Pathogenicity for Chickens of a Paramyxovirus Type 1, Isolated from Racing Pigeons in Sweden

Abstract

Strains of paramyxovirus type 1 (PMV-1) have been isolated from diseased racing pigeons in Sweden. One of these isolates was selected for studies of the pathogenicity and contagiousness in chickens.

The same isolate was previously found to have a high intravenous pathogenicity index (IVPI) in 6 weeks old chickens.

In three experiments it was found that the PMV-1 isolate was very pathogenic for 1 week old chickens but not pathogenic for 120 day old pullets inoculated intranasally and ocularly.

Symptoms in the young chickens were similar to those seen in the neurotropic form of Newcastle disease. The mortality was high and the incubation period 5–11 days.

The disease easily spread to young chickens kept in contact with diseased birds.

The microscopic examination revealed an interstitial nonpurulent pneumonia and a nonpurulent encephalitis in the young chickens. In the pullets the only finding was a mild encephalitis.

PMV-1 was recovered from all young chickens but not from the pullets.

Both the chickens and the inoculated pullets developed antibodies to PMV-1.

Sammandrag

Vid sjukdomsutbrott bland brevduvor i södra Sverige isolerades paramyxovirus av samma typ, som is olerats från sjuka duvor vid utbrott i andra delar av Europa.

En vecka gamla kycklingar infekterade via näsa och öga med ett av dessa PMV-1 isolat insjuknade akut efter 5–11 dagar med symtom lika dem som ses vid neurotrop form av Newcastle sjuka. Även de oympade kycklingarna som gick i samma bur insjuknade med samma symtom en vecka senare. Dödligheten var hög bland kycklingarna.

Unghönor, 120 dagar gamla, som infekterades med samma virus på samma sätt blev däremot inte sjuka och ingen dog.

De döda kycklingarna hade en nonpurulent encephalit och pneumoni, unghönsen endast lindrig encephalit.

PMV-1 återisolerades från alla kycklingar men ej från unghönsen. Både kycklingar och unghönsen bildade antikroppar mot viruset.