Salmonella enterica frequency in backyard chickens in Vermont and biosecurity knowledge and practices of owners

Zoonotic Gastroenteric Diseases of Exotic Animals

Exotic pet ownership has steadily increased over the last decade, and with increased numbers of these species in close contact with humans, the risk of gastrointestinal zoonoses has also increased. Non-typhoidal serovars of Salmonella enterica are one of the most prevalent and important zoonoses of exotic pets, and reptile and backyard poultry are common asymptomatic carriers of these bacteria. Outbreaks of reptile-associated salmonellosis have occurred yearly in the United States since 2019 but contact with backyard poultry has actually been associated with more Salmonella outbreaks in the United States than any other animal species to date.

Multistate outbreaks of salmonellosis linked to contact with backyard poultry-United States, 2015-2022

AIMS

Contact with backyard poultry (i.e., privately-owned, non-commercial poultry) was first associated with a multistate outbreak of salmonellosis in 1955. In recent years, backyard poultry-associated salmonellosis outbreaks have caused more illnesses in the United States than salmonellosis outbreaks linked to any other type of animal. Here, we describe the epidemiology of outbreaks from 2015-2022 to inform prevention efforts.

METHODS AND RESULTS

During 2015-2022, there were 88 multistate backyard poultry-associated salmonellosis outbreaks and 7866 outbreak-associated illnesses caused by 21 different Salmonella serotypes. Salmonella Enteritidis accounted for the most outbreaks (n = 21) and illnesses (n = 2400) of any serotype. Twenty-four percent (1840/7727) of patients with available information were <5 years of age. In total, 30% (1710/5644) of patients were hospitalized, and nine deaths were attributed to Salmonella infection. Throughout this period, patients reported behaviours that have a higher risk of Salmonella transmission, including kissing or snuggling poultry or allowing poultry inside their home.

CONCLUSIONS

Despite ongoing efforts to reduce the burden of salmonellosis associated with backyard poultry, outbreak-associated illnesses have nearly tripled and hospitalizations more than quadrupled compared with those in 1990-2014. Because this public health problem is largely preventable, government officials, human and veterinary healthcare providers, hatcheries, and retailers might improve the prevention of illnesses by widely disseminating health and safety recommendations to the public and by continuing to develop and implement prevention measures to reduce zoonotic transmission of Salmonella by backyard poultry.

Megaplasmid Dissemination in Multidrug-Resistant Salmonella Serotypes from Backyard and Commercial Broiler Production Systems in the Southeastern United States

Over the past decade, there has been a rise in U.S. backyard poultry ownership, raising concern for residential area antimicrobial-resistant (AMR) Salmonella contamination. This study aims to lay the groundwork to better understand the persistence of AMR Salmonella in residential broiler production systems and make comparisons with commercial systems. Ten backyard and 10 commercial farms were sampled at three time points across bird production. Both fecal (n = 10) and environmental (soil, n = 5, litter/compost, n = 5, feeder, and waterer swabs, n = 6) samples were collected at each visit on days 10, 31, and 52 of production for backyard farms and days 10, 24, and 38 of production for commercial farms. AMR Salmonella was characterized phenotypically by broth microdilution and genotypically by whole-genome sequencing. Overall, Salmonella was more prevalent in commercial farm samples (52.31%) over backyard farms (19.10%). Kentucky (sequence type (ST) 152) was the most common serotype found in both backyard and commercial farms. Multidrug-resistant (MDR, resistance to ≥3 or more antimicrobial classes) isolates were found in both production systems, while ciprofloxacin- and nalidixic acid-resistant and intermediate isolates were more prevalent in commercial (33%) than backyard samples (1%). Plasmids that have been associated with MDR were found in Kentucky and Infantis isolates, particularly IncFIB(K)_1_Kpn3 megaplasmid (Infantis). Our study emphasizes the need to understand the selection pressures in disseminating megaplasmids in MDR Salmonella in distinct broiler production systems.

Innate immune response to double-stranded RNA in American heritage chicken breeds

Backyard poultry flocks that employ heritage breeds of chicken play a crucial role in the maintenance of poultry pathogens of economic and zoonotic importance. This study examined innate immunity to viral pathogens in heritage chicken breeds using a model of viral double-stranded RNA (dsRNA). Following intraperitoneal injection of high molecular weight (HMW) -poly(I:C)/Lyovec into 4-wk-old chicks, we evaluated gene expression in peripheral blood mononuclear cells (PBMCs) and splenocytes. There was a significant difference across breeds in the expression of IL-4, IL-12p40, IFNγ, and B-cell activating factor (BAFF) in the spleen. In PBMCs, a significant difference in IFN-α expression was seen across breeds. Approximately 57% of IFN-α transcripts in PBMCs was explained by levels of expression of MDA5 transcripts. Using flow cytometry, we showed that only monocytes/macrophages (KUL01+ cells) expressed the scavenger receptor CD163. Regression analysis showed that 42% of fold change in CD163 expression on PBMCs was explained by breed (P < 0.0004). In general, breeds that responded to HMW-poly(I:C) by showing higher upregulation of IFNγ, IL-1β, and IL-12p40 transcripts in the spleen, and higher IFNα transcripts in peripheral blood, expressed less CD163 on blood monocytes. These findings suggest a genetic basis for the response of chickens to double-stranded RNA. Surface expression of the scavenger receptor CD163 in PBMCs following injection of high molecular weight poly(I:C) may be a rapid method to select chickens for breeding based on innate immune response to viral dsRNA.

