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A New Flu

Sunday, December 11, 2011 // Uncategorized

This is a report from Pro Med Digest, a” bug watch” bulletin, that I get several times a day about a new strain of flu.  This strain is  usually transmitted from  contact with pigs, is not very infective, is not very virulent and is responsive to antiviral meds. Since it is related to older strains, people who have been immunized over the years may have some immunity to the virus.

CDC confirms 2 human infections with novel influenza viruses
– ————————————————————
The Centers for Disease Control and Prevention (CDC) have confirmed 2
cases of human infection with 2 different novel influenza A viruses in
different states. Both patients have fully recovered. While the
viruses infecting both patients have been found in US swine and some
of the prior human infections with these viruses have been associated
with direct or close swine contact, there are no reports of direct or
close contact with swine prior to illness onset in either of these
cases. Laboratory testing at CDC has confirmed that both novel viruses
are susceptible to the antiviral medications oseltamivir (Tamiflu) and
zanamivir (Relenza).

West Virginia
– ————-
One case of human infection with a novel influenza virus was reported
by West Virginia and involves infection of a child with the novel
influenza A (H3N2) virus with genes from swine, human, and avian
lineages with the M gene from the 2009 H1N1 virus that was first
identified in August 2011. Ten prior human infections with this virus
in 4 other states have been confirmed. These occurred in Indiana (2),
Pennsylvania (3), Maine (2), and Iowa (3).

These novel influenza A (H3N2) viruses are substantially different
from currently circulating seasonal (human) influenza A (H3N2)
viruses, but are distantly related to human influenza viruses that
circulated among people in the 1990s. For that reason, some adults may
have some residual immunity against this virus. This might help
explain why 10 of the 11 cases that have been detected have occurred
in children.

Most human infections with viruses that circulate in swine (but not
humans) have been associated with swine exposure, but limited
human-to-human transmission associated with these viruses is thought
to have occurred as well, most recently in Iowa. While an
investigation is ongoing in West Virginia, no direct or indirect
contact with swine has been reported, implying that limited
human-to-human transmission of this virus may have occurred again.

No ongoing community transmission of this virus has been detected in
the United States. However, CDC is taking this situation very
seriously. Surveillance surrounding reported cases is being further
enhanced and, as a precaution, a vaccine virus has been developed and
provided to manufacturers for them to begin vaccine production should
that become necessary.

Minnesota
– ———
The other case of novel influenza A virus infection was reported by
Minnesota, and is associated with a different influenza virus; an
influenza A (H1N2) virus that circulates in swine  in the United
States, but does not normally infect or cause illness in humans. This
case also was in a child. This is only the second case of human
infection with this novel influenza A (H1N2) virus reported to CDC
since novel influenza virus infections became nationally notifiable in
2007. The first such case was identified in Michigan in 2007. By some
characteristics, this H1N2 virus is close to human influenza A (H1N1)
viruses called “A/New Caledonia /20/99-like”, which circulated and
caused illness among people as recently as 2007. As a result, people
who were exposed to A/New Caledonia/20/99-like viruses may have some
existing immune protection against the virus detected in Minnesota.
Again, no direct or indirect contact with swine has been reported with
this case, implying that limited human-to-human transmission may have
occurred in this instance as well.

Detection of swine influenza infections in humans
– ————————————————-
Human infections with novel influenza A viruses normally found in
swine are rare events. Recently, however, the frequency of such
detections has increased. This could be occurring for a number of
reasons, including one or more of the following factors:
Firstly, laboratory methods for testing for these viruses in the
United States were improved following the 2009 H1N1 pandemic. These
improvements may be resulting in viruses being identified now that
would have gone undetected previously.
Secondly, this could be due to increased surveillance in the United
States for influenza at this time of year. CDC has requested that
states analyze, and then send, their first influenza virus specimens
of the season for seasonal influenza surveillance purposes. This
practice, coupled with very low levels of seasonal flu activity at
this time, could mean that sporadic novel influenza infections are
more likely to be tested.
Thirdly, it is possible that the increased frequency of detection of
novel influenza viruses with swine origins identified by CDC
represents a true increase in the number of such cases, possibly
occurring from exposure to infected swine or through subsequent,
limited human-to-human transmission.

The novel influenza A (H1N2) virus identified in Minnesota is known to
circulate in US swine herds. While the prevalence of the novel
influenza A H3N2 virus with the 2009 H1N1 M gene in swine is unknown,
the virus has been detected in US swine through the United States
Department of Agriculture’s swine influenza surveillance program.

In response to recent human infections with novel influenza viruses,
CDC would like to convey the following information:

* CDC recommends an annual seasonal flu vaccine to protect against
seasonal influenza viruses; however, a seasonal flu vaccine is
unlikely to protect against flu viruses that normally circulate in
swine.
* There are two FDA–cleared drugs that are expected to be effective
in treating illness associated with these viruses. The antiviral drugs
oseltamivir and zanamivir -– which are used to treat infection with
human seasonal influenza viruses –- also have shown activity against
influenza viruses from swine. (For more information about influenza
antiviral medications, please see
<www.cdc.gov/flu/antivirals/whatyoushould.htm>)
* Influenza has not been shown to be transmissible to people through
eating properly handled and prepared pork (pig meat) or other products
derived from pigs. For more information about the proper handling and
preparation of pork, visit the USDA website fact sheet “Fresh Pork
From Farm to Table”.

At this time, CDC recommends the following:
* People who experience flu symptoms following direct or close contact
with swine and who require medical attention (see below) should
mention this exposure to their doctor or health care provider. (A list
of flu symptoms is available at
<www.cdc.gov/flu/about/disease/symptoms.htm>.)
* For people who have NOT had exposure to swine and develop ILI
(influenza-like illness), CDC’s recommendations for seeking
treatment are the same as they are for seasonal influenza.
* If you have symptoms of flu and are very sick or worried about your
illness contact your health care provider.
* Certain people are at greater risk of serious flu-related
complications (including young children, elderly people pregnant women
and people with certain long-term medical conditions) and this is true
both for seasonal flu and novel flu virus infections. (For a full list
of people at higher risk of flu related complications, see
<www.cdc.gov/flu/about/disease/high_risk.htm>).
* If these people develop ILI, it’s best for them to contact their
doctor. (The majority of recent novel influenza A (H3N2) cases have
been in children.)
* Your doctor may prescribe antiviral drugs that can treat the flu.
These drugs work better for treatment the sooner they are started.

More information about swine influenza and links to all previous
reports related cases of novel influenza A (H3N2) viruses infections
are available on the CDC swine influenza website at
<www.cdc.gov/flu/swineflu/index.htm>.

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