In livestock, brucellosis is mainly an asymptomatic disease except when abortion occurs; therefore, two serological tests are used for diagnosis as no single test is suitable. Abattoir samples enable a combination of culture, molecular, and serological tests to detect brucellosis. This study assessed Brucella-specific PCR (ITS-PCR) to detect brucellosis and to conduct a molecular characterization of Brucella spp. isolated from PCR-positive livestock (n = 565) slaughtered at abattoirs and the appropriate sample tissue(s). ITS-PCR detected Brucella DNA in 33.6% of cattle, 14.5% of sheep, and 4.7% of pig tissues. Impure Brucella cultures from PCR-positive tissues were 43.6% (44/94) of cattle, 51.7% (15/29) of sheep, and 50% (2/4) of pigs with predominantly B. abortus identification with AMOS-PCR and low isolation of mixed B. abortus and B. melitensis in all species. In cattle, 33% of isolates were from lymph nodes, while in sheep 38.0% were from the liver and kidney and only from tonsils in pigs (2/4). Brucella infections identified with AMOS-PCR were present in seropositive and mainly seronegative (75.6–100%) livestock with the potential to cause brucellosis during pregnancy or breeding. This study demonstrated the value of the polyphasic approach, especially with chronic infections and the potential risk of these asymptomatic animals.

Brucellosis is an economically important zoonotic disease affecting humans, livestock, and wildlife health globally and especially in Africa. Brucella abortus and B. melitensis have been isolated from human, livestock (cattle and goat), and wildlife (sable) in South Africa (SA) but with little knowledge of the population genomic structure of this pathogen in SA. As whole genome sequencing can assist to differentiate and trace the origin of outbreaks of Brucella spp. strains, the whole genomes of retrospective isolates (n = 19) from previous studies were sequenced. Sequences were analysed using average nucleotide identity (ANI), pangenomics, and whole genome single nucleotide polymorphism (wgSNP) to trace the geographical origin of cases of brucellosis circulating in human, cattle, goats, and sable from different provinces in SA. Pangenomics analysis of B. melitensis (n = 69) and B. abortus (n = 56) was conducted with 19 strains that included B. abortus from cattle (n = 3) and B. melitensis from a human (n = 1), cattle (n = 1), goat (n = 1), Rev1 vaccine strain (n = 1), and sable (n = 12). Pangenomics analysis of B. melitensis genomes, highlighted shared genes, that include 10 hypothetical proteins and genes that encodes for acetyl-coenzyme A synthetase (acs), and acylamidase (aam) amongst the sable genomes. The wgSNP analysis confirmed the B. melitensis isolated from human was more closely related to the goat from the Western Cape Province from the same outbreak than the B. melitensis cattle sample from different cases in the Gauteng Province. The B. melitensis sable strains could be distinguished from the African lineage, constituting their own African sub-clade. The sequenced B. abortus strains clustered in the C2 lineage that is closely related to the isolates from Mozambique and Zimbabwe. This study identified genetically diverse Brucella spp. among various hosts in SA. This study expands the limited known knowledge regarding the presence of B. melitensis in livestock and humans in SA, further building a foundation for future research on the distribution of the Brucella spp. worldwide and its evolutionary background.

Zoonotic infections were investigated in a cross-sectional study on asymptomatic livestock slaughtered in abattoirs in the Eastern Cape. Antibodies against Brucella spp., Coxiella burnetii, Toxoplasma gondii, and the coexposure were investigated in sera using serological tests. A total of 565 animals comprising of 280 cattle, 200 sheep, and 85 pigs were screened using RBT, iELISA, CFT, and AMOS-PCR. The Mast Toxoreagent test and iELISA were used for the detection of T. gondii and C. burnetii, respectively. The Brucella positivity based on at least two tests was 4.3 (12/280), 1.0 (2/200), and 0.0 (0/85) in cattle, sheep, and pigs, respectively. Toxoplasma gondii seropositivity of 37.90 (106/280), 1.50 (3/200), and 7.10 (6/85) was observed in cattle, sheep, and pigs, respectively. Coxiella burnetii seropositivity of 26.40 (74/280), 15.00 (30/200), and 2.40 (2/85) was observed in cattle, sheep, and pigs, respectively. Coexposure was detected in cattle for positivity against C. burnetii and T. gondii 40.54, Brucella spp. and T. gondii 1.35, and Brucella spp. and C. burnetii 4.05. Coexposure for Brucella spp., C. burnetii, and T. gondii 4.05 was detected in cattle. Coexposure of Brucella spp. and C. burnetii 6.67 was detected in sheep. The AMOS-PCR identified B. abortus in cattle and a mixed infection of B. abortus and B. melitensis in sheep in 64.71 seropositive samples. To our knowledge, the coexposure of Brucella spp., T. gondii, and C. burnetii in cattle has not been reported. Coexposure of Brucella spp. and C. burnetii in cattle and sheep is significant as it results in reproductive losses and constitutes an infectious risk to humans. The detection of antibodies against multiple zoonotic infections in livestock from abattoirs has implications for public health.

