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Journal of Infection and Public Health (2009) 2, 157—166
REVIEW
Swine flu
Manish Sinha ∗
Senior Resident, Department of Neurology, Chhatrapati Shahuji Maharaj Medical University,
Lucknow 226003, India
Received 9 June 2009 ; received in revised form 20 August 2009; accepted 27 August 2009
KEYWORDS
Swine influenza;
H1N1;
Swine flu;
Oseltamivir
Summary The recent outbreak of human infection with a novel Swine-Origin
Influenza A (H1N1) virus is spreading rapidly through sustained human-to-human
transmission in multiple countries. Human-to-human transmission occurs by inhalation of infectious droplets and droplet nuclei, and by direct contact, which is
facilitated by air and land travel and social gatherings. The most frequently reported
symptoms are fever, cough, myalgia, and sore throat. Detailed contact and travel
histories and knowledge of viral activity in community are essential for prompt
case detection by the health personnel. Real-time Reverse Transcriptase-Polymerase
Chain Reaction analysis of throat swabs or lower respiratory samples is a sensitive
means of diagnosis. Use of oral oseltamivir may be warranted for the treatment of
severe illness.
© 2009 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier
Ltd. All rights reserved.
Contents
Introduction ................................................................................................
Clinical features ............................................................................................
Transmission............................................................................................
Infectious period .......................................................................................
Incubation period ......................................................................................
Symptoms ..............................................................................................
Complications ..........................................................................................
Mortality ...............................................................................................
Management ................................................................................................
Case detection .........................................................................................
Specimen collection ....................................................................................
∗
Tel.: +91 522 2756268.
E-mail address: [email protected].
1876-0341/$ — see front matter © 2009 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.jiph.2009.08.006
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M. Sinha
Virus detection .........................................................................................
Real-time Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) ............................
Viral culture .....................................................................................
Rapid antigen tests...............................................................................
Immunofluorescent antibody testing .............................................................
Case definition [13].....................................................................................
Hospitalization .........................................................................................
Antiviral agents ........................................................................................
Oseltamivir ......................................................................................
Zanamivir ........................................................................................
Recommendations................................................................................
Post-exposure chemoprophylaxis .................................................................
Antiviral resistance.....................................................................................
Additional therapy .....................................................................................
Prevention ..................................................................................................
Immunization...........................................................................................
Household and close contacts ..........................................................................
Travel ..................................................................................................
Public gathering ........................................................................................
Global efforts ...............................................................................................
Conclusions .................................................................................................
Conflict of interest..........................................................................................
Acknowledgment ..........................................................................................
References ................................................................................................
Introduction
The recent outbreak of a novel Swine-Origin
Influenza A (H1N1) virus (S-OIV), which was first
detected in April 2009 in California (USA) [1],
has now migrated to other parts of the Americas,
Europe, Australia, and Asia. S-OIV is a ‘triplereassortment’ influenza virus, containing genes
from human, swine, and avian influenza A viruses
[2]. As of 19 August 2009, 210 countries have
officially reported over 182,166 cases of S-OIV
infection, including 1799 deaths reported by over
40 countries. The United States has reported the
majority of fatal cases: 7511 laboratory-confirmed
human cases, including 477 deaths. The other
countries reporting laboratory-confirmed cases are
Mexico, Canada, the United Kingdom, Australia,
Thailand, Chile, Spain, Panama, Brazil, India, etc.
[3]. On April 29, 2009 the World Health Organization
designated the outbreak a pandemic.
Clinical features
Transmission
Transmission of S-OIV is thought to occur in the
same way as seasonal flu [4,5]. Human-to-human
transmission occurs by inhalation of large infectious droplets and droplet nuclei as well as by
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direct contact with secretions or aerosols [6]. Possibly, swine-to-human transmission may occur [7].
At present, there is no evidence of spread of infection by eating pork, or through water. Judging the
pandemic potential of S-OIV is difficult with limited
data, though recent epidemiological analyses suggest its transmissibility is substantially higher than
that of seasonal flu, and comparable with previous
influenza pandemics [8].
