Abstract
Background: Malaria in highland areas of Kenya affects children and adults. Local clinicians include symptoms other than fever when screening for malaria because they believe that fever alone does not capture all cases of malaria. Methods. Individuals who presented to dispensaries in a highland Kenya site of low, unstable malaria transmission from 2007-2011 with 1 or more of 11 symptoms were tested by microscopy for malaria. Clinical malaria was defined as asexual Plasmodium falciparum infection on peripheral blood smear in an individual with any screening symptom. Asymptomatic P. falciparum infection was assessed in a cohort at ten time points to determine the extent to which symptomatic episodes with parasitaemia might be attributable to baseline (asymptomatic) parasitaemia in the community. Results: 3,420 individuals were screened for malaria, 634 < 5 years of age and 2,786 ≥ 5 years of age. For the diagnosis of clinical malaria, the symptom of fever had a sensitivity and specificity of 88.9% and15.4% in children <5 years, and 55.8% and 54.4% in children ≥5 years, respectively. Adding the symptom of headache increased sensitivity to 94. 4% in children <5 years and 96.8% in individuals ≥5 years, but decreased specificity to 9.9% and 11.6%, respectively, and increased the number of individuals who would be tested by 6% and 92%, respectively. No combination of symptoms improved upon the presence fever or headache for detection of clinical malaria. In the cohort of asymptomatic individuals, P. falciparum parasitaemia was infrequent (0.1%). Conclusion: In areas of low, unstable malaria transmission, fever is a sensitive indicator of clinical malaria in children <5 years, but not in older children and adults. Adding headache to fever as screening symptom increases sensitivity of detection in individuals ≥5 years old at the cost of decreased specificity. Screening for symptoms in addition to fever may be required to accurately capture all cases of clinical malaria in individuals ≥5 years old in areas of low malaria transmission.
| Original language | English (US) |
|---|---|
| Article number | 163 |
| Journal | Malaria Journal |
| Volume | 13 |
| Issue number | 1 |
| DOIs | |
| State | Published - Apr 30 2014 |
Bibliographical note
Funding Information:We would like to thank the study participants for their participation in the study, Jackson Abuya and the field microscopy team for reading blood smears, study clinical officers for clinical evaluation and study field assistants for site demography. The study was supported by grants U0AI056270 from the National Institutes of Allergy, Immunology, and Infectious Disease; D43TW0080085 from the Fogarty International Center; and a University of Minnesota Department of Pediatrics Amplatz Research award. This paper was published with the permission of the Director, Kenya Medical Research Institute.
Keywords
- Fever
- Highland
- Malaria
- Plasmodium falciparum
- Symptom
- Unstable transmission
