The prevalence of antibodies to Toxoplasma gondii in sheep in the Western Cape, South Africa.

Kenneth Hammond-Aryee,Paul D Van Helden,Lesley S Van Helden

doi:10.4102/ojvr.v82i1.993

Abstract

The seroprevalence of Toxoplasma gondii antibodies in a sample of 292 merino sheep farmed in a semi-intensive manner in the Overberg region of the Western Cape, South Africa, was investigated. Antibody seroprevalence was determined by enzyme-linked immunosorbent assay. Of the total sample, 23 sheep tested positive for T. gondii antibodies (8%; 95% CI: 4.7688–10.9846). There was no statistically significant relationship between seroprevalence and age of the sheep. The highest seroprevalence was found in sheep between 28 and 40 months old; a total of 19 sheep were seropositive by 40 months. No seropositive sheep were found in the age group between 16 and 28 months. The seroprevalence reported in this study is higher than what has previously been reported for the Western Cape (6%) and across South Africa on average (4.7%). As sheep farming is economically significant in South Africa, the presence of T. gondii amongst sheep may pose a production threat to the small-stock industry as well as to public health and food security. We therefore recommend further surveillance to identify high-risk animal populations so that local control measures can be put in place.

Highlights

Toxoplasma gondii is an apicomplexan, obligate intracellular protozoan parasite of global importance
The current study focused on the seroprevalence of T. gondii antibodies in a flock of sheep in South Africa
Lind and Mukaratirwa (2005) reported a seroprevalence of 67.9% in a population of sheep and goats from different parts of Zimbabwe. They reported an eightfold difference in seroprevalence between sheep from a large commercial farm (10%) and sheep reared under a communal grazing system (80%), reporting the presence of many domestic cats and a high household density as potential risk factors for T. gondii infection

Summary

Introduction

Toxoplasma gondii is an apicomplexan, obligate intracellular protozoan parasite of global importance. T. gondii infection causes the disease toxoplasmosis in humans and animals and its antibodies are known to be present in about a third of the global human population, local and regional prevalences vary widely. Toxoplasma gondii is very successful as a pathogen owing to its ability to infect almost all mammals and birds (Dubey 2002). Cats can become infected by feeding on prey already infected with dormant T. gondii cysts or tachyzoites and by drinking oocyst-contaminated water. Infected cats are known to shed infective oocysts in their faeces 5–12 days post ingestion of oocysts (Al Kappany et al 2010; Dubey 1995; Elmore et al 2010), thereby contaminating the environment and posing a risk of transmission to other species

Methods

Results

Discussion

Conclusion