Background: Avian pathogenic Escherichia coli (APEC) causes economic losses in the chicken industry worldwide. Objective: In this study, virulence-associated gene profiles of APEC isolates were investigated by polymerase chain reaction (PCR). Materials and Methods: A total of 60 Escherichia coli isolates were collected from 60 colibacillosis cases from 30 broiler poultry farms in Alborz, Tehran, and Golestan provinces, Iran. After identification by biochemical tests, DNA was extracted by boiling method and 5 virulence-associated genes including: iutA, hlyF, iroN, ompT, and iss were detected by 2 multiplex PCR protocols. Results: Of the 60 APEC isolates, 26 (43.3%) isolates had at least three virulence genes from which 12 (20%) isolates were positive for all 5 virulence genes, whereas 34 (56.6%) carried no investigated virulence genes. Presence of iutA, hlyF, iroN, ompT, and iss genes in the APEC isolates were 17 (28.3%), 17 (28.3%), 24 (40%), 26 (43.3%), and 23 (38.3%), respectively. Conclusion: According to the results, four different virulence-associated gene profiles were seen in isolates, from which profile 1 with 12 (20%) isolates was predominant. These findings were in agreement with the previous reports.

This survey was carried out to determine the seroprevalence of Mycoplasma gallisepticum (MG) and

The objective of the present work was to perform the efficacy of one attenuated live vaccine Nobilis CAV P4 (Intervet Co., Netherland) in broiler breeder and their progenies compared to naturally infected flock. The vaccine was administrated to Ross 308 broiler breeder at 6 week old through S.C. rout. A total of 352 serum samples were collected from vaccinated and unvaccinated breeder flocks (that infected naturally) from 6 to 33 weeks old and 2 times in their progenies at one-day old. Sera were analyzed using indirect Elisa kit (Synbiotic Corporation, USA) and data obtained were compared between 2 groups statistically. Due to natural infection of chicken infectious anemia (CIA) in unvaccinated breeder, mean titer in breeder and their progenies was significantly higher than vaccinated breeder and their progenies (P<0.05). The CV%s in breeders was not different significantly (P>0.05) but CV% in progeny of unvaccinated breeder flock was twice more than progeny of vaccinated flock. There were 5 and 12% of zero titers of antibody in hens and progenies in unvaccinated breeder flock respectively. All breeders from vaccinated flock were positive serologically. It seems that vaccination could be an efficient rout for eliminating susceptible birds, decreasing variation in antibody titers and induction persistent and homogenous antibody titer in progeny.