Cestodes of Untreated Large Stray Dog Populations in Algeria: A Reservoir for Herbivore and Human Parasitic Diseases

Taeniids are frequent in dogs of Mediterranean countries and most studies have focused on the zoonotic Echinococcus granulosus, although several other species of cestodes are usually collected. We necropsied 127 stray dogs in two areas of eastern Algeria, in order to characterize the cestode communities and the factors that may structure these communities in conditions where anthelmintic treatments are not interfering with infection. The maximum number of species in one single dog was four, among Echinococcus granulosus, Taenia hydatigena, Taenia pisiformis, Taenia multiceps, Dipylidium caninum, or Mesocestoides lineatus. T. hydatigena was the most prevalent in both areas (over 40%) and E. granulosus had different prevalences (16 versus 42%) in the two areas. The associations between cestode species were studied using pairwise and multivariate methods, the latter being more realistic in case of species associations. E. granulosus was positively associated with T. hydatigena whereas the other species were negatively associated with the group T. hydatigena and E. granulosus. The large use of efficient anthelmintics may modify the structure of these communities. Risk factors were evaluated for each species of cestode. Older dogs harbored more T. hydatigena and less T. multiceps, M. lineatus and D. caninum. The latter was less frequent in rural areas.