Acta Vet. Brno 2007, 76: 415-421

Naturally Occurring Egg Drop Syndrome Infection in Turkeys

Z. Biđin1, I. Lojkić1, M. Mikec2, B. Pokrić3

1Department of Poultry Diseases, Faculty of Veterinary Medicine, University of Zagreb, Croatia
2Poultry Centre, Croatian Veterinary Institute, Zagreb, Croatia
3Ruđer Bošković Institute, Zagreb, Croatia

Received February 12, 2007
Accepted July 9, 2007

A decrease in the egg quality, production, fertility and hatchability without serious clinical signs of illness was recorded in turkey fl ocks in Croatia at the beginning of 2002. It was assumed that the egg drop syndrome virus might be one of the etiological agents responsible for the abnormalities in the egg production. The systematic serological monitoring, using a haemagglutination inhibition test, showed that the antibodies to the egg drop syndrome virus existed in 94.4 and 55.1% of the sera analysed in 2002 and 2003, respectively. The haemagglutination inhibition titres ranged from 16 to 128. The sera samples were randomly collected from 11 - to 46-week-old hens from the affected fl ocks. The serological evidence of the egg drop syndrome virus infection was confirmed by detection of the presence of the virus genome in the turkey sera by the polymerase chain reaction. Vaccination of the 18- and 25-week-old turkey hens against the egg drop syndrome virus started in March 2003. After this period, the presence of antibodies to the egg drop syndrome virus (the haemagglutination inhibition titres between 16 and 256) was found in 96.7% of the analysed sera, while the egg production reached normal or higher values for the Nicholas hybrid line of turkeys.