Avaliação do RDW em equinos da raça Quarto de Milha saudáveis e hospitalizados, e como biomarcador da infecção por Strongylus vulgaris

Abstract

RDW (Red Blood Cell Distribution Width) is a hematimetric index used to diagnose anisocytosis. In human medicine, RDW has been widely used as a predictor and biomarker of various diseases, such as acute mesenteric ischemia. In equines, this ischemia has been associated with vermintic colic, a potentially fatal syndrome triggered by the larvae of the nematodes Strongylus vulgaris. However, there are few studies in equine medicine on RDW and its relation to S. vulgaris infection, as well as the standardization of RDW-CV in this species. In the first phase, the objective was to compare the values of RDW-CV in equine horses of the healthy Quarter Horses and in horses attended in a Veterinary Hospital School. A total of 176 horses were evaluated, 95 of which were healthy, reared on 27 farms in the region of Presidente Prudente, São Paulo, and 81 horses hospitalized. Blood samples were evaluated to obtain the RDW index, from automated cell counter. The RDW values in hospitalized horses (18.6%) were significantly higher (p = 0.0006) than those observed in healthy horses (17.8%). The RDW-CV value (17,8%) can be used as a reference for horses of Quarter Horse breed. It is suggested that further studies are needed to evaluate the use of RDW as a biomarker or predictor of several other diseases in horses. For the second phase of the study, it was hypothesized that RDW-CV could also be used as a biomarker for Strongylus vulgaris infection. We evaluated 160 healthy horses (Quarter Horse and Quarter Horse mixed), at least two years old and of both sexes. The ELISA showed a positive result in 80% of the samples; however, the co-culture and the specific PCR were negative for S. vulgaris, despite the high number of animals (91.25%) positive for egg counts (> 50 epg). No evidence of association was observed between RDW-CV and ELISA. These results are discussed and, despite the lack of association, further investigations are needed to evaluate the role of RDW as a biomarker/predictor of vermintic arteritis in horses with colic.