Characterization of Onthophagus sellatus as the major intermediate host of the dog esophageal worm Spirocerca lupi in Israel

Spirocerca lupi is a parasitic nematode of dogs, that causes significant morbidity and mortality. Its intermediate hosts in Israel have never been described. The aim of this study was therefore to identify the intermediate hosts of S. lupi in Israel and to describe their abundance and annual infection rate with the nematode, in different microenvironments (i.e., the effects of irrigation and shade) in an endemic area. Dog dung pads were collected every 2 months from two different public parks for 1 year. Dung beetles were identified to the species level in infested dog feces and were examined for the presence of S. lupi larvae through dissection. The Scarabid beetle Onthophagus sellatus was the most abundant dung beetle species in dog dung pads and the only one infected with S. lupi larvae. The minimal period for development of the S. lupi L3 infective stage was 7 days. Significant differences were observed between the two different microenvironments and along the year. The highest risk for infection of dogs with the nematode was during the summer, in an irrigated, shady microenvironment.