Newcastle disease vaccine virus I-2 fails to acquire virulence during repeated passage .

This study determined whether the naturally attenuated, thermotolerant Newcastle disease vaccine virus I-2 could acquire virulence after five passages through SPF chickens. Study design was to international requirements including European Pharmacopoeia, Ph. Eur.

Household-level risk factors for Newcastle disease seropositivity and incidence of Newcastle disease virus exposure in backyard chicken flocks in Eastern Shewa zone, Ethiopia.

A cross-sectional study with repeated sampling was conducted to investigate potential risk factors for Newcastle disease (ND) seropositivity and for incidence of ND virus (NDV) exposure in household flocks of backyard chickens in Eastern Shewa zone, Ethiopia. Data were collected from 260 randomly selected households in 52 villages in Adami Tulu Jido Kombolcha and Ada'a woredas (districts) using a structured questionnaire, and serum samples from chickens were tested for NDV antibodies using a blocking enzyme-linked immunosorbent assay (ELISA). Sampling took place during September 2009 and the same households were again sampled in May 2010.

Determination of the distribution of lentogenic vaccine and virulent Newcastle disease virus antigen in the oviduct of SPF and commercial hen using immunohistochemistry.

The control of Newcastle disease (ND) in South Africa has proved difficult since 2002 following the introduction of lineage 5d/VIId Newcastle disease virus (NDV) strain ("goose paramyxovirus" - GPMV) to which commercially available ND vaccines appeared less effective. Most of the ND infections, even in fully vaccinated hens were characterized consistently by a drop in egg production. In this study, commercial and SPF hens-in-lay were vaccinated with La Sota vaccine and challenged with a GPMV isolate.

Identification of risk factors associated with highly pathogenic avian influenza H5N1 virus infection in poultry farms, in Nigeria during the epidemic of 2006-2007.

We conducted a matched case-control study to evaluate risk factors for infection with highly pathogenic avian influenza (HPAI) H5N1 virus in poultry farms during the epidemic of 2006-2007 in Nigeria. Epidemiologic data were collected through the use of a questionnaire from 32 case farms and 83 control farms. The frequency of investigated exposure factors was compared between case and control farms by using conditional logistic regression analysis.