An Overview on Mareks Disease Virus Evolution and Evidence for Increased Virulence in Brazil

Mareks disease virus (MDV) has been shown to be evolving to higher virulence. One of the genetic sites involved in virulence which enables such characterization is the 339-amino acid Meq protein encoding gene (meq). The reemergence of clinical Mareks disease (MD) in vaccinated flocks can be associated to changes in meq. Our studies have shown the presence of very virulent MDV strains in the Brazilian industrial and free-range poultry. We present an overview of MD increasing severity and indicate the necessity of using phylogenetic tools for best accompanying MDV evolution.(AU)

An Overview on Mareks Disease Virus Evolution and Evidence for Increased Virulence in Brazil

Mareks disease virus (MDV) has been shown to be evolving to higher virulence. One of the genetic sites involved in virulence which enables such characterization is the 339-amino acid Meq protein encoding gene (meq). The reemergence of clinical Mareks disease (MD) in vaccinated flocks can be associated to changes in meq. Our studies have shown the presence of very virulent MDV strains in the Brazilian industrial and free-range poultry. We present an overview of MD increasing severity and indicate the necessity of using phylogenetic tools for best accompanying MDV evolution.

Serological diagnosis of influenza A subtype H1 on family poultry of Belo Horizonte, Minas Gerais and Santa Maria, Rio Grande Do Sul, in Brazil

Serum samples (n=687) from Gallus gallus domesticus were collected for the investigation of antibodies to avian influenza virus (AIV-A) in the family poultry of the surrounding counties of Santa Maria/RS and the metropolitan region of Belo Horizonte/MG, totaling twenty different counties. Additional samples of seventeen (n=17) free-flying ducks (C. moschata pure or hybrid with Anas platyrhynchos) were collected in Belo Horizonte. The chosen tests for the survey were performed as described by the World Organization for Animal Health (OIE), including agar gel immunodiffusion (AGID) for antibodies to AIV-A nucleoprotein (N) and haemagglutination- inhibition (HI) for antibodies to subtype H1. Out of the 704 serum tests performed by AGID, eight (8/704) were revealed positive for antibodies to AIV-A N protein, with six (6/704) retested positive for subtype H1. Two sera tested positive by AGID were shown to be non reactive to the H1 subtype, suggesting specificity to another subtype. A low occurrence of antibodies to influenza A (1.13%) was found, and mostly (75%) specific to subtype H1. This represents an approximately 0,85% overall occurrence for subtype H1 antibodies, with an unknown subtype specific antibodies detected in one free-flying anatid. The low occurrence of antibodies in the family poultry may suggest a low AIV-A activity during the period of study, information which remains to be confirmed by virus detection.(AU)

Serological diagnosis of influenza A subtype H1 on family poultry of Belo Horizonte, Minas Gerais and Santa Maria, Rio Grande Do Sul, in Brazil

Serum samples (n=687) from Gallus gallus domesticus were collected for the investigation of antibodies to avian influenza virus (AIV-A) in the family poultry of the surrounding counties of Santa Maria/RS and the metropolitan region of Belo Horizonte/MG, totaling twenty different counties. Additional samples of seventeen (n=17) free-flying ducks (C. moschata pure or hybrid with Anas platyrhynchos) were collected in Belo Horizonte. The chosen tests for the survey were performed as described by the World Organization for Animal Health (OIE), including agar gel immunodiffusion (AGID) for antibodies to AIV-A nucleoprotein (N) and haemagglutination- inhibition (HI) for antibodies to subtype H1. Out of the 704 serum tests performed by AGID, eight (8/704) were revealed positive for antibodies to AIV-A N protein, with six (6/704) retested positive for subtype H1. Two sera tested positive by AGID were shown to be non reactive to the H1 subtype, suggesting specificity to another subtype. A low occurrence of antibodies to influenza A (1.13%) was found, and mostly (75%) specific to subtype H1. This represents an approximately 0,85% overall occurrence for subtype H1 antibodies, with an unknown subtype specific antibodies detected in one free-flying anatid. The low occurrence of antibodies in the family poultry may suggest a low AIV-A activity during the period of study, information which remains to be confirmed by virus detection.