Infectious period
Data regarding the estimated duration of S-OIV
shedding by patients is limited and based upon
seasonal influenza virus infection. In general, persons with S-OIV infection should be considered
potentially infectious from 1 day before to 7
days following illness onset or until symptoms
resolve. Children, patients with lower respiratory
tract infections, elderly and immunocompromised
patients might be infectious for up to 10 days
or longer [9,10]. This is due to low cytotoxic Tlymphocyte activity which is responsible for viral
clearance and recovery from infection [11]. Cytotoxic T-lymphocyte activity declines in the elderly
as well as in immunocompromised individuals so
that viral shedding could persist longer in them
[12]. However, studies of viral shedding to define
the infectious period of S-OIV are needed. The
potential for persons with asymptomatic infection
Swine flu
to be the source of infection to others is unknown
but should be investigated.
Incubation period
The precise incubation period has not been established for S-OIV infection, it could range from 1
to 7 days, and most likely from 1 to 4 days [13].
This is comparable to the incubation period of avian
influenza A (H5N1) which is 1—8 days [14], but
longer than that of seasonal human influenza (1—4
days) [15].
Symptoms
Novel S-OIV Investigation Team of Centers for Disease Control and Prevention, United States of
America report a series of 642 cases from United
States identified by enhanced surveillance and
confirmed by real-time RT-PCR, viral culture, or
both. The most frequently reported symptoms in
this series are fever (94%), cough (92%), and sore
throat (66%); 25% of patients report diarrhoea,
and a further 25% report vomiting [16]. Myalgia and joint pains may also be present. Nine
percent of patients in this series required hospitalization. Of 22 hospitalized patients, 8 required
admission to an intensive care unit, 4 had respiratory failure, and two expired. Eleven patients
(50% of hospitalized patients in this series) had
radiologically confirmed pneumonia, including one
patient each of pneumomediastinum, necrotizing
pneumonia, and empyema. Radiographic changes
in patents with pneumonia include diffuse, multifocal, or patchy infiltrates, interstitial infiltrates, and
segmental or lobular consolidation with air bronchograms [17,18].
Complications
People of any age with certain chronic medical conditions, children less than 5 years, persons 65 or
older, and pregnant women might be at increased
risk for complications from S-OIV infection [19].
Complications like pneumonia and dehydration
have required hospitalization in approximately
2—5% of confirmed cases in the United States
and 5—6% in Mexico [5,18]. Few bacterial infections have been detected in patients with S-OIV;
these include empyema, necrotizing pneumonia,
as well as ventilator-associated pneumonia due to
Acinetobacter baumannii, Achromobacter xylosoxidans, methicillin-resistant Staphylococcus aureus,
and Escherichia coli. Patients with ventilatorassociated pneumonia have serious risk of death
(up to 58%) mainly due to multi-organ failure [18].
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Neurological complications in form of seizures is
reported in four children in Texas with S-OIV developed, though all four recovered fully [20].
There are few characteristics of this pandemic
which appear unusual compared with a typical
influenza seasonal outbreak. First, the percentage
of patients requiring hospitalization (2—6%) appears
to be higher than would be expected during a typical influenza season (0.4—1%) [21]. Second, the
need for hospitalisations for S-OIV infection has
been particularly high among persons aged between
the ages of 1.5 and 59 years [22], which is different than that of seasonal influenza, in which
severe infection requiring hospitalizations typically
occurs in children aged less than 1 year and adults
aged more than 65 years [21]. Why only few elderly
individuals have been affected during the current
pandemic is intriguing. This may be due to some
degree of preexisting immunity in older individuals against antigenically similar influenza viruses
that circulated prior to 1957 [23]. Of five pregnant
women requiring hospitalization for S-OIV infection, one had spontaneous abortion (at 13 weeks of
gestation) and one developed premature rupture of
membranes (at 35 weeks of gestation) [19].
Mortality
As of August 19, 2009, there have been 182,166
laboratory-confirmed cases of S-OIV worldwide,
including 1799 deaths (0.98%) [3]. Most of the
deaths are reported by the Americas (1579 deaths).
Asian countries have reported 106 deaths. Europe
and Africa have reported fewer deaths.
