infectious bursal disease (ibd) is a highly contagious disease of chickens caused by the infectious bursal disease virus (ibdv). this study was conducted to characterize three ibdv strains from iran. a reverse transcriptase-polymerase chain reaction (rt-pcr) procedure was used to amplify a 715-bp fragment of the vp1 gene from ibdv strains. amplified vp1 fragments of the three iranian ibdv strai...

Infectious bursal disease (IBD) is a highly contagious disease of chickens caused by the infectious bursal disease virus (IBDV). This study was conducted to characterize three IBDV strains from Iran. A reverse transcriptase-polymerase chain reaction (RT-PCR) procedure was used to amplify a 715-bp fragment of the VP1 gene from IBDV strains. Amplified VP1 fragments of the three Iranian IBDV strai...

In this study, twenty-five strains of Mycobacterium tuberculosis resistant to isoniazid (INH) were isolated from patients with tuberculosis (TB). Nine strains (36%) were found to be virulent in guinea-pigs [root index virulence (RIV» 1 ]. The remaining sixteen strains (64%) were non-virulent (RIV <1). Of the nine strains resistant to INH as well as virulent to guinea-pigs, eight of them wer...

background and aims: infectious laryngotracheitis virus (iltv) infection causes a highly contagious respiratory disease in poultry leads to significant economic losses in the poultry industry. the genomic and antigenic characteristics between virulent and vaccine strains of iltv are very similar. the ability of embryonated chicken neural stem (cns) cell for differential diagnosis of iltv strain...

in this study, twenty-five strains of mycobacterium tuberculosis resistant to isoniazid (inh) were isolated from patients with tuberculosis (tb). nine strains (36%) were found to be virulent in guinea-pigs [root index virulence (riv» 1 ]. the remaining sixteen strains (64%) were non-virulent (riv <1). of the nine strains resistant to inh as well as virulent to guinea-pigs, eight of them were fo...

Abstract: This study was conducted to characterize infectious bursal disease virus (IBDV) isolates collected from different parts of Iran during 2005-2006. Pooled bursal samples from 49 broiler and layer pullet flocks suspected to IBD infection were collected and processed. A reverse transcriptase-polymerase chain reaction (RT PCR) procedure was used to amplify a VP2 gene fragment (743 bp) from...

Gallid herpesvirus 2 (GaHV-2) causes malignant lymphomas in chickens (Marek's disease, MD). Although MD is controlled through vaccination efforts, field isolates of GaHV-2 have increased in virulence worldwide and even cause MD in vaccinated chickens. GaHV-2 strains are classified into four categories (mild, virulent, very virulent and very virulent +) based on the virulence exhibited in experi...

Could some vaccines drive the evolution of more virulent pathogens? Conventional wisdom is that natural selection will remove highly lethal pathogens if host death greatly reduces transmission. Vaccines that keep hosts alive but still allow transmission could thus allow very virulent strains to circulate in a population. Here we show experimentally that immunization of chickens against Marek's ...

A novel isolate of infectious bursal disease virus (IBDV) was designated GX-NN-L. The GX-NN-L IBDV was a very virulent infectious bursal disease virus (vvIBDV) isolated from broiler flocks in Guangxi province, China, in 2011. The GX-NN-L IBDV caused high mortality, immunosuppression, low weight gain, and bursal atrophy in commercial broilers. Here, we report the complete genome sequence of the ...