Occurrence of chicken anemia virus in backyard chickens of the metropolitan region of Belo Horizonte, Minas Gerais

Abstract

The occurrence of CAV in backyard chickens in the metropolitan area of Belo Horizonte, Brazil, was evaluated. The spleen and thymus of chickens from different origins were collected for DNA extraction and nested-PCR. CAV genome was detected in 30% of the flocks (n=20) examined. CAV origin for backyard chickens is speculated, taking into consideration its widespread incidence in the chicken industry, the contamination of live vaccines with CAV prior to its eradication from SPF flocks, and the use of attenuated CAV vaccines.

Experimental Coinfection of Chicken Anemia Virus and Mycoplasma gallisepticum Vaccine Strains in Broiler Chicks

“…Immunosuppressive diseases usually negatively affect chickens of the poultry industry by increasing the susceptibility to opportunistic infections by viruses and bacteria (Lutticken, 1997;Balamurugan & Kataria, 2006). Among the known immunosuppressive agents, CAV stands out for its worldwide occurrence, not only in commercial poultry, but also in SPF chickens (Schat, 2003;Balamurugan & Kataria, 2006), backyard chickens (Barrios et al, 2009), as well as contaminates poultry vaccines (Barrios et al, 2012). CAV presents tropism for T-lymphocytes, rendering the cellular immune response ineffective, especially in young chickens, by destroying CD8+ T cells (Adair et al, 1993;Adair, 2000;Brentano, 2009), disabling the protection against intracellular agents.…”

Molecular and Pathological Analysis of Chicken Anemia Virus Isolated from Field Infection in Three Egyptian Provinces

“…The obtained result revealed the detection of CAV DNA in 65% of tissues of investigated broiler chicken flocks and agreed with Mohamed (2010) Bülow and Schat (1997) reported CAV even in the presence of high neutralizing antibodies titers and Imai et al (1999) suggesting that the virus may persist in the presence of antibodies. In addition, live vaccines produced with CAV, contaminated eggs and cells may have played a role in the dissemination of CAV to chickens due to the previously undetected CAV infection in SPF flocks (Barrios et al, 2009). …”

A retrospective PCR investigation of avian Orthoreovirus, chicken infectious anemia and fowl Aviadenovirus genomes contamination in commercial poultry vaccines in Brazil

“…Fowl Aviadenovirus (FAdV), avian Orthoreovirus (ARV) and chicken anemia virus Gyrovirus (CAV) are major pathogens which had been present sub-clinically in specific pathogen free (SPF) flocks of chickens (Yuasa et al, 1979;Cardona et al, 2000;Miller et al, 2001) and may be horizontally transmitted, on failed biosecurity, and vertically to the embryos (Schat, 2003). CAV was previously described in industrial (Brentano et al, 1991) and free-range chickens (Barrios et al, 2009) in Brazil. SPF flocks are used in research and for the production of vaccines, and their infection may represent a most relevant epidemiological risk, especially concerning lack of purity of live vaccines, therefore requiring highly sensitive and specific monitoring assays.…”