Neospora caninum DNA in feces of crab-eating fox (Cerdocyon thous - Linnaeus, 1776) from northeastern Brazil.

Neospora caninum is an obligate intracellular tissue cyst-forming coccidian parasite and it was first described in dogs. Despite the relevance of wild canids in the transmission chain of N. caninum, there are few studies in Brazil. The aim of the present study was to detect N. caninum DNA in feces of free-range and captive crab-eating fox (Cerdocyon thous) from different states of northeastern Brazil. Fecal samples of eighteen crab-eating foxes (fifteen individually and three pools) were collected in sterile containers and were kept cool at -20 °C until further processing. All fecal samples were subjected to DNA extraction. A nested PCR targeting the ITS-1 gene was performed for N. caninum. All the positive bands were extracted from the gel and purified. Forward and reverse strands were sequenced and the nucleotide sequences obtained were compared with N. caninum sequences deposited in Genbank. The alignment was edited and phylogenetic reconstruction was based on the ITS1 gene sequences. Thirteen stool samples were PCR-positive for N. caninum DNA. Nine out of thirteen positive samples showed similarity between 99%-100% for N. caninum in relation to the sequence U25044.1 stored at GenBank. The crab-eating fox could have an important role in the sylvatic cycle of Neospora caninum in Brazil. Experimental infections studies involving these wild canids may confirm if the crab-eating foxes are definitive hosts of N. caninum.