Seroprevalence and risk factors for Toxoplasma gondii in sheep in Grosseto district, Tuscany, Italy

Abstract Background Serum samples from 630 milk sheep, in 33 dairy flocks representative of the southern area of the Tuscany region, were tested for the presence of antibodies to Toxoplasma gondii using an indirect immunofluorescence antibody test (IFAT). Questionnaires exploring the management system were completed by the veterinarian in charge of the flocks. Results At least one seropositive animal was found in 32 of the 33 flocks tested (97.0%; 95% CI: 84.2%, 99.9%). In the positive flocks, median seroprevalence was 29.4% (interquartile range: 15.9%-46.1%). Overall animal-level seroprevalence, adjusted for sampling weights and test sensitivity and specificity, was 33.3% (95% CI: 24.8%, 42.7%). In a multivariable negative binomial regression model the number of seropositive animals in a flock decreased with increasing flock size (for >400 vs. CR) = 0.62; 95% CI: 0.41, 0.95; P = 0.028) and was greater on farms where stray cats had access to animals’ water (CR = 1.54; 95% CI: 1.05, 2.26; P = 0.027). Conclusions Small flock size and access of cats to water are potential risk factors for Toxoplasma infection in sheep in the Grosseto district in Tuscany, Italy. Sheep could be an important source of T. gondii infection in humans, since we estimate that between 25% and 43% of sheep in the district were seropositive. Toxoplasmosis is also likely to be an important cause of abortion in sheep in the district. Control and prophylactic measures must be adopted to improve the rearing system and the implementation of health promoting programmes in a joint effort between sheep farmers, farmers’ associations and veterinarians to inform about the means of transmission of the infection and for a better understanding of the disease.</p

Seroprevalence and risk factors for Toxoplasma gondii in sheep in Grosseto district, Tuscany, Italy

BACKGROUND: Serum samples from 630 milk sheep, in 33 dairy flocks representative of the southern area of the Tuscany region, were tested for the presence of antibodies to Toxoplasma gondii using an indirect immunofluorescence antibody test (IFAT). Questionnaires exploring the management system were completed by the veterinarian in charge of the flocks. RESULTS: At least one seropositive animal was found in 32 of the 33 flocks tested (97.0%; 95% CI: 84.2%, 99.9%). In the positive flocks, median seroprevalence was 29.4% (interquartile range: 15.9%-46.1%). Overall animal-level seroprevalence, adjusted for sampling weights and test sensitivity and specificity, was 33.3% (95% CI: 24.8%, 42.7%). In a multivariable negative binomial regression model the number of seropositive animals in a flock decreased with increasing flock size (for >400 vs. <300 animals: count ratio (CR) = 0.62; 95% CI: 0.41, 0.95; P = 0.028) and was greater on farms where stray cats had access to animals’ water (CR = 1.54; 95% CI: 1.05, 2.26; P = 0.027). CONCLUSIONS: Small flock size and access of cats to water are potential risk factors for Toxoplasma infection in sheep in the Grosseto district in Tuscany, Italy. Sheep could be an important source of T. gondii infection in humans, since we estimate that between 25% and 43% of sheep in the district were seropositive. Toxoplasmosis is also likely to be an important cause of abortion in sheep in the district. Control and prophylactic measures must be adopted to improve the rearing system and the implementation of health promoting programmes in a joint effort between sheep farmers, farmers’ associations and veterinarians to inform about the means of transmission of the infection and for a better understanding of the disease.Additional file 1: Audit form on rearing practices from 33 farms in Grosseto district, Tuscany, Italy.The study idea was conceived by BCG. BCG, PS and AC participated in the design of the study. FV and IM participated in the acquisition of the laboratory data. AC collected serum samples with the attending veterinarians and helped administering the questionnaire. PT and VC provided previously acquired reference data. BCG and PT carried out the statistical analysis. Data interpretation was done by all authors. BCG and PT drafted the manuscript. All authors contributed to the critical revision of the manuscript for important intellectual content and have seen and approved the final draft.The authors thank all those colleagues who have helped in our on-going research projects, in particular Prof. Barend Louis Penzhorn and Dr Nada Abu Samra of the University of Pretoria, Faculty of Veterinary Science, Onderstepoort, South Africa; Dr Carlo Crotti and Dr Ludovico Renda, veterinary practitioners in Perugia, Italy, and Prof. Piergili Fioretti, University of Perugia, Italy. The authors also express sincere appreciation to members of Polyglot, Perugia, for a careful reading and comments on the article. The findings and conclusions in this paper are those of the authors and do not necessarily represent the views of the University of Perugia. Within the framework of the dottorato di ricerca «Sanità animale, produzioni zootecniche e sicurezza degli alimenti – XXVIII Ciclo» this research was supported by a grant from Fondazione Cassa di Risparmio di Perugia, Italy.http://www.biomedcentral.com/1746-6148/9/25am2013ab201

Seroepidemiological study of toxoplasmosis in sheep in rural areas of the Grosseto district, Tuscany, Italy

Six hundred and thirty individual serum samples from dairy sheep were tested for the presence of antibodies to Toxoplasma gondii using an indirect immunofluorescence antibody test (IFAT). The sampled animals came from 33 dairy herds representative of the southern area of the Tuscany region. Questionnaires exploring the management system were filled in by the veterinarian in charge of the herds. Using a cut-off of 1:64, 214 animals (33.97%) were positive with a herd prevalence of 96.97%. Using a sensitivity and specificity of 80% and 95% respectively, the true prevalence was calculated as 38.62% (CI, 34.82%, 42.43%). In the multivariate statistical analysis, T. gondii seropositivity in sheep was significantly associated with herd size &lt;300 (OR=2.046, CI=1.284-3.261), still water source (OR=1.514, CI=1.050-2.182), and access of cats to water given to animals (OR=1.585, CI=1.057-2.379)