Experimentally infected domestic ducks show efficient transmission of Indonesian H5N1 highly pathogenic avian influenza virus, but lack persistent viral shedding

PLoS One. 2014 Jan 2;9(1):e83417. doi: 10.1371/journal.pone.0083417. eCollection 2014.

Abstract

Ducks are important maintenance hosts for avian influenza, including H5N1 highly pathogenic avian influenza viruses. A previous study indicated that persistence of H5N1 viruses in ducks after the development of humoral immunity may drive viral evolution following immune selection. As H5N1 HPAI is endemic in Indonesia, this mechanism may be important in understanding H5N1 evolution in that region. To determine the capability of domestic ducks to maintain prolonged shedding of Indonesian clade 2.1 H5N1 virus, two groups of Pekin ducks were inoculated through the eyes, nostrils and oropharynx and viral shedding and transmission investigated. Inoculated ducks (n = 15), which were mostly asymptomatic, shed infectious virus from the oral route from 1 to 8 days post inoculation, and from the cloacal route from 2-8 dpi. Viral ribonucleic acid was detected from 1-15 days post inoculation from the oral route and 1-24 days post inoculation from the cloacal route (cycle threshold <40). Most ducks seroconverted in a range of serological tests by 15 days post inoculation. Virus was efficiently transmitted during acute infection (5 inoculation-infected to all 5 contact ducks). However, no evidence for transmission, as determined by seroconversion and viral shedding, was found between an inoculation-infected group (n = 10) and contact ducks (n = 9) when the two groups only had contact after 10 days post inoculation. Clinical disease was more frequent and more severe in contact-infected (2 of 5) than inoculation-infected ducks (1 of 15). We conclude that Indonesian clade 2.1 H5N1 highly pathogenic avian influenza virus does not persist in individual ducks after acute infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Viral / blood
  • Antibodies, Viral / immunology
  • Ducks / virology*
  • Influenza A Virus, H5N1 Subtype / classification
  • Influenza A Virus, H5N1 Subtype / isolation & purification
  • Influenza A Virus, H5N1 Subtype / physiology*
  • Influenza in Birds / immunology
  • Influenza in Birds / pathology
  • Influenza in Birds / transmission*
  • Influenza in Birds / virology*
  • Serotyping
  • Virus Shedding / immunology

Substances

  • Antibodies, Viral

Grants and funding

The study was jointly funded by CSIRO and the Australian Centre for International Agriculture Research (ACIAR) grant number AH/2004/040. Hendra Wibawa was supported by an ACIAR John Allwright Fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.