Prevalence of proteases and other virulence genes in APEC associated with respiratory viral infections in broilers
Journal Title: UNKNOWN - Year 2019, Vol 26, Issue 2
Abstract
Acute upper respiratory disease in chickens is a major cause of economic losses due to high mortality rates especially in poorly managed cases. Respiratory disease in poultry is initiated by variety of viruses, bacteria and fungi. The current study aims to investigate the prevalence of avian pathogenic E. coli (APEC), their proteases and other virulence genes in respiratory viral disease outbreaks in broiler chickens. Quantitative RT-PCR (qRT-PCR) was performed on samples from 25 farms with respiratory affections, APEC was isolated and virulence determinants in E. coli were investigated phenotypically and genotypically. E. coli was isolated from different flocks (100%, n=25). They were positive to Congo red binding (100%, n=25), iss gene (100%, n=25), iutA gene (92%, n= 23), tsh gene (24%, n=6), vat gene (20%, n=5). Presence of iss gene and CR binding proves that all isolates are APEC. Although the entire 25 APEC isolates carried more than one virulence gene; either 2 genes (n=17), 3 genes (n=7) and 4 genes (n=1), no effect of the number of genes harbored on the mortality rates in different flocks was observed. The presence of two serine proteases genes (tsh and vat) was confirmed in a total of 10 isolates (40% of the isolates) with positivity to tsh gene (24%) and vat gene (20%). qRT-PCR for detection of IBV-S1, AIV-H9, AIV-H5 and velogenic NDV-F genes revealed that 96% (n=24), 44% (n=11), 12% (n=3) and 4% (n=1) of 25 farms were positive to IBV, AIV-H9, velogenic NDV and AIV-H5, respectively. The results showed that among the 25 flocks, single viral infection was observed in 12 flocks (11 IBV and 1 AIV-H9), while mixed viral infections were detected in 13 flocks; IBV/AIV-H9 (n=9), IBV/velogenic NDV (n=3) and IBV/AIV-H9/AIV-H5 (n=1).The average mortality rate was the lowest in flocks infected with IBV, higher rates of mortality were observed in flocks infected with AIV-H9, velogenic NDV and AIV-H5. Flock age seems to affect the mortality rate in flocks infected with AIV-H9 where flocks aging 16:20, 21:25 and 26:30 days suffered from 2.38%, 8.13%, 11.48% average mortality rates, respectively.
Authors and Affiliations
Asmaa A. Tolba, Azza A. El-Sawah, Salama A. S. Shany* Poultry Diseases Department, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef 62511, Egypt.
Keywords
Related Articles
- EP ID EP675755
- DOI -
- Views 115
- Downloads 0
Pathogenicity of Escherichia coli O125 in commercial broiler chickens
Commercial broiler chickens are frequently infected with Ecoli serotypes in form of collibacillosis which characterized as an initial respiratory infection (air sacculitis) followed by generalized septicemia, perihepati...
Evaluation of the bioassay of Commiphora molmol extract (Mirazid) against praziquantel in experimentally infected mice with Schistosoma mansoni
Schistosoma mansoni worms inhabit the portal triad affecting blood elements. Therefore, the current study aimed to compare ameliorative effects of Commiphora molmol extract (Mirazid, MZD) and praziquantel (PZQ) on some...
Molecular characterization and genotyping of recent isolate of Infectious Bronchitis Virus (IBV) in Egypt
In this study a total number of 22 organ samples (including trachea, lung and kidney) from 22 broiler farms from northern Upper Egypt were collected from Mars 2017 to June 2018 from chickens showing clear clinical and...
The ameliorative effect of methanolic red carrot extract and vitamin E against cadmium-induced testicular toxicity in rats
The current study aimed to investigate the effects of methanolic red carrot extract (MRCE) against cadmium intoxication on testis of adult Wister albino male rats. For that purpose, forty eight Wister albino male rats...
Ultrasonography of the mammary gland in ruminants
Information regarding the use of ultrasonography in the diagnosis of udder and teat affections is scarce in ruminant. The present study was conducted on 30 cows, 20 ewes and 45 does. The surgical affections of udder an...