EGG-NEWS is indebted to Dr. Nati Elkin publisher of PoultryMed for updated information on progress in E.U. research on bovine influenza-H5N1. Immediately following the revelation that H5N1 avian influenza virus can infect dairy cattle in the U.S., the Federal Friedrich-Loeffler Institute (F-LI) in Germany initiated an intensive study of the virus and its effect on dairy cattle using available laboratory resources and their BL-3 isolators suitable for large animals. To date, the studies have shown that both a U.S. H5N1 isolate (B3.13) and a field isolate derived from a wild bird in Germany, replicate in secretory tissue of the bovine utter. Lactating cows can be infected by introduction of a virus suspension into the teat. This route reproduces the clinical syndrome including elevated temperature, anorexia, reduced milk secretion and profound alteration in the consistency of milk.
The Institute has evaluated 1,400 serum samples from herds in regions with documented avian influenza among commercial flocks and wild bird without demonstrating antibodies to H5N1. In addition, 350 milk samples from bulk tanks have been subjected to PCR assay again without demonstrating virus. This initiative will be extended to 1,500 milk samples as part of an ongoing surveillance program.
Recent studies in Germany have demonstrated that H5N1 viruses obtained from domestic field outbreaks of avian influenza are capable of replication in vitro in bovine respiratory epithelial cells. Detection of virus was evident within 24 hours of inoculation of the cell systems that supported proliferation of virus for at least three days post-inoculation.
The implication is that H5N1 virus can infect the respiratory tract of cattle. Studies are in progress to determine whether H5N1 can be transmitted between cows by the aerogenous route as is suspected.
The question arises as to how the Friedrich-Loeffler Institute was able to conduct studies and release data with intensity and speed as required by epidemiologists and the industry in comparison with our own uncoordinated efforts by USDA-APHIS, ARS. CDC, and state departments of Agriculture and Health?