Experimental coinfection of chicken anemia virus and Mycoplasma gallisepticum vaccine strains in broiler chicks

This study aimed at determining the clinical and pathological effects of the coinfection of young SPF chickens with chicken anemia virus (CAV) and Mycoplasma gallisepticum (MG) vaccine strains. The clinical signs, gross and microscopic lesions were determined after the experimental coinfection broilers with a CAV genotype 1 vaccine strain given intraperitoneally on the first day of age and a MG F-strain vaccine given intranasally on the 8th day of age. The experimental groups included the negative control (group 1), a group infected with the MG F-strain vaccine (group 2), and a group coinfected with CAV and MG vaccines (group 3). Chicks were examined clinically and post mortem at 23 days of age, and gross and microscopic lesions of the trachea, thymus, and air sacs were compared among treatments (Kruskal-Wallis test). Infections were confirmed by PCR for specific genetic fragments of each agent in the target tissues. Mortality was only observed in chicks on group 3, with two deaths and more severe lesions in the trachea, thymus and air sacs compared with groups 1 and 2 (p < 0.01). Dead chicks presented reduced thymus and spleen size, hemorrhagic trachea with catarrhal exudate and partial obstruction, pericarditis, catarrhal airsacculitis, lungs with liquid and ascites. The surviving chicks in group 3 showed more severe respiratory changes than those in group 2, in addition to thymus and spleen size reduction. Results indicate the adverse effects of the coinfection of young chickens with MG F-strain and CAV genotype 1 vaccines.

Experimental coinfection of chicken anemia virus and Mycoplasma gallisepticum vaccine strains in broiler chicks

This study aimed at determining the clinical and pathological effects of the coinfection of young SPF chickens with chicken anemia virus (CAV) and Mycoplasma gallisepticum (MG) vaccine strains. The clinical signs, gross and microscopic lesions were determined after the experimental coinfection broilers with a CAV genotype 1 vaccine strain given intraperitoneally on the first day of age and a MG F-strain vaccine given intranasally on the 8th day of age. The experimental groups included the negative control (group 1), a group infected with the MG F-strain vaccine (group 2), and a group coinfected with CAV and MG vaccines (group 3). Chicks were examined clinically and post mortem at 23 days of age, and gross and microscopic lesions of the trachea, thymus, and air sacs were compared among treatments (Kruskal-Wallis test). Infections were confirmed by PCR for specific genetic fragments of each agent in the target tissues. Mortality was only observed in chicks on group 3, with two deaths and more severe lesions in the trachea, thymus and air sacs compared with groups 1 and 2 (p < 0.01). Dead chicks presented reduced thymus and spleen size, hemorrhagic trachea with catarrhal exudate and partial obstruction, pericarditis, catarrhal airsacculitis, lungs with liquid and ascites. The surviving chicks in group 3 showed more severe respiratory changes than those in group 2, in addition to thymus and spleen size reduction. Results indicate the adverse effects of the coinfection of young chickens with MG F-strain and CAV genotype 1 vaccines.(AU)

Molecular Diagnosis of Beak and Feather Disease in Native Brazilian Psittacines

The incidence of the psittacine beak and feather disease virus (BFDV) was investigated in Brazilian native parrots with normal feathering arriving at rescue and triage centers for wild animals (CETAS, IBAMA) in the state of Minas Gerais, Brazil. BFDV DNA was investigated by previously described PCR technique for the partial amplification of BFDV ORF-1 in DNA extracts from blood, cloacal swab or liver of psittacines. Some birds provided more than one sample. Nine species of psittacines were sampled between January 2009 and October 2010. Blood (n=46) or cloacal swab (n=128) samples were obtained from psittacines immediately upon arrival at the triage centers. Liver samples were collected from necropsied birds dead on arrival (n=167). All swab samples were negative, except for one Ara ararauna individual (n=3) which blood presented the BFDV DNA. On the other hand, 11 liver samples were positive for BFDV DNA, with a prevalence of 7.8% in Amazona aestiva (n=140). No BFDV DNA was detected in the liver of Amazona amazonica (n=11), A. vinacea (n=5), A. rhodochorytha (n=4), Anodorhynchus hyacinthinus (n=3), Ara ararauna, (n=3), Aratinga leucophtalma (n=2), Guarouba guarouba (n=1) and Pionus maximiliani (n=1). In most cases, alopecia was not associated with BFDV detection in liver, and liver histopathology was inconclusive. Although all cloacal swab samples were negative, a few psittacines (n=19) that died at CETAS-Belo Horizonte were retested, and 21% were detected as positive in liver. A group of psittacines (n=16) was clinically evaluated, and despite showing feather dystrophy, all birds were negative in the cloacal swabs, except for one, which blood sample was positive (A. ararauna). The obtained sequences of the BFDV strains BH 215 and BH 732 were deposited in the GenBank (JQ649409 and JQ649410). A 98% similarity with strain sequences described in Australia, Japan, and New Zealand was observed. It is possible that these strains arrived in Brazil through the legal and illegal trade of parrots. However, it was not possible to associate BFDV infection with the geographical origin of birds and no local marker was detected. The rates of detection, although similar to other studies, indicate the tendency of a high incidence of the disease, possibly associated with stress, and high bird density and wide transmission in captivity conditions.

