Modelling the effect of climate change on the distribution of Amblyomma hebraeum in South Africa

Abstract

It has been postulated that climate change has brought about a change in the distribution of Amblyomma hebraeum and subsequently, its potential tick-borne parasites in South Africa and that the effects of climate change may well lead to further future distribution changes. This study demonstrated that A. hebraeum may be present in the Western Free State and, although evidence could not be found of E. ruminantium or R. africae infection in ticks, laboratory results confirmed the presence of the former parasite in brain smears from on-farm mortalities. Habitat suitability modeling using Maxent demonstrated that the distribution of A. hebraeum has altered compared to previous scenarios, is still changing, and that by the year 2065, most of the central and eastern parts of South Africa would have a high habitat suitability index for its presence. This indicates that diseases caused by E. ruminantium and R. africae would also have to be considered in these previously unaffected areas when animals or humans show signs of illness. The economic and health impact of these diseases in the expanded areas could well be quite substantial.