Developed with joint collaboration of
Ministry of Health-Government of Pakistan, World Health
Organization and the National Institute of Health, Islamabad
2 Collection and transportation of specimen
4 Risk factors for increased transmission
5 Prevention and control measures
6 Hospital infection control guidance
7 Safety measures for Poultry bird workers, cullers and
Avian influenza is a contagious infectious disease of birds
caused by type A strains of the influenza virus. The disease,
which was first identified in Italy in 1878, occurs worldwide
among poultry populations. Birds are an especially important
species because all known subtypes of influenza A viruses
circulate among wild birds, which are considered the natural
hosts for this variety of viruses. However, avian influenza
viruses usually do not make wild birds sick, but can make
domesticated birds very sick and often kill them.
This form of
influenza is not usually known to infect humans, however once
transmitted the infection may lead to development of this
disease with symptoms of avian influenza ranging from typical
influenza-like symptoms (e.g., fever, cough, sore throat and
muscle aches) to eye infections, pneumonia, acute respiratory
distress, viral pneumonia, and other severe and life-threatening
Confirmed instances of avian influenza viruses
infecting humans have been reported since 1997 mainly among the
South East Asian countries known as the Hong Kong outbreak. All
genes are of avian origin, indicating that the virus has not
acquired human genes. The acquisition of human genes is known to
increase the likelihood that a virus of avian origin can be
readily transmitted from one human to another.
The current epidemic was first reported in October 2003 in
Vietnam and is now known to spread to South Korea, Thailand and
Laos and in all these countries it has been reported to be
caused by the H5N1 strain of Influenza Type A variety of
viruses. The World Health Organization (WHO) has reported that
the H5N1 strain implicated in the outbreak has been sequenced.
According to the latest figures provided by the WHO, that there
have been 15 reported laboratory-confirmed cases of H5N1 strain
in Vietnam,11 of which have been fatal. 5 cases have been
reported from Thailand with all of them dying from the
Infectious agent • H5N1 strain of
Type A Influenza virus
Fifteen people have died among the 22 laboratory
confirmed human cases. Median age among the human
cases is 16.5 years and half of the cases were
females. Since the beginning of the outbreak, nearly
3 million chickens have died/culled in the country.
First time reported in the country on 12th December
2003, and nearly 1.1 million chickens and ducks have
died/culled. No human cases have been reported
• The 1st case was a 7-year-old boy from Suphanburi
province who developed fever and cough on 3 Jan 2004
and progressed to Acute Respiratory Distress
Syndrome (ARDS) on 13 Jan 2004. The 2nd case was a
6-year-old boy from Kanchanaburi province who
developed fever on 6 Jan 2004 followed by severe
pneumonia with ARDS a week later. Nearly 6 million
chickens have died/culled in this country. To date a
total of 9 cases have been reported with 7 of them
dying from the disease. The median age of the human
cases is 6 years and 20% of them are females.
More than 10,000 chickens have died/culled. First
reported during the outbreak on the 12th of Jan
2004, there have been no reports of any human case
of avian influenza.
Nearly 50,000 chickens have died with no reports of
any human cases to date
Thousands of chicken have died (the exact number is
yet to be disclosed ) however there have been no
human cases reported officially to date
Millions of chickens are reported to have died over
the recent months and is now confirmed to be caused
by H5N1 strain of the Type A influenza virus.
Reports of avian influenza among bird populations
(poultry chickens and ducks) have been reported
(suspected or confirmed) from 14 of the countries 31
provinces and regions. The exact numbers of affected
population are increasing and the outbreak is now
confirmed to be cause by H5N1 strain. No human cases
have been reported to date by the Chinese
Till now the reservoir seems to be wild and domestic
chickens and turkeys, with humans being reported to only have
Mode of transmission
Route and mode of spread according to current evidences
• Bird to bird
• Bird to person contact
• There is no scientific consensus on human to human spread of
the H5N1 strain.
Incubation Period and characteristics of H5N1 virus
Incubation period is known to be of one week on an average. The
virus is can be killed by heat (56 0 C for 6 hours or 60 0 C for
30 minutes). The virus is known to survive at cool temperatures,
in contaminated manure of poultry birds for at least three
months. In water the virus is known to survive upto 4 days at 22
degrees Celsius and more than 30 days at zero degrees C.
Period of Communicability
There is no evidence of transmission during the incubation
period or convalescence periods. Communicability increases with
the severity of disease and degree of direct exposure. The virus
is known to survive in cold temperatures and in contaminated
manure of birds for upto three months. In water it may survive
upto 4 days at 22 degrees C and more than 30 days at zero
Portal of entry
Faeco-oral route (amongst human or birds)
Upper respiratory tract among humans
Portal of exit
• Faeces, saliva and nasal secretions of infected birds
• Main upper respiratory tract among humans
Source of infection
• Faeces among birds
• Respiratory discharge among humans
Susceptibility and resistance
• All age and sex groups are susceptible. Most of the cases have
occurred among the poultry bird handlers, which could be
explained by length and degree to the source of infection.