Molecular Diagnosis of Beak and Feather Disease in Native Brazilian Psittacines

The incidence of the psittacine beak and feather disease virus (BFDV) was investigated in Brazilian native parrots with normal feathering arriving at rescue and triage centers for wild animals (CETAS, IBAMA) in the state of Minas Gerais, Brazil. BFDV DNA was investigated by previously described PCR technique for the partial amplification of BFDV ORF-1 in DNA extracts from blood, cloacal swab or liver of psittacines. Some birds provided more than one sample. Nine species of psittacines were sampled between January 2009 and October 2010. Blood (n=46) or cloacal swab (n=128) samples were obtained from psittacines immediately upon arrival at the triage centers. Liver samples were collected from necropsied birds dead on arrival (n=167). All swab samples were negative, except for one Ara ararauna individual (n=3) which blood presented the BFDV DNA. On the other hand, 11 liver samples were positive for BFDV DNA, with a prevalence of 7.8% in Amazona aestiva (n=140). No BFDV DNA was detected in the liver of Amazona amazonica (n=11), A. vinacea (n=5), A. rhodochorytha (n=4), Anodorhynchus hyacinthinus (n=3), Ara ararauna, (n=3), Aratinga leucophtalma (n=2), Guarouba guarouba (n=1) and Pionus maximiliani (n=1). In most cases, alopecia was not associated with BFDV detection in liver, and liver histopathology was inconclusive. Although all cloacal swab samples were negative, a few psittacines (n=19) that died at CETAS-Belo Horizonte were retested, and 21% were detected as positive in liver. A group of psittacines (n=16) was clinically evaluated, and despite showing feather dystrophy, all birds were negative in the cloacal swabs, except for one, which blood sample was positive (A. ararauna). The obtained sequences of the BFDV strains BH 215 and BH 732 were deposited in the GenBank (JQ649409 and JQ649410). A 98% similarity with strain sequences described in Australia, Japan, and New Zealand was observed. It is possible that these strains arrived in Brazil through the legal and illegal trade of parrots. However, it was not possible to associate BFDV infection with the geographical origin of birds and no local marker was detected. The rates of detection, although similar to other studies, indicate the tendency of a high incidence of the disease, possibly associated with stress, and high bird density and wide transmission in captivity conditions.(AU)

Occurrence of Aviadenovirus in chickens from the poultry industry of Minas Gerais / Ocorrência de Aviadenovirus em aves da industria avícola de Minas Gerais

The occurrence of Aviadenovirus (FAdV) was investigated in chickens from the poultry industry of Minas Gerais state, Brazil. The investigation was conducted due to the scarcity of recent data in the country and its description in neighboring countries. For this purpose, livers were collected from layer chicks (n=25), older layers (n=25), broilers (n=300), and livers (n=25) and stool (n=25) samples from broiler breeders, representing the major poultry regions of the state. FAdV DNA was demonstrated using a previously described PCR protocol for amplifying part of the hexon gene encoding sequence. FAdV was found in layer chicks (36 percent), widespread (100 percent) in older layers, and with regional differences in broilers (24-86 percent). Although all broiler breeder stools were negative, FAdV DNA was detected in livers (16 percent, 4/25) of stool-negative birds. In order to obtain additional information on the circulation of the infection, livers of subsistence chickens collected from one poultry intensive region, were evaluated (n = 12), with FAdV being detected in all samples. FAdV was found in young and old layers, broilers, broiler breeders and free-range chickens, and results suggest the circulation of FAdV among different types of chickens. The detection in older layer chickens may indicate an extended risk of horizontal transmission in regions of Minas Gerais with mixed activity of egg and meat type chickens and poor biosecurity strategies. The infection in breeders may indicate vertical transmission and the continuous production of infected progenies. The hexon-gene-targeted PCR amplicon sequences aligned with FAdV of species D of Aviadenovirus. Results indicate the necessity for biosecurity, especially for breeders, separating flocks according to origin, age and health status, which will be an advantage regarding any pathogen.(AU)

Descreve-se a ocorrência de Aviadenovirus (FAdV) na avicultura mineira. Foram amostrados fígados de poedeiras jovens (n=25) e velhas (n=25) e de frangos de corte (n=300). Em matrizes pesadas foram amostrados fígados (n=25) e fezes (n=25). O estudo envolveu as principais regiões avícolas do Estado de Minas Gerais. O DNA de FAdV foi pesquisado por PCR universal, descrito para a amplificação do gene que codifica o hexon de Aviadenovirus, usando FAdV Phelps como referência. Foi demonstrada a presença do DNA de FAdV em 100 por cento (25/25) das poedeiras velhas (78 semanas de idade) e em 36 por cento (9/25) das jovens (18 dias). Em frangos de corte, a detecção variou entre 24 e 86 por cento. Embora as fezes das matrizes tenham sido negativas, foi obtido o amplicon específico em 4/25 dos fígados dessas mesmas aves, indicando menor sensibilidade para detecção nas fezes. Em amostras da avicultura familiar (fígado), colhidas de uma das regiões de avicultura intensificada, foi detectado o genoma de FAdV em 100 por cento das galinhas (n=12). A constatação de alta disseminação de FAdV em aves da avicultura industrial e familiar de Minas Gerais contribui para o entendimento da epidemiologia de Aviadenovirus. As sequências nucleotídicas dos produtos de PCR alinharam com FAdV da espécie D de Aviadenovirus. A demonstração de FAdV em reprodutores indica risco de transmissão vertical e reforça a necessidade de biosseguridade estrita nesses plantéis. A presença de FAdV em diversos setores avícolas, incluindo poedeiras comerciais, frangos de corte, reprodutores e galinhas da avicultura familiar, recomenda a biosseguridade estrita entre as criações de mesmo tipo e de tipos diferentes de aves. A detecção em matrizes pode indicar a continuada geração de progênies infectadas.(AU)

Health assessment of raptors in triage in Belo Horizonte, MG, Brazil

Falconiformes (n=82), Strigiformes (n=84) and Cathartiformes (n=14) at a triage center (CETAS-Belo Horizonte, IBAMA, Brazil) were examined between 2008 and 2010 . No bird was reactive at hemagglutination-inhibition (HI) for antibodies against Mycoplasma gallisepticum (Mg). Two Caracara plancus (2/68) had HI titers (16-32) against Newcastle disease virus. No Chlamydophila psittaci DNA was detected in the liver (PCR; n=95). Blood smears (Giemsa; n=89) and spleen fragments (PCR; n=82) were 13.5% and 8.5% positive, respectively, for Haemoproteus only. Necropsy of Cathartiformes (n=10), Falconiformes (n=42) and Strigiformes (n=57) showed that trauma injuries were the main cause (63.3%) of admission and death, being fractures (38.5%) of the thoracic limbs (57.1%) the most frequent. Nematode (12.8%), cestode (1.8%), trematode (0.9%), and acanthocephalan (2.7%) parasite infections were relevant. Mites (Acari) were the most frequent (17.4%) external parasites, particularly Ornithonyssus sylviarum in Asio clamator and Amblyomma cajennense in Tyto alba. Chewing lice (10.1%) and Pseudolynchia spp. (9.2%) were also found. Histomonas spp. (6.4%) was found in the ceca of Bubo virginianus, Athene cunicularia, Tyto alba, and Asio clamator, but not in Falconiformes or Cathartiformes. Trichomonas spp. (oral cavity, pharynx and upper esophagus; 9.1%) was detected in Falconiformes and Strigiformes, but not in Cathartiformes. Trichomonas spp. were found in A. cunicularia, Asio clamator, Glaucidium brasilianum and Tyto alba (Strigiformes), and in Rupornis magnirostris, Milvago chimachima, Falco femoralis, Falco sparverius and Caracara plancus (Falconiformes). Coccidia (9.1%) (Sarcocystis spp., 6.4%) and mycosis were observed in most Tyto alba (70%). The evaluated Orders may not pose risks for commercial poultry production. Habitat loss and urban adaptation may be increasingly affecting raptors.

