title: Molecular evidence for sustained transmission of zoonotic Ascaris suum among zoo chimpanzees (Pan troglodytes).
abstract: Chimpanzees in the Copenhagen Zoo frequently excrete ascarid worms onto the cage floor in spite of a regular anthelmintic treatment program. Previously it had been shown that the source of the infections was of pig origin. However, it was unknown whether the recurrence of the infection was due to reintroduction of eggs from an external source or to a sustained transmission cycle within the zoo. We found that isolated eggs were able to embryonate to the infective J3 stage and PCR-RFLP analysis on the ITS region amplified from single embryonated eggs suggest these to be Ascaris suum. In addition, sequence analysis of the cox1 gene ('barcoding') on expelled worms followed by cluster analysis revealed that the chimpanzees are infected with pig A. suum which now, in spite of control efforts, has stabilized into a permanent transmission cycle in the zoo's chimpanzee troop.
authors.affiliation: Danish Centre for Experimental Parasitology, Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Dyrlaegevej 100, DK-1870, Frederiksberg C, Copenhagen, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Nejsum
authors.forename: Mads Frost
authors.initials: MF
authors.lastname: Bertelsen
authors.forename: Martha
authors.initials: M
authors.lastname: Betson
authors.forename: J Russell
authors.initials: JR
authors.lastname: Stothard
authors.forename: K Darwin
authors.initials: KD
authors.lastname: Murrell
mesh_terms: D000818:Animals; D000836:Animals, Zoo; D018420:Ape Diseases / Q000469:parasitology*; D001196:Ascariasis / Q000662:veterinary*; D017165:Ascaris suum; D005243:Feces / Q000469:parasitology; D006801:Humans; D007814:Larva; D010063:Ovum; D002679:Pan troglodytes; D010270:Parasite Egg Count / Q000662:veterinary