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

Brucellae as resilient intracellular pathogens: epidemiology, host-pathogen interaction, recent genomics and proteomics approaches, and future perspectives

Brucellosis is considered one of the most hazardous zoonotic diseases all over the world. It causes formidable economic losses in developed and developing countries. Despite the significant attempts to get rid of Brucella pathogens in many parts of the world, the disease continues to spread widely. Recently, many attempts proved to be effective for the prevention and control of highly contagious bovine brucellosis, which could be followed by others to achieve a prosperous future without rampant Brucella pathogens. In this study, the updated view for worldwide Brucella distribution, possible predisposing factors for emerging Brucella pathogens, immune response and different types of Brucella vaccines, genomics and proteomics approaches incorporated recently in the field of brucellosis, and future perspectives for prevention and control of bovine brucellosis have been discussed comprehensively. So, the current study will be used as a guide for researchers in planning their future work, which will pave the way for a new world without these highly contagious pathogens that have been infecting and threatening the health of humans and terrestrial animals.

Seroepidemiology of selected transboundary animal diseases in goats in Zambia

Transboundary pathogens of goats present significant constraints to the livelihoods of millions of farmers in countries such as Zambia. Consequently, this study aimed to investigate the seroprevalence of Mycoplasma capricolum subsp. capripneumoniae (Mccp), foot and mouth disease virus (FMDV), Brucella spp., Crimean Congo haemorrhagic fever virus (CCHFV), and Rift Valley fever virus (RVFV) in Zambian goats. Another aim was to identify associations between seroprevalence and different predictor variables, such as trade and border proximity. From September to October 2019, 962 serum samples were collected from goats in seven Zambian districts, four of which have an international border while the remaining three do not. A questionnaire survey was conducted with each household, focusing on trade routines, management strategies and herd disease history. Animal-level seroprevalence adjusted for herd-level clustering was 8.2 % (95 % confidence interval [CI] 7.5-9.0) for Mccp, 12.9% (95% CI 12.0-13.7) for FMDV, 13.0 % (95% CI 12.1-13.9) for Brucella spp., 3.3 % (95% CI 2.8-3.7) for CCHFV, and 0.4 % (95 % CI 0.3-0.7) for RVFV. The association between herd-level seroprevalence and border proximity and trade appeared negligible, with the exception of selling goats at least twice a year which was identified as a potential risk factor for Brucella spp. (OR 4.1, 95 % CI 1.1-16.0, p = 0.040). In addition, a positive association between herd-level seroprevalence of FMDV and a herd size of 21 goats or more (OR 3.3, 95 % CI 1.0-11.1, p = 0.049) was detected. Also, positive associations between animal-level seroprevalence of Brucella spp. and increasing age (OR 7.7, 95 % CI 1.5-40.7, p = 0.016), and CCHFV and keeping pigs in the household (OR 2.7, 95 % CI 1.0-7.1, p = 0.044), were found. For FMDV (OR 3.8, 95 % CI 1.4-10.9, p = 0.011) and Brucella spp. (OR 4.5, 95 % CI 1.2-17.3, p = 0.031) on the other hand, animal-level seroprevalence was significantly higher in households without pigs. To the best of the authors' knowledge, this is the first study to describe the presence of antibodies for CCPP and CCHF in the Zambian goat population. While the association between seroprevalence and trade and border proximity generally appeared negligible, it is recommended that their influence is further evaluated in future studies, preferably through in-depth longitudinal studies incorporating impacts of different biosecurity measures and trade variations, linked to for example seasonality and trade peaks.