Alterações hematológicas e humorais de eqüinos expostos à infecção por Babesia equi, na região sul do Rio Grande do Sul

Abstract

The equine babesiosis is one of the most important parasitic disease of the equines, it causes great damage to animal health. The disease is a haemoparasitosis caused by Babesia equi. Through infecting and destroying red blood cells, it can compromise the equine function, leading to loss of vitality and decrease in the performance of infected animals. The purpose of this work was the evaluation of humoral and hematological characteristics of carrier animals. A group of 93 thoroughbred mares, 52 thoroughbred foals and 20 Crioulo horses were analyzed. Blood samples were taken once a month during twelve months for laboratorial examination, to determine: the prevalence of B. equi seropositive animals using IFAT; the infection incidence in the property; dynamics of antibodies anti-B. equi in carrier animals; the white and red blood cell changes in infected and healthy equines and the infection by B. equi using the PCR technique. Infection free foals were splenectomized and infected with B. equi stabilate to obtain high parasitaemias and production of the antigen for the IFAT. Different levels of positivity were detected by IFAT among the studied categories; and the occurrence of one newborn with prenatal infection and typical sintomatology, from a persistently infected mother. Antibody levels, differential counts for leucocytes, packed cell volume and total plasmatic protein value did not reveal significant statistic variation. Both PCR and IFAT were able to demonstrate the carrier state in persistently infected animals.