Aviadenovirus na avicultura industrial, familiar e vacinas comerciais em Minas Gerais: detecção por reação em cadeia pela polimerase e avaliação histopatológica

Abstract

An epidemiological study on the occurrence of Aviadenovirus (FAdV) in poultry of Minas Gerais, Brazil was performed, in view of the lack of recent information and of the occurrence in neighboring countries. During 2010, young and adult layer (n=50), broiler (n=300) and breeder (n=25) chickens, representative of the poultry industry of major Minas Gerais State poultry regions were examined. Livers or for breeders, livers and feces, were evaluated by a previously described PCR.and by histopathology. FAdV DNA was found in 100% (25/25) of adult and in36% (9/25) of immature layers. Broiler flocks presented FAdV varying from 24 to 86% entre os lotes estudados. In broiler breeders FAdV DNA was found in 16% of liver extracts (4/25), although not detectable in feces. Subsistence chickens (n=12) and live lyophilized commercial poultry vaccines (n=15) were examined in order to investigate their potential role in FAdV epidemiology. Subsistence chickens were from one of the intensified poultry regions and presented 100% positivity (12/12). Live vaccines were against Newcastle disease, infectious bursal disease, infectious bronchitis, avian infectious encephalomyelitis, Mareks disease and fowl pox and presented 20% positivity (3/15) only for Newcastle vaccine batches produced in January/1991 and May 1992 and encephalomyelitis produced in January 94, all from the same manufacturer. It was not possible to establish a correlation between FAdV DNA and histopathological alterations. The evaluation of livers for aflatoxins B1, B2, G1 and G2 did not reveal levels from 2ppb or above, although with suggestive histopathological changes, possibly associated to other mycotoxins. It was shown that the rate of infection with Aviadenovirus is high and widespread in the poultry industry and free-range chickens of Minas Gerais, Promiscuity between industrial and subsistence poultry may perpetuate Aviadenovirus infections. The detection of FAdV DNA in live vaccines produced up to 1992 may represent another important source of infection for industrial and free-range poultry. Falta comentar CAV.