In livestock, brucellosis is mainly an asymptomatic disease except for abortion, therefore two serological tests are used for diagnosis as no single test is suitable. Abattoir samples enable a combination of culture, molecular and serological tests to detect brucellosis. This study assessed Brucella specific PCR (ITS-PCR) to detect brucellosis and to conduct molecular characterization of Brucella spp. isolated from PCR-positive livestock (n=565) slaughtered at abattoirs and the appropriate sample tissue(s). ITS-PCR detected Brucella DNA in 33.6% cattle, 14.5% sheep and 4.7% pig tissues. Impure Brucella cultures from PCR-positive tissues were 43.6% (44/94) cattle, 51.7% (15/29) sheep, and 50% (2/4) pigs with predominantly B. abortus identification with AMOS-PCR and low isolation of mixed B. abortus and B. melitensis in all species. In cattle 33% of isolates were from lymph nodes while in sheep 38.0% were from liver and kidney and only from tonsils in pigs (2/4). Brucella infections identified with AMOS-PCR were present in seropositive and mainly seronegative (75.6-100%) livestock with the potential to cause brucellosis during pregnancy or breeding. This study demonstrated the value of the polyphasic approach, especially with chronic infections and the potential risk of these asymptomatic animals.

Brucellosis, a zoonotic bacterial disease caused by Brucella spp., poses a major threat to livestock, wildlife, and human health. Infected animals act as reservoirs, facilitating cross-species transmission. In South Africa, Brucella abortus and B. melitensis have been reported in livestock and humans, even prior to the introduction of a partial bovine brucellosis control scheme in the 1980s targeting high-risk populations, such as dairy cattle. Despite this intervention, the disease remains endemic and continues to spread due to inadequate vaccination, poor husbandry, limited resources, and unrestricted animal move- ment. Diagnostic protocols rely on serological screening using the Rose Bengal Test, with confirmation by the Complement Fixation Test. While serological methods have proven effective in eradication campaigns in developed countries, they are less suitable in en- demic settings where only a small portion of the livestock population— mainly cattle—is tested. Chronic or latent infections often evade detection by serology and even by culture, which has low sensitivity unless performed on aborted material, rarely obtainable from wildlife. Cross-species transmission is well documented. Brucella melitensis has been iso- lated from cattle, while Brucella spp. Have been detected in wildlife, including African buffalo, sable antelope, giraffe, plains zebra, hippopotamus, elephant, and African wild dog. Diagnostic capacity remains limited, with serological testing restricted to bovine and buffalo specimens. Although brucellosis is a controlled disease, financial and logisti- cal constraints undermine effective government response. The current bovine brucelosis scheme has had limited success in halting transmission. Sustainable control in endemic countries like South Africa requires moving away from eradication models designed for non-endemic regions. Instead, a context-specific strategy focusing on vaccination of livestock, improved diagnostics, and integrated surveillance under a One Health framework is essential to limit transmission, protect public and animal health and reduce long-term socioeconomic impacts.

Background: Workers handling infected animals and carcasses are at risk of zoonotic diseases. However, knowledge, practices and the burden of zoonotic infections among abattoir workers in Africa remain poorly characterized. Objectives: This study aimed to assess knowledge and practices regarding selected zoonoses among abattoir workers in the Eastern Cape, determine seroprevalence of Coxiella burnetii among brucellosis‐seropositive workers in Gauteng, and evaluate variability in seroprevalence of brucellosis, Q‐fever and toxoplasmosis across Africa through a meta‐analysis. Methods: A cross‐sectional study was conducted among 76 abattoir workers using a structured questionnaire to assess knowledge and practices related to zoonotic diseases. In addition, 92 workers with known brucellosis seropositivity were tested for C. burnetii antibodies. A meta‐analysis was conducted to assess the seroprevalence of brucellosis, Q‐fever and toxoplasmosis across African studies. Results: Univariate analyses revealed that job description and education level were significantly associated ( p ≤ 0.05) with knowledge of brucellosis and toxoplasmosis. The overall C. burnetii seropositivity was 61.9% (95% Cl: 51.3–71.9). A total of 57/92 (61.96%) had IgG antibodies and 1/92 (1.09%) had IgM and IgG antibodies. The meta‐analysis showed that brucellosis seroprevalence ranged from 1.3% to 46.4%, based on two or more tests conducted in 12 African countries. Toxoplasmosis seroprevalence, detected using various single tests, ranged from 2.2% to 84.0% in eight countries, while Q‐fever seroprevalence, assessed in three countries, varied from 6.5% to 37.1%. Conclusions: This study emphasizes the importance of educating abattoir workers about zoonotic diseases to improve their practices, attitudes and understanding. Abattoir facilities management may improve practices and PPE to encourage workers to follow necessary protocols. The study further demonstrates the limited number of abattoir worker studies on the selected zoonotic diseases observed across Africa, illustrating the importance of further investigations.