Jim Collins
Veterinary Medicine
PHOTO BY MICHELLE RIEDEL |
In 1918, in the last year
of World War I, soldiers on both sides of the battle suddenly faced
a new threat--Spanish Flu. What started as an influenza outbreak
in Kansas army barracks soon spread through U.S. military bases
and then to the world along the trenches of the war and trade routes.
In Philadelphia alone, over 12,000 people died within a month of
the outbreak reaching the city. Eventually, over one third of the
U.S. population and one fifth of the world's population were infected
by the virus, and 20 to 40 million lives were lost--more than 3
times the number that died in the war.
Subsequent influenza outbreaks in 1957 and 1968, while not as severe,
still caused immense social disruption and economic losses. Despite
much improved public health infrastructures, the 1957 Asian Flu
claimed 70,000 lives in the U.S. alone and the 1968 Hong Kong outbreak
claimed between 1 and 4 million lives worldwide.
Outbreaks of this magnitude are called pandemics, which
occur when a new influenza virus appears against which the human
population has no immunity, resulting in several, simultaneous epidemics
worldwide with widespread illness and enormous numbers of deaths.
No one knows just when the next influenza pandemic will hit, but
public health experts agree that another pandemic is a near-certainty.
The World Health Organization (WHO) has even made elaborate pandemic
preparations, setting-up a Global Influenza Surveillance Network
of 112 National Influenza Centers to monitor for any unusual influenza
viruses.
Such planning is imperative, as the Centers for Disease Control
(CDC) and WHO estimate between 89,000 and 207,000 American deaths
and up to 650,000 deaths in industrialized countries alone from
the next pandemic. The impact will be even greater in developing
countries where healthcare resources are strained and the general
population is weakened by poor health and nutrition.
If and when the next pandemic hits, an efficient global transportation
system and increased urbanization will push the spread of the disease
in a way not seen in previous pandemics. Therefore, the ability
to respond quickly to disease outbreak will be critical, especially
considering that public health leaders have already identified a
potential candidate for the next pandemi--avian influenza, currently
simmering in Asia. According to Michael Osterholm, avian influenza
"is the perfect storm. The only question now is: Will this
set of circumstances be sufficient to push the microbial genetics
over the edge and create a new strain of influenza virus that rivals
past pandemic strains?"
Fighting zoonotic diseases
There is a web of Minnesotans working on the front lines of this
battle to identify and mitigate the impact of a pandemic, including
many at the University of Minnesota. As important members of Minnesota's
first responder team in cases of emerging infectious diseases, the
University's Veterinary Diagnostic Laboratory (VDL) plays a vital
role in protecting the public from food-borne and zoonotic diseases
(those that can be transmitted from animals to humans).
Located in the University's College of Veterinary Medicine, the
VDL is the official laboratory of the Minnesota Board of Animal
Health and is accredited by the American Association of Veterinary
Laboratory Diagnosticians as a full-service diagnostic laboratory
for all animal species. It provides laboratory analysis required
for local, inter-state, and international movement of animals and
animal genetic material, and in 2003 the lab performed more than
1.4 million diagnostic tests. "The health of animals and people
depends on timely and accurate diagnostic testing and monitoring
of animal diseases. Our lab gives us that ability," says Jim
Collins, director of the laboratory.
Part of the University of Minnesota since 1904, the laboratory's
primary activity is to provide animal health support to livestock
and poultry producers, practicing veterinarians, and other animal
health consultants. To do this, the VDL works with a wide range
of constituents, including the dairy, swine, and poultry industries;
companion animal groups; the DNR; and both local zoos. The VDL also
develops new and more effective diagnostic methods and trains veterinarians
and graduate students.
Integrated into all of this work, however, is the laboratory's role
in identifying emerging diseases. It is this role that helps protect
not only Minnesotans, but people all over the world. By collaborating
with the Minnesota Board of Animal Health, the Minnesota Department
of Agriculture, the Minnesota Department of Health, and within the
University of Minnesota, the VDL holds a key position in the public
health web.
According to state Epidemiologist Harry Hull, "this collaboration
brings great strength to our ability to protect the people of Minnesota;
strength not seen anyplace else in the country. The University's
Veterinary Diagnostic Laboratory is a vital resource, not just for
the state but also for the nation, in helping us deal with the potential
threats of emerging infectious diseases."
Tracking avian influenza
There is a striking list of zoonotic diseases that have caught the
public's attention in recent years--Mad Cow disease, SARS, West
Nile virus, Monkeypox, Chronic Wasting disease, and others have
all gathered significant column space in print media and prime-time
television coverage. But as dangerous as these are, avian influenza
holds the potential to be the most destructive.
There are three types of influenza viruses associated with annual
outbreaks and epidemics of influenza: A, B, and C. Of the three
types, only influenza A virus has the potential to cause a pandemic.
Type A viruses can infect several animal species, including birds,
pigs, horses, seals, and whales. However, birds are an especially
important species because all known subtypes of influenza A viruses
circulate among wild birds, which are considered the natural hosts
for influenza A viruses.
Influenza viruses that infect birds are called avian influenza
viruses, but they do not usually directly infect or circulate
among humans. However, each of the previous pandemics was caused
by an avian influenza A virus. A change in the virus's hemagglutinin
(H) protein made it possible for the virus to jump the species barrier
and attach to human cells. Unfortunately, because these viruses
do not normally infect humans, people had little or no immune protection.
