Abstracts of the Annual Meeting of the Hungarian Society for Microbiology, October 15–17, 2008 Keszthely, Hungary

Abstract

Infectious bursal disease (IBD) is a highly contagious immunosuppressive disease of young chickens with significant economic impact on the poultry industry. The emergence of very virulent strains in late 1980´s resulted in mortality up to 60% in infected flocks. Very virulent IBD (vvIBD) was recognized in Croatia in 1995 and still occurs in farm and backyard chickens. In order to reveal phylogenetic traits of the epidemic in Croatia, we analysed the VP2 variable region of vvIBD virus isolates collected in north-wastern and southern Croatia during the period 1996-2009. All analysed isolates had amino acids in the VP2 variable region typical for very virulent viruses at the positions 256 (isoleucine), 294 (isoleucine) and 299 (serine). Nevertheless, significant genetic diversity of isolates from 1996 indicates not only possible multiple introduction of the virus into Croatia, bur also its circulation in Croatia poultry before 1995. In contrast, some molecular markers and high similarity of certain isolates from the same region, obtained over a span of almost a decade, indicate enzootic character of the virus in certain areas of the country. Clustering of several Croatian isolates with isolates from neighbournig countries implicates spreading of the viruses between the countries.