Most of the deaths are related to respiratory
failure resulting from severe pneumonia and acute
respiratory distress syndrome [24]. Renal or multiorgan failure occurs in 24% cases. In Mexico,
most of the deaths (54%) occurred in previously
healthy individuals between the ages of 20 and 59
[24]. In other parts of world, most of the deaths
occurred in individuals with underlying health problems [25,26]. One death in Mexico and one death
in the US occurred in women who were in the
third trimester of pregnancy when they became ill
[19,24].
The number of deaths in US was highest among
people 25—49 years of age (39%), followed by people 50—64 year of age (25%) and people 5—24 year of
age (16%) [27]. This pattern is different from what
is seen in seasonal influenza, where an estimated
90% of influenza-related deaths occur in people 65
years of age and older [21].
At present, the data seem to imply that this new
virus is relatively mild, with case fatality ratios
around 1%, similar to or less than that seen for
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seasonal influenza [28]. However, simple interpretations of these crude figures at the beginning of a
pandemic may be misleading in terms of assessing
severity. This may occur due to bias in estimates
of the case fatality ratio (with time, efforts may
become more focused on the most severe cases,
leading to an overestimation of the case fatality
ratio) and from the inevitable delay between symptom onset and death, which in the early phase of
the epidemic can lead to underestimation of the
case fatality ratio if it is not adjusted for [29].
Management
Case detection
The possibility of S-OIV infection should be considered in all patients with severe acute respiratory
illness in countries or territories with known S-OIV.
Clinicians should consult their individual health
ministries for information about incidence of
the disease in their countries and guidelines for
case detection. Recommendations can also be
found at the World health organization website
(http://www.who.int/csr/resources/publications/
swineflu/interim guidance/en/index.html) and the
United States Centers for Disease Control and Prevention website (http://www.cdc.gov/swineflu).
As per United States Centers for Disease Control
and Prevention guidelines [13], testing for S-OIV
should be considered in individuals with an acute
febrile respiratory illness (a measured temperature of 37.8 ◦ C or higher and recent onset of at
least one of the following: rhinorrhea, nasal congestion, sore throat, or cough) or sepsis-like syndrome.
Priority for testing should be given to those who
require hospitalization and those who are at high
risk for severe complications. In addition, patients
having influenza-like illness developing within 7
days of close contact with a person who is a
confirmed case of S-OIV infection, or who has travelled to areas with known S-OIV activity in past 7
days, the possibility of S-OIV warrants consideration
[30].
Not all individuals with suspected S-OIV infection
need to have the diagnosis confirmed, particularly if
the illness is mild [13]. Recommendations on whom
to test may differ by state or country and clinicians
should be aware of them. For countries with limited
laboratory capacity, or limited access to laboratory
capacity, World Health Organization recommends
that they should aim to test a number of samples
per week in order to verify that disease activity is
still largely due to S-OIV [30].
M. Sinha
Specimen collection
To test for S-OIV, upper respiratory specimens, such
as a nasopharyngeal swab or aspirate, nasal wash,
or tracheal aspirate should be collected with appropriate personal protective precaution. Specimens
should be sent to the nearest laboratory which has
been equipped to test S-OIV. Swabs with a synthetic tip (e.g., polyester or Dacron) and aluminum
or plastic shaft should be used. Swabs with cotton
tips and wooden shafts are not recommended. The
collection vial in which the swab is placed should
contain 1—3 mL of viral transport media. Specimens
should be placed in viral transport media and placed
on ice (4 ◦ C) or refrigerated immediately for transportation to the laboratory. Once the samples arrive
in the laboratory, they should be stored either in
a refrigerator at 4 ◦ C or in a −70 ◦ C freezer. If a
−70 ◦ C freezer is not available, they should be kept
refrigerated, preferably for ≤1 week. Specimens
should be shipped on dry ice to the state public health laboratory in clearly labeled containers
and should include all information requested by the
state health laboratory [13,30].
Virus detection
Real-time Reverse Transcriptase-Polymerase
Chain Reaction (RT-PCR)
The recommended test to confirm the diagnosis of
S-OIV is real-time RT-PCR for influenza A, B, H1,
and H3 [13,30]. The strain of H1N1 influenza A virus
associated with the 2009 pandemic tests positive
for influenza A and negative for H1 and H3 by realtime RT-PCR.
