High Pathogenicity Avian Influenza Virus in the Reproductive Tract of Chickens13 August 2013
New research from the US demonstrates the dissemination of the highly pathogenic avian influenza (HPAI) virus over time in the reproductive tract of hens after intranasal inoculation and its replication in the oviduct. The work was presented at the 2013 American Veterinary Medical Association (AVMA) convention in Chicago in July 2013.
High pathogenicity avian influenza virus (HPAIV) has been associated with a wide range of clinical manifestations in birds and mammals worldwide, reported first-named author, Mariana Sá e Silva of the USDA ARS Southeast Poultry Research laboratory in Athens, Georgia.
In a paper co-written with Daniel R. Rissi (University of Georgia), Mary Pantin-Jackwood and David E. Swayne, they state that although adult hens of reproductive age are susceptible to infection and hence can shed virus in the eggs, little is known about the pathogenesis of HPAIV in the reproductive tract of poultry.
To evaluate viral infection and dissemination in the reproductive tract of chickens, adult hens were inoculated intranasally with three different HPAIV strains.
Oral swabs were tested for viral shedding and all segments of the reproductive tract were evaluated for pathological changes and presence of viral antigen using immunohistochemistry. The average viral shedding titers were similar between all three groups but differences in the onset of lesions and mortality differed among these groups.
All three viral strains induced lesions in the reproductive tract 36-48 hours post inoculation. Positive cytoplasmic and/or nuclear immunostaining was observed in all segments of the reproductive tract, occurring predominantly in ovarian stromal cells and superficial germinal epithelium, mucosal epithelial cells and less often glandular epithelium throughout the oviduct, and vascular endothelium.
The present study generates important data regarding virus dissemination over time in the reproductive tract of hens after intranasal inoculation with HPAIV, and explains previously reported virus isolation from yolk, due to ovarian virus replication and virus recovery from albumin, due to virus replication in several segments of the oviduct.
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