Health assessment of raptors in triage in Belo Horizonte, MG, Brazil

Falconiformes (n=82), Strigiformes (n=84) and Cathartiformes (n=14) at a triage center (CETAS-Belo Horizonte, IBAMA, Brazil) were examined between 2008 and 2010 . No bird was reactive at hemagglutination-inhibition (HI) for antibodies against Mycoplasma gallisepticum (Mg). Two Caracara plancus (2/68) had HI titers (16-32) against Newcastle disease virus. No Chlamydophila psittaci DNA was detected in the liver (PCR; n=95). Blood smears (Giemsa; n=89) and spleen fragments (PCR; n=82) were 13.5% and 8.5% positive, respectively, for Haemoproteus only. Necropsy of Cathartiformes (n=10), Falconiformes (n=42) and Strigiformes (n=57) showed that trauma injuries were the main cause (63.3%) of admission and death, being fractures (38.5%) of the thoracic limbs (57.1%) the most frequent. Nematode (12.8%), cestode (1.8%), trematode (0.9%), and acanthocephalan (2.7%) parasite infections were relevant. Mites (Acari) were the most frequent (17.4%) external parasites, particularly Ornithonyssus sylviarum in Asio clamator and Amblyomma cajennense in Tyto alba. Chewing lice (10.1%) and Pseudolynchia spp. (9.2%) were also found. Histomonas spp. (6.4%) was found in the ceca of Bubo virginianus, Athene cunicularia, Tyto alba, and Asio clamator, but not in Falconiformes or Cathartiformes. Trichomonas spp. (oral cavity, pharynx and upper esophagus; 9.1%) was detected in Falconiformes and Strigiformes, but not in Cathartiformes. Trichomonas spp. were found in A. cunicularia, Asio clamator, Glaucidium brasilianum and Tyto alba (Strigiformes), and in Rupornis magnirostris, Milvago chimachima, Falco femoralis, Falco sparverius and Caracara plancus (Falconiformes). Coccidia (9.1%) (Sarcocystis spp., 6.4%) and mycosis were observed in most Tyto alba (70%). The evaluated Orders may not pose risks for commercial poultry production. Habitat loss and urban adaptation may be increasingly affecting raptors.(AU)

A retrospective PCR investigation of avian Orthoreovirus, chicken infectious anemia and fowl Aviadenovirus genomes contamination in commercial poultry vaccines in Brazil / Estudo retrospectivo de vacinas avícolas vivas por PCR para os vírus da anemia das galinhas, Aviadenovirus aviário e Orthoreovirus aviário

Vacinas avícolas vivas comerciais produzidas entre 1991 e 2005 foram examinadas para a presença de genomas dos vírus da anemia infecciosa das galinhas (Gyrovirus CAV), da hepatite por corpúsculo de inclusão (Aviadenovirus FAdV) e da artrite viral/síndrome da má absorção (Orthoreovirus aviário ARV). Vinte e seis partidas de vacinas vivas liofilizadas de oito fabricantes com lacre original foram examinadas. As extrações de DNA e PCR de CAV e FAdV, e de RNA e RT-PCR para ARV, foram descritas previamente. Contaminações triplas de ARV, CAV e FAdV foram detectadas em vacinas de mesmo fabricante, produzidas em 1991 e 1992 contra a doença de Newcastle (DN), e para a encefalomielite aviária, produzida em 1994. ARV e CAV em co-infecção foram encontrados em vacinas contra a doença de Marek liofilizadas produzidas em 1996 por dois fabricantes diferentes. Genoma de ARV foi detectado em vacinas contra a bronquite infecciosa de setembro e dezembro de 1998, doença infecciosa bursal, de dezembro de 1998 e DN de janeiro de 1998. Três dos oito fabricantes apresentaram vacinas com contaminação e cinco nunca apresentaram vacinas contaminadas. Nenhuma vacina produzida a partir de 2001 apresentou contaminação. Cogita-se um papel epidemiológico para vacinas vivas, como fonte de infecção para ARV, CAV e FAdV e, potencialmente determinante da atual alta disseminação destes.(AU)

The occurrence of Orthoreovirus, Rotavirus and chicken anemia virus in chickens of the poultry industry in Minas Gerais, Brazil / Ocorrência de Orthoreovirus, Rotavirus e vírus da anemia das galinhas em frangos de corte da indústria avícola de Minas Gerais

