JOSHI, B. P.DESHMUKH, MANOHAR MADHAV2018-07-042018-07-042016http://krishikosh.egranth.ac.in/handle/1/5810056995The present research work was carried out to know the incidence of LPAI and concurrent presence of secondary E. coli infection in broiler birds affected with LPAI. The study comprised of epidemiological information in relation to autopsy incidence and farm wise mortality, gross and histopathological examination of different organs, detection of LPAI (H9N2) virus by RT-PCR, isolation of E. coli from the birds infected with LPAI and molecular characterization of E. coli isolates. The autopsy records of last five years (January 2011 to December 2015) revealed that year wise incidence of LPAI ranged between 13.06 to 18.43 per cent with an overall average relative incidence of 15.64 per cent Out of a total 1,242 LPAI affected flocks received during last five years, the highest number of cases (33.98%) were recorded during fourth week of age followed by third week (27.18%), fifth week (25.84%), second week (7.64%) and sixth week (4.35%) of age. The seasonal autopsy incidence revealed that the highest cases of LPAI were recorded during summer i.e. from March to June (51.20%) followed by winter i. e. from November to February (28.26%) and monsoon i. e. from July to October (12.48%) season.enVETERINARY PATHOLOGYA STUDYThesis