Lack of Evidence for Vertical Transmission of Campylobacter spp. in Chickens

Abstract

Campylobacter jejuni is a major cause of bacterial food-borne infection in the industrial world. There is evidence that C. jejuni is present in eggs and hatchery fluff, opening the possibility for vertical transmission from hens to progeny. Poultry operations in Iceland provide an excellent opportunity to study this possibility, since breeding flocks are established solely from eggs imported from grandparent flocks in Sweden. This leaves limited opportunity for grandparents and their progeny to share isolates through horizontal transmission. While Campylobacter was not detected in all grandparent flocks, 13 of the 16 egg import lots consisted of eggs gathered from one or more Campylobacter-positive grandparent flocks. No evidence of Campylobacter was found by PCR in any of the 10 relevant quarantine hatchery fluff samples examined, and no Campylobacter was isolated from the parent birds through 8 weeks, while they were still in quarantine rearing facilities. After the birds were moved to less biosecure rearing facilities, Campylobacter was isolated, and 29 alleles were observed among the 224 isolates studied. While three alleles were found in both Sweden and Iceland, in no case was the same allele found both in a particular grandparent flock and in its progeny. We could find no evidence for vertical transmission of Campylobacter to the approximately 60,000 progeny parent breeders that were hatched from eggs coming from Campylobacter-positive grandparent flocks. If vertical transmission is occurring, it is not a significant source for the contamination of chicken flocks with Campylobacter spp.

Impact of Rurality, Broiler Operations, and Community Socioeconomic Factors on the Risk of Campylobacteriosis in Maryland

“…. However, there is little evidence of vertical transmission of Campylobacter in chickens (Callicott, 2006). Most studies in which Campylobacter has been measured in eggs have postulated that this transmission is due to fecal contamination (Newell and Fearnley, 2003).…”

Quo vadis? — MonitoringCampylobacterin Germany

“…In principle, the prevalence of foodborne zoonotic pathogens can be reduced at different levels of the food chain, such as primary production (prevention of pathogen entry into the food processing chain), slaughtering process (prevention of fecal contamination), and post slaughtering (decontamination). Unlike Salmonella, Campylobacter is not vertically transmitted from breeder flock to progeny but its dissemination is merely horizontal [28]. Therefore, hygienic measures in primary production are essential to avoid spread of the bacterium and are considered to be key strategies for reduction of Campylobacter loads on food [3].…”

Longitudinal Molecular Epidemiological Study of Thermophilic Campylobacters on One Conventional Broiler Chicken Farm

“…Campylobacter is rarely recovered from intensively reared broiler chicks until 14 to 21 days of age (12,36,39), and vertical transmission is now generally dismissed as an important source of flock infection (7,28). Campylobacters are ubiquitous in most environments, and horizontal transmission is considered the major route for colonization of housed broilers.…”