MORPHOMETRIC FEATURES OF INVASIVE OESOPHAGODONTUS ROBUSTUS LARVAE AND SPREAD OF EQUINE OESOPHAGODONTOSIS IN THE ALTAI MOUNTAINS

Abstract

The research purpose was to characterize morphometric features of invasive larvae of Oesophagodontus robustus and to study the spread of equine oesophagodontosis in the Altai Mountains. Fecal samples from animals spontaneously infected with helminths were examined using the Berman-Orlov larvoscopic method followed by calculation of abundance rates (prevalence, %) and infection intensity (larvae/g). Infective Oesophagodontus larvae were identified with reference to morphometric features. It was found that the average larvae length and width were 1022.4±14.2 (min, 939.5 µm, max, 1068.4 µm) and 34.5±0.2 µm (min, 33.1 µm, max, 35.5 µm), respectively, including the length of esophagus, intestines, body and caudal end of the larval cap of 187.0; 387.3; 682.8 and 339.6 µm, respectively. In view of the results obtained, species of the family Strongylidae, Oesophagodontus robustus Giles, 1982; Railliet et Henry, 1902, were recorded in the community of gastrointestinal equine nematodes for the first time in the Altai Mountains. Their widespread distribution was detected within boundaries of the Altai Mountains; the infection rate in horses was low and varied from 12.2 to 17.6 and averaged 16.7%. The average number of larvae per gram of feces was 0.7 larvae/g. The high infection intensity rates in horses in the mountain-forest zone of the Kosh-Agachsky District were due to landscape features of the area.