Detection and examination of avian adenovirus in the outbreaks on farms
2009
Yanagisawa, F., Yamaguchi-ken. Chubu Livestock Hygiene Service Center (Japan) | Otani, A. | Nakatani, S. | Nakatani, H.
Epidemiological study of six cases was conducted between 2004 and 2008. In these cases the erosion of gizzard was confirmed and avian adenovirus (AAV) was detected. A high rate of AAV was isolated from the chicken kidney cells inoculated with gizzard emulsion, when intranuclear inclusion bodies were seen in the gizzard erosion. Infection resistance was suggested, judging from the confirmation of high AAV neutralizing antibody titer. All the farm outbreaks were caused by broiler chickens, and their raising forms were open windows and floor feeding. In two cases no clinical signs were noticed, but AAV was disclosed by an inspection after their shipment. In four other cases, outbreaks occurred on farms where clinical signs were noticed. With one exception, all the outbreaks occurred on the farms which belonged to the same integrated company, and which bought the chicks from the affiliated breeding farm. The outbreaks were found among 7-71 day old chickens. Especially 7-15 day old chickens showed some serious clinical signs, such as gizzard ulcer and blood vomiting. Even in this serious case, the condition improved with the passage of time. The death rate was the minimum 0.72%/week and the maximum 1.00%/day. The death rate was lower in the cases in which only gizzard erosion was present. However, the rate reached strikingly higher in the cases in which complex infections, such as chicken anemia virus, bacteria, and coccidium, coexisted with management errors.
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