Indian J Anim Health (2023), 62(2): 397-400 DOI: https://doi.org/10.36062/ijah.2023.15922 Prevalence of potentially disease producing Escherichia coli in ducks of organized farms/ backyards and their associated environments in different agro-climatic zones of West Bengal A. Paul 1 , I. Samanta 1 , K. Batabyal 1 , S. Dey 1 and S. N. Joardar 1* 1 Department of Veterinary Microbiology, West Bengal University of Animal and Fishery Sciences, Kolkata- 700 037, West Bengal, India Abstract The present study was undertaken to assess the prevalence of Escherichia coli possessing different virulence genes in healthy ducks reared in organized farms, the backyards and their associated environments covering various agro-climatic zones of West Bengal. A total of 272 samples were collected and screened for E. coli based on cultural, morphological and biochemical properties followed by PCR for confirmation of 16S rRNA gene. A total of 342 isolates were generated. The virulence genes, viz., stx1, stx2, eaeA and ehxA were detected in 79 (23.10%), 51 (14.91%), 43 (12.57%) and 77 (22.51%) isolates, respectively. The present study revealed that healthy ducks might play a role in transmitting disease producing E. coli to other animal species including human through direct contact and/or the food chain, that warrants serious attention and strategic intervention. Keywords: Duck, E. coli, EHEC, STEC Highlights  Virulence genes (stx, stx2, eaeA and ehxA) were observed in E. coli isolated from apparently healthy ducks.  The healthy ducks are carriers of potentially disease producing E. coli.  Prevalence of E. coli having virulence genes was highest in the Undulating Red and Laterite zones of West Bengal. Short Communication Shiga toxin-producing Escherichia coli (STEC) also known as verotoxin-producing E. coli is a subdivision of an important pathogenic group called Enterohaemorrhagic E. coli (EHEC). STEC are food borne pathogens that can cause bloody diarrhoea to several other diseases such as haemorrhagic colitis (HC), thrombotic thrombocytopenic purpura (TTP) and life- threatening haemolytic uremic syndrome (HUS) (Paton and Paton, 1998). Shiga toxins which inhibit protein synthesis of the host cell leading to cell death are divided into two groups – Shiga toxin 1 and Shiga toxin 2 (Karmali et al., 2010). The toxins are phage-encoded cytotoxins, the most commonly assayed virulence factors of STEC that are encoded by the stx1 and stx2 genes, respectively. The protein intimin, which is encoded by the chromosomal gene eae, are responsible for the intimate attachment of the bacteria to intestinal epithelial cells and the production of attaching and effacing (AE) lesion (Paton and Paton, 1998). Some of the STEC strains exhibit haemolysis in washed sheep blood agar because of enterohaemolysin production, encoded by the ehxA gene (Beutin et al., 1993). STEC have been found in various animals, including cattle, sheep, goats, pigs, cats, dogs, chickens and gulls. In terms of human infection, cattle and pigs are the most significant animal species. The STEC strains commonly obtained from healthy animals can cause early episodes of diarrhoea in young animals, followed by asymptomatic colonization (Rivera et al., 2012). When these strains are present with a greater frequency in farm animals, humans are presumably exposed more often to such strains. There are limited data available from India regarding the isolation of STEC and other pathotypes of E. coli from ducks reared in the organized and unorganized sectors. Environmental samples, viz. feed, water and soil including faecal samples from duck farms, are not routinely evaluated for these pathogens. In this study, a total of 272 samples comprising of the tracheal swabs (n=127), cloacal swabs (n=127) and environmental samples (n=18) were collected from indigenous ducks (n=25), Pekin ducks (n=24) and Khaki Campbell ducks (n=78) reared in the backyard and organized farms, respectively. These samples were collected on a random basis from different districts covering various agro-climatic zones of West Bengal. The sample collection area included farms of Pathar Pratima, South 24 Parganas district (Coastal Saline Zone), Mohanpur, Nadia district (Gangetic Alluvial Zone) and * Corresponding Author, E-Mail: joardar69@gmail.com