Growing concern has been raised in the scientific community
since the onset of outbreak is that there may be a possibility
of reassortment of the H5N1 strain with an existing human
influenza strain among such persons who get exposed to the H5N1
strain while concurrently suffering from a exposure/episode of
human influenza. In such cases a combination (reassortment) of
the two strains may lead to a new/mutated version of the
influenza virus for which currently no medication and vaccine
have been developed and which may carry high transmission
properties and may lead to higher case fatality rates than the
H5N1 form. Initial analysis of viruses isolated from the
recently fatal cases in Vietnam indicates that the viruses are
invariably resistant to the anti-retroviral drugs like M2
inhibitors (rimantidine and amantadine). Studies to confirm the
effectiveness of neuraminidase inhibitors against the current
H5N1 strains are currently underway.
• Initially flu-like symptoms
• Rapid onset of high grade fever (> 38oC) followed by muscle
headache, sore throat.
• In some cases there may be unilateral or bilateral pneumonia,
progressing to acute respiratory distress requiring assisted
breathing on respirator.
Case Fatality Rate (CFR)
• In the current outbreak, the case fatality rate is ranging
from 70 - 75 % among the reported human cases of Vietnam and
Diagnosis Hemagglutinin inhibition (HAI), ELISA, IFA with HF5
monoclonal antibodies and RT-PCR have been developed. Virus
isolation is the key factor in identifying the sub-type of the
Specimens for laboratory tests
• Throat and/or nasopharyngeal swab
• Nasopharyngeal aspirate
Blood for complete examination and serology
• Blood for molecular biological studies
Collection and transportation of clinical specimens
Procedure for specimen collection among humans
• Insert a sterile swab beneath the inferior turbinate of either
nostrils and leave in place for a few seconds.
• Slowly withdraw with a vigorous rotating motion against the
mucosal surface of the nostril.
• Repeat the same procedure in the other nostril using a new
• Collect the tip of each swab in a vial containing 2-3 ml of
viral transport media (VTM) with the applicator stick broken
• Take a swab after vigorous rubbing from the posterior pharynx.
• Collect the swab into vial with the applicator stick broken
off containing VTM in it.
• Nasopharyngeal secretions are aspirated through a catheter
connected to a mucous trap and fitted to a vacuum source.
• The catheter is connected into a nostril parallel to the
palate, vacuum is applied and the catheter is slowly withdrawn
with a rotation motion.
• Mucous from the other nostril is collected with the same
catheter in similar manner.
• After collecting mucous from both the nostrils, the catheter
is flushed with 3 ml of VTM.
Collect 3-5 ml of human blood soon after the onset of clinical
symptoms. Two samples need to be taken from each patient, one
sample during the first week of illness and the second 2-4 weeks
• Collect tissue and heart blood in fatal cases.
• Divide lungs tissue into two, place half portion in 10%
formalin or formal-saline and the remaining half as fresh.
Procedure for specimen collection among poultry birds
In liaison with designated laboratories, full blood and post
mortem specimens (intestinal contents, anal and oro-nasal swabs,
trachea, lung, intestine, spleen, kidney, brain, liver and
heart) may be collected for identification of virus through
similar diagnostic techniques as for humans.
Draft case definition
Person with acute respiratory illness, characterized by fever
(temperature >38 degrees C) and cough and/or sore throat and
contact with a confirmed case of influenza A (H5N1) during the
period OR recent (less than 1 week) visit to a poultry farm in
known to have outbreaks of Pathogenic avian influenza (HPAI) OR
worked in a laboratory that is processing samples from persons
or animals that are suspected for highly HPAI virus infection.
Possible case AND limited laboratory evidence for Influenza A
(H5N1) (such as IFA + using HF5 monoclonal antibodies) OR no
evidence for another cause of disease.
Positive viral culture for avian influenza A (H5N1) virus OR
for influenza (H5) virus OR a 4-fold rise in H5-specific Ab
Exclusion criteria • A case should be excluded if an alternative
diagnosis can fully explain the illness
Incidence and Geographical Distribution • The avian influenza
began with reports in poultry birds in Vietnam since October
2003. Since then poultry birds have been affected in South
Korea, Thailand, Taiwan, Japan, Cambodia and Indonesia
• From the available information and retrospective surveillance,
it is apparent that the human form of the disease may have
started in Vietnam in October 2003, however on January 26, 2004
the Vietnam government reported its first confirmed cases in the
south of the country, with two cases in Ho Chi Minh City. Since
then human cases have been reported from Thailand.
Seasonality Cases among bird populations can occur year round.
However cases and outbreaks in poultry chicken are known to
occur more commonly during winter months.
Human outbreaks have been reported since 1997 (5 outbreaks in
all before the present one). Seasonal patterns may converge with
the bird outbreak seasonality, which is known to be more common
Alert threshold Even a single case must lead to an alert and
4. Risk factors for increased transmission
Population movement • Travel to/from the countries from where
cases of avian influenza have been reported.
Access to health services • