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Avian infectious bronchitis (IB), caused by avian infectious bronchitis virus (IBV), is a worldwide endemic disease of chickens that affects all branches of the poultry industry. Multiple geno/serotypes occur, and lowvaccine cross-protection results from the highly divergent IBV types. In view of the lack of consistent data on the economic losses caused by IB and the poor protection resulting from the use of the Massachusetts type as a live vaccine in Brazil, this survey aimed to estimate the losses per 1000 birds in broiler and breeder flocks positive for IBV. Thirty-two different IBV genetic types were found. In breeders, the total loss per 1,000 birds was US $3567.4 and US $4210.8 at 25-26 and 42 weeks old, respectively, whereas in broilers (48 days old), the estimated loss was US $266.3 per 1,000 birds. Taken together, the results show a significant and measurable economic impact on the broiler and breeder industries, with an age-dependent increasing trend and an association with multiple genetic types of the virus.

Avian infectious bronchitis (IB), caused by avian infectious bronchitis virus (IBV), is a worldwide endemic disease of chickens that affects all branches of the poultry industry. Multiple geno/serotypes occur, and lowvaccine cross-protection results from the highly divergent IBV types. In view of the lack of consistent data on the economic losses caused by IB and the poor protection resulting from the use of the Massachusetts type as a live vaccine in Brazil, this survey aimed to estimate the losses per 1000 birds in broiler and breeder flocks positive for IBV. Thirty-two different IBV genetic types were found. In breeders, the total loss per 1,000 birds was US $3567.4 and US $4210.8 at 25-26 and 42 weeks old, respectively, whereas in broilers (48 days old), the estimated loss was US $266.3 per 1,000 birds. Taken together, the results show a significant and measurable economic impact on the broiler and breeder industries, with an age-dependent increasing trend and an association with multiple genetic types of the virus.

Infectious bronchitis (IB) casues multi-systemic infection in chickens with signs similar caused by other poultry pathogens and thus a high diagnostic accuracy can only be achieved by s series of laboratory assays. This article reviews in a brief way the traditional virus assays such as embryo innoculation, tracheal rings and virus neutralization assays for the direct detection of Avian infectious bronchitis virus (IBV) and methods based on gene molecular biology and some assays for the detection of anti-IBV antibodies, including ELISA. A critical view on each technique is also provived by the author.

Multiple lineages of Brazilian strains from 2007 to 2008 of avian infectious bronchitis virus (IBV) were detected in flocks of breeders, broilers, and layers. Organs samples from 20 IBV-positive flocks with variable clinical signs were submitted to the partial amplification of S gene (nucleotides 726-1071) of IBV. Fifteen of the 20 sequenced strains segregated in a unique Brazilian cluster subdivided in three subclusters (Brazil 01, 02, and 03). Whereas three strains could be classified as Massachusetts (Mass) genotype, the remaining two strains, originating from flocks with reproductive and respiratory disorders, grouped within the 4/91-793B genotype, a genotype that has not been detected before in Brazil. The potential relevance of the findings to the poultry industry is discussed because the low level of identity of the sequenced part of the S gene from 17 of 20 detected field strains and the vaccines of the Massachusetts serotype used suggest that the level of cross-protection by the Massachusetts vaccines might be low.