Fifty-four fecal samples taken from broiler chickens from 1 to 45 days of age, and of pullets from 10 to 13 weeks of age, original from eight different poultry regions in the state of Minas Gerais, Brazil, were collected from March 2008 to January 2010 for avian Orthoreovirus (ARV) and avian Rotavirus (AvRV) analyses. For the assay of ARV, RNA was immediately extracted (Trizolâ) and transcribed into cDNA for assaying in a nested-PCR with ARV-specific primers. For AvRV, polyacrylamide gel electrophoresis (PAGE) was performed with RNA extracts obtained by phenol-chloroform extraction. CAV was additionally investigated through a nested-PCR of thymus and spleen. Results found 5.55% positive for ARV and 9.25% for AvRV. Also, CAV and ARV genomes were detected in co-infection, in a highly prostrated and claudicating chicken flock. No ARV or AvRV infections were detected in pullets. Material of a clinically affected flock was inoculated into SPF embryos, resulting in embryonic hemorrhage, whitish foci in the chorio-allantoic membrane and death. Sequencing of ARV amplicons and isolate cDNA grouped local strains with the ARV S1133 strain, historically used in live vaccines, suggesting the continued circulation of this vaccine virus strain in intensive poultry regions. Detection rates for ARV and AvRV, as well as the presence of CAV, were additionally indicative of failing biosecurity strategies for the intensive poultry regions examined.(AU)

Avaliou-se a ocorrência de Orthoreovirus (ARV) e Rotavirus (AvRV) aviários na avicultura industrial de Minas Gerais. Foram colhidas cinquenta e quatro amostras de fezes de frangos de corte entre um e 45 dias e de frangas de postura de 10 a 13 semanas de idade. Para análise de ARV, o RNA foi imediatamente extraído (Trizol), transcrito em cDNA e avaliado em uma PCR com oligonucleotídeos iniciadores específicos para ARV. Para a investigação de AvRV, os extratos de RNA foram obtidos por fenol-clorofórmio e submetidos à eletroforese em gel de poliacrilamida. Todas as amostras foram também avaliadas para o DNA do vírus da anemia das galinhas (CAV) em uma nested-PCR específica. Em frangos de corte, a positividade encontrada para ARV foi de 5,55% e para AvRV de 9,25%. CAV foi detectado em coinfecção em um plantel com refugagem, claudicação e prostração. Nenhuma amostra de poedeiras foi positiva para ARV ou AvRV. Material de plantel com sinais clínicos foi purificado e inoculado em ovos SPF embrionados, sendo obtidas lesões hemorrágicas e focos brancos na membrana cório-alantóide. O sequenciamento dos produtos de PCR e de embrião agrupou os isolados de ARV com a estirpe S1133, historicamente usada como vacina viva. Os resultados sugerem a continuada circulação da infecção por estirpes assemelhadas a ARV S1133 nas regiões de avicultura industrial. Os índices de detecção de ARV, AvRV e CAV indicam que a intensificação nas regiões produtoras tem resultado em falhas de biosseguridade.(AU)

Bronquite infecciosa das galinhas / Avian infectious bronchitis

RESUMO A bronquite infecciosa das galinhas (BIG) é uma doença respiratória altamente contagiosa causada por um Coronavírus, o vírus da bronquite infecciosa das galinhas (VBIG). Embora o VBIG seja um patógeno primário do trato respiratório, ele é também uma causa comum de redução da produção e qualidade dos ovos em galinhas. Certos tipos de VBIG causam lesões renais, com significativa mortalidade. Há também mortalidade por conseqüências respiratórias. A doença possui grande importância econômica devida às perdas na produção, sendo estas maiores que as perdas por mortalidade. A ocorrência de múltiplos sorotipos e as características mutantes de seu agente etiológico tem complicado e aumentado os custos de produção e dificultado sua prevenção através da imunização. Recentemente, uma variante do VBIG tem sido descrita associado com a miopatia dos músculos peitorais em muitas partes do mundo, inclusive no Brasil.

ABSTRACT Avian infectious bronchitis (IB) is a highly contagious respiratory disease of chickens caused by a Coronavirus, infectious bronchitis virus (IBV). Although IBV is primarily a respiratory tract pathogen, it is also a common cause of reduced egg production and egg quality in laying hens, and certain strains of IBV cause kidney lesions with significant mortality. Mortality by tracheal blockage also occurs. The disease has high economic importance due the loss of production, which is more important than the loss by mortality. The occurrence of multiple serotypes and mutants of the IBV have complicated and increased the production costs and have impaired its prevention through immunization. Recently, a variant IBV has been reported associated with pectoral muscle myopathy in many parts of world including Brazil.