Viral diseases have caused devastating effect on poultry industry leading to significant losses in economy of world. In the presented study, the ability of Newcastle disease virus (NDV), infectious bursal disease virus (IBDV) and avian influenza virus (AIV) to grow in two cell lines was evaluated. Both chicken embryo fibroblast (CEF) and DF-1 cells were used and cytopathic effects (CPE) produced by these viruses were observed. The titer of virus in terms of TCID50 was determined after 24h up to four days for each virus. The same type of CPE was observed for all viruses used in the study in both DF-1 and CEF cells. IBDV showed CPE causing rounding of cells while NDV caused formation of multicellular large nuclei, cell fusion and rounding of cells. Giant cells with inclusions and aggregation of cells with intact monolayer was observed for AIV. In growth kinetic study, higher titer of IBDV and NDV was observed in CEF cells than DF-1 cells while for AIV, DF-1 cells showed higher titer than CEF cells. These results would be useful for furthers comparative studies on growth of different cell lines of various viruses to find a suitability for vaccine production.

Members of Enterobacteriaceae are known to produce extended-spectrum beta-lactamases (ESBL) which hydrolyze the beta-lactam group of antibiotics. The existence of ESBL-producing Salmonella enterica ( S. enterica) and Escherichia coli ( E. coli) harbored by urban avifauna was investigated in this study. Dropping samples (n= 180) were collected from six different bird species in the district Jhang, Punjab province, Pakistan. Isolation and identification of ESBL isolates were made by using cefotaxime- (4 mg/L) supplemented MacConkey agar and double disc synergy test (DDST). Polymerase chain reaction (PCR) was performed for the detection of four different ESBL genes including bla _CTX-M, bla _TEM, bla _SHV and bla _OXA. A total of 42.69% isolates were confirmed as ESBL via DDST including 30.64% S. enterica and 49.54% E. coli. The incidence of ESBL S. enterica and ESBL E. coli was found highest in egret ( Ardea alba) and pigeon ( Columba livia) as 64.28% and 78.95%, respectively. The bla _CTX-M gene was detected in 57.89% and 64.81% of isolates of S. enterica and E. coli, respectively. Among other genes in S. enterica and E. coli, bla _TEM (21.05%, 20.4%); bla _SHV (15.78%, 9.26%), and bla _OXA (5.26%, 5.56%) were detected, respectively. All of the tested isolates were found resistant to at least one of the thirteen antimicrobial agents except meropenem. To the best of our knowledge, this is the first study reporting the incidence and genetic diversity of ESBL bacteria associated with urban avifauna in Pakistan. The urban avifauna can serve as a potential subject of bio-surveillance to monitor the emergence of antimicrobial-resistant bacteria.