Wild and backyard food use during COVID-19 in upstate New York, United States

Introduction

COVID-19 acutely shocked both socio-economic and food systems in 2020. We investigated the impact of COVID-19 on production and consumption of gardened produce, backyard poultry, wild game and fish, and foraged mushrooms, berries, and other plants in New York State, aiming to understand crisis influenced food choice and motivations, including food security.

Methods

We conducted an online, cross-sectional survey in October-December 2020 with a convenience sample of participants (n = 505) with an interest in gardening, poultry rearing, foraging, hunting, and/or fishing from six counties in upstate New York. We recruited through the New York Department of Environmental Conservation, Cornell Cooperative Extension, and other relevant email and social media pages.

Results

Across the wild and backyard food production strategies, 4.0-14.3% of respondents reported engaging for the first time and 39.6-45.7% reported increased production (a little or a lot more), and 31.6-42.7% of respondents' production was the same as the previous year. Consumption of foods produced was widespread, including fruit and vegetables (97.6% of producers also consumed), backyard eggs (92.7%), and foraged foods (93.8%). For meats, a majority consumed backyard poultry meat (51.2%), wild-caught fish (69.7%), and wild game they hunted (80.1%). The frequency of consumption of fruit and vegetables (average of 13.5 times/month) and eggs (16.4 times/month) was very high, while average consumption of poultry meat, foraged foods, fish, and wild game ranged from 3.1 to 5.8 times/month. The number of respondents who reported "have more control over food availability" as motivation to produce all wild and backyard foods increased from 2019 to 2020 (p < 0.05 - p < 0.001). There was also a significant relationship between experiences of COVID-19 related hardship (i.e., food insecurity, income loss) with gardening and poultry-rearing (p ≤ 0.05), but not with other production methods or with consumption of wild and backyard foods.

Discussion

Our findings help to locate wild and backyard foods within COVID-19 impacted food environments, and describe food security as a particularly relevant motivation, among others, reported by respondents in 2020. Given this, New York State service providers can use these findings to tailor current future support for households exerting control over their own food environments with wild and backyard foods, allowing the state to be better prepared for future crises.

The attitude-behaviour gap in biosecurity: Applying social theories to understand the relationships between commercial chicken farmers' attitudes and behaviours

Introduction

Traditionally, it is believed that people's behaviours align with their attitudes; however, during COVID-19 pandemic, an attitude-behaviour gap in relation to preventive measures has been observed in recent studies. As such, the mixed-methods research was used to examine the relationships between farmers' biosecurity attitudes and behaviours in Taiwan's chicken industry based on the cognitive consistency theory.

Methods

Content analysis of face-to-face interviews with 15 commercial chicken farmers identified their biosecurity responses to infectious disease threats.

Results

The results indicated the mismatch of farmers' attitudes and behaviours towards specific biosecurity measures, in that they act differently than they think. The findings of the qualitative research allowed the research team to conduct the subsequent quantitative, confirmatory assessment to investigate the mismatch of farmers' attitudes and behaviours in 303 commercial broiler farmers. Survey data were analyzed to discover the relationships between farmers' attitudes and behaviours in relation to 29 biosecurity measures. The results show a mixed picture. The percentage of the farmers who had the attitude-behaviour gap towards 29 biosecurity measures ranged from 13.9 to 58.7%. Additionally, at the 5% significant level, there is an association between farmers' attitudes and behaviours for 12 biosecurity measures. In contrast, a significant association does not exist for the other 17 biosecurity measures. Specifically, out of the 17 biosecurity measures, the disconnection of farmers' attitudes and behaviours was observed in three specific biosecurity measures such as using a carcass storage area.

Discussion

Based on a fairly large sample of farmers in Taiwan, this study confirms the existence of an attitude-behaviour gap in context and applies social theories to provide an in-depth understanding of how infectious diseases are managed in the animal health context. As the results demonstrate the necessity of tailoring biosecurity strategies to address the gap, it is time to reconsider the current approach by understanding farmers' real attitudes and behaviours in relation to biosecurity for the success of animal disease prevention and control at the farm level.