Viral culture
A virus culture is diagnostic, but culture is usually
too slow to help guide clinical management. A negative viral culture does not exclude pandemic S-OIV
infection [13,31].
Rapid antigen tests
Clinicians may consider using rapid influenza antigen tests as part of rapid evaluation of patients
suspected of having S-OIV infection, but results
should confirmed by real-time Reverse Transcriptase (RT)-PCR or culture [32]. The sensitivity
and specificity of rapid antigen testing for S-OIV
infection have not been established. Based on
limited data, the sensitivity of rapid antigen testing for detecting S-OIV is probably similar to, or
lower than, the sensitivity for detecting seasonal
influenza [33]. A negative rapid influenza test does
not exclude infection [32].
Swine flu
Immunofluorescent antibody testing
A patient with a positive Immunofluorescent antibody testing may be considered a probable case if
he or she meets the other criteria. A negative test
does not exclude S-OIV infection since these tests
have unclear sensitivity to detect this virus [34].
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Antiviral agents
S-OIV is susceptible to oseltamivir and zanamivir,
neuraminidase inhibitor antiviral medications,
which target the early phase of the infection. However, this strain is resistant to adamantanes, such
as amantadine and rimantadine [35].
Case definition [13]
A suspected case of S-OIV infection is defined
as a person with acute febrile respiratory illness
(fever = 37.8 ◦ C) with onset:
(i) within 7 days of close contact with a person
who is a confirmed case of S-OIV infection, or
(ii) within 7 days of travel to areas where there
are one or more confirmed S-OIV cases, or
(iii) resides in a community where there are one or
more confirmed swine influenza cases.
A probable case of S-OIV infection is defined as
a person with an acute febrile respiratory illness
who:
(i) is positive for influenza A, but unsubtypable for
H1 and H3 by influenza RT-PCR or reagents used
to detect seasonal influenza virus infection, or
(ii) is positive for influenza A by an influenza rapid
test or an influenza immunofluorescence assay
plus meets criteria for a suspected case, or
(iii) individual with a clinically compatible illness
who died of an unexplained acute respiratory
illness who is considered to be epidemiologically linked to a probable or confirmed case.
A confirmed case of S-OIV infection is defined
as a person with an acute febrile respiratory illness
with laboratory-confirmed S-OIV infection by one or
more of the following tests:
(i) Real-time RT-PCR
(ii) Viral culture
(iii) Four-fold rise in S-OIV specific neutralizing
antibodies.
Hospitalization
Most cases of S-OIV infection tend to be mild and
self-limited and do not require visit to a health
care provider or hospitalization [16]. Patients
with severe illness and those at high risk for
complications from influenza should seek medical
care. Those with severe illness and complications
may require prolong hospitalization, and in some
cases ventilatory support [5,18]. If patients are
discharged early, both the patients and their families require education on personal hygiene and
infection-control measures.
Oseltamivir
Oseltamivir is a prodrug that is hydrolyzed by the
liver to its active metabolite, oseltamivir carboxylate, with an elimination half-life of about 6—10 h.
Oseltamivir is a neuraminidase inhibitor, serving as
a competitive inhibitor of sialic acid, found on the
surface proteins of normal host cells. By blocking
the activity of the neuraminidase, oseltamivir prevents new viral particles from being released by
infected cells [36]. The therapeutic oral dosage
for S-OIV infection in adults is 75 mg taken twice
daily for 5 days, starting within 48 h of the initial symptoms to capture the early phase of viral
replication (Table 1). For chemoprophylaxis, the
recommended dosage is 75 mg taken once daily
for 10 days after exposure. Therapeutic and prophylactic dosing schedules for children are similar
(about 2 mg/kg twice a day for 5 days for treatment,
and 2 mg/kg once a day for 10 days for prophylaxis) [13]. Adverse effects of oseltamivir includes
nausea, vomiting and transient neuropsychiatric
events (self-injury or delirium). These dangerous
side effects occur more commonly in children and
adolescents [37]. Nausea and vomiting might be less
severe if oseltamivir is taken with food.
