Horizontal transmission of turkey herpesvirus to chickens. 3. Transmission in three different lines of chickens.

Horizontal transmission of turkey herpesvirus (HVT) was studied in three separate trials using three different lines of chickens in each trial. There was no horizontal spread of HVT to contact cagemates through 8 weeks regardless of the line of donor chickens, when inoculated subcutaneously with 9.2 times 10-3 plaque-forming units (PFU) of HVT at 1 week of age. The virus spread poorly to a few cagemates from an experimental line of White Leghorns (W.S.U.-V.S.), but not from a commercial line of White Leghorns (C.-W.L.) or meat-type (C.-M.T.) chickens, when inoculated with 9.4 times 10-4 PFU of HVT at 1 week of age. The virus spread readily to contact cagemates from W.S.U.-V.S. but not at all from C.-W.L. or C.-M.T. chickens when inoculated with 2 times 10-4 PFU of HVT at 8 weeks of age. The incidence among cagemates of contact infection by HVT appeared similar regardless of genetic lines. This observation indicated a difference among different genetic lines of chickens in the development and/or shedding of infectious HVT following virus inoculation.