In vitro study on H9 avian influenza cytopathic effect in al-Najaf al-Ashraf-Iraq

الملخص EN

During a period extending from July 2012 to July 2013, a total of 251 avian cases admitted for medically care unit in the veterinary hospital in Al-Najaf governorate were examined and involved in this study.

The study was applied to determine risk factors affecting by avian influenza virus infection among poultry flocks in Al-Najaf-Iraq.

The study revealed that poultry flocks had a considerable risk of infection with H9 subtypes according to the PCR assay.

Primarily, infected birds were investigated by rapid test for the detection of type A of influenza viral antigen, based on monoclonal antibodies.

Identification was also confirmed by PCR assay for the amplification of a specific region within the H9 genome.

Propagation and adaptation of 5 strong positive H9 isolates on rhabdomyosarcoma cells (RD) and chick embryo fibroblast was done by cell culture techniques, for the demonstration of specific type of cytopathic effect (CPE) caused by these isolates.

The observation of specific H9 cytopathic effect was also confirmed by indirect immunoflourescent antibody technique.

The two types of cells involved different degrees of sensitivity for supporting the growth of H9 virus; RD cell line was sensitive enough to support the growth of the virus, followed by chick embryo fibroblast cells.

The halve tissue culture infective dose(TCID50) of the virus was elevated with the subsequent passages till reach its peak (108 TCID50/0.1ml) during 6th passage on RD cells and 105 TCID50 /0.1ml during 7th passage on chick embryo cells, Our results indicated that H9 type is dominant in Najaf area, RD cell line is typical for culturing the virus, the addition of trypsin is very helpful for the cultivation of H9 influenza virus.

Vaccination and increasing workers knowledge could prevent future infections.