Effects of vaccination with live or inactivated aqueous-suspension NDV vaccine in pigeons previously infected with paramyxovirus type 1

The authors compared the effects of vaccination of previously PMV1 infected pigeons, either with live-NDV-LaSota strain or with the inactivated aqueous-suspension vaccine (Colombovac PMV). Young susceptible pigeons were inoculated by intramuscular injectionwith pigeon PMV1 and vaccinated 4 days later ocularly/intranasally with live-LaSota strain or by subcutaneous injection of one 0.2 ml dose of Colombovac PMV. Cumulative nervous signs/mortality rates reached 95% in the live-LaSota vaccinated group, 70% in the control group and 60% in the Colombovac PMV vaccinated group. As compared to the control group, vaccination with Colombovac PMV had no beneficial but no disadvantageous effects on the disease while vaccination with live-LaSota significantly increased viral excretion in the faeces and number of pigeons with polyuria at the beginning of the clinical phase of infection. Consequently, percentages of pigeons having developed polyuria and cumulative percentages of nervous signs/mortality were significantly lower in the Colombovac PMV vaccinated group than in the live LaSota vaccinated group. In conclusion, when first symptoms are appearing in a PMV1 infected pigeon-house, vaccinated with Colombovac PMV may be attempted without heightening the disease while vaccination with live-Lasota increases the severity of the disease.