Study shows songbirds might aid in H7N9 spread
H7N9 avian flu replicates well in finches, sparrows, and parakeets experimentally inoculated with the pathogen, and the birds shed the virus in high numbers and show few signs of disease, scientists reported today in Emerging Infectious Diseases.
Researchers from St. Jude Children’s Research Hospital in Memphis, Tenn., and from China and Hong Kong inoculated groups of zebra finches, society finches, parakeets, and house sparrows with the H7N9 virus either intranasally, intraocularly, or orally and housed them with birds that were not inoculated (contact birds).
All inoculated birds shed virus, but only via the beak and not via the cloaca (anus). Shedding levels were highest in the two finch species, which shed virus for 6 days. Parakeets also shed virus for 6 days, while the sparrows shed virus for 4 days.
All species of birds were susceptible to H7N9 infection, but only one sparrow showed signs of clinical disease: lethargy, loose and discolored feces, and ruffled feathers.
Contact finches and sparrows showed evidence of H7N9 infection, but only one infected contact finch shed high levels of the virus. The contact parakeets did not become infected.
The authors conclude, “Our demonstration that parakeets and multiple species of songbirds are susceptible to influenza A(H7N9) virus isolated from humans during the recent outbreak in China further supports the possible contribution of songbirds and parakeets to the ecology, maintenance, and transmission of novel A(H7N9) viruses.”