Range expansion of the economically important Asiatic blue tick, <i>Rhipicephalus microplus</i>, in South Africa.

The Asiatic blue tick, Rhipicephalus microplus, a known vector of bovine babesiosis and bovine anaplasmosis, is of great concern in the cattle industry. For this reason, detailed knowledge of the distribution of R. microplus is vital. Currently, R. microplus is believed to be associated mainly with the northern and eastern Savanna and Grassland vegetation in South Africa. The objective of the study was to record the distribution of R. microplus, and the related endemic Rhipicephalus decoloratus, in the central-western region of South Africa that comprises Albany Thicket, Fynbos and Savanna vegetation. In this survey, ticks were collected from 415 cattle in four provinces (Eastern Cape, Northern Cape and Western Cape and Free State provinces) and from the vegetation in the Eastern Cape province of South Africa between October 2013 and September 2015. More than 8000 ticks were collected from cattle at 80 localities of which R. microplus was present at 64 localities and R. decoloratus at 47 localities. A total of 7969 tick larvae were recorded from the vegetation at 20 localities of which 6593 were R. microplus and 1131 were R. decoloratus. Rhipicephalus microplus was recorded in each of the regions that were sampled. Rhipicephalus microplus is now present throughout the coastal region of the Eastern Cape province and at multiple localities in the north-eastern region of the Northern Cape province. It was also recorded in the western region of the Western Cape province and one record was made for the Free State province. The observed range changes may be facilitated by the combined effects of environmental adaptability by the tick and the movement of host animals.