Onchocerca cervicalis Railliet & Henry, 1910 is a nematode that parasite equines. Its ocurrence has already been reported in the States of Mato Grosso and Rio de Janeiro, Brazil. Different diagnostic techniques were used in this study to establish the prevalence of the parasite in Rio de Janeiro State and the biting behaviour of the simuliid and ceratopogonid species suspected of being vectors was studied. All of the biopsies made in the region of the withers, shoulder and umbilicus of 57 animals were negative. Necropsies carried out on 28 equines revealed 4 to be positive for the parasite; 2 for microfilariae and 2 for adults. Simuliid flies showed preference for biting the ventral region and ceratopogonids the lower parts of the legs of horses. It was concluded that a more detailed investigation is required to determine a better diagnostic technique in order to verify prevalence rates of the parasite in horses in the State.
Onchocerca cervicalis; equines; black flies; biting-midges; Rio de Janeiro; Brazil