Pathogenicity and Preliminary Antigenic Characterization of Six Infectious Bursal Disease Virus Strains Isolated in France from Acute Outbreaks

Abstract

Six isolates originating from acute outbreaks of infectious bursal disease recently reported in broiler and pullet flocks in France were studied with respect to their pathogenicity and their antigenic relatedness to the Faragher 52/70 reference strain. Although the mortality experimentally induced in susceptible chickens by the field strains was sometimes four times higher than that which followed the inoculation of the reference strain (16 to 48 % versus 12 YO), neither mortality nor morbidity were observed in chickens previously vaccinated with a commercial live vaccine and then challenged under the same conditions. Agar gel precipitation tests demonstrated the existence of common antigens in the different strains, and high cross-neutralization indices measured in embryonated specific pathogen free eggs showed them all to belong to serotype I. These data are discussed with reference to previous European and North-American studies on the antigenic status of infectious bursal disease virus.

Extensive antigenic changes in an atypical isolate of very virulent infectious bursal disease virus and experimental clinical control of this virus with an antigenically classical live vaccine

“…The 89163 virus was initially cloned by limiting dilution in SPF hen eggs and has since been maintained by propagation in SPF chickens. The cloned virus has been identified by its pathogenicity, antigenicity and genome sequence as a typical vvIBDV (Eterradossi et al, 1992.…”

“…The original 99323 homogenate was inoculated into 5-week-old specific pathogen free (SPF) White Leghorn chickens in the containment facilities (negative pressure, filtered air) of AFSSA-Ploufragan. Bursae collected 4 days post-inoculation were used as described previously (Eterradossi et al, 1992) to prepare a stock virus that was used in the subsequent steps of the present study.…”

“…These viruses caused mortality at least twice as high as that induced by the classical serotype 1 viruses (van den Berg et al, 1991;Eterradossi et al, 1992). It has been shown that some Ivorian isolates excepted , the vvIBDV isolates share close genetic relationships in both genome segment A (which encodes IBDV capsid proteins) (Brown et al, 1994) and genome segment B (which encodes virus polymerase) (Islam et al, 2001).…”

“…As far as vvIBDVs are concerned, isolates collected in Europe in the late 1980s were shown to be clinically controlled by live vaccines with a classical antigenicity (van den Berg & Meulemans, 1991;Eterradossi et al, 1992). In order to check whether an antigenic drift could occur among vvIBDVs and lead to the emergence of vvIBDV with an atypical antigenicity, the authors have been engaged since 1999 in a worldwide survey of IBDV isolates collected during acute IBD outbreaks.…”

Diagnosis of infectious bursal disease by immunoperoxidase technique

“…However, these procedures can be relatively time consuming and some strains either can not adapt themselves or not show characteristic changes on embryos. Therefore, diagnosis of the disease might be difficult and demonstration of viral antigen by immunoperoxidase (IP) method useful for differential diagnosis and confirmation of histopathological changes (2,3,5).…”