Department of Veterinary Pathology

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Browsing Department of Veterinary Pathology by Subject "Brucellosis"

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    Bovine tuberculosis and brucellosis in livestock at the Greater Ruaha Ecosystem
    (The Tropical Veterinarian, 2020) Medardus, J. J.
    A cross-sectional study was conducted to determine the prevalence of bovine tuberculosis (BTB) and the seroprevalence of brucellosis in livestock at the Greater Ruaha Ecosystem in Tanzania. The study further characterized the Mycobacterium spp. from the slaughtered livestock. Survey conducted to assess potential herd-level risk factors for BTB and brucellosis revealed that the respondents’ ethnicity and herd mixing were the significant risk factors. Twenty-eight percent of 102 cattle herds had at least one positive or suspect BTB reactor. The overall prevalence of BTB infection in the cattle was 1.32% (18/1368). Forty-two percent of 93 flocks of the small ruminants had at least one brucellosis seropositive animal. The overall seroprevalence of brucellosis in the cattle and small ruminants was 6.6%. Although the prevalence of both diseases was relatively low for individual animals, herd-level prevalence was high, suggesting that infection is widespread in the study area and a significant number of households are at risk. Mycobacterium bovis strain identified via polymerase chain reaction (PCR) was confirmed by spoligotyping as spoligotype SB0133. This cattle strain of M. bovis was similar to previously reported involving wild animals in adjacent protected areas. Isolation of identical M. bovis from the wildlife and livestock and the demonstration of Brucella spp. seroprevalence in livestock in the same interface, strongly suggest livestock-wildlife interspecies sharing of these pathogens. Occurrence of the microorganisms poses a serious challenge to disease management strategies in pastoralist communities in the interface area.
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    Circulating Brucella species in wild animals of the Serengeti ecosystem, Tanzania
    (Springer, 2021) Sambu, R. M; Mathew, C; Nonga, H. E; Lukambagire, A. S; Yapi, R. B; Akoko, J; Fokou, G; Keyyu, J. D; Bonfoh, B; Kazwala, R. R
    Background: Brucellosis is a bacterial zoonosis of public health and economic importance worldwide. It affects a number of domestic animals, wild animals and humans. Human brucellosis originates from either livestock or wildlife. The species of Brucella circulating in wild animals in Tanzania is largely unknown due to insufficient surveillance. This study was carried out to identify Brucella species found in selected wildlife hosts in the Serengeti ecosystem. Methodology: The study used a total of 189 archived samples that were obtained from cross-sectional studies previously conducted between 2000 and 2017 in the Serengeti ecosystem in Tanzania. Whole blood, serum and amniotic fluid collected from buffalos, lions, wildebeest, impala, zebra and hyena were available for DNA extraction. Multiplex polymerase chain reaction for B. abortus, B. melitensis, B. ovis and B. suis (AMOS PCR) and quantitative real time PCR (qPCR) targeting the bcsp31 and IS711 genes for Brucella genus detection and the IS711 targets alkB for B. abortus and BMEI1162 for B. melitensis were used to detect Brucella strains. Results: Out of the 189 samples tested, 12 (6.35 %) and 22 (11.6 %) were positive to AMOS-PCR and qPCR, respectively. Most of the positive samples were from lions (52.6 %) and buffaloes (19.6 %). Other animals that were positive included: wildebeest (13.6 %), impala (13.6 %), zebra (4.5 %) and hyena (4.5 %). Out of 22 positive samples, 16 (66.7 %) were identified as B. abortus and the other six samples did not amplify for neither B. abortus nor B. melitensis. Conclusions: The detection of Brucella DNA in archived wild animal samples shows testing potential of samples collected from this population. The zoonotic species B. abortus and B. melitensis detected in wild animals have previously been reported in livestock and humans in the region. The findings suggest that, due to the contact network, some of the identified wild animal hosts in this study could be reservoirs for infections in domestic animals and humans within the Serengeti ecosystem while others are likely dead-end hosts. One Health control strategies and continuous surveillance programs in other wildlife reserved areas should be implemented to help predicting transmission in livestock and humans in the region.
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    Seroprevalence of brucellosis in small ruminants and related risk behaviours among humans in different husbandry systems in Mali
    (PLoSONE, 2021) Traore, S; Coulibaly, K; Mathew, C; Fokou, G; Bonfoh, B; Yapi, R. B.; Kazwala, R. R.; Alambedji, R. B.
    Mali has a high pastoral potential with diverse coexisting production systems ranging from traditional (nomadic, transhumant, sedentary) to commercial (fattening and dairy production) production systems. Each of those systems is characterised by close interactions between animals and humans, increasing the potential risk of transmission of zoonotic diseases. The nature of contact network suggests that the risks may vary according to species, production systems and behaviors. However, the study of the link between small ruminants and zoonotic diseases has received limited attention in Mali. The objective of this study was to assess brucellosis seroprevalence and determine how the husbandry systems and human behaviour expose animal and human to infection risk. A cross-sectional study using cluster sampling was conducted in three regions in Mali. Blood was collected from 860 small ruminants. The sera obtained were analysed using both Rose Bengal and cELISA tests. In addition, 119 farmers were interviewed using a structured questionnaire in order to identify the characteristics of farms as well as the risk behaviors of respondents. Husbandry systems were dominated by agro-pastoral systems followed by pastoral systems. The commercial farms (peri-urban and urban) represent a small proportion. Small ruminant individual seroprevalence was 4.1% [2.8–5.6% (95% CI)]. Herd seroprevalence was estimated at 25.2% [17.7–33.9% (95% CI)]. Peri-urban farming system was more affected with seroprevalence of 38.1% [18.1–61.5 (95% CI)], followed by pastoral farming system (24.3% [11.7–41.2 (95% CI)]). Identified risk behaviors of brucellosis transmission to animals were: exchange of reproductive males (30.2%); improper disposal of placentas in the farms (31.1%); and keeping aborted females in the herd (69.7%). For humans, risk factors were: close and prolonged contact with animals (51.2%); consumption of unpasteurized dairy products (26.9%); and assisting female animals during delivery without any protection (40.3%). This study observed a high seroprevalence of brucellosis in small ruminants and also identified risky practices that allow cross transmission between the two populations. This calls for control strategy using a multi-sectoral and multidimensional approach.