Outbreak of cutaneous form of avian poxvirus disease in previously pox-vaccinated commercial turkeys / Surto de bouba aviária na forma cutânea em perus comerciais previamente vacinados

This study describes an outbreak of avian poxvirus disease in previously pox-vaccinated turkeys in Brazil. The turkeys had suggestive gross lesions of cutaneous avian poxvirus in the skin of the head and cervical area without changes in the flock mortality rates. In the slaughterhouse, 30 carcasses were removed from the slaughter line to collect tissue from cutaneous lesions for histological analyses and characterization of the virus. The virus was identified by conventional polymerase chain reaction (PCR) and subsequent gene sequencing. Acanthosis, hyperkeratosis, and hydropic degeneration were seen on skin histopathology. Eosinophilic intracytoplasmic inclusion bodies (Bollinger) on keratinocytes were observed in 46.6% of the samples. Avian poxvirus DNA was detected on PCR in 83.3% of the total samples. PCR associated with histopathology had 93.3% of positivity for avian poxvirus. In the phylogenetic study, samples show 100% matching suggesting that the outbreak occurred by a single viral strain and was different from those strains affecting other wild birds such as canaries and sparrows. A single mutation (Adenine for Guanine) was detected in our study's strain and in the strains of turkey, chickens, and vaccine strains published in GenBank. Also, when the sequence strain of the present study and sequences from GenBank of canarypox and sparrowpox strains were aligned, a Thymine was found replacing the Adenine or Guanine. The in ovo vaccination method as single-use in turkeys of this study apparently did not provide adequate protection against avianpox disease, but additional vaccination administered by wing-web when turkeys were 45-60 days old in the new flocks controlled the disease. In the subsequent year, new cases of this disease were not found. It was not possible to confirm the source of the virus strain, but infection with a field strain derived from chickens is one possibility, considering the poultry farm population in the area and biosecurity aspects. For wide characterization of avipoxvirus and differentiation among strains, the complete sequence of the viral genome is required.(AU)

Este estudo descreve um surto de bouba aviária em perus previamente vacinados contra poxvirus aviário no Brasil. Os perus apresentaram lesões macroscópicas, sugestivas de bouba aviaria cutânea, na pele da cabeça e região cervical sem alteração nas taxas de mortalidade do lote. No abatedouro, 30 carcaças foram retiradas da linha de abate para coleta de dois fragmentos de pele com lesões para análise histológica e caracterização do vírus. A identificação do vírus foi realizada por PCR convencional e posterior sequenciamento. No exame histopatológico das lesões de pele, houve acantose, hiperqueratose e degeneração hidrópica. Corpúsculos de inclusão intracitoplasmáticos eosinofílicos (Bollinger) foram encontrados em 46,6% das amostras. A técnica de PCR detectou o DNA do vírus da bouba aviária em 83,3% do total de amostras. PCR associado com a histopatologia resultou em 93,3% de positividade para o vírus da bouba aviária. No estudo filogenético, as sequências resultaram em 100% de identidade, sugerindo que o surto ocorreu por uma única estirpe de vírus diferenciada das outras estirpes que acometem canários e pardais. Uma única mutação (Adenina para Guanina) foi detectada nas estirpes deste estudo e nas sequências de perus, galinhas e estirpes vacinais publicadas no GenBank. Além disso, quando a sequência da estirpe do presente estudo e as sequências das estirpes de canarypox e sparrowpox foram comparadas, a Timina foi encontrada em substituição a Adenina ou Guanina. A vacinação in ovo em dose única utilizada nos perus deste estudo aparentemente não forneceu proteção adequada contra a doença causada pelo poxvirus aviário. Entretanto, a revacinação na membrana da asa em perus com 45-60 dias de idade dos novos lotes controlou a doença. No ano subsequente, novos casos desta doença não foram registrados. Não foi possível confirmar a origem da estirpe viral, mas estirpes de campo oriundas de galinhas seria uma possibilidade, considerando a população na área e os aspectos de biosseguridade. Para caracterização ampla do avipoxvirus e diferenciação entre as estirpes, a sequência completa do genoma viral é requerida.(AU)

Follow-up of the development of femoral degeneration lesions in broilers / Seguimiento del desarrollo de lesiones por degeneración en pollos de engorde

A study was carried out in the experimental facilities of FMVZ/UNESP-Botucatu, with the aim of following-up the development and the incidence of femoral degeneration (FD). A total of 305 one-day-old male broilers were housed in six pens of 5m² each. Histological analyses of femur head collected when broilers were 0, 7, 14, 21, 28, 35, and 42 days of age were carried out. At 42 days of age, 30 birds were taken to the experimental processing plant of FMVZ for leg gross examination. Ten legs per FD score where selected, and histologically analyzed to determine the most probable age at the beginning of the lesions, and to standardize femoral degeneration lesion scores. The histological results showed that cell architecture started to disorganize at 21 days of age in the resting and proliferation zones, and that angiogenesis increased, invading the joint cartilage, The gross lesion indexes due to femoral degeneration were 22.5 percent, 42.5%, and 65% at 28, 35, and 42 days of age, respectively.

Se realizó un estudio en las instalaciones experimentales de FMVZ/UNESP-Botucatu, con el objetivo de seguir el desarrollo y la incidencia de degeneración femoral (DF) en pollos. Se utilizaron 305 polluelos de un día, machos, distribuidos en seis corrales de 5m² cada uno. Se analizaron cortes histológicos de cabezas de fémur recolectadas a los 0, 7, 14, 21, 28, 35 y 42 días de edad. A los 40 días de edad, se llevaron 30 aves al Matadero Experimental de FMVZ, para análisis macroscópico de las piernas. Se escogieron 10 muslos por escore de DF, y se analizaron histológicamente para determinar la edad más probable del inicio de la lesión y estandarizar los escores de lesión por degeneración femoral. Los resultados histológicos indicaron que a los 21 días ocurre el inicio de la desorganización celular en la zona de reposo y de proliferación, además del aumento de la angiogénesis, invadiendo el cartílago articular. Microscópicamente, el índice de lesión por degeneración femoral fue del 22.5 por ciento, 42.5% y 65% a los 28, 35 y 42 días de edad, respectivamente.