Vertical transmission of reticuloendotheliosis virus in chickens

In this study, the vertical transmission of reticuloendotheliosis virus (REV) in chickens was examined using 6-month-old birds with viraemia which had persisted since birth. Eggs collected from such hens were incubated within 24 hours of lay and it was found that 18 of 35 of the progeny were infected with REV. Seventeen of the 18 died before they were 28 days of age, due to a nervous syndrome. Some of the eggs laid by viraemic hens were stored at room temperature between 1 and 10 days and were then incubated. Hatched progeny from the eggs stored up to 4 days were infected. Hens free of REV, but inseminated by roosters with persistent viraemia seroconverted to REV. A small proportion of chickens which hatched (2/24) were infected with REV. Embryos were a better source for virus isolation than albumen samples.