Brucellosis Seropositivity Using Three Serological Tests and Associated Risk Factors in Abattoir Workers in Gauteng Province, South Africa

Francis B Kolo; Abiodun A Adesiyun; Folorunso O Fasina; Bernice N Harris; Jennifer Rossouw; Charles Byaruhanga; Hermanus De Wet Geyer; Lucille Blumberg; John Frean; Henriette van Heerden

doi:10.3390/pathogens13010064

Brucellosis Seropositivity Using Three Serological Tests and Associated Risk Factors in Abattoir Workers in Gauteng Province, South Africa

Pathogens. 2024 Jan 9;13(1):64. doi: 10.3390/pathogens13010064.

Affiliations

¹ Faculty of Veterinary Science, Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria 0182, South Africa.
² Faculty of Veterinary Science, Department of Production Animal Studies, University of Pretoria, Pretoria 0182, South Africa.
³ School of Health Systems and Public Health, Faculty of Health Science, University of Pretoria, Pretoria 0084, South Africa.
⁴ Centre for Emerging, Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, a Division of the National Health Laboratory Service, Johannesburg 2132, South Africa.
⁵ Faculty of Health Sciences, University of Witwatersrand, Johannesburg 2050, South Africa.

Abstract

Abattoir workers are liable to zoonotic infections from animals and animal products, primarily to diseases with asymptomatic and chronic clinical manifestations in animals, such as brucellosis. No published reports exist on the seroprevalence of brucellosis in abattoir workers in South Africa. Therefore, this cross-sectional study was conducted to estimate the occurrence and risk factors for Brucella exposure in abattoir workers in Gauteng Province. A total of 103 abattoir workers and managers from 6 abattoirs, where brucellosis-positive slaughtered cattle and sheep were previously detected, were interviewed and tested with serological assays using the Rose Bengal test (RBT), BrucellaCapt, and IgG-ELISA. A pre-tested questionnaire was administered to consenting respondents to obtain information on risk factors for brucellosis. Of the 103 respondents tested, the distribution of female and male workers was 16 (15.5%) and 87 (84.5%), respectively. The seroprevalence for exposure to brucellosis was 21/103 (20.4%, 95%CI: 13.1-29.5) using a combination of RBT, BrucellaCapt, or IgG-ELISA. For test-specific results, seroprevalences by RBT, BrucellaCapt, and IgG-ELISA were 13/103 (12.6%, 95%CI: 6.9-20.6), 9/103 (8.74%, 95%CI: 4.1-15.9), and 18/103 (17.5%, 95%CI: 10.7-26.2), respectively. Low-throughput abattoirs were identified as associated risks, as 29.3% of workers were seropositive compared with 12.7% of workers in high-throughput abattoirs, which highlights that direct contact at abattoirs poses higher risk to workers than indirect and direct contact outside abattoirs. This study confirms the occurrence of Brucella spp. antibodies among abattoir workers in South Africa, possibly due to occupational exposure to Brucella spp., and highlights the occupational hazard to workers. Furthermore, findings underscore that abattoir facilities can serve as points for active and passive surveillance for indicators of diseases of public health importance. We recommend periodic implementation of brucellosis testing of abattoir workers country-wide to establish baseline data for informing appropriate preventive practices and reducing the potential burden of infection rates among these high-risk workers.

Keywords: South Africa; abattoir; brucellosis; human; serology.

Grants and funding

5 NU2GGH001874-02-00/CC/CDC HHS/United States