Prevalence of intestinal parasites and molecular characterization of Giardia duodenalis from dogs in La Habana, Cuba

Giardia duodenalis is a worldwide protozoan parasite that infects humans and other mammals including dogs. Due to the risk of zoonotic transmission between dogs and humans, we aimed in this study to determine the prevalence of the intestinal parasites and the distribution of assemblages of G. duodenalis among dogs analysed. A descriptive cross-sectional study was carried out in La Habana from June 2014 to March 2015 in the Zoonosis Unit of La Lisa municipality. A total of 98 dogs were analysed by three different techniques (microscopy with faecal concentration, Enzyme-Linked ImmunoSorbent Assay, and Polymerase Chain Reaction) in order to detect Giardia in stool samples. Out of 98 dogs studied, 43 (43.9%) were infected with intestinal parasites. The zoonotic parasites Ancylostoma caninum (21.4%), Trichuris vulpis (16.3%) and the protozoan Giardia duodenalis (11.2%) were the most prevalent parasites. In regards to the G. duodenalis, seven dogs were positive by microscopy after faecal concentration, nine by NOVITEC® Giardia Microplate Assay, and ten and eleven samples were amplified by the β-giardin and SSU-RNA PCRs, respectively. After PCR sequence analysis of both genes only zoonotic assemblages (A and B) were detected. The SSU-RNA sequence results revealed a distribution of 8 assemblage A and 4 assemblage B, whereas only assemblage A were identified by the β-giardin analysis. Among subassemblage classification by β-giardin phylogenetic tree, four isolates showed an AI pattern and one isolate displayed an AII distribution. Mixed infections were detected in three isolates. These findings highlight the risk of zoonotic transmission of Giardia duodenalis between dogs and humans.