Gh. Ajam - DVM, student of medical virology, Poultry Health Office Manager, South Khorasan IVO
M. Naseh - MSc, Central Veterinary Laboratory, South Khorasan IVO
M. A. Bakhshi Kareshk - DVM, Health deputy of South Khorasan Veterinary Main Office
A. Hamzehee - DVM, Deputy of Birjand Local veterinary Office, South Khorasan IVO
Z. Zangooee Motlagh - DVM, Poultry Health Office, South Khorasan IVO
S. Ghasemi - Head of Central Veterinary Laboratory, South Khorasan IVO

Introduction and Objectives: Salmonella contamination of food, especially eggs, is one of the major causes of digestive disorders in humans. Contamination of Salmonella in laying hens is important for the transmission of contamination to the production and consumer food chain. The aim of this study was to investigate the contamination of laying hens in southern Khorasan province with Salmonella spp. using fecal culture methods. Materials and Methods: This cross-sectional study was carried out in all Layer hen farms in south Khorasan Province, from April to June 2019. A 150 g weight fresh stool sample from at least 10 points of each farm was sent to central veterinary laboratory under cold chain procedure. Samples were cultured according to the protocol number CVL/DM/P/010 of the IVO. Positive results were confirmed with specific anti-serum. Positive and suspected samples were sent to Zahedan Veterinary Laboratory for PCR. Also, by sampling blood from positive fields, a rapid test was performed using the SP antigen.Results and Conclusion: Of the total 35 samples submitted, 3 samples (8.5%) were positive for fecal culture and anti-sera. These specimens were sent to another laboratory for PCR testing, which were all positive again. Salmonella species in one of positive was diagnosed Salmonella cholerasuiss using specific anti-serum. The result of a rapid test with SP antigen was negative in two samples and suspicious for one sample, which was also reported negative at a dilution of 1/16. The rate of infection from fecal culture in this study was 8.5%. This rate was reported in Bokai et al., 3.5%, Morshed et al., 9% and Akbrian et al., 6.5%. So, the prevalence of salmonellosis in South Khorasan province was not significantly different from other studies in the country. Basically, the presence of Salmonella in a producing layer hen farm is a major risk factor for public health. Therefore, continuous monitoring of these farms by high-sensitivity laboratory methods and further identification of Salmonella species and its effective contamination should be done by related government offices. Another issue that the findings of this study showed, were the difference between the results obtained from the three methods of testing and their different specificity and sensitivity. So, it is necessary to find the best screening and confirmation methods for Salmonella monitoring based on more detailed studies.

Salmonella, Prevalence, Fecal culture, Layer hens, south Khorasan