Zanamivir
Zanamivir is administered by inhalation with a dry
powder inhaler. The bioavailability of the drug is
10—20% by inhalation, compared with 2% by oral
administration. About 90% of the absorbed dose
is excreted unchanged in the urine. The elimination half-life in serum of zanamivir is about
2—5 h [38]. The mechanism of action is similar to
oseltamivir. The therapeutic dose is 10 mg inhaled
twice daily for 5 days starting within 48 h of the initial symptoms. For chemoprophylaxis, the dose is
10 mg inhaled once daily for 10 days after exposure
(Table 1). The recommended doses for children are
the same. Because zanamivir therapy requires the
patient to voluntarily inhale through the device,
oseltamivir may be preferred over zanamivir for
young children. Zanamivir is not recommended for
treatment for patients with chronic airway disease
or asthma as it can induce bronchospasm [38].
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Table 1
M. Sinha
Antiviral medication dosing recommendations for treatment or chemoprophylaxis of S-OIV infection.
Agent, group
Oseltamivir
Adults
Children ≥12 months
15 kg or less
15—23 kg
24—40 kg
>40 kg
Zanamivir
Adults
Children
Treatment
Chemoprophylaxis
75 mg capsule twice daily
for 5 days
60 mg per day divided into
2 doses
90 mg per day divided into
2 doses
120 mg per day divided
into 2 doses
150 mg per day divided
into 2 doses
75 mg capsule once daily
Two 5 mg inhalations
(10 mg total) twice daily
Two 5 mg inhalations
(10 mg total) twice daily
(age, 7 years or older)
Two 5 mg inhalations
(10 mg total) once daily
Two 5 mg inhalations
(10 mg total) once daily
(age, 5 years or older)
Recommendations
During the current pandemic, patients with mild
illness do not require antiviral agents unless they
have risk factors for complications [13]. However,
the decision of whether to initiate antiviral therapy
for each patient should be based upon the clinician’s judgment, especially in areas with limited
antiviral availability. Clinicians should consult with
their ministries of health and/or the World Health
Organization for specific recommendations.
The United States Centers for Disease Control
and Prevention has released guidelines for the use
of antivirals for patients with confirmed or suspected S-OIV infection and close contacts which are
as follows [13].
Adults. Antiviral therapy should be started in all
adult hospitalized patients with confirmed, probable, or suspected patients and in those at increased
risk for complications. Therapy should be started
as soon as possible, since evidence of benefit is
strongest when treatment is started within 48 h of
illness onset. Some studies of hospitalized patients
have demonstrated benefit even when therapy for
seasonal influenza is started >48 h after onset of
illness [5,17,18]. In patients with severe infection,
therapy can be started even past 48 h of symptoms.
Recommendations for use of antivirals may change
as data on antiviral effectiveness, clinical spectrum
of illness, adverse events from antiviral use, and
antiviral susceptibility data become available.
Pregnancy. Oseltamivir and zanamivir are Pregnancy Category C drugs, reflecting that clinical
studies have not been done to assess the safety
of their use during pregnancy [13,35]. Because of
30 mg once daily
45 mg once daily
60 mg once daily
75 mg once daily
more data about its safety in pregnancy, the use
of oseltamaivir is preferred over zanamavir during pregnancy. Both oseltamivir and zanamivir are
considered to be compatible with breastfeeding
[39]. Pregnant women who meet case definitions for
confirmed, probable, or suspected S-OIV infection
should receive antiviral therapy with oseltamivir,
since the potential benefit outweighs the theoretical risk to the fetus. Treatment should be initiated
as early as possible.
In addition to antiviral therapy, use of
acetaminophen is important when fever is present,
since hyperthermia during the first trimester has
been associated with neural tube defects and other
birth defects [40]. In addition, fever during labor is
a risk factor for neonatal seizures, encephalopathy,
cerebral palsy, and neonatal death [41].
Children. All hospitalized children with confirmed, probable, or suspected S-OIV infection and
those at higher risk of complications should receive
antiviral agents. In addition, all children younger
than 5 years of age, particularly those less than 2
years of age, are at increased risk for complications
of influenza. Either oseltamivir or zanamivir can be
given in children, when indicated, during the current pandemic [13]. For children less than 1 year
of age, oseltamivir is the recommended drug. Children taking oseltamivir should be closely observed
for serious neuropsychiatric events as described
above.
