Experimental Newcastle disease virus infections in three species of wild birds

Three species of wild birds--the red-winged blackbird (Agelaius phoeniceus), an African weaver finch (Quelea quelea), and the sandhill crane (Grus canadensis)--were exposed to Newcastle disease virus (NDV) to determine susceptibility and host response. The NDV used were a vaccine strain (LaSota) and a viscerotropic velogenic strain (New York Parrot). Host response was monitored by virus isolation, signs of disease, and serologic response. Both the red-winged blackbirds and the quelea shed little virus and developed low antibody titers. A low mortality in the blackbirds did not appear to be due to ND alone. Vaccinated cranes were well protected against velogenic challenge, whereas unvaccinated cranes shed the velogenic virus from the cloaca for weeks. The ramifications of the low antibody titers produced in birds of two species are discussed, as well as the potential involvement of each species in transmission of the virus.