THE (FERRET) SNEEZE HEARD AROUND THE WORLD: THE CASE OF THE
BIOENGINEERED BIRD FLU
CASE STUDY FOR AAC&U STIRS PROJECT
Jill M. Manske, Professor of Biology, University of St. Thomas, St. Paul, MN
Summary of the Avian H5N1 Airborne Transmission Experiments*
Ron Fouchier and researchers of the Erasmus Medical Centre in Rotterdam, The
Netherlands, and Yoshihiro Kawaoka and researchers of the School of Veterinary
Medicine at the University of Wisconsin–Madison in Wisconsin, United States, induced
and identified genetic mutations that enabled H5N1 to become airborne transmissible
between ferrets.
The Basics of the Experiments

The researchers induced mutations in the HA surface protein to alter its binding
specificity (what cells it could bind to and enter).

In the lab, the HA was mutated from the wild type (natural) virus that binds to
avian respiratory tract cells to one that could bind to cells in the respiratory tract
of ferrets. Ferrets are used in influenza research because they develop disease
similar to humans when infected with influenza virus.

The researchers then took the original laboratory-mutated virus and studied it so
see if it could transmit between ferrets via airborne route. This initial mutated
virus did not spread from ferret to ferret.

They then transferred—this is called passing—the virus from ferret-to-ferret.
They took virus from the nose of one infected ferret and put it into the nose of
another ferret; when ferret no. 2 became ill, the virus from ferret no. 2 was
transferred to ferret no.3, and so on. They did this passaging ten times. This
allowed the virus to adapt and change within the cells of the ferrets.

Lastly, virus was taken from ferret no. 10 and was tested to see if it could be
transmitted from ferret-to-ferret via airborne route.
*Herfst S, Schrauwen EJ, Linster M, Chutinimitkul S, de Wit E, Munster VJ, Sorrell EM,
Bestebroer TM, Burke DF, Smith DJ, Rimmelzwaan GF, Osterhaus AD, Fouchier RA. “Airborne
Transmission of Influenza A/H5N1 Virus Between Ferrets“ Science, 22 June 2012: Vol. 336 no.
6088 pp. 1534–54. DOI: 10.1126/science.1213362.