The impact of two dipping systems on endemic stability of bovine babesiosis and anaplasmosis in cattle at four communal grazing areas in Limpopo Province, South Africa

Abstract

A twelve-month study was conducted at four communal grazing areas namely, Oakley, Cunningmore, Mkhuhlu and Ronaldsy in the Bushbuckridge region, Limpopo Province, South Africa. The main objective of the study was to investigate the impact of reduced acaricide application on the endemic stability to bovine babesiosis (Babesia bigemina and Babesia bovis) and anaplasmosis in a sample of the local cattle population. The study should be of assistance to farmers who are attempting to move from intensive to strategic tick control strategies and reduce the frequency of dipping, whilst maintaining endemic stability. Sixty cattle per communal grazing area were bled at the beginning and the end of the experimental period and the sera were assayed for B. bovis, B. bigemina and Anaplasma antibodies. Cattle in the intensively dipped group were dipped 26 times and maintained on a fourteen-day dipping interval throughout the study, whereas, cattle in the strategic group had their acaricide application frequency reduced and were only dipped 13 times. Three cattle per village were selected from which adult ticks were collected and immature ticks were also collected by dragging the veld. A questionnaire to assess the prevalence of clinical cases of tick-borne diseases, abscessation and mortalities was completed by an Animal Health Technician at each diptank during dipping. This was done to determine the number of clinical cases of bovine babesiosis, anaplasmosis as well as abscessation. An increase in seroprevalence to B. bovis and B. bigemina and a decrease in seroprevalence to Anaplasma was detected in the strategically dipped group whilst in the intensively dipped group a decrease in seroprevalence to B. bovis and B. bigemina and an increase in seroprevalence to Anaplasma was detected. Amblyomma hebraeum was the most abundant tick species found on the cattle in this region, whilst Rhipicephalus (Boophilus) microplus and Rhipicephalus (Boophilus) decoloratus were also collected and R. (B.) microplus was the more abundant of the two species. Drag samples yielded more A. hebraeum immatures than Rhipicephalus (Boophilus) and a seasonal pattern was displayed. An increase in the number of clinical cases of tick-borne diseases and abscesses was recorded at the beginning of the survey in the strategically dipped group.