Children who may have influenza infection
should not take aspirin or aspirin-containing products, such as bismuth subsalicyclate due to the
increased risk of Reye syndrome [42].
Swine flu
Post-exposure chemoprophylaxis
Post-exposure chemoprophylaxis should be considered for both close contacts of cases and health
care personnel who have had a recognized, unprotected close contact exposure to a confirmed,
probable or suspected case during the infectious
period of that patient. Close contact is defined as
person who has cared for or lived with a person who
is a confirmed, probable or suspected case of S-OIV
infection, or having been to a setting where there
was a high likelihood of contact with respiratory
droplets and/or body fluids of such a patient. Examples of close contact include kissing or embracing,
sharing eating or drinking utensils, physical examination, or any other contact between persons likely
to result in exposure to respiratory droplets. Close
contact typically does not include activities such as
walking by an infected person or sitting across from
a symptomatic patient in a waiting room or office
[43].
For antiviral chemoprophylaxis of S-OIV infection, either oseltamivir or zanamivir can be given
(Table 1). Antiviral post-exposure chemoprophylaxis should be given for 10 days after the last
known exposure to S-OIV.
Antiviral resistance
As with other antiviral agents, resistance to
the agent is expected with widespread use of
oseltamivir and zanamivir. At least five isolates
of S-OIV with resistance to oseltamivir have been
detected from patients in Denmark, Japan, Hong
Kong, and Canada [44,45]. Mutations conferring
resistance are single amino acid residue substitutions (His274Tyr) in the neuraminidase enzyme [46].
However, in locations where oseltamivirresistant virus is circulating, zanamivir may be
given. In such a setting, for patients who are
unable to take zanamivir, rimantadine, amantadine
or ribavarine may be added to oseltamivir [47].
One recent study has reported reduced zanamivir
susceptibility in nine influenza A (H1N1) viruses isolated between 2006 and early 2008 from Australasia
and South East Asia which contained a previously
undescribed Gln136Lys (Q136K) neuraminidase
mutation [48].
Additional therapy
Additional therapy such as antibiotics should be
used at the discretion of the clinicians if the
patient’s clinical condition warrants. Patients with
pandemic S-OIV infection who develop pneumonia
should be treated empirically for communityacquired pneumonia [49]. In patients with severe
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community-acquired pneumonia requiring intensive care unit admission who also have either necrotizing/cavitary infiltrates or empyema, pathogens
like methicillin-resistant S. aureus (MRSA), A. baumannii, A. xylosoxidans and E. coli infection should
be suspected and treated aggressively as mortality
may be high among them [18].
Role of corticosteroids in the management of
severely ill patients with novel S-OIV infection
is unclear, and routine corticosteroid use is not
recommended. Low doses of corticosteroids may
be considered for patients in septic shock who
require vasopressors and have suspected adrenal
insufficiency. Prolonged use of or high dose corticosteroids can result in serious adverse events in
influenza virus-infected patients, including opportunistic infection and possibly prolonged viral
replication [50].
Prevention
Immunization
Vaccines are the most powerful public health tool
for control of influenza. Seasonal influenza vaccines
are not expected to provide protection against
S-OIV infection because this novel strain hemagglutinin is different from seasonal influenza A (H1N1)
[51]. Around 20 vaccine manufacturers are preparing to make S-OIV vaccine, and it is expected to
be available as early as September 2009 [52]. As
vaccines available initially will not be sufficient, a
step-wise approach to vaccinate particular groups
may be considered. The Strategic Advisory Group of
Experts of the World Health Organization suggested
the following groups for consideration, noting that
countries need to determine their order of priority based on country-specific conditions: healthcare
providers; pregnant women; those aged above 6
months with one of several chronic medical conditions; healthy young adults of 15—49 years of age;
healthy children; healthy adults of 50—64 years of
age; and healthy adults of 65 years of age and
above. Since the S-OIV vaccine is not intended to
replace the seasonal flu vaccine, individuals should
be encouraged to get their seasonal flu vaccine
along with it [52].
