Reference type

Journal Article
 

Record Number

116

Author

Zanella, Dr. Tassi, C and Volorio, A.

Year

2002

Title

Viral Diseases related to egg laying problems

Journal

World Poultry

Volume

18

Pages

34-37

Label

Journal

Keywords

Poultry. viral diseases. egg laying.

Notes

Vaccine producers will sometimes maintain flocks of laying hens, or will monitor the health of commercial flocks from which they obtain eggs. The authors provide useful information on viral diseases whose clinical signs may include reduction in egg production.

-    Infectious bronchitis virus. There are numerous serotypic variants of this virus, which usually produces respiratory disease. However female chicks infected when less than two weeks old may undergo infection of the oviduct which reduces or prevents later production of eggs. Infection of hens during lay results in drops of egg production to greater than 40% and production may not return to pre-infection levels.
- Avian encephalomyelitis virus. This virus usually causes neurological signs in very young chicks. Infection of layers results in no neurological signs, but a temporary drop in egg production (to 30% over 2 weeks)
- Egg drop syndrome virus. This adenovirus often causes infection of the oviduct that remains latent until the hen enters lay. Infected birds, apparently in normal health, produce thin-shelled or shell-less eggs.
-    Newcastle disease virus. Hens with partial immunity can show a serious drop in egg production when infected with virulent strains of Newcastle disease virus. The clinical signs seen in outbreaks in unvaccinated chickens include loss of egg production.
- Avian influenza virus. While highly pathogenic strains of this virus cause severe mortalities, strains of less pathogenicity leave surviving hens with severely reduced egg production (to 50%) for up to 10 weeks.
- Infectious laryngotracheitis virus. Birds undergoing infection and showing typical signs of respiratory disease may also show reduced egg production.