Morphological and molecular identification of Toxocara vitulorum in water buffalo calves (Bubalus bubalis) in Tabasco, Mexico.

Toxocara vitulorum is an intestinal nematode of cattle, water buffaloes, and other bovids. This parasite can cause high morbidity and mortality in calves and economic losses. Although T. vitulorum has been reported in cattle in Mexico, there are no records in water buffaloes. This study details the morphological and molecular identification of T. vitulorum obtained from three buffalo calves in Tabasco, Mexico. Nematodes collected from buffalo calves were studied using morphological techniques and partial sequences of the 28S ribosomal RNA (28S) gene and the cytochrome c oxidase 1 mitochondrial (COI) gene. Three female nematodes showed morphological characteristics and measurements reported for T. vitulorum. Two 28S sequences and one COI sequence of T. vitulorum isolated from buffalo calves were obtained and used in phylogenetic analyses, confirming species identity. This study provides the first record and genetic sequences of T. vitulorum in Mexico. It is recommended to establish surveillance and control programs for intestinal parasites of buffalo herds in Mexico.