[Newcastle disease virus carrier state after aerosol vaccination against the disease in chickens of various ages]

Abstract

Studied was the carrier status with the Newcastle disease virus in experiments with a total of 665 birds at the age of 10 days, one month, and two months following an aerosol vaccination with a La Sota strain vaccine as well as the possibility to isolate the velogenic strain Texas GB after control infection of 10-day-old and one-month-old birds. Established was a short-term carrier status with the La Sota strain in the organs of birds up to the 6th-9th day following the aerosol vaccination. In an experiment with month-old birds originating from parental flocks immunized against Newcastle disease the La Sota virus was isolated also from the brain up to the sixth day. The resistance of birds to the infection was demonstrated at the aerosol immunization of 10-day-old and month-old- birds followed by challenging the birds with high doses of the velogenic virus strain Texas GB.