Epidemiology and predilection-site distribution of tick infestation in communal cattle systems of Limpopo Province, South Africa

Abstract

BACKGROUND: Ticks and tick-borne diseases are major constraints to cattle productivity in sub-Saharan Africa. This study assessed the epidemiology and host-level determinants of tick infestation in communal cattle systems in South Africa. METHODS: This cross-sectional study examined 787 cattle across 17 villages. Animal-level data included sex, breed (Nguni, Drakensberg, Bonsmara, Brahman, Hereford, Simmentaler, and crossbreeds), age, and body condition score. Tick burden was quantified on six anatomical sites, and whole-body burden was estimated from one-sided counts. RESULTS: Tick burden was heterogeneously distributed across anatomical predilection sites, with the ears (mean = 50.7 ticks), lower perineum (mean = 44.4 ticks), and upper perineum (mean = 34.2 ticks) exhibiting the highest infestation intensities. Older cattle (> 8 years; IRR = 1.58, 95% CI: 1.39-1.79) and adult cattle (> 2-8 years; IRR = 1.43, 95% CI: 1.26-1.63) harboured significantly more ticks than young cattle (≤ 2 years). Indigenous and crossbred cattle exhibited lower tick burdens than exotic breeds, although breed was not a significant predictor of tick burden after adjustment. Multilevel negative binomial modelling confirmed age and body condition score as independent predictors of total tick burden, while accounting for farm-level clustering. Sex was not a significant predictor, and farm-level clustering accounted for 47% of variance in tick burden. Indigenous and crossbred cattle exhibited lower tick loads than exotic breeds. CONCLUSION: Tick infestation is prevalent in communal cattle systems in South Africa, particularly in the ears and perianal regions of exotic cattle breeds. These findings provide evidence-based epidemiological data on aggregate tick burden and host-level predictors to inform communal livestock health planning and guide future species-resolved investigations.