A two-year prospective study of small poultry flocks in Ontario, Canada, part 1: prevalence of viral and bacterial pathogens

Abstract

In Ontario, within the past few years, there has been a marked increase in the number of non-commercial poultry flocks (referred to as "small flocks"). Small poultry flocks may act as a reservoir of avian and zoonotic pathogens, given the flocks' limited access to veterinary services, inadequate biosecurity practices, and increased risk of contact with wild birds. Despite these potential risks, there is a scarcity of data concerning the prevalence of poultry and zoonotic pathogens among these flocks. To assess the baseline prevalence of bacterial and viral infectious pathogens, prospective surveillance of small flock postmortem submissions to the Animal Health Laboratory was conducted over a 2-y period. With the owner's consent, a postmortem examination and pre-set tests for infectious agents were conducted. A total of 160 submissions, mainly chickens (84%), were received. Among bacterial pathogens, Brachyspira spp., Mycoplasma synoviae, Campylobacter spp., Mycoplasma gallisepticum, and Salmonella spp. were detected in 37%, 36%, 35%, 23%, and 3% of tested submissions, respectively. Among viral pathogens, infectious bronchitis virus, fowl adenovirus, infectious laryngotracheitis virus, avian reovirus, and infectious bursal disease virus were detected in 39%, 35%, 15%, 4%, and 1% of submissions, respectively. We detected non-virulent avian avulavirus 1 from two chickens in a single submission, and low-pathogenic H10N8 influenza A virus from a single turkey submission. Our study provides baseline prevalence of viral and bacterial pathogens circulating in Ontario small flocks and may help animal and human health professionals to educate small flock owners about disease prevention.

Antimicrobial resistance in fecal Escherichia coli and Salmonella enterica isolates: a two-year prospective study of small poultry flocks in Ontario, Canada

“…Nonetheless, the presence of AMR in Salmonella in small flocks is concerning because of the risk that resistant salmonellae pose in human cases with bacteremia or a compromised immune system. Although the frequency of Salmonella enterica was very low in our study [26], and many of the Salmonella isolates were pan-susceptible, some were resistant to streptomycin alone, or to streptomycin, sulfisoxazole, trimethoprim-sulfamethoxazole, and tetracycline. Our findings agree with a recent study that evaluated AMR in Salmonella isolated from small flock cases at the California Animal Health and Food Safety Laboratory System, and found resistance to streptomycin, sulfonamides, and tetracycline [34].…”

“…Limitations of this study include a sampling bias, as most submissions came from southwestern and eastern Ontario, which might have been the consequence of the geographic proximity to the diagnostic laboratories in Guelph and Kemptville, respectively [26]. Also, small flocks were not randomly selected, and our study included only owners who had a flock veterinarian, as ciprofloxacin; NAL = nalidixic acid; TET = tetracycline.…”

“…Over the 2-year period, the Animal Health Laboratory received 160 small flock submissions, with a median of 1 bird per submission (range = 1-5), from flocks ranging in size from 1 to 299 birds (median 25) and birds ranging in age from 6 days to 7 years (median 7 months). The majority of submissions were chickens (84%, 134 submissions), although a few turkey (10), duck (8), and game bird (8) submissions were also received [26].…”

“…(a sample from one chicken submission was not available), a total of 5 isolates were recovered (5 pooled samples, 1 isolate recovered from each pooled sample). Serotypes included S. Anatum, S. Indiana, and S. Ouakam (3 chicken pooled samples), S. Uganda (1 turkey pooled sample), and S. Montevideo (1 duck pooled sample) [26]. Three Salmonella isolates were pan-susceptible (1 S. Indiana, 1 S. Montevideo, and 1 S. Uganda).…”

A two-year prospective study of small poultry flocks in Ontario, Canada, part 2: causes of morbidity and mortality

“…Details concerning the study design are reported in part 1 of the series. 2 Information on the bird species, age, sex, flock size, location, date of submission, and clinical history was collected as part of the postmortem submission. A routine postmortem examination was performed on all birds from each submission, including ancillary tests to determine the cause of morbidity or mortality.…”