Scarabaeus cristatus (Coleoptera: Scarabaeidae) as intermediate host of Physocephalus dromedarii (Nematoda: Spirocercidae)--a contribution to the epidemiology of camel physocephalidosis.

In UAE, camel Physocephalus dromedarii was diagnosed for the first time in 2011 in dromedaries from a farm that previously had imported animals from foreign countries. The large scarab beetle, Scarabaeus cristatus, was found to be the major intermediate host for this parasite in Dubai. A total of 638 specimens of S. cristatus were collected and examined for the presence of third-stage larvae of nematode larvae at two sites in the Dubai Emirate (Emirates Industry for Camel Milk and Products and horse endurance training track) within a distance of 15 km. Third-stage larvae of P. dromedarii were detected in 94 and 97 % of beetles collected from the territory of the camel milk farm and the endurance training track, respectively. In addition to third-stage larvae, 264 beetles contained second-stage larvae. Only four beetles were infected with other than P. dromedarii larvae. The average larval burden in beetles from camel milk farm was significantly higher compared to those in beetles collected from the other site (1538 vs. 697). Comparison of larval burdens in juvenile and adult beetles collected at the camel milk farm showed a significantly higher intensity in adult specimens (501 vs. 1734) while in beetles found on the horse endurance track, larval burdens were comparable (548 vs. 858). The results suggest that S. cristatus become infected at the camel milk farm, and in search for other sources of food, they fly to places where they were found feeding on feces of other animals.