Development of Porrocaecum ensicaudatum (Nematoda: Ascaridoidea) in starlings (Sturnus vulgaris)

Abstract

Laboratory-raised starlings (Sturnus vulgaris L.) were experimentally infected with third-stage larvae of Porrocaecum ensicaudatum (Zeder, 1800) from earthworms. Within 2 h postinfection, larvae penetrated the koilin matrix of the gizzard and moulted in 36 h. Larvae appeared to avoid host response by remaining in the relatively inert koilin matrix. Fourth-stage larvae moved directly from the gizzard into the duodenal mucosa 48 h postinfection. The final moult occurred in the intestinal wall 11 days postinfection. Development of fourth-stage and adult worms in the tissues elicited a localized granulomatous inflammatory response. Adult worms emerged from the intestinal mucosa at 28 days and were found thereafter in the intestinal lumen. Eggs were first detected in the faeces of infected starlings 33 days postinfection and longevity of P. ensicaudatum in the definitive host was approximately 70 days. Challenge infections showed that starlings were susceptible to repeated infection. The number of adult P. ensicaudatum that matured in the intestine was independent of the number of larvae ingested. Clinical signs were not observed throughout the course of infection.