Already the current strain of avian influenza has caused the death
of over 20 people in Asia, and there has been a confirmed human
case in Canada. In each case, the virus was transmitted directly
from birds to humans. These infections come despite vigorous containment
efforts that included the slaughter of roughly 19 million chickens
and turkeys in the Frasier Valley in southern British Columbia.
Minnesota, for its part, has a cooperative avian influenza control
plan in place that includes education, monitoring, reporting, and
response. "Early recognition of influenza in poultry flocks
is of critical importance for rapid disease control," says
Collins. "The Veterinary Diagnostic Laboratory maintains extensive
diagnostic capabilities for rapid influenza detection in poultry.
These tests include PCR (polymerase chain reaction) testing (which
can detect very small quantities of viral RNA), virus isolation,
antigen capture ELISA (enzyme-linked immuno sorbent assay) testing,
serologic screening for blood antibodies and immunohistochemistry
staining of fixed tissues. With this array of tests, the laboratory
has demonstrated great flexibility in how it can confirm a diagnosis
in poultry. Through continued research and collaboration with world-renowned
influenza experts, the laboratory continues to improve its ability
to rapidly identify and characterize these potentially devastating
infections."
In addition to poultry, the VDL monitors other potential avian influenza
carriers. For example, swine can act as an intermediary host animal
between wild birds and humans, serving as a mixing vessel
for the virus. Two of the three pandemics (1957 and 1968) spread
to humans from pigs, and there is evidence that the 1918 pandemic
also made the jump to humans from pigs. The VDL is a major contributor
of swine influenza genetic sequence information to the Influenza
Sequence Database, a national database for influenza researchers
maintained at the Los Alamos National Laboratory.
According to Hull, "the vast majority of emerging infectious
diseases are zoonotic, so the importance of accurately monitoring
animal health is immeasurable. The University is key to that monitoring."
Precautions such as those in place in Minnesota make it very unlikely
that the current strain of avian influenza will enter the U.S.,
at least through birds. If, however, the virus shifts so that it
can be transmitted from human to human, it will be virtually impossible
to keep it from moving into this country's general population.
Tracking other zoonotic threats
In addition to their work with potential avian influenza threats,
the Veterinary Diagnostic Laboratory plays an important role in
monitoring other emerging infectious diseases. The lab was recently
selected by the CDC as the national testing site to screen for the
Monkeypox virus in animals. Monkeypox is a rare disease that occurs
naturally in the tropical rainforest area of western and central
Africa. If passed to humans, the disease behaves similarly to smallpox.
The VDL is the first veterinary diagnostic lab to be selected as
a full member of the CDC's Laboratory Response Network (LRN). This
inclusion gives the University access to CDC protocols, immediate
emerging disease information, and coordinated communications.
"We would not have received this designation without having
the appropriate biosafety classification to contain viruses and
prevent contamination of other samples or laboratory areas,"
says Collins. "And because we have the same state-of-the-art
molecular technology as the CDC labs, we are able to accommodate
the high volume of testing samples. Membership in the CDC's LRN
provides the University a great opportunity to rapidly diagnose
and prevent diseases transmissible from animals to people."
The laboratory is also part of the state's Chronic Wasting disease
surveillance program and does important work on West Nile virus.
And last fall the laboratory received U.S. Department of Agriculture
approval to offer a new, rapid, and low-cost diagnostic test for
Johne's disease, a bacterial infection causing intestinal inflammation
in ruminants--cattle, sheep, and goats. The disease poses a significant
threat to Minnesota's dairy and beef production industries, and
controlling it is one of the state's top agricultural priorities.
Developed by University scientists Kay Faaberg and Carrie Wees,
the new DNA-based PCR test is only available at the VDL. The test
takes only 48 hours to complete compared to 4 months for the standard
test, enables the lab to test hundreds of animals at a time, and
is affordable for livestock producers.
Diagnostic tests such as these are an important part of the lab's
work. The VDL offers 24/7 electronic results reporting of its diagnostic
tests so that customers can securely access real-time results and
download key data. "All of this material from throughout the
country is fed to us because of our facilities and expertise,"
says Collins. "The work that is done here is not hypothetical;
it is real. And there is payback in terms of food safety from healthier
animal populations, infectious disease discoveries, diagnostic test
development, and vaccines. And the laboratory even receives direct
monetary payback from user fees for diagnostics tests, research
grants and contracts, and from royalty income from discoveries made
here."
Surveillance system
Diseases that jump from animals to humans are not new, but they
continue to be a very real threat. These diseases have the potential
to get into our food supply, can be transmitted efficiently by the
modern transportation system, and can potentially be passed as easily
as the common cold. That makes the response to disease outbreaks
more important than ever. "Fortunately, Minnesota has an excellent
surveillance system to combat infectious diseases," says Collins.
Rapid detection of outbreaks, isolation of possible pandemic viruses,
and the quick development of diagnostic tools will be the front
line weapons in the next battle against pandemic influenza. And
the University's Veterinary Diagnostic Laboratory will be in the
trenches helping to protect us.
Written
by Brian Lieb
Reprinted with permission from the summer 2004 Gateway
to Research and Inventions,
a publication of the Office of the Vice President for Research.
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