H5N1 Avian Flu Strain Shown to Infect Bovine Calves
The H5N1 strain of avian influenza can infect bovine calves, at least after high-titer intranasal inoculation, and conventional tests may underestimate such infections, a team of German researchers reported in the July issue of CDC's Emerging Infectious Diseases journal. The team had experimentally inoculated a few calves with highly pathogenic H5N1 in a Biosafety Level 3+ animal facility to test bird-to-calf transmission and also calf-to-calf transmission. "Although the question whether calf-to-calf transmission of HPAIV (H5N1) occurs could not be definitely answered by our study, bird-to-calf transmission resulting in seroconversion is probable," they concluded. (Seroconversion is the development of antibodies in the blood in response to an infection.)
The study was funded by Germany's Federal Ministry of Food, Agriculture and Consumer Protection and conducted by Dr. Donata Kalthoff, a veterinarian at the Institute of Diagnostic Virology at FLI Insel Riems, and colleagues there. Her research interests are the pathogenesis of H5NI in bird and mammal species and vaccine development, according to the paper, which is available at www.cdc.gov/ncidod/eid/index.htm.
The authors said their data are the first to be reported to their knowledge on the susceptibility of cattle to infections with H5N1. The calves remained healthy throughout the study.