Pathogenicity of a Chicken Anemia Virus in SPF Chickens at Different Ages
In order to evaluate the pathogenicity of the chicken anemia virus AV1550 strain,1-day-old,7-day-old and 14-day-old SPF chickens were injected intramuscularly into the chest with different virus titers.At the same time,normal controls were set up and kept in isolation for 21 days.Blood was collected to measure the hematocrit on the 14th day after the challenge.Mortality,body weight changes,and lesions of the thymus,bone marrow,and bursa of Fabricius of all SPF chickens were counted,and the viral loads in different tissues of 1-day-old SPF chickens were measured on the 21st day after the challenge.1-day-old SPF chickens infected with the AV1550 strain showed obvious clinical symptoms such as depression,slowed weight gain,and anemia,with a mortality rate of 53.9%;necropsy of dead chickens or surviving chickens at the end of the observation period showed thymus atrophy;the bone marrow turned light yellow or pink and the hematocrit was significantly reduced on 14th day after infection at different doses;the thymus virus load is the highest,reaching 106.7 copies/mg on the 21st day.7-day-old SPF chickens showed weight gain slowed down and anemia occurred at high challenge doses(100,000 EID50),some chickens developed thymus atrophy and bone marrow lesions,but the lesion rate was less than 30%.No obvious clinical symptoms were caused after infection of 14-day-old SPF chickens.The study confirmed that the pathogenicity of CAV to SPF chickens was obviously age-dependent,and reduced hematocrit,bone marrow lesions,thymus atrophy and thymus viral load measurement could be used as indicators of CAV pathogenicity.
万方数据
维普
