Home' Trinidad and Tobago Guardian : May 10th 2017 Contents A24 body & soul
guardian.co.tt Wednesday, May 10, 2017
As if Lyme disease isn't troubling enough, a more
serious tick-borne disease may be emerging, experts
warn. Powassan virus, which is a far rarer and more
deadly pathogen than the bacterium that produces
Lyme,is also transmitted by the deer tick (also called
blacklegged tick).The virus can cause inflammation
in the brain, which leads to death or permanent dis-
ability in 60 per cent of cases.
So far, 75 instances of severe disease have been report-
ed to the US Centers for Disease Control and Prevention.
Just in the last couple weeks, a five-month-old baby from
Connecticut was diagnosed after developing neurological
"The bottom line is that we should be very scared of it
because nobody is safe from it," said DrJennifer Lyons, chief
of the division of neurological and inflammatory diseases at
the Brigham and Women's Hospital and an assistant pro-
fessor of neurology at the Harvard Medical School. "And
it could be that it is emerging and will explode over the
next few years."
Especially worrying, the virus can be transmitted from
the tick in as little as 15 minutes, Lyons said. In comparison,
the Lyme bacterium needs 24 hours to pass from a tick to
The reported cases have mostly come from the Northeast
and the northern part of the Midwest USA. List of cases
by US state through 2015, per the CDC: Maine ---2; Mas-
sachusetts---8; Minnesota---20; New Hampshire---1; New
Jersey---3; New York---16; Pennsylvania---1; Virginia---1; and
Few have heard of Powassan virus, but it's been around
for a long time. The first reported case was in the 1950s in
Ontario, said Durland Fish, a professor emeritus of epi-
demiology and microbiology at the Yale School of Public
Health. It wasn't considered a big problem then because the
virus had been transmitted by a tick that rarely bit human
beings, Fish said.
But that changed when it appeared in deer ticks.
"It's no longer a disease that'sjust caused by a tick species
that hardly ever bites people," Fish said. "Now it's being
transmitted by a tick species that bites people readily. And
that's not good. This is a disease that there is no treatment
for and that you can die from."
Experts don't yet have a handle on how many people have
actually become infected with the virus, since the current
stats are based on people who developed severe disease.
"It's quite possible that many, many more are infected and
not identified because their symptoms are mild," said Ann
Powers, chief of virology activity in the arboviral diseases
branch at the CDC.
Right now, nobody knows how fast or far the virus will
"Regarding the question of whether or not there will be
a huge outbreak like there was with Lyme, I would hope
not," Powers said. "We're trying to identify the trends that
would signal that type of emergence."
There is some evidence that the virus's range may be
on the rise in the Northeast. A 2013 study that looked at
New England deer found that the per cent showing signs
of infection had been steadily increasing between 1979 and
2010. Since the deer tick picks up pathogens from the deer
it bites, this suggests that the number of ticks carrying the
disease is also on the rise.
A recent report from the Maine Medical Center Research
Institute backs that up. Researchers found that seven per
cent of adult ticks and about 10 per cent of ticks in the
nymph stage carried the Powassan virus.
Not everyone is convinced that the virus is spreading
fast. Rafal Tokarz and his colleagues studied ticks in New
York state and found only one to two per cent carried the
virus. That's compared to 20 per cent carrying the Lyme
bacterium, said Tokarz, an associate research scientist at the
Center for Infection and Immunity at the Mailman School
of Public Health at Columbia University. "If it's 20 per cent
then your chances are one in five that the tick on you will
give you Lyme," he added.
One thing experts do know is how the virus becomes
"The virus goes up to the brain and attacks the parts
that keep you awake, keep your heart rate steady and your
breathing drive going," Lyons explained.
Symptoms of the virus can include:fever,headache, vom-
iting, weakness, confusion, loss of coordination, speech
difficulties, and seizures. (NBC)
Rare, tick-borne Powassan
virus worries some experts
about possible spread
Health officials in Canada are broadening their screening of the blacklegged ticks
for Powassan virus---after a dramatic rise in the number of cases of the disease in
the USA. Photo shows the blacklegged tick, I. pacificus, which is a known vector
for Lyme disease.
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