On Call Fall / Winter 2011 - School of Veterinary Medicine ...

The West Nile virus casts a broad
net of influence, entwining itself
in the mosquitoes that transmit
it, the birds that carry it, the
animals and people that are affected
by it, and the environment
it spreads through. But to understand
that complex picture, you
need to understand the virus itself.
Dr. Kristen Bernard, an associate
professor in the Department of
Pathobiological Sciences, is using
her research to untangle the functions
of West Nile virus.
“I’m trying to understand
how the virus causes disease,” said
Bernard. “What I want is to understand
each step of what the virus is
doing in the body.”
The virus, first seen on the east
coast in 1999 before spreading
rapidly across the US, is an arthropod
(insect)-borne virus. Although
not common in Wisconsin, West
Nile presents a serious threat as
it has no known treatment. The
18
Research
Understanding west Nile virus
West Nile can linger,
especially in the brain,
long after the animal
recovers from the illness
virus cycles between mosquitoes
and birds, then spreads when an
infected mosquito bites a healthy
animal. According to Bernard,
some are more affected than others,
with humans, horses, and
some types of birds hit the hardest.
“Crows are exquisitely sensitive
to the virus,” said Bernard. “Other
animals can become infected,
it’s just not very common. Dogs,
wolves, alpacas—there was an outbreak
in alligators in 2002.”
But the common thread among all
these species is one tiny buzzing
insect. “In nature, there isn’t any
vertebrate to vertebrate transmission,”
Bernard said. “You need to
have that mosquito.”
Using a mouse model, Bernard
dr. tony goldberg joins global health institute
as Associate director for research
tony Goldberg, PhD, DVM, will
soon take up the position of Associate
Director for Research at the
University of Wisconsin’s new Global
Health Institute, in addition to his
work at the UW School of Veterinary
Medicine. The institute, a product of
a new merger between the University’s
Center for Global Health and
the Global Health Initiative, seeks
to unite professionals from a broad
range of fields with the goal of
tackling health concerns that have a
worldwide reach. The institute will
draw together the best and brightest
minds from the UW campus and
beyond, uniting disparate fields of
study with the common purpose of
improving UW–Madison’s ability to
study, practice, and deliver global
health. “This is a watershed moment
for global health on the UW
campus,” said Goldberg. “The new
Global Health Institute unites a
diversity of units across campus into
a single overarching organization.
This will improve the efficiency of
our campus’s global health efforts
while creating new synergies and
opportunities.”
Goldberg’s research here in
Madison focuses on epidemiology
and the evolution of infectious
diseases, including big picture concepts
like interactions between the
virus, the host, and diverse ecosystems.
With work ranging from the
spread of West Nile in urban hot
spots like Chicago; to interactions
between humans, primates, and
livestock in Uganda; to viral diseases
in swine and fish, Goldberg’s broad
knowledge of ecosystems and
interactions makes him a perfect
fit for the Global Health Institute.
This long-term view, encompassing
all the players in an ecosystem,
is invaluable for the institute’s aim
Dr. Kristen Bernard examines the
cells used to grow and replicate West
Nile virus, a key tool for her research
into how the virus causes disease.
is examining what happens after
that mosquito bites. This includes
interactions between the body,
the virus, and even the mosquito
saliva. Her work is yielding interesting
findings. “We get more virus
replication when there’s mosquito
to solve problems in a holistic and
sustainable fashion, without causing
unintended consequences down
the line.
Others in the institute come from
a range of backgrounds, including
veterinary and human medicine,
sociology, anthropology, agriculture,
and population studies. Many have
an interdisciplinary background,
with diverse interests that add to a
wide cumulative experience pool.
In this new appointment, Goldberg
will team up with major partners in
Belize, Ethiopia, China, Thailand,
Mexico, Uganda, and Ecuador to
address issues like the spread and
control of disease and implications
of pesticides on long-term development.
With this team of experts, the
Global Health Institute is moving
closer than ever to an understanding
of our world that could help create a
truly positive impact.
saliva there,” said Bernard. She explained
how this might indicate
the presence of a protein in the
saliva that changes the impact of
the virus. “The long-term idea is,
if you could identify that protein,
you could make a vaccine.”
Bernard’s work is also taking
steps towards understanding the
lasting effects of West Nile on the
body. “It’s typically thought that
West Nile infects the host, the host
mounts a response, and then it’s
gone,” said Bernard. But her research
shows that West Nile can
linger, especially in the brain, long
after the animal recovers from
the illness. She explained that the
body’s immune system is responsible
for eliminating the virus, but
too strong of an immune response
can actually damage the body’s
healthy tissue, especially sensitive
tissue like the brain. “That’s the
fine line the body’s walking down,”
said Bernard. “In this case, it’s an
advantage to the virus.” The body
protects the brain, and accidentally
leaves some virus behind.
But what’s the difference if
you carry the virus around with
you, as long as you’re not sick?
According to Bernard, it makes
all the difference in the world to
someone who receives an organ
donation or a blood transfusion
from a previously infected donor,
and the recipient may become
dangerously ill even if the donor
showed no symptoms at all.
For Bernard, this research is
all about digging into the fundamental
functions of the virus. She
hopes that her research will pave
the way for future advances in
West Nile prevention and cure,
with a better understanding of the
disease itself. “I want to do the
basic research with the goal that it
will be useful in human and veterinary
medicine,” said Bernard.
Ali Bartol