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Overdiagnosis of Malaria Illness in an Endemic Setting: A Facility-Based Surveillance Study in Malawi.
- Source :
-
The American journal of tropical medicine and hygiene [Am J Trop Med Hyg] 2021 May 03; Vol. 104 (6), pp. 2123-2130. Date of Electronic Publication: 2021 May 03. - Publication Year :
- 2021
-
Abstract
- In endemic settings where asymptomatic malaria infections are common, malaria infection can complicate fever diagnosis. Factors influencing fever misdiagnosis, including accuracy of malaria rapid diagnostic tests (mRDTs) and the malaria-attributable fraction of fevers (MAF), require further investigation. We conducted facility-based surveillance in Malawi, from January 2012 through December 2013 in settings of high perennial (Chikhwawa), high seasonal (Thoylo), and moderate seasonal (Ndirande) malaria transmission. Consecutive patients presenting to outpatient departments were screened; those with suspected malaria illness were tested by mRDT or routine thick-smear microscopy. Test positivity rates (TPRs), positive predictive value (PPVs) of mRDTs, and MAFs were calculated by site, age, and season. Of 41,471 patients, 10,052 (24.2%) tested positive for malaria. The TPR was significantly greater in Chikhwawa (29.9%; 95% CI, 28.6-30.0) compared with Thyolo (13.2%; 95% CI, 12.5-13.7) and Ndirande (13.1%; 95% CI, 12.2-14.4). The overall PPV was 77.8% (95% CI, 76.8-78.7); it was lowest among infants (69.9%; 95% CI, 65.5-74.2) and highest among school-age children (81.9%; 95% CI, 80.3-83.4). Malaria infection accounted for about 50% of fevers in children younger than 5 years old with microscopy-confirmed Plasmodium falciparum infection, and less than 20% of such fevers in school-age children. Outpatient settings in Malawi had a high burden of malaria illness, but also possible overdiagnosis of malaria illness. Interventions to reduce malaria transmission and rapid testing for other common febrile illness may improve diagnostic clarity among outpatients in malaria endemic settings.
- Subjects :
- Child, Preschool
Female
Fever epidemiology
Fever etiology
Humans
Infant
Infant, Newborn
Malawi epidemiology
Male
Plasmodium falciparum pathogenicity
Predictive Value of Tests
Seasons
Endemic Diseases
Epidemiological Monitoring
Malaria, Falciparum diagnosis
Malaria, Falciparum epidemiology
Overdiagnosis statistics & numerical data
Subjects
Details
- Language :
- English
- ISSN :
- 1476-1645
- Volume :
- 104
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- The American journal of tropical medicine and hygiene
- Publication Type :
- Academic Journal
- Accession number :
- 33939628
- Full Text :
- https://doi.org/10.4269/ajtmh.20-1209