Newcastle disease virus-attenuated vaccine LaSota played a key role in the pathogenicity of contaminated exogenous virus

Abstract

Newcastle disease virus (NDV)-attenuated vaccine has been widely used since the 1950s and made great progress in preventing and controlling Newcastle disease. However, many reports mention exogenous virus contamination in attenuated vaccines, while co-contamination with fowl adenovirus (FAdV) and chicken infectious anaemia virus (CIAV) in the NDV-attenuated vaccine also emerged in China recently, which proved to be an important reason for the outbreaks of inclusion body hepatitis–hydropericardium syndrome in some flocks. It is amazing that exogenous virus contamination at extremely low doses still infected chickens and induced severe disease; thus, we speculated that there must be some interaction between the NDV-attenuated vaccine and the contaminated exogenous viruses within. Accordingly, simulation experiments were launched using FAdV and CIAV isolated from the abovementioned vaccine. The results showed that the pathogenicity of FAdV and CIAV co-infection through the contaminated vaccine was significantly higher than that of direct oral infection, while the synergistic reaction of these viruses and LaSota prompted their multiplication in vivo and disturbed the production of antibodies against each other. This study showed the interactions of FAdV, CIAV and LaSota after using contaminated NDV-attenuated vaccine, helping us to understand how the contaminated exogenous viruses cause infection and induce severe disease at a relatively low dose through the oral route.

Immune effect of a Newcastle disease virus DNA vaccine with IL-12 as a molecular adjuvant delivered by electroporation

“…Incomplete inactivation of killed NDV vaccine may lead to infections in animals. Studies have found some attenuated vaccines to be contaminated with exogenous viruses, including fowl adenovirus and chicken infectious anemia virus, [19,31]. In addition, traditional vaccines have the disadvantage of needing to be kept cold during shipping, which is difficult in some developing countries and remote rural areas.…”

Research Note: Molecular relationship of the fowl adenovirus serotype 4 isolated from the contaminated live vaccine and wild strains isolated in China, 2013-2018

“…The FAdV-4 strain ( F-Vac ) used in this study was isolated from a Newcastle disease virus attenuated vaccine and stored in our laboratory at −80°C, and it can induce obvious HHS in specific-pathogen-free chicken ( Su et al., 2018a , b ). Detailed isolation and identification procedures can be found in the previous report ( Su et al., 2018a ).…”

“…However, it is still not clear how the strain spread in China at an incredible fast speed. Previous studies have shown that the use of attenuated vaccines contaminated with FAdV-4 may be an important reason for the outbreak of HHS in some flocks ( Su et al., 2018a , b ). However, the complete genome of the vaccine-contaminated strain is not provided, which hinders the further determination of its relationship with other identified strains.…”

Emergence of fowl aviadenovirus C-4 in a backyard chicken flock in California

“…15 The spread of the outbreaks was exacerbated mostly by contamination by both FAdV and CAV. 16 The suggested vaccine associated with these outbreaks is in use in the United States, although we are not aware of any contamination issues. The spread of FAdV through contaminated vaccines does not seem likely to be a primary route of exposure for backyard chickens, given that small hobby flocks tend to have minimal vaccination strategies.…”