Ecological analysis and description of the intestinal helminths present in dogs in Mexico City.

The objective of the present study was to determine the prevalence of parasitoses in stray dogs from Mexico City, as well as to describe the structure of the intestinal helminth communities present in said hosts. One hundred and twenty dog intestines were collected and dissected to evaluate their parasitic load; finding parasites in 102 dogs (85%). The cestodes collected were: Dipylidium caninum in 72 dogs (60%), Taenia hydatigena in three (2.5%), Taenia pisiformis in two (1.6%), Echinococcus granulosus, Mesocestoides vogae and Mesocestoides variabilis in only one animal each (0.83%), the latter two being collected for the first time ever in Mexico City. Nematodes collected were: Ancylostoma caninum in 75 (62.5%) animals, Toxocara canis in 16 (13.3%) and Toxascaris leonina in 5 (4.16%). By age, D. caninum and A. caninum were the most prevalent species in older animals, while T. canis was more prevalent in young animals (P<0.05). By season, T. canis was most common in the dry season (P<0.05). At the parasitic community level, the diversity value was 0.32, while that of equality was 0.1; the dominant species was M. vogae (Berger-Parker index of 0.95). At the infracommunity level, both diversity and equality were low (0.31 and 0.32, respectively) as compared to that observed in wild canines; the dominant species was A. caninum (Berger-Parker index of 0.37). Qualitative similarity was 33.8%, while quantitative similarity was 32.2%. Based upon the low values for mean diversity, equality and species richness, it is possible to deduce that helminth fauna in dogs from Mexico City is weakened, especially if one compares it to that of other wild canines.