Soroprevalência de Lawsonia intracellularis em equinos na região sul do Rio Grande do Sul, Brasil

Abstract

Lawsonia intracellularis is a bacterium that causes the disease Equine Proliferative Enteropathy (EPE) and which has become emerging in horse farming in recent years. Interest in clinical research with L. intracellularis has increased in recent years, mainly associated with the negative impact on the breeding, development and sales price of foals positive for L. intracellularis. Serological tests do not confirm the presence of the disease, but they identify the health status of vaccinated animals and track the circulation of the agent in the locations studied. The objective of this thesis is to present two articles, the first article focused on the description of the seroprevalence of L. intracellularis in horses from 6 PSI breeding studs in the southern region of Rio Grande do Sul. 686 horses were used, divided according to the range age and serum samples were evaluated by IPMA for detection of anti-L. intracellularis antibodies. The overall seroprevalence rate was 51.02%, where broodmares had the highest percentage of detection. The second article aimed to describe the development and standardization of an ELISA test for the diagnosis of IgG against L. intracellularis in horses. Serum samples from 100 broodmares were used in this study. The IPMA test was used as the gold standard. The Western blot test was also performed to confirm the expression of the target L. intracellularis protein in the proven positive and negative sera and to rule out cross-reactivity with homologous epitopes. The ELISA value mean of negative sera was 0.209 ± 0.048 and the cutoff point was 0.354. The sensitivity and specificity of the ELISA test were 45.12% and 85.71%, respectively. The ELISA test developed in this study to identify anti-L. intracellularis IgG Ab had the potential to be used as a screening test for the serological diagnosis of L. intracellularis in horses, however, more research must be carried out to improve the accuracy of this test and provide a more accurate diagnosis in horses.