Experimental co-infections of domestic ducks with a virulent Newcastle disease virus and low or highly pathogenic avian influenza viruses

Abstract

Infections with avian influenza viruses (AIV) of low and high pathogenicity (LP and HP) and Newcastle disease virus (NDV) are commonly reported in domestic ducks in many parts of the world. However, it’s not clear if co-infections with these viruses affect the severity of the diseases they produce, the amount of virus shed, and transmission of the viruses. In this study we infected domestic ducks with a virulent NDV virus (vNDV) and either a LPAIV or a HPAIV by giving the viruses individually, simultaneously, or sequentially two days apart. No clinical signs were observed in ducks infected or co-infected with vNDV and LPAIV, but co-infection decreased the number of ducks shedding vNDV and the amount of virus shed (P <0.01) at 4 days post inoculation (dpi). Co-infection didn’t affect the number of birds shedding LPAIV, but more LPAIV was shed at 2 dpi (P <0.0001) from ducks inoculated with only LPAIV compared to ducks co-infected with vNDV. Ducks that received the HPAIV with the vNDV simultaneously survived fewer days (P <0.05) compared to the ducks that received the vNDV two days before the HPAIV. Co-infection also reduced transmission of vNDV to naïve contact ducks housed with the inoculated ducks. In conclusion, domestic ducks can become co-infected with vNDV and LPAIV with no effect on clinical signs but with reduction of virus shedding and transmission. These findings indicate that infection with one virus can interfere with replication of another, modifying the pathogenesis and transmission of the viruses.

Viral interference between H9N2-low pathogenic avian influenza virus and avian infectious bronchitis virus vaccine strain H120 in vivo

“…It can be inferred that the transitory inhibition of viral replication may have an effect on the severity of the disease; the induced clinical signs were not perceptible and only microscopic lesions were noticed. These findings are in concordance with other reported results [18,21,16]. Besides, lower specific antibody titers were produced since both viruses inhibited the growth of each other's, early after infection.…”

“…The viruses were administered either alone, mixed or consecutively, 3 days apart, as previous reported and showing that the maximum of virus replication in the organism is reached three days after infection [15,16].…”

Pathobiology of Avian avulavirus 1: special focus on waterfowl

“…Infection of the Gaoyou duck at 15, 30, 45, 60, and 110 with different routes indicate that their susceptibility to disease and virus shedding decreases with the age and birds seldom die after infection through the natural route [46]. Experimental co-infection of ducks with APMV-1, and low or high pathogenic avian influenza virus (LPAIV and HPAIV) indicate that it decreases the virus shedding and transmission to the naïve ducks by contact [51]. Duck after immunization with inactivated vaccine of APMV-1, and challenge with the same live virulent Kenyan APMV-1 resulted in the development of more antibody titer than the unchallenged birds [52].…”

Infectious bursal disease virus suppresses H9N2 avian influenza viral shedding in broiler chickens

“…On necropsy, tissue samples of the trachea and the bursa of Fabricius were immediately collected and preserved at -80°C until analyzed. Samples were subsequently tested for possible contamination with Newcastle disease virus, AIV [13], IBDV [14], and infectious bronchitis virus using RT-PCR analysis [15]. Negative results were required before starting the inoculations.…”