An improved heamagglutination inhibition test for rapid diagnosis and stereotyping of avian infectious bronchitis virus

ABSTRACT

Infectious bronchitis virus (IBV) causes an acute, highly contagious viral respiratory disease in poultry with huge economic impact and extremely difficult to control due to its multiple serotypes. The disease could be prevented by rapid diagnosis either molecular or serological test. However, the later test is inexpensive such as heamagglutination inhibition test (HI), but IBV fail to give Heamagglutination (HA) reaction without pretreatment. Therefore, we designed this study for preparation of IBV antigen by treating with different enzymes for HA reaction. IBV local isolates were characterized by SDS-PAGE and RT-PCR. The indigenous isolate HA antigens were treated with different proteolytic enzymes trypsin, neuraminidase and phospholipase C. The prepared antigen were stored at -86oC and used for HA test. All antigen prepared by different enzyme were found to give significant HA titer up to 7 log2 . During stability test antigen prepared by phospholipase C were found most stable up to six month by giving constant 7 log2 HA titer, while neuraminidase induced antigen were stable up to five months (7 log2). Trypsin treated antigen were readily lost its activity from 7 log2 to 2 log2 after two months of incubation. During specificity test all antigens showed specific effect on IBV by eliciting agglutination of RBCs while other avian viruses avian influenza (AI), new castle disease virus (NDV) and infectious bursal disease virus (IBDV) were not affected by enzymatic inductions. Therefore, the antigen prepared by phospholipase C has been found to be more effective for HI test for rapid diagnosis of IBV during infection.