in order to adapt lasota strain of newcastle disease virus (ndv) on chick embryo fibroblast (cef) cells, 0.1 ml from lasota vaccine produced in razi vaccine and serum research institute inoculated to the cef cells and was passaged five times in the cef grown in eagle’s minimum essential medium (mem). first to third passages were blind but in fourth passage cytopathic effect of virus was observe...

avian influenza (ai) is a viral respiratory disease of domestic and wild birds. in the diagnostic laboratory, it is essential to have methods for rapid detection of avian respiratory viruses. cloacal swabs collected from chickens experimentally infected with h9 subtype ai virus, used in a reverse transcription-polymerase chain reaction (rt-pcr) assay for detection of ai. in infected animals, ai...

The pathogenesis, virus shedding, and serologic response in specific-pathogen-free (SPF) chickens and commercial turkeys against H4, H6, and H9 type low pathogenic avian influenza viruses (LPAI) from wild birds was examined. Four-week-old chickens and three-week-old turkeys were given 1 x 10(6) EID50 of LPAI per bird, intrachoanally, and examined for clinical signs for 3 wk. Oropharyngeal and c...

Introduction Highly pathogenic avian influenza (HPAI) is a markedly contagious viral disease of domestic chickens and turkeys, characterized by severe illness with high morbidity and mortality (Easterday et al. 1997). Human infections with the HPAI virus H5N1 frequently cause death since 1997 (Class et al., 1998, Subbarao et al., 1998). Two surface glycoproteins, the haemagglutinin (HA) and neu...

The H5N1 avian influenza viruses emerged in Southeast Asia in the late 20th century and have evolved into multiple phylogenetic clades based on their hemagglutinin (HA)-encoding genes. The clade 7.2 viruses were first detected in chickens in northern China in 2006, and vaccines specifically targeted to the clade were developed and have been used in poultry in China since 2006. During routine su...

Ouinea pigs exposed by the respiratory route to sublethal doses of influenza virus, PR8 strain, resisted subsequent challenge with a lethal doso of Coxiella burnetti administered by the same route. This note describes this interference phenomenon. PRECEDING PAGE BLANK 5 INTERFERENCE WITH COXIELIA BURNETII INFECTIONS OF GUINEA PIGS BY INFLUENZA A VIRUS Guinea pigs* exposed by the respiratory rou...