ABSTRACT
RESEARCH HIGHLIGHTS: Different field IBDVs were found to circulate in the Near and Middle East.Multiple atypical genotypes (A3B1, A4B1, A6B1) were found to circulate extensively.Traditional very virulent IBDVs (A3B2) were a minority of the detected strains.Viral exchanges can be hypothesized between the region and different continents.
Subject(s)
Birnaviridae Infections , Infectious bursal disease virus , Poultry Diseases , Animals , Chickens/genetics , Infectious bursal disease virus/genetics , Molecular Epidemiology , Indian Ocean , Birnaviridae Infections/epidemiology , Birnaviridae Infections/veterinary , Phylogeny , Middle East/epidemiology , Viral Structural Proteins/geneticsABSTRACT
RESEARCH HIGHLIGHTSEight IBDV strains with unique VP2 features were detected in Portugal.Based on two distinct classification methods, the strains belong to a new genotype.
Subject(s)
Birnaviridae Infections , Infectious bursal disease virus , Poultry Diseases , Animals , Birnaviridae Infections/epidemiology , Birnaviridae Infections/veterinary , Chickens , Genotype , Infectious bursal disease virus/genetics , Phylogeny , Portugal/epidemiology , Poultry Diseases/epidemiology , Viral Structural Proteins/geneticsABSTRACT
Outbreaks of a previously unrecorded disease have recently affected Pyrenean chamois (Rupicapra pyrenaica pyrenaica) populations across the mountain range. A pestivirus was hypothesized to be the cause of this emerging disease and this type of virus can cross the species barrier and be transmitted to or from wildlife. Using an epidemiological survey conducted from 1995 to 2004 at Orlu, France, we characterized the virus and analyzed its transmission. A phylogenetic analysis of viral sequences and virus neutralization tests showed that the virus belonged to the newly described border disease virus-4 group. The increase of seroprevalence with age indicated that infection can occur at any age and resulted in lifelong immunity. Overall, 70.3% of 323 samples were positive for anti-p80 antibodies and 10.2% of 167 samples showed viremia, as demonstrated by either positive ELISA antigen test or RT-PCR. Infection has thus been widespread in this population since 1995, whereas no mass mortality or clinical signs have been observed. Incidence and seroprevalence varied seasonally and according to number of individuals aged less than 2 years old in the population, so viral transmission was dependent on host population age structure. We propose that the virus is now endemic in this population and is likely detrimental for reproduction and juveniles. Further investigation is needed to estimate the impact of pestivirus on host population dynamics and the risk of cross-transmission to farm animals.