Related Experiment Videos
Duck influenza lacking evidence of disease signs and immune response
Abstract:
Influenza viruses A/duck/Hokkaido/5/77 (Hav7N2), A/budgerigar/Hokkaido/1/77 (Hav4Nav1), A/Kumamoto/22/76 (H3N2), A/Aichi/2/68 (H3N2), and A/New Jersey/8/76 (Hsw1N1) were experimentally inoculated into Pekin ducks. Of these, the influenza viruses of duck and budgerigar origin replicated in the intestinal tract of the ducks. The infected ducks shed the virus in the feces to high titers, but did not show clinical signs of disease and scarcely produced detectable serum antibodies. Using immunofluorescent staining, we demonstrated that the target cells of the duck virus in ducks were the simple columnar epithelial cells which form crypts in the large intestines, especially in the colon. After primary infection, the birds resisted reinfection with the duck virus at least for 28 days, but from 46 days onward they were susceptible to reinfection. These infections were quickly restricted by a brisk secondary immune response, reflected in the rapid appearance of high titers of antibody after reinoculation. In contrat to the avian influenza viruses, the remaining three influenza viruses of human origin did not replicate in the intestinal tract but did cause a serum antibody response.
Insights
Avian influenza viruses, originating from ducks and budgerigars, replicate in Pekin ducks' intestines and are shed in feces. Ducks develop temporary immunity but remain susceptible to reinfection later.
Area of Science:
- Virology
- Immunology
- Avian Health
Background:
- Influenza viruses pose a significant threat to poultry health and can potentially spill over to other species.
- Understanding avian influenza virus tropism and host immune responses is crucial for disease control.
Purpose of the Study:
- To investigate the replication and pathogenicity of various avian and human influenza viruses in Pekin ducks.
- To identify target cells and characterize the immune response following avian influenza virus infection in ducks.
Main Methods:
- Experimental inoculation of Pekin ducks with different influenza virus strains (Hav7N2, Hav4Nav1, H3N2, Hsw1N1).
- Detection of viral replication in the intestinal tract via fecal shedding and immunofluorescent staining.
- Assessment of clinical signs, serum antibody response, and susceptibility to reinfection.
Main Results:
- Avian influenza viruses of duck and budgerigar origin replicated in the intestinal tract and were shed in feces without causing clinical signs or significant antibody production.
- Target cells for duck influenza virus were identified as simple columnar epithelial cells in the large intestine crypts.
- Ducks exhibited resistance to reinfection for at least 28 days post-primary infection, with susceptibility returning by 46 days, followed by a rapid secondary immune response.
Conclusions:
- Pekin ducks can serve as a reservoir for avian influenza viruses, with replication occurring in the intestinal tract.
- The immune response in ducks provides temporary protection against homologous reinfection.
- Human influenza viruses did not replicate in the duck intestinal tract but did elicit a serum antibody response.