sub-Saharan Africa and was in the recommendations proposed by the Integrated Management of Childhood Illnesses (IMCI) [1-6]. However, there are many causes of childhood fevers, Plasmodium falciparum malaria being one of them [7-12]. Although fever usually has a high sensitivity for the diagnosis of malaria, it suffers from poor specificity and critically depends on the prevalence of both asymptomatic infection and the overall prevalence of fever. There is a growing evidence indicating that the intensity of P. falciparum transmission is declining across many parts of Africa as reflected in reduction of childhood morbidity and mortality resulting from the wide scale use of different malaria interventions [13-15]. Recent demographic and health surveys (DHS) in malaria endemic countries of sub-Saharan Africa show similar trends whereby 11 of the 12 national surveys conducted since 2004 showed declines in under- fives mortality estimates over the previous five years (declines of 5% to 30%, median 23%) [16]. Thus, a decline in P. falciparum prevalence from 37.0% before the year 2000 to 17.0% after the year 2000 onwards has been observed in African children aged 2-10 years as a result of wide scale use of ACTs and ITNs [17,18]. A decline in malaria infection prevalence may conceivably alter the sensitivity and specificity (diagnostic accuracy) of fever as a marker of malaria as well as a reduction in the proportion of fevers attributable to malaria [4,5,19,20]. Following the roll out of ACT and ITNs in Tanzania, a survey in 21 districts covering about 8,000 under-fives found that malaria infection prevalence declined from 20.0% in 2006 to 14.0% in 2008-a relative reduction of approximately 30.0% [21]. This decline has continued in subsequent surveys such that a decline from 18.1% (2007/08) to 4.2% (2011/12) malaria infection prevalence was recorded in under-fives representing a relative reduction of approximately 77.0% [22,23]. Malaria Chemotherapy Control & Elimination Tarimo et al., Malar Chemoth Cont 2014, 3:1 http://dx.doi.org/10.4172/2090-2778.1000121 Research Article Open Access Malar Chemoth Cont ISSN:2090-2778 MCCE, an open access journal Volume 3 • Issue 1 • 1000121