E
|
astern equine encephalitis
(EEE) is a potentially deadly illness caused by a mosquito-borne virus. While
infections in humans have been rare in the United States, an upsurge in
reported cases this year has caused experts to wonder whether EEE could be the
next Zika or West Nile.
Share
on PinterestA rare virus has been infecting more and more people in the U.S.
Experts are calling for a strategy to address a potential outbreak.
The EEE virus is carried by
mosquitoes — through mosquito bites, it can be transmitted to equines, such as
horses or zebras, and to humans.
This virus has been present
in the U.S. for centuries, though it has rarely infected people.
However, if it does infect a person and the infection evolves into a severe form of the disease, EEE can be deadly.
Only a handful of these infections in humans had been reported throughout the U.S. each year for the past few years.
However, if it does infect a person and the infection evolves into a severe form of the disease, EEE can be deadly.
Only a handful of these infections in humans had been reported throughout the U.S. each year for the past few years.
According to dataTrusted Source from the Centers
for Disease Control and Prevention (CDC), last year there were six reported
cases of EEE and five in 2017.
Until this year, the
highest annual number of EEE cases in the country over the last decade had been
15, in 2012.
But as of November, this
year has seen an upsurge in EEE cases in humans, including fatalities due to
the illness. The CDC reportTrusted Source that there have been "36
confirmed cases of [EEE] virus disease [...] this year, including 14
deaths."
This situation has made
some specialists wonder whether the EEE virus may not become the next threat to
public health, much like the Zika or
West Nile viruses.
'A new era' for mosquito-borne viruses?
Recently, experts from the
National Institute of Allergy and Infectious Diseases (NIAID) published a
commentary in The New England Journal of
Medicine describing the EEE virus and how researchers plan to
address this potential threat.
In the article — the first
author of which is Dr. David Morens — the experts place EEE in the context of
recent mosquito-borne virus (arbovirus) outbreaks worldwide.
"In recent years, the
Americas have witnessed a steady stream of other emerging or reemerging
arboviruses, such as dengue, West Nile, chikungunya, Zika, and Powassan, as
well as increasing numbers of travel-related cases of various other arboviral
infections," they write, warning that:
"This year's EEE outbreaks may thus be a
harbinger of a new era of arboviral emergences."
Part of what makes the EEE
virus potentially dangerous for humans is that its symptoms are sometimes indistinguishable
from those of other viral infections. Some individuals report no symptoms at
all in the initial stages of infection.
MEDICAL
NEWS TODAY NEWSLETTER
Stay in the know. Get our free daily newsletter
Expect in-depth,
science-backed toplines of our best stories every day. Tap in and keep your
curiosity satisfied.
SIGN
UP NOW
Your privacy is important to us
The EEE virus takes 3–10
days to incubate inside a human host, and its — nonspecific — symptoms
include fever, malaise,
intense headaches, muscle
aches, nausea, and vomiting.
Moreover, the specialists
explain, EEE infections are difficult to diagnose with tests, as it is tricky
to isolate the virus in samples of blood or spinal fluid. Yet, if neurologic
symptoms of EEE do appear, these will be visible within approximately 5 days of
infection.
And these, too, may be
initially indistinguishable from the symptoms of viral meningitisTrusted Source.
"However, [after this
period,] rapid clinical progression ensues," the experts write. "By
the time definitive serologic diagnosis is possible, within a week after
infection, neurologic damage may already have occurred."
"An estimated 96% of
people infected with EEE [virus] remain asymptomatic; however, of those who
have symptoms, 33% or more die, and most of the rest sustain permanent, often
severe, neurologic damage," the specialists report.
Worrying lack of a prevention strategy
So what can we do in the
event of an EEE outbreak? So far, not much, according to Dr. Morens and
colleagues. Currently, no known antiviral drugs are safe and effective in the
treatment of this viral infection.
For the time being, people
who become infected will receive no more than "supportive treatmentTrusted Source,"
according to the CDC.
Some researchers have
experimented with fighting the virus using monoclonal antibodies — artificially
created antibodies that can help boost the immune response to a given pathogen.
However, though this approach has shown some promise, scientists have, at this
point, only tested it in animals.
Moreover, the monoclonal
antibody treatment only appears to be effective if the researchers administer
it to the animals before they become infected with the EEE virus.
Dr. Morens and colleagues
believe that finding a vaccine for EEE would be an effective method of
prevention, and some research has already gone into this.
"However,"
they note, "there may not be strong incentives to proceed to advanced
development and licensure because of the nature of the disease: Outbreaks are
rare, brief, and focal, and they occur sporadically in unpredictable locations,
making it difficult to identify an appropriate target population for
vaccination."
This is why the NIAID
specialists are calling for a nationwide strategy for preventing an EEE
outbreak before it gets the chance to become a reality.
"In the absence of
vaccines or specific treatments, state and local health departments can provide
early warning of imminent human infections by surveilling equids, birds, and
mosquitoes," the team advises. Yet, "Even these blunt prevention
tools are continuously threatened by underfunding of public health
efforts."
"Sadly, the [U.S.']
ability to control arboviral diseases is little better in 2019 than it was more
than a century ago," Dr. Morens and colleagues warn.
"Though the best way
to respond to these threats is not entirely clear, to ignore them completely
and do nothing would be irresponsible," the specialists conclude.
No comments:
Post a Comment