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bioRxiv · 10.1101/2021.12.07.471573

Seroprevalence of brucellosis and molecular characterization of Brucella spp. from slaughtered cattle in Rwanda

Ntivuguruzwa, J. B.·Babaman Kolo, F.·Mwikarago, I. E.·vanHeerden, H.
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Abstract

Bovine brucellosis is endemic in Rwanda, although, there is paucity of documented evidence about the disease in slaughtered cattle. A cross-sectional study was conducted in slaughtered cattle (n=300) to determine the seroprevalence of anti-Brucella antibodies using the Rose Bengal Test (RBT), and indirect enzyme-linked immunosorbent assay (i-ELISA). Corresponding tissues were cultured onto a modified Centro de Investigacion y Tecnologia Agroalimentaria (CITA) selective medium and analysed for Brucella spp. using the 16S-23S ribosomal interspacer region (ITS), AMOS, and Bruce-ladder PCR assays. The RBT seroprevalence was 20.7% (62/300), and 2.9% (8/300) with i-ELISA and 2.9% (8/300) using both tests in parallel. Brucella specific 16S-23S ribosomal DNA interspace region (ITS) PCR detected Brucella DNA in 5.6% (17/300; Brucella culture prevalence). AMOS-PCR assay identified mixed B. abortus and B. melitensis (n=3), B. abortus (n=3) and B. melitensis (n=5) while Bruce-ladder PCR also identified B. abortus (n=5) and B. melitensis (n=6). The gold standard culture method combined with PCR confirmation identified 5.6% Brucella cultures which is higher than the more sensitive seroprevalence of 2.9%. This emphasizes the need to validate the serological tests in Rwanda. The mixed infection caused by B. abortus and B. melitensis in slaughtered cattle indicates cross-infection and poses a risk of exposure potential to abattoir workers. It is essential to urgently strengthen the national bovine brucellosis control program through vaccination as well as test- and-slaughter.

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Ntivuguruzwa, J. B., Babaman Kolo, F., Mwikarago, I. E., vanHeerden, H.. 2021-12-07. Seroprevalence of brucellosis and molecular characterization of Brucella spp. from slaughtered cattle in Rwanda. https://doi.org/10.1101/2021.12.07.471573

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