Molecular characterization of protozoan parasites and Ehrlichia in domestic animals from uMkhanyakude district of KwaZulu-Natal

Abstract

Protozoan and ehrlichial diseases are a major threat to domestic animals in tropical and sub-tropical regions of Africa. Economically important animal diseases in sub-Saharan Africa include theileriosis, babesiosis, trypanosomosis, hepatozoonosis, toxoplasmosis, besnoitiosis and ehrlichiosis. These diseases have a considerable impact on the country's economic security and impact negatively on poor communities who are depended on livestock production as their source of income and nutritional needs, and as labour for fieldwork and transport. As such, it is documented that the occurrence of protozoan parasites in South African domestic animals hinders the development of livestock industry, which contributes for up to 49% of the agricultural yield. It is important to keep up to date data on occurrence of these diseases using modern molecular diagnostic techniques. Therefore, this study was aimed at improving the current knowledge about the occurrence and genetic diversity of protozoan parasites and Ehrlichia in domestic animals from north eastern KwaZulu-Natal (KZN). A total of 208 blood samples collected from apparently healthy domestic animals (cattle, dogs, goats and sheep) in three different municipalities of uMkhanyakude district, (KZN) were screened using genus and species-specific PCR techniques for the detection of Besnoitia besnoiti, Theileria spp., Babesia spp., Hepatozoon canis, Trypanosoma spp., Toxoplasma gondii, and Ehrlichia canis species-specific genes. The PCR amplicons were sequenced for detected species confirmation and phylogenetic analysis. The maximum likelihood trees were constructed to evaluate genetic diversity between protozoan parasites and Ehrlichia sequences of randomly selected isolates. Overall infection rates of T. ovis in sheep, B. bigemina, B. bovis in cattle and Trypanosoma spp. in cattle, T. gondii in cattle and Ehrlichia canis in dogs were 3 (30%), 33 (30.3%), 24 (22.2%), 20 (18.35%), 5 (4.58%), 20 (40.8%), respectively. The co-infection of two pathogens were detected in 4 (3.7%) for B. bovis and B. bigemina. The generated nucleotide sequences were confirmed to correspond with GenBank strains of respective PCR positive species. Analysis of phylograms constructed with RAP-1, B1, 18S and 16S sequences of B. bovis, T. gondii and E. canis indicated a close relationship between isolates detected in this study and GenBank strains. On the other hand, a tree constructed with SpeI-AvaI restriction fragment sequences revealed a high degree of polymorphism among the B. bigemina isolates investigated in this study. Taken together, the results of the current study indicated that protozoan parasites are prevalent in domestic animals from uMkhanyakude district of KZN province. A large scale epidemiological study covering the rest of the district municipalities in KZN province is needed, in order to provide a clearer picture of the prevalence of these protozoan and ehrlichial pathogens in domestic animals. Ultimately, this prevalence data will contribute in formulation of control strategies against diseases caused by these pathogens.