Evidence of Zoonotic Transmission of Helicobacter canis Between Sheep and Human Contacts.

Abstract

Helicobacter species are newly emerging bacteria with great public implications but till now its epidemiology is not fully understood; so, this study was conducted to investigate the possible role of ruminants in the epidemiology of these pathogens. For this purpose, fecal samples were collected from 149 animals (76 sheep, 33 goats, 21 cattle, and 19 buffaloes) and stool specimens from 10 animal caretakers in intimate contact with the examined animals. All samples were examined for the presence of Helicobacter species through detection of Helicobacter genus specific 16S rRNA using PCR. Then, all positive Helicobacter spp. amplicons were sequenced to recognize their species through BLAST analysis at GenBank. The overall prevalence of Helicobacter spp. was 14.8% while the distribution among the different animals was 26.3%, 3%, 4.8%, and 0% in sheep, goats, cattle, and buffaloes respectively. Helicobacter canis was the predominant species and detected only in sheep (21%) and goats (3%). Moreover, Helicobacter winghamensis and Helicobacter canadensis were also detected in sheep but not in other animals, whereas the only positive bovine sample was identified as Helicobacter bovis. On the other hand, 4 out of 10 humans were positive for Helicobacter spp. and all sequences were identified as H. canis. The sequences identity matrix and phylogenetic analysis of H. canis sequences from humans and sheep contacts revealed that one human sequence was identical to that of sheep and making sister group clade, which prove the zoonotic transmission of this pathogen between sheep and human contacts. However, our findings highlight sheep as a potential reservoir for H. canis, further researches are needed to address the potential role of sheep in the food-borne transmission of such emerging pathogen.