Seroprevalence of Bovine Brucellosis in Selected Districts of Zambia

Abstract

Brucellosis is an infectious zoonosis that has huge economic and public health implications globally. The disease is prevalent in humans, livestock and wildlife in Sub-Saharan Africa. A cross-sectional study was conducted between 6 May 2017 and 31 July 2020 during which 1712 sera from 175 cattle herds in five districts from Southern, Western and Eastern Provinces of Zambia were collected and screened against brucellosis. The Rose Bengal Test (RBT) and competitive Enzyme-linked Immuno Assay (c-ELISA) were used in serial testing for the detection of antibodies against Brucella species. A total of 127 animals from 37 herds tested positive, giving overall individual animal and herd-level seroprevalences of 7.53% (95% CI: 6.28–8.78%) and 21.14% (95% CI: 15.0–27.2%), respectively. Namwala district had the highest herd seroprevalence (33.9%, 95% CI: 21.6–46.1%), while Lundazi did not record any seropositivity. Comparably, Southern Province had the highest individual animal (8.97%, 95% CI: 7–11%) and herd-level (28.5%, 95% CI: 20.3–36.7%) seroprevalences, although this was not statistically significant. Within Southern Province, higher seropositivity was observed in Namwala district (OR: 8.55; CI: 2.66–27.44), among female animals (OR: 2.48; CI: 1.38–4.46) and in those aged 11 years and above (OR: 2.67; CI: 1.34–5.34) as well as in gravid cows (OR: 4.34; CI: 2.08–8.92). Seropositivity was also observed among some animals with hygromas (OR: 6.5; CI: 0.45–94.08) and those with a history of abortion (OR: 1.13; CI: 0.18–7.28) although the findings were not statistically significant. Brucella seroprevalence among traditional cattle in Zambia remains high. Control programs against bovine brucellosis must be introduced to reduce its impact on human health and animal production.

Documenting the absence of bovine brucellosis in dairy cattle herds in the southern region of Malawi and the associated knowledge, attitudes and practices of farmers

“…In the Nabibe province of Angola, the seroprevalence of brucellosis in animals and herds was found to be 14.96% and 40.10%, respectively (Mufinda, Boinas & Nunes 2017 ) whilst in Zambia, the individual prevalences of 7.9%, 14.3% and 18.7% (Chimana et al 2014 ), 8.7% and 19% (Muma et al 2006 ) were reported. A recent study in selected districts of Zambia by Mfune et al ( 2021 ) reported individual and herd prevalences in ranges of 0.0% – 7.3% and 0.0% – 21.1%, respectively. In Zimbabwe, seroprevalences of 9.9% and 5.6% were found (Gomo et al 2012 ; Matope et al 2011 ), whilst Mozambique reported a 9.7% seroprevalence in wildlife-livestock interface areas (Tanner et al 2014 ).…”

Brucella Seroprevalence and Associated Risk Factors in Occupationally Exposed Humans in Selected Districts of Southern Province, Zambia

“…Further, these workers were at a high risk of injury (knife-cuts) as compared to herdsmen, which increases the risk of exposure to the Brucella pathogen (20). A Brucella cattle herd seroprevalence of 28.5% has been previously been estimated in this study area (24). Comparable seropositive results among the study districts showed that Namwala had the highest (26.8%), followed by Monze (19.4%), while Choma had the lowest (11.4%).…”

“…The province and study districts were purposively selected because they are the top cattle producers in Zambia ( 29 ). Furthermore, these areas are endemic for bovine brucellosis as documented by several serological surveys ( 24 , 29 , 30 ). Southern Province lies between latitudes 15°14′ S and 17°42′ S and longitudes 25°E and 28° S. It has a total land surface area of 85,283 Km 2 with an estimated human population of 1,907,784 and a cattle population of 2,105,891 ( 31 ).…”

“…The province and study districts were purposively selected because they are the top cattle producers in Zambia (29). Furthermore, these areas are endemic for bovine brucellosis as documented by several serological surveys (24,29,30). Southern Province lies between latitudes 15 (31).…”

“…The seroprevalence and the associated risk factors of human infection in high-risk populations have not been well-understood and documented in the Southern Province of Zambia. Yet, a recent brucellosis study conducted in cattle in the same province found a herd seroprevalence of 28.5% ( 24 ). Considering that more than a third of Africa's population depend solely on livestock and livestock products for their livelihoods ( 25 ), the likelihood of human infection is therefore high.…”