Long-term follow-up of owned, free-roaming dogs in South Africa naturally exposed to Babesia rossi

•Of 109 dogs tested in a South African settlement, 31% were seropositive to Babesia rossi.•These seropositive dogs had no history of severe babesiosis.•Clinical signs varied amongst other dogs in the settlement which were PCR-positive to B. rossi.•Tick control and treatment for babesiosis are not routine in the settlement.•Acquired immunity through repeated exposure to ticks might explain these observations.