Isolation and Characterization of Brachyspira spp. Including “Brachyspira hampsonii” from Lesser Snow Geese (Chen caerulescens caerulescens) in the Canadian Arctic

Abstract

Brachyspira is associated with diarrhea and colitis in pigs, and control of these pathogens is complicated by their complex ecology. Identification of wildlife reservoirs of Brachyspira requires the discrimination of colonized animals and those simply contaminated through environmental exposure. Lesser snow geese (Chen caerulescens caerulescens) were sampled in the Canadian arctic during the summer of 2011, and cloacal swabs were cultured on selective media. Brachyspira isolates were obtained from 15/170 (8.8 %) samples, and 12/15 isolates were similar to isolates previously recovered from pigs, including "Brachyspira hampsonii", a recently characterized species associated with dysentery-like disease in pigs in North America. A pilot inoculation study with one strongly β-hemolytic B. hampsonii isolate resulted in fecal shedding of the isolate by inoculated pigs for up to 14 days post-inoculation, but no severe clinical disease. Results of this study indicate that lesser snow geese can be colonized by Brachyspira strains that can also colonize pigs. Millions of lesser snow geese (C. caerulescens caerulescens) travel through the major pork-producing areas of Canada and the USA during their annual migration, making them a potential factor in the continental distribution of these bacteria.

Molecular Epidemiology of Novel Pathogen “Brachyspira hampsonii” Reveals Relationships between Diverse Genetic Groups, Regions, Host Species, and Other Pathogenic and Commensal Brachyspira Species

“…B. intermedia isolates are known to cause disease in chickens, and although they are frequently isolated from swine, they are not usually associated with disease in this host species (24). Similarly, although B. hampsonii has been isolated from birds (10,11), to our knowledge it is only known to cause disease in swine (1).…”

“…The migratory patterns of wild birds, their close contact with livestock, and contamination of drinking water sources by their feces may allow the spread of and exposure of livestock to infectious agents, thus suggesting their potential role as reservoirs (34). Additionally, a previous study (11) reported colonization without clinical signs in an experimental inoculation of a B. hampsonii clade II (or genetic group II) isolate that was isolated from a migratory bird (snow goose). Therefore, the clustering of migratory wild bird-origin B. hampsonii isolates with those of swine origin in this study provides further support for the hypothesis of B. hampsonii transmission between these host species.…”

“…Specifically, clade I and II genotypes included in this study originated from swine in North America, some clade I genotypes originated from swine and migratory wild birds in Europe, and some genotypes that were not clearly classified as belonging to either clade originated from swine and migratory wild birds in Europe. Further, in a previous study (11), two isolates originating from migratory wild birds in North America were shown to cluster most closely with B. hampsonii clade II. It therefore appears that B. hampsonii clade I is widespread globally (in swine and migratory wild birds in North America and Europe), which based on current knowledge is in contrast to clade II, which as of now has been detected only in North America.…”

“…This novel pathogenic species, comprising two genetically diverse clades (I and II) in North America, has been designated "Brachyspira hampsonii" (1). Since its discovery, it has been identified in migratory waterfowl in Europe (10) and North America (11). Interestingly, it has also been detected in commercial pigs transported between European countries, including the Czech Republic, Belgium, and Germany (12,13).…”

A review of the current state of antimicrobial susceptibility test methods forBrachyspira

“…Sequence analysis at present is considered the gold standard for specieslevel identification Perez et al 2016). DNA sequencing has revealed phylogenetic diversity within the genus Brachyspira, including the novel strain "B. hampsonii" and a large number of other strains that have not yet been characterized but appear to be distinct from recognized species (Patterson et al 2013;Rubin et al 2013b). …”