Abstract:
BACKGROUND : Human-to-animal transmission of M. tuberculosis (Mtb) is reported in South Africa but there is a
paucity of epidemiological data. The aim of this One Health manuscript is to describe zooanthroponotic exposure
of domestic animals to TB patients, virtually all of whom had laboratory confirmed pulmonary Mtb disease.
METHODS : This cross-sectional study was nested within two TB contact tracing studies and collected data from
2017 to 2019. TB index patients and their households in three provinces of South Africa were recruited. A
questionnaire was administered to households, assessing type and number of animals owned, degree of exposure
of animals to humans, and veterinary consultations. For this analysis, we compared descriptive variables by
animal-keeping status (animal-keeping vs non-animal keeping households), calculated the chi square and
respective p-values.
RESULTS : We visited 1766 households with at least one confirmed case of TB, 33% (587/1766) had livestock or
companion animals. Of non-animal-owning households, 2% (27/1161) cared for other community members'
livestock. Few (16%, 92/587) households kept animals in their dwelling overnight, while 45% (266/587) kept
animals outside the home, but within 10 m of where people slept and ate. Most (81%, 478/587) of people in
animal-owning households were willing for their animal/s to have a TB skin test, but <1% (5/587) of animals
had been skin-tested; 4% (24/587) of animal-owning households had a veterinary consultation in the past six
months, and 5% (31/587) reported one of their animals dying from natural causes in the prior six months.
CONCLUSION : Our survey suggests that a high proportion of patients with TB live in settings facilitating close
contact with domestic animal species with known susceptibility to Mtb. There is a substantial exposure of
household animals to patients with TB and therefore risk of both transmission to, and spillback from animals to
humans.
