An experimental turkey rhinotracheitis (TRT) infection in breeding turkeys and the prevention of its clinical effects using live‐attenuated and inactivated TRT vaccines

Abstract

The experimental inoculation of 38-week-old turkey hens with a pool of field isolates of turkey rhinotracheitis virus (TRTV) induced a marked respiratory infection and a substantial drop in egg production. Administration of a live-attenuated TRT vaccine at 1 week of age did not protect the layers against respiratory infection, but provided good protection against the effects of challenge on laying performance. However, a combination of live priming followed by injection of inactivated vaccine provided excellent protection against both respiratory infection and drops in egg production.

Experimental and field evaluation of a live vaccine against avian pneumovirus

“…Live attenuated viruses are good vaccine candidates as they induce strong immune responses and protection (Murphy et al, 1988;Cook et al, 1996;Collins et al, 1999). Although it has been shown that vaccines developed against subgroups A and B protect against the US isolates (Cook et al, 1999), it is advisable to develop a homologous subgroup C vaccine to avoid the introduction of subgroups A and B into the US.…”

Preliminary antigenic characterization of an avian pneumovirus isolated from commercial turkeys in Colorado, USA

“…This was performed as described previously (Cook et al, 1996) , using a subgroup A strain, a subgroup B strain, or the Colorado isolate as antigen. Antibody titres of $ log27.0 were considered to be positive.…”

“…In May 1996, a respiratory infection, characterized by coughing, rhinitis and sinusitis, was described in commercial turkeys in the state of Colorado, USA (Senne et al, 1997). Serum samples collected from these turkeys were examined in the UK for APV antibodies by enzyme-linked immunosorbent assay (ELISA), using a subgroup A strain of TRT as antigen (Cook et al, 1996), and low antibody titres to APV were detected in some of the sera. A virus was subsequently isolated from these turkeys (Senne et al, 1998a,b) and shown to have some antigenic relationship with existing TRT isolates (Cook et al, 1998a,b).…”

Hatchability, serology and virus excretion followingin ovovaccination of chickens with an avian metapneumovirus vaccine

“…In addition to the influence on laying birds it is most significantly a respiratory disease of mainly young birds, especially in turkeys but also in chickens. Early vaccination straight after hatch by spray or aerosol is already widely practised in turkeys to protect the birds (Williams et al, 1991;Cook et al, 1996).…”

“…Serological testing was carried out by enzyme-linked immunosorbent assay as described previously (Cook et al ., 1996). In this enzyme-linked immunosorbent assay, a subtype A virus was used as coating antigen, purified after two sucrose gradient steps.…”