Mpumalanga lab data point to brucellosis surveillance hotspots

A new South African surveillance study suggests routine lab data may be more useful for brucellosis control than many programs currently assume. An analysis of bovine Rose Bengal Test results from Mpumalanga Province found that positivity shifted over time, place, and season between 2021 and 2024, with a marked increase in 2023 followed by a decline in 2024. The paper positions those patterns as actionable signals for disease monitoring in an endemic province, rather than as background noise in a passive testing system. That framing fits with a broader brucellosis literature showing that surveillance signals can emerge differently depending on host species and test strategy: in southeastern Türkiye, for example, investigators studying aborting nomadic sheep and goats found 20.99% seropositivity by RBPT versus 24.78% by indirect ELISA, with 19.53% positive on both assays and treated as confirmed positive, highlighting how apparent burden can shift depending on which tools are used. (pmc.ncbi.nlm.nih.gov)

That matters because bovine brucellosis remains a long-running animal health and zoonotic challenge in South Africa. National materials describe the disease as endemic across all nine provinces, and South African rules treat it as a controlled animal disease, with compulsory vaccination of heifers between 4 and 8 months of age and restrictions tied to infected cattle and herds. Prior South African literature has also argued that control weakened after decentralization and a shift in responsibility from government-led programs toward livestock keepers, contributing to uneven implementation over time. (nda.gov.za)

The Mpumalanga study used anonymized routine diagnostic data generated by the Mpumalanga Provincial Veterinary Laboratory, the province’s central reference laboratory for brucellosis testing. According to the article summary, the researchers modeled batch-level RBT positivity and examined temporal, seasonal, and spatial predictors. Their central finding was not a simple linear increase, but an episodic pattern: positivity rose sharply in 2023, then fell back toward earlier levels, while district-level differences suggested that transmission pressure or detection intensity may not be uniform across the province. The authors also flagged an important operational limitation: confirmatory assays such as complement fixation testing or ELISA were not systematically available for all submissions, which means the dataset is most useful for surveillance patterning rather than definitive burden estimates. That caution is consistent with the Türkiye small-ruminant study, where RBPT and i-ELISA showed agreement by kappa but still differed significantly by McNemar’s test, reinforcing that screening and confirmation are not interchangeable in endemic settings. (pmc.ncbi.nlm.nih.gov)

That limitation is especially relevant because RBT is widely used as a practical screening tool, but control programs depend on what happens after screening. South African brucellosis guidance and recent provincial research describe a framework built around screening, confirmatory testing, vaccination, quarantine, movement controls, and removal of positive animals. In other words, the value of a signal-rich surveillance system depends on whether veterinary services can translate positive screens into confirmatory diagnosis and herd-level intervention. The Türkiye paper makes much the same point from a different production system: in nomadic small-ruminant populations, where abortion-associated brucellosis can be especially hard to track, RBPT remains useful in resource-limited conditions, but the authors argue that wider use of more sensitive and specific antigen-based assays is essential for more reliable surveillance in endemic areas. (pmc.ncbi.nlm.nih.gov)

Industry and field-facing commentary in South Africa has consistently stressed the same pressure points: silent infection, abortion losses, human exposure risk, and the need for vaccination plus biosecurity. Farmers Weekly, citing Afrivet’s technical leadership, described bovine brucellosis as easy to miss until abortions occur and emphasized heifer vaccination and human health precautions. South African awareness materials have similarly framed brucellosis as both a herd productivity problem and a public health issue, particularly where raw milk exposure or contact with aborted material occurs. Those concerns are not limited to cattle. A recent four-year shelter-dog study from southern Italy reported Brucella canis seroprevalence of 17.3% and found that while sex, year, and province were not independent predictors of simple IFAT positivity, year and province did significantly influence antibody magnitude, with titres increasing toward 2025. That kind of pattern matters because it suggests infection pressure may intensify before crude positive/negative prevalence shifts clearly enough to trigger action. (farmersweekly.co.za)

Why it matters: For veterinarians, diagnostic labs, and animal health officials, the study is a reminder that retrospective surveillance can help prioritize scarce field capacity. If certain districts or seasons repeatedly generate higher RBT positivity, that can inform where to intensify herd investigations, vaccine compliance checks, producer education, and human exposure messaging. It also offers a model for provinces that don’t yet have perfect confirmatory coverage: even imperfect routine data can support smarter surveillance design, provided decision-makers are clear about the difference between screening positivity and confirmed infection. The added lesson from the Türkiye and Italy studies is that surveillance may be strengthened by looking beyond a single binary result—either by pairing screening with confirmatory assays or, where appropriate, by tracking antibody intensity over time as a possible marker of changing transmission pressure. (pmc.ncbi.nlm.nih.gov)

There’s also a broader takeaway for companion animal and mixed-practice veterinarians serving rural communities. Brucellosis is a classic One Health problem, and cattle surveillance trends can have implications beyond herd fertility and trade. Better detection in cattle can reduce occupational exposure for farm workers, abattoir staff, and pet parents in agricultural households who may be exposed through raw dairy products or reproductive materials. The canine data from southern Italy add another reminder that brucellosis surveillance cannot stay siloed by species: B. canis is an emerging zoonotic pathogen, and the authors called for mandatory screening and coordinated One Health surveillance after documenting endemic infection in shelter dogs and rising antibody magnitude over time. That makes surveillance quality, not just treatment or outbreak response, a practical veterinary public health issue. (aphis.usda.gov)

What to watch: The next meaningful step will be whether Mpumalanga and other provinces connect routine RBT data to stronger confirmatory pipelines and herd-level epidemiology, including animal movement, vaccination history, and farm management variables. If that happens, the current paper could become less a descriptive snapshot and more a template for targeted brucellosis control in endemic regions. More broadly, watch for surveillance programs to incorporate lessons from other endemic settings: confirmation strategies like those highlighted in nomadic small-ruminant work, and richer trend metrics like antibody magnitude from canine studies, could help veterinary services detect intensifying infection pressure earlier and respond more precisely. (pmc.ncbi.nlm.nih.gov)