Detection of Brucella spp. in raw milk from various livestock species raised under pastoral production systems in Isiolo and Marsabit Counties, northern Kenya

Abstract

Introduction Brucellosis is an important zoonotic disease in Kenya, and identifying the bacteria in milk is important in assessing the risk of exposure in people. Methods A cross-sectional study that involved 175 households was implemented in the pastoral counties of Marsabit and Isiolo in Kenya. Pooled milk samples (n = 164) were collected at the household level, and another 372 were collected from domesticated lactating animals (312 goats, 7 sheep, 50 cattle and 3 camels). Real-time polymerase chain reaction (qPCR) testing of the milk samples was performed to identify Brucella species. Brucella anti-LPS IgG antibodies were also detected in bovine milk samples using an indirect enzyme-linked immunosorbent assay (ELISA). Results Based on the qPCR, the prevalence of the pathogen at the animal level (considering samples from individual animals) was 2.4% (95% confidence interval (CI) 1.1–4.5) and 3.0% (CI: 1.0–7.0) in pooled samples. All 14 samples found positive by qPCR were from goats, with 10 contaminated with B. abortus and 4 with B. melitensis. The Brucella spp. antibody prevalence in bovine milk using the milk ELISA was 26.0% (95% CI: 14.6–40.3) in individual animal samples and 46.3% (95% CI: 30.7–62.6) in pooled samples. Conclusion The study is the first in Kenya to test for Brucella spp. directly from milk using qPCR without culturing for the bacteria. It also detected B. abortus in goats, suggesting transmission of brucellosis between cattle and goats. The high prevalence of Brucella spp. is a significant public health risk, and there is a need for intervention strategies necessary in the study area.

Seroprevalence of Brucella spp. and Rift Valley fever virus among slaughterhouse workers in Isiolo County, northern Kenya

“…and RVFV seroprevalence among slaughterhouse workers was comparable to previous community-level findings from the same region [15,51]. However, our findings on the seropositivity to both infections was not associated to the frequently mentioned risk factors, such as eating patterns and animal husbandry techniques [18,52]. Our findings are also comparable to other studies from Africa that did not find significant association for the risk factor variables and seropositivity for RVFV and Brucella in humans [9,37].…”

“…Despite more than 90% of the respondents consuming both milk and meat, this was not significantly associated with either Brucella or RVFV seropositivity. This suggests limited exposure to the infectious pathogen through this route for the slaughterhouse workers, this could be attributed to reported low prevalence of Brucella in milk [ 18 ]. This further corroborates our hypothesis of likely occupational exposure at the slaughterhouse since most sampled workers did not keep livestock.…”

“…In Kenya, the two diseases are ranked among the top five zoonoses due to their significant public health burden and associated economic impacts [12]. Brucellosis is endemic in most arid and semi-arid regions of Kenya, while RVF is an epidemic-prone disease that is associated with cyclic outbreaks every five to ten years in the country [13][14][15][16][17][18].…”

Seroprevalence and risk factors associated with brucellosis in goats in Nyagatare district, Rwanda

“…Furthermore, the findings in this study are in agreement with study findings published on the risk factors for bovine brucellosis in Uganda and Tanzania (68,69). A study conducted in Kenya also revealed the transmission of Brucella abortus between cattle and goats (70). Transfer of brucellosis infection between cattle and goat herds could be easily facilitated by the improper disposal of an aborted fetus (65,71) and the fact that there is no vaccination campaign in Rwanda against brucellosis in both large animals and small animals (72).…”

Prevalence of <em>Brucella</em> spp. in milk from aborted and non-aborted animals in Dhamar governorate, Yemen

“…Humans generally acquire the disease through direct contact with infected animals, by eating or drinking contaminated animal products or by inhaling airborne agents. Most cases are cause by ingesting unpasteurized milk or cheese from infected goats or sheep (Wainaina et al ., 2020 : Negrón et al ., 2019 : WHO, 2005 ; Corbel, 2006 ). The disease has been recorded in Middle Eastern countries such as Jordan, Algeria, Iraq, and Egypt with different rates of infection (Aggad & Boukraa, 2006 ; Refai, 2002 ; Hamdy and Amin, 2002 ; Ali, 1998 ; Hadad et al , 1997 ; Aldomy et al , 1992 ).…”