Household and close contacts
Household contacts of persons with confirmed cases
of S-OIV should receive post-exposure prophylaxis
as described above. Contacts of a patient with
proven or suspected virus should monitor their tem-
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perature and symptoms. Medical attention should
be sought if they have fever greater than 37.8 ◦ C
plus one or more of the following: rhinorrhea or
nasal congestion; sore throat; cough. All people
of patient’s family, including patient, should cover
their cough and wash hands often. People with
influenza-like illness should remain at home until
at least 24 h after they are free of fever (37.8 ◦ C),
or signs of a fever without the use of fever-reducing
medications [53]. In community and home settings,
the use of facemasks and respirators are not recommended, except for persons at increased risk of
severe illness from influenza. However, healthcare
providers caring for persons with confirmed, probable or suspected S-OIV infection should wear N-95
respirator [54].
Travel
People with symptoms of flu should not leave home
or travel. If symptoms develop during flight or public transport vehicle, the person with illness should
protect others by wearing a facemask if tolerable to reduce the number of droplets coughed or
sneezed into the air or use a tissue to cover their
nose and mouth when coughing or sneezing. The
person with illness should sit at least 6 feet apart
from others without compromising flight safety. If
the person with illness is travelling to a different
country, the captain of the plane should report the
illness to quarantine officials in the jurisdiction of
the airport where the plane is expected to land
prior to arrival or as soon as illness is noted. Quarantine officials will work with the airline and local
and state health departments to assist with medical
transportation of the patient upon arrival, disease
control and containment measures, passenger and
crew notification and surveillance activities, and
airline disinfection procedures [55].
M. Sinha
ings in communities where S-OIV is circulating. All
persons should be reminded to use appropriate respiratory and hand hygiene precautions.
Further, large public gatherings offer a good
opportunity for public health officials and event
organizers to deliver key educational messages
about measures attendees can take to help reduce
the spread of S-OIV infection. Other measures like
hand washing facilities with soap and running water,
hand sanitizer, tissues, and on-site medical assessment can be provided by event organizers to help
reduce the risk for infection. [57].
School closures are not universally recommended due to ethical concerns, though policies
may vary in different countries [58]. However, it
is pertinent to mention that the current pandemic
spread to United States from Mexico in March—April
2009 after some students of a New York school contracted S-OIV infection during a visit to Mexico over
spring break [1].
Global efforts
World Health Organization (WHO) is actively monitoring the progress of the pandemic through
consultations with its Regional Offices and member states. WHO has teamed up with agencies
like United States Centers for Disease Control
and Prevention, the Pan-American Health Organization/(PAHO/WHO), Global Outbreak Alert and
Response Network, European Centre for Disease
Prevention and Control, and the China Centre
for Disease Prevention and Control to better
understand the outbreak, including clinical illness
severity and transmission patterns, and to facilitate
the production and distribution of S-OIV vaccine.
Public gathering
Conclusions
In public gatherings, it is difficult to maintain physical distance between people. As a result, there
may be increased risk for spread of S-OIV. Such
gatherings can include school or college classes,
church services, sporting events, concerts, social
and cultural celebrations, weddings, conferences,
and other similar activities attended by relatively
large groups of people. It is recommended that persons with influenza-like illness should avoid such
gatherings and stay at home for 7 days after the
onset of illness or at least 24 h after symptoms have
resolved, whichever is longer [56]. Persons who are
at high risk of complications from S-OIV infection
should consider staying away from public gather-
Although it has been just over four month since
the first few cases were identified, the outbreak
of human infection with a novel S-OIV is spreading rapidly through sustained human-to-human
transmission in multiple countries. The spread of
infection has been facilitated by air and land travel
and social gatherings. The better understanding of
routes of transmission, clinical features, pathogenesis, and perhaps, response to treatment is required
to check the spread of infection. Detailed contact
and travel histories and knowledge of viral activity in community are essential for prompt case
detection by the health personnel. Real-time RTPCR analysis of throat swabs or lower respiratory
Swine flu
samples may offer sensitive means of diagnosis.
Use of oral oseltamivir may be warranted for the
treatment of severe illness. Above all, there is an
urgent need for global coordination in clinical and
epidemiologic research to control this outbreak.
Conflict of interest
Funding: None.
Competing interests: None declared.
Ethical approval: Not required.
Acknowledgment
None.
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