Poor performance of the rapid test for human brucellosis in health facilities in Kenya

Human brucellosis is considered to be an important but typically under-diagnosed cause of febrile illness in many low and middle-income countries. In Kenya, and throughout East Africa, laboratory diagnosis for the disease is based primarily on the febrile antigen Brucella agglutination test (FBAT),...

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Main Authors: Glanville, William A. de, Conde-Álvarez, R., Moriyón, I., Njeru, J., Díaz, R., Cook, Elizabeth A.J., Morin, M., Bronsvoort, B.M. de C., Thomas, Lian F., Kariuki, S., Fèvre, Eric M.
Format: Journal Article
Language:Inglés
Published: Public Library of Science 2017
Subjects:
Online Access:https://hdl.handle.net/10568/80714
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author Glanville, William A. de
Conde-Álvarez, R.
Moriyón, I.
Njeru, J.
Díaz, R.
Cook, Elizabeth A.J.
Morin, M.
Bronsvoort, B.M. de C.
Thomas, Lian F.
Kariuki, S.
Fèvre, Eric M.
author_browse Bronsvoort, B.M. de C.
Conde-Álvarez, R.
Cook, Elizabeth A.J.
Díaz, R.
Fèvre, Eric M.
Glanville, William A. de
Kariuki, S.
Morin, M.
Moriyón, I.
Njeru, J.
Thomas, Lian F.
author_facet Glanville, William A. de
Conde-Álvarez, R.
Moriyón, I.
Njeru, J.
Díaz, R.
Cook, Elizabeth A.J.
Morin, M.
Bronsvoort, B.M. de C.
Thomas, Lian F.
Kariuki, S.
Fèvre, Eric M.
author_sort Glanville, William A. de
collection Repository of Agricultural Research Outputs (CGSpace)
description Human brucellosis is considered to be an important but typically under-diagnosed cause of febrile illness in many low and middle-income countries. In Kenya, and throughout East Africa, laboratory diagnosis for the disease is based primarily on the febrile antigen Brucella agglutination test (FBAT), yet few studies of the diagnostic accuracy of this test exist. Assessment of the performance of the FBAT is essential for its appropriate clinical use, as well as for evaluating surveillance data reported by public health systems. To assess FBAT performance, we collected sera from people with symptoms compatible with brucellosis attending two health facilities in Busia County, Kenya. Sera were tested using the FBAT and results compared with those from the Rose Bengal Test (RBT), an assay with well-known performance characteristics. Positives on either test were confirmed using the classical serum agglutination test (SAT)-Coombs test combination and a rapid IgM/IgG lateral flow immunochromatography assay (LFA). A questionnaire focussing on known risk factors for exposure to Brucella spp. was also conducted, and relationships with FBAT positivity examined using logistic regression. Out of 825 recruited individuals, 162 (19.6%) were classified as positive using the FBAT. In contrast, only eight (1.0%) were positive using the RBT. Of the 162 FBAT positives, one (0.62%) had an atypical agglutination in SAT and three (1.9%) showed low Coombs titres. Out of 148 FBAT positive individuals tested using the LFA, five (3.4%) were IgM positive and none were IgG positive. Poor or no correlation was observed between FBAT results and most established risk factors for Brucella infection. We observed substantial disagreement between the FBAT and a number of well-known serological tests, with the majority of reactive FBAT results appearing to be false positives. Poor FBAT specificity, combined with a lack of confirmatory testing, strongly suggests overdiagnosis of brucellosis is common in this low prevalence setting. This is expected to have important economic impacts on affected patients subjected to the long and likely unnecessary courses of multiple antibiotics required for treatment of the disease.
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spelling CGSpace807142025-12-08T09:54:28Z Poor performance of the rapid test for human brucellosis in health facilities in Kenya Glanville, William A. de Conde-Álvarez, R. Moriyón, I. Njeru, J. Díaz, R. Cook, Elizabeth A.J. Morin, M. Bronsvoort, B.M. de C. Thomas, Lian F. Kariuki, S. Fèvre, Eric M. animal diseases livestock health brucellosis diagnosis zoonoses infectious diseases Human brucellosis is considered to be an important but typically under-diagnosed cause of febrile illness in many low and middle-income countries. In Kenya, and throughout East Africa, laboratory diagnosis for the disease is based primarily on the febrile antigen Brucella agglutination test (FBAT), yet few studies of the diagnostic accuracy of this test exist. Assessment of the performance of the FBAT is essential for its appropriate clinical use, as well as for evaluating surveillance data reported by public health systems. To assess FBAT performance, we collected sera from people with symptoms compatible with brucellosis attending two health facilities in Busia County, Kenya. Sera were tested using the FBAT and results compared with those from the Rose Bengal Test (RBT), an assay with well-known performance characteristics. Positives on either test were confirmed using the classical serum agglutination test (SAT)-Coombs test combination and a rapid IgM/IgG lateral flow immunochromatography assay (LFA). A questionnaire focussing on known risk factors for exposure to Brucella spp. was also conducted, and relationships with FBAT positivity examined using logistic regression. Out of 825 recruited individuals, 162 (19.6%) were classified as positive using the FBAT. In contrast, only eight (1.0%) were positive using the RBT. Of the 162 FBAT positives, one (0.62%) had an atypical agglutination in SAT and three (1.9%) showed low Coombs titres. Out of 148 FBAT positive individuals tested using the LFA, five (3.4%) were IgM positive and none were IgG positive. Poor or no correlation was observed between FBAT results and most established risk factors for Brucella infection. We observed substantial disagreement between the FBAT and a number of well-known serological tests, with the majority of reactive FBAT results appearing to be false positives. Poor FBAT specificity, combined with a lack of confirmatory testing, strongly suggests overdiagnosis of brucellosis is common in this low prevalence setting. This is expected to have important economic impacts on affected patients subjected to the long and likely unnecessary courses of multiple antibiotics required for treatment of the disease. 2017-04-07 2017-04-12T11:43:19Z 2017-04-12T11:43:19Z Journal Article https://hdl.handle.net/10568/80714 en Open Access Public Library of Science Glanville, W.A. de, Conde-Álvarez, R., Moriyón, I., Njeru, J., Díaz, R., Cook, E.A.J., Morin, M., Bronsvoort, B.M. de C., Thomas, L.F., Kariuki, S. and Fèvre, E.M. 2017. Poor performance of the rapid test for human brucellosis in health facilities in Kenya. PLoS Neglected Tropical Diseases 11(4): e0005508.
spellingShingle animal diseases
livestock
health
brucellosis
diagnosis
zoonoses
infectious diseases
Glanville, William A. de
Conde-Álvarez, R.
Moriyón, I.
Njeru, J.
Díaz, R.
Cook, Elizabeth A.J.
Morin, M.
Bronsvoort, B.M. de C.
Thomas, Lian F.
Kariuki, S.
Fèvre, Eric M.
Poor performance of the rapid test for human brucellosis in health facilities in Kenya
title Poor performance of the rapid test for human brucellosis in health facilities in Kenya
title_full Poor performance of the rapid test for human brucellosis in health facilities in Kenya
title_fullStr Poor performance of the rapid test for human brucellosis in health facilities in Kenya
title_full_unstemmed Poor performance of the rapid test for human brucellosis in health facilities in Kenya
title_short Poor performance of the rapid test for human brucellosis in health facilities in Kenya
title_sort poor performance of the rapid test for human brucellosis in health facilities in kenya
topic animal diseases
livestock
health
brucellosis
diagnosis
zoonoses
infectious diseases
url https://hdl.handle.net/10568/80714
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