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influenza
34
NOV / DEC 2013
I
Healthcare Journal of NEW ORLEANS
strains as well as avian and human strains.
This deadly combination, particularly severe
for pregnant women, resulted in over 18,000
deaths by May of 2010, according to the
World Health Organization (WHO). In New
Orleans, as elsewhere, children were hit
hard by the virus. Children’s Hospital was
burdened with over 150 cases that required
hospitalization, 3 deaths, and one boy who
struggled for almost 500 days there, even-
tually requiring a kidney transplant. At this
point in time, the pandemic seems to have
crested, though cases continue to be seen,
including a large outbreak in Venezuela last
May that infected 250 people and killed
17. This season’s vaccine (2013-2014) also
includes an H1N1-like virus designed to pro-
tect against this strain of influenza.
In addition to H1N1-2009, two other non-
seasonal influenza strains are currently of
concern.The first, H7N9, is an avian flu asso-
ciated with poultry in China, first reported
in April of this year. The symptoms of this
influenza strain are particularly severe; as
of July 20, 2013, out of 134 cases of H7N9
reported in humans, 46 resulted in death.
that far, theoretical point in
the future, we will need to
continue with the current
system of getting a new
flu vaccine each year.)
Vaccination is impor-
tant. Even “regular,” sea-
sonal flu is deadly; each year,
several thousand U.S. residents
die of influenza. While deaths are
generally confined to the elderly, the very
young, and patients with certain chronic
health conditions, when healthy people con-
tract the flu it is no fun either. Influenza is
not a cold; it lasts up to 2 weeks, with severe
fatigue, fever, headaches, andmuscle aches.
Getting vaccinated in Louisiana is easy;
in addition to doctors’ offices, many phar-
macies offer vaccination on a drop-in basis.
Since seasonal flu virus infections follow a
pattern of gradually increasing in late Fall,
peaking around the end of the year, and then
diminishing through early spring, the rec-
ommended time for vaccination is in the
early Fall, or as early as possible after that.
In Louisiana, influenza activity generally
follows this pattern well. For example, last
year’s flu season (2012-2013) saw a gradual
increase in flu cases starting around the
beginning of October, until cases peaked
around late December/early January, fol-
lowed by a gradual decline until the end
of spring. However, two seasons showed a
remarkably different pattern here. In 2008-
2009 and again in 2010-2011, there was a
sharp spike in flu cases in August/Septem-
ber, and, in general, the flu cases in 2009 far
outnumbered those of other years. This cor-
responded to the year when a pandemic of a
different type of influenza virus, H1N1-2009,
swept across Mexico, the United States, and,
eventually, over 200 other countries.
The distinctiveness of the H1N1-2009
genome sequence is remarkable: 27.2% dif-
ferent from its predecessor, the 2008 “sea-
sonal flu” strain of H1N1, and 6.1% different
from the closest known influenza virus in
nature. Its genome is a prime example of
the power of reassortment, with elements
of American and European swine influenza
Influenza is
not a cold; it
lasts up to 2
weeks, with
severe fatigue,
fever, headaches,
and muscle
aches.
No human-to-human transmission has been
seen, however. Chinese officials have taken
action to contain the virus, including the clo-
sure of live bird markets, and the number of
new cases has declined. No cases have been
detected outside of China, but the Centers for
Disease Control (CDC) ismonitoring this virus
closely because of the severity of the disease.
The other emerging strain of concern is
H3N2v. This strain normally circulates in
pigs, but has also infected humans, and has
shown limited human-to-human spread. No
sustained community spread has been seen,
however, andmost of the U.S. infections have
been associated with prolonged exposure
to pigs at agricultural fairs. Symptoms are
similar to those of seasonal flu.
Of course, in states like Louisiana, the
popularity of waterfowl hunting may pres-
ent another source of new influenza strains—
direct infection of hunters with wild-bird
viruses. Louisiana hosts the largest har-
vest of wild birds in the USA. University of
Georgia researchers Dorea et al. explored
the possibility of a new viral strain emerg-
ing through reassortment between a human