Assessment of experimental pathogenicity of avian influenza virus H9N2 isolates by intravenous pathogenicity index (IVPI) test and histopathology

Pathogenicity and haemagglutinin gene sequence analysis of Iranian avian influenza H9N2 viruses isolated during (1998–2001)

Sixteen avian influenza (AI) H9N2 viruses were isolated from disease outbreaks in different parts of Iranduring (1998–2001). These AI isolates were used for pathogenicity, haemagglutinin (HA) gene variation andphylogenetic analysis. Results in both pathogenicity tests and HA gene cleavage site sequence detectionrepresented a non-highly pathogenic feature for all Iranian AI isolates studied. The...

Modulation of the immune responses in chickens by low-pathogenicity avian influenza virus H9N2.

Most low-pathogenicity avian influenza (LPAI) viruses cause no or mild disease in avian species. Little is known about the mechanisms of host defence and the immune responses of avian influenza-infected birds. This study showed that chicken macrophages are susceptible to infection with LPAI H9N2 and H6N2 viruses and that infection led to apoptosis. In H9N2 virus-infected chicken macrophages, To...

Passaging impact of H9N2 avian influenza virus in hamsters on its pathogenicity and genetic variability.

INTRODUCTION Avian influenza viruses of the H9N2 subtype have been reported to cause human infections. This study demonstrates the impact of nasal viral passaging of avian H9N2 in hamsters on its cross species-pathogenic adaptability and variability of amino acid sequences of the hemagglutinin (HA) and neuraminidase (NA) stalk. METHODOLOGY Three intranasal passagings of avian H9N2 in hamsters...

Experimental Study on the Pathogenicity of Avian Influenza A/Ch/It/5093/99(H7N1) Virus in Chicken

In this study, the pathogenicity of A/Ch/It/5093/1999 H7N1 which had been isolated from chicken during the outbreak in Italy was assessed in chicken by experimental infection virus. Ten SPF chickens of four week-old were inoculated with this virus, and five chickens were inoculated with uninfected allantoic fluid. For determination of virus shedding, oropharyngeal and cloacal swabs were taken f...

Isolation and Identification of Avian Influenza Virus H9N2 Subtype