Genetic characterization and epidemiology of Helicobacters in non-domestic animals

Novel helicobacter infections and associated disease are being recognized with increasing frequency in animals and people. Yet, the pervasiveness of infection in distantly related animal taxa, genetic diversity of helicobacters, and their transmissability are not known.

To better understand the ecology of helicobacters, we did a PCR survey and epidemiologic analysis of 154 captive or wild vertebrate taxa originating from 6 continents.

One hundred twenty nine helicobacter 16s rRNA gene segments were amplified by PCR and sequenced from ninety-three mammalian, reptilian, avian, or amphibian host species. Prevalence estimates were generated, and univariate logistic regression analyses were used to explore relationships between infection status and the health and characteristics of the 220 individual animals.

One hundred and nineteen novel helicobacter DNA sequences were found. No significant relationship between infection and host health was found; however, multi-infection or infections with particular genotypes were associated with mild clinical signs. Phylogenetic and genetic comparisons of helicobacters suggested prolonged co-adaptation and niche-associated divergence as well as periodic inter-species transmission.

The genus Helicobacter should accordingly be viewed as a collection of hundreds of organisms that have colonized most tetrapod taxa and have the potential to expand into new hosts as contact among animals and between animals and people increases.