Vol 41 # 3 September 2009 - Kma.org.kw

September 2009
KUWAIT MEDICAL JOURNAL 185
Editorial
Swine-origin Influenza A (H1N1) Virus Pandemic:
Is it a Sprint or a Marathon
Nasser Behbehani
Department of Medicine, Faculty of Medicine, Kuwait University, Kuwait
Kuwait Medical Journal 2009; 41 (3): 185-186
The new influenza virus pandemic, Swine-origin
Influenza A(H1N1), is a major threat to public health
and several authorities have been warning us about
this risk. History tells us that such pandemics usually
cause tremendous morbidity and mortality. The most
prominent Influenza A virus pandemics occurred from
1918 through 1919 (H1N1), from 1957 through 1963
(H2N2), and from 1968 through 1970 (H3N2) [1] . The
current H1N1 pandemic started in late March 2009
in Mexico and by July 6, 2009 there were 94,512 (429
deaths) laboratory confirmed cases in 135 countries
including 35 cases in Kuwait. Out of the 35 cases, 18
were among American soldiers in Kuwait while the
rest were sporadic cases [2] .
The virus which is causing the current pandemic is
triple-reassortant swine influenza A virus. This means
that the H1N1 virus genome includes combinations
of avian, human and swine influenza virus gene
segments. It has been hypothesized for some time that
pigs may act as a mixing vessel for the reassortment of
avian, swine and human influenza viruses and might
play an important role in the emergence of a potential
pandemic caused by a novel influenza virus. Even
prior to the emergence of this pandemic, the Centre for
Disease Control (CDC) in the United states received
notification of 11 sporadic human cases of infection
with this virus which occurred between 2005 and
2009 [3] . There was confirmed history of exposure to
pigs in nine out of the 11 cases prior to the development
of influenza like symptoms. All of the 11 cases had
recovered. However, four patients were hospitalized
and two required mechanical ventilation.
The pandemic started on a large scale in late
March 2009 when this novel virus was able to cause
sustained human to human transmission. The pace
of spread of this virus has been very extraordinary.
During the month of April 2009, there were 367
(nine deaths) new confirmed cases of H1N1 in 11
countries, followed by 17,043 (108 deaths) new cases
in 62 countries in May, and 59,791 (217 deaths) in 135
countries in June [4] . The clinical presentation of the
initial 642 confirmed cases that were reported to CDC
between April 15 and May 5, 2009 showed that the age
range of patients with H1N1 was from three months
to 81 years and 60% were 18 years or younger [5] .
Only 9% of patients required hospitalization and
two died. The most common presenting symptoms
were fever (94%), cough (92%) and sore throat (66%);
25% of patients had diarrhea and 25% had vomiting.
Despite the fact that most countries reported that
most of the cases were mild, Mexico reported a
greater number of severe cases and deaths related to
this novel virus initially. The first 18 cases of severe
pneumonia related to H1N1 reported from Mexico
showed that the age range was from eight months
to 61 years and only eight cases had pre-existing
medical conditions [6] . Out of the 18 cases with severe
pneumonia, 12 cases required mechanical ventilation
and seven died. The clinical features of the severe
cases included bilateral patchy pneumonia, increased
serum lactate dehydrogenase level and increased
creatinine kinase level (62%) and lymphopenia
(61% patients). Also, out of those 18 patients, 14
received oseltamivir after admission (a mean eight
days after onset of symptoms). However, it is worth
noting that all the four patients who did not receive
oseltamivir survived. From this initial hospital-based
epidemic, 22 health care workers (HCW) developed
mild to moderate flu like illness within seven days
of contact with the cases and all HCW’s treated with
oseltamivir recovered completely. It is interesting to
note that in seasonal influenzae epidemics, severe
cases and deaths usually occur among the very
young (< 5 years of age) or the elderly. However, the
current pandemic seems to have a different pattern
that the majority of severe cases occur in middle aged
individuals. In a study from Mexico reporting on
the first 2,155 cases of pneumonia related to H1N1
involving 821 hospitalizations and 100 deaths, 87%
of deaths and 71% of cases of severe pneumonia
Address correspondence to:
Professor Nasser Behbehani, FRCPC, Department of Medicine, Kuwait University, PO Box 24923, Safat 13110, Kuwait. Fax: (965) 25338907,
E-mail: Nasser_beh@hsc.edu.kw