Vineyarders
asked to help on biodefense against tularemia
January 13, 2005
By
Nelson Sigelman
Martha’s
Vineyard may appear to be far removed from the war on terror, but
next week Islanders will be asked to enlist in the broad effort
to shore up the nation’s defense against biological attack
as part of a research project to develop a vaccine against tularemia.
Tularemia, sometimes called rabbit fever, is a potentially fatal
disease caused by the Francisella tularensis bacterium. Scientists
around the world consider the bacterium a prime candidate for use
as a bioterror agent because it occurs naturally and can be cultured.
It is the unusually high number of pneumonic, or air borne tularemia,
cases diagnosed on the Vineyard in recent years that has drawn to
the Island the attention of researchers at Epivax, a Providence,
R.I., based biotechnology company working under a grant from the
National Institutes of Health (NIH).
On Thursday, Jan. 20, representatives of Epivax will sponsor a public
lecture and forum about tularemia on Martha’s Vineyard and
the company’s upcoming research study to develop a vaccine
against the potentially fatal disease. The forum begins at 5:30
pm in the Baylies room at the Whaling Church in Edgartown.
In the weeks ahead, the company hopes to find at least 20 people
who have been infected with tularemia and who are willing to give
blood. The research goal is to find scientific markers that will
pave the way to the development of an effective vaccine.
Deadly infection
Small wild animals, mainly rabbits, carry the bacteria that cause
tularemia. Humans can contract the disease through a bite from a
dog tick that has fed on an infected animal, by handling infected
animals, or by breathing dust contaminated by the bacteria (aerosols).
Pneumonic tularemia is thought to occur when bacteria from an infected
animal becomes airborne when the dead animal or the ground around
it is stirred up during mowing, brushcutting, or excavating. The
pneumonic form of the disease is the most dangerous and if left
untreated has a mortality rate as high as 60 percent.
Tularemia has been prevalent on the Island over the past several
years and created something of a public health mystery. Local, state,
and federal medical experts have been unable to provide any solid
explanation for the outbreaks. The worst occurred in summer of 2000
when there were 15 cases confirmed on the Island and one death,
the first confirmed tularemia death in the state since 1996.
The Centers for Disease Control and Prevention (CDC) said about
200 cases of tularemia in humans are reported each year in the United
States.
According to a Jan. 9 news story by Paul Rincon, BBC News science
reporter, about a soon-to-be-published report in Nature Genetics,
a scientific journal, scientists have unlocked the genetic code
of Francisella tularensis, which the report described as one of
the most infectious human pathogens known. A small number of bacteria
(10-50 organisms) can cause the disease, making it an attractive
agent for terrorists.
The World Health Organization estimates that airborne dispersal
of 50 kg (110 pounds) of F.tularensis over an urban area with 5
million inhabitants would kill 19,000 people and incapacitate a
further 250,000, said the report.
Tularemia was first described as a plague-like disease of rodents
in 1911 and as a potentially fatal disease in humans shortly afterwards.
The Japanese were the first to study its candidacy as a germ warfare
agent, in a program lasting from 1932 to 1945. The US military created
a weapon from the bacterium during the 1950s and 1960s. A parallel
Soviet effort allegedly continued into the early 1990s said the
BBC report.
Tularemia symptoms are similar to those of a bad case of flu. They
may include fever and/or respiratory symptoms; chest congestion,
tightness, or pain; lethargy; cough; or chills. Skin sores and/or
swollen lymph glands can also accompany the infection.
Health experts stress that although tularemia is a serious disease,
it can be diagnosed through a blood test and is easily treated with
antibiotics. Prompt treatment is crucial to reduce the mortality
threat.
During recent Island outbreaks landscapers and brushcutters were
advised to wear well-fitting masks to prevent the inhalation of
air-borne particles that could cause tularemia. Regular tick checks
are an important preventive measure to prevent tick-borne tularemia.
Volunteers needed
Epivax, the company leading the Vineyard-based study, received a
$860,000 NIH Biodefense grant in September to develop a tularemia
vaccine. The company, which has close links to Brown University,
is also working on vaccines for tuberculosis, HIV, and pandemic
flu, and in December it received a $993,771 NIH grant to develop
a vaccine for smallpox.
Julie McMurray, Epivax project manager, said any time someone gets
an infection, the body reacts with an immune response that may,
or may not, be sufficient to contain the infection. Researchers
want to study the immune response to natural tularemia infection
and use that information to develop a vaccine that mimics those
responses.
She said each person responds a little differently to infection
and that is why the company wants to get as many people as possible
to participate in the study.
“What we are trying to do is essentially combine into a vaccine
the knowledge that each person’s immune system has gained from
natural infection,” she said.
She said Epivax has developed very powerful tools to predict what
sorts of responses are going to be most important. The company hopes
to come up with a vaccine that would protect against the aerosolized
and tick-borne varieties of tularemia.
She said Martha’s Vineyard was selected as a research site
because it is one of the few places where the air-borne form of
the disease has been seen with any frequency. And it is the airborne
version that would most likely be used as bioterror agent.
Ms. MacMurray said next week’s forum will provide an opportunity
to talk about how people can protect themselves against tularemia
and describe the research project. The Epivax study is expected
to take one year and a half. The company hopes to have a vaccine
ready for testing on animals at its completion.
“We are committed to doing research that translates into medicines
and vaccines quickly,” she said, noting that the company leaves
basic research to other people.
The company has hired Donna Enos of Edgartown, a registered nurse
with experience in tick-borne infectious diseases, to interview
candidates and draw blood. Participants will be paid $100 for their
time.
Ms. Enos, who works at the Martha’s Vineyard hospital, said
the vaccine project is very exciting news.
She said given the many Island people who work and play outdoors,
“it would be very nice if they did not have to worry about
tularemia.”
For more information call Ms. Enos at 1-508-246-0076.
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