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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Exotic & Emerging Avian Viral Diseases Research » Research » Publications at this Location » Publication #304101
Title: Experimental co-infections of domestic ducks with a virulent Newcastle disease virus and low or highly pathogenic avian influenza viruses

Author
item PANTIN JACKWOOD, MARY
item COSTA-HURTADO, MAR - U.S. DEPARTMENT OF AGRICULTURE (USDA)
item MILLER, PATTI
item AFONSO, CLAUDIO
item Spackman, Erica
item Kapczynski, Darrell
item SHEPHERD, ERIC
item SMITH, DIANE
item SWAYNE, DAVID

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2015
Publication Date: 5/1/2015
Citation: Pantin Jackwood, M.J., Costa-Hurtado, M., Miller, P.J., Afonso, C.L., Spackman, E., Kapczynski, D.R., Shepherd, E.M., Smith, D.M., Swayne, D.E. 2015. Experimental co-infections of domestic ducks with a virulent Newcastle disease virus and low or highly pathogenic avian influenza viruses. Veterinary Microbiology. 177:7-17.

Interpretive Summary: Avian influenza virus (AIV) and Newcastle disease virus (NDV) are two of the most economically important viruses affecting poultry. Domestic ducks also become infected with these viruses, but because these viruses cause similar clinical signs in infected birds, co-infection of ducks with these viruses is difficult to recognize. Co-infections also may affect the severity of clinical signs, virus shedding and virus transmission. In this study we infected domestic ducks with a velogenic NDV virus (vNDV) and 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. Co-infection did not affect the number of birds shedding LPAIV, but did affect the amount of virus shed. All ducks that got HPAIV, co-infected or not with vNDV, died in less than 4 days, however some co-infected ducks survived for longer and virus shedding was also affected. Co-infection also affected the transmission of the viruses to direct contact ducks. In conclusion, domestic ducks can become co-infected with vNDV and LPAIV with no effect on clinical signs but some effect on virus shedding and consequently transmission.

Technical 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 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 velogenic NDV virus (vNDV) and 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 at 4 days post inoculation (dpi). Co-infection did not affect the number of birds shedding LPAIV, but differences in the amount of virus shed was observed between ducks inoculated only with LPAIV and ducks co-infected with vNDV. All ducks inoculated with the HPAIV, co-infected or not with vNDV, presented similar clinical signs and died in less than 4 days, however some co-infected ducks survived for longer and HPAIV cloacal virus shedding was significantly affected if ducks had been previously infected with vNDV. Co-infection also affected the transmission of the viruses to direct contact ducks. In conclusion, domestic ducks can become co-infected with vNDV and LPAIV with no effect on clinical signs but some effect on virus shedding and consequently transmission. This and the increased survival observed in some ducks co-infected with vNDV and HPAIV, indicates that infection with one virus can interfere with replication of another.