Biosecurity Assessment and Seroprevalence of Respiratory Diseases in Backyard Poultry Flocks Located Close to and Far from Commercial Premises

Abstract

Raising backyard chickens is an ever-growing hobby in the United States. These flocks can be a substrate for respiratory disease amplification and transmission to commercial facilities. Five hundred fifty-four chickens from 41 backyard flocks were sampled in this study. ELISA kits were used to detect antibodies against avian influenza (AI), infectious laryngotracheitis (ILT), Newcastle disease (ND), infectious bronchitis (IB), Ornithobacterium rhinotracheale (ORT), Mycoplasma gallisepticum (MG), and Mycoplasma synoviae (MS). All visited flock owners answered a biosecurity questionnaire that assessed biosecurity measures. The questionnaire revealed that backyard poultry owners lack simple biosecurity measures such as use of dedicated shoes, their chicken sources are unreliable, and few of them benefit from veterinary oversight. Only one flock had a clear vaccination history against ND and IB. ORT, ND, IB, MS, MG, and ILT were the most seroprevalent in backyard poultry flocks with 97% (41/42), 77.5% (31/40), 75% (30/40), 73% (31/42), 69% (29/42), and 45% (19/42), respectively. The vaccinated flock was not considered in these calculations. When examining the distance between backyard flocks and the nearest commercial poultry facility, ND and MG were significantly more likely to be found in backyard flocks close to (<4 miles) whereas ORT was significantly more likely in backyard chickens located far from (>4 miles) commercial poultry. Birds purchased directly from National Poultry Improvement Plan hatcheries showed a reduced ND, MG, and MS antibody prevalence. Wearing dedicated shoes decreased MS antibody-positive birds. Finally, history of wild bird contact had a clear effect on an increased seroprevalence of NDV and MG. Serological results suggest that backyard poultry flocks have the potential to serve as a reservoir or amplifier for poultry respiratory diseases. The information generated in this project should direct extension efforts toward emphasizing the importance of small flock biosecurity and chick acquisition sources.

Seroprevalence of Newcastle disease virus in backyard chickens and herd-level risk factors of Newcastle disease in poultry farms in Oman

“…The high seroprevalence of NDV in backyard poultry has an implication on the maintenance of the virus and spread of the disease to commercial flocks. The present study recorded a high NDV seroprevalence (71.4%) at flock level, which is consistent with the findings from other authors [11], [12], [13], [14]. The likely reasons for such finding could be the poor biosecurity, introduction of infected birds to existing flocks, lack of vaccination, close relationship with neighboring birds and, unhygienic feeding practices.…”

“…Based on the respondents’ data, these aforementioned practices were adequately adhered to, especially amongst farms with history of ND outbreaks. Furthermore, recent studies advocated for better quarantine, management of sick and dead birds, and improved technical efficiency, especially in backyard poultry systems [11], [28]. However, most of the farmers in this study were little informed about the ND and they rarely submitted samples to appropriate centres during disease outbreaks.…”

“…Furthermore, several studies have reported vital risk factors for the transmission of ND in poultry flocks in various countries. Accordingly, the role of migratory birds and trade in live birds have been reported as vital routes of ND transmission [10], [11]. Most importantly, high seroprevalence of NDV was reported in backyard poultry and serving as a potential risk factor for ND transmission to commercial flocks [12], [13].…”

Small-scale and backyard livestock owners needs assessment in the western United States

“…In recent years, several studies have focused on urban and backyard poultry flocks in North America [9,14,15,19,21,29] but few have characterized other non-poultry backyard and small-scale livestock owners [20]. In the present study, most respondents utilized their animals’ products for their own consumption but about half sold animal products (eggs and meat), primarily through internet sales or farmers’ markets with sales less than $10,000 a year.…”

“…A recent study of 41 backyard poultry flocks in California demonstrated a high prevalence of antibodies (between 45% and 97%) to avian respiratory pathogens (e.g., infectious bronchitis, Mycoplasma synoviae and M . gallisepticum ), indicating their potential as a reservoir or amplifier for these diseases [29] and spill-over to commercial production systems. Disease outbreaks in commercial operations, such as virulent Newcastle Disease (vND, known as Exotic Newcastle Disease) and Marek’s Disease, have originated in backyard flocks and spread to commercial flocks [3,11].…”