Effect of species, breed and route of virus inoculation on the pathogenicity of H5N1 highly pathogenic influenza (HPAI) viruses in domestic ducks

Abstract

H5N1 highly pathogenic avian influenza (HPAI) viruses continue to be a threat to poultry in many regions of the world. Domestic ducks have been recognized as one of the primary factors in the spread of H5N1 HPAI. In this study we examined the pathogenicity of H5N1 HPAI viruses in different species and breeds of domestic ducks and the effect of route of virus inoculation on the outcome of infection. We determined that the pathogenicity of H5N1 HPAI viruses varies between the two common farmed duck species, with Muscovy ducks (Cairina moschata) presenting more severe disease than various breeds of Anas platyrhynchos var. domestica ducks including Pekin, Mallard-type, Black Runners, Rouen, and Khaki Campbell ducks. We also found that Pekin and Muscovy ducks inoculated with two H5N1 HPAI viruses of different virulence, given by any one of three routes (intranasal, intracloacal, or intraocular), became infected with the viruses. Regardless of the route of inoculation, the outcome of infection was similar for each species but depended on the virulence of the virus used. Muscovy ducks showed more severe clinical signs and higher mortality than the Pekin ducks. In conclusion, domestic ducks are susceptible to H5N1 HPAI virus infection by different routes of exposure, but the presentation of the disease varied by virus strain and duck species. This information helps support the planning and implementation of H5N1 HPAI surveillance and control measures in countries with large domestic duck populations.

Pathogenicity and Transmission of H5 and H7 Highly Pathogenic Avian Influenza Viruses in Mallards

“…Experimental infection of juvenile Muscovy ducks (Cairina moschata) with another reassortant virus belonging to clade 2.3.4.4, A/chicken/ BC/FAV-002/2015 (H5N1), caused neurological signs and death and transmitted to naive contact ducks (75). Muscovy ducks are more susceptible to HPAI virus infection than other domestic ducks, which explains the differences observed when comparing these results to those obtained in mallards infected with the H5 clade 2.3.4.4 viruses in our study (76). The PB1, PA, NA, and NS gene segments of this H5N1 virus were of North American lineage, whereas PB2, HA, NP, and M were derived from the Eurasian lineage H5N8 virus.…”

Role of Poultry in the Spread of Novel H7N9 Influenza Virus in China

“…Of the four species, Muscovy ducks shed the most virus. This is not surprising, since Muscovy ducks have been shown to be more susceptible to infection with highly pathogenic H5N1 AIV strains, show more severe disease, and shed larger amounts of virus than other domestic duck species (39)(40)(41). Muscovy ducks, it must be remembered, are a different species (Cairina moschata) than Pekin and Mallard ducks (Anas platyrhynchos) and should not be expected to have a similar response to infection (42).…”

Natural Reassortants of Potentially Zoonotic Avian Influenza Viruses H5N1 and H9N2 from Egypt Display Distinct Pathogenic Phenotypes in Experimentally Infected Chickens and Ferrets

“…Quantification of the titer (TCID 50 ) of virus from the collected swab specimens was based on the quantification cycle (C q ) values obtained by real-time reverse transcriptase quantitative PCR (RT-qPCR). Correlation of the C q values and the infectivity titers was done as outlined by Pantin-Jackwood et al (45). Briefly, a standard C q curve for virus quantification was generated using viral RNA extracted from serially diluted (log 10 ) HPAIV H5N1 suspensions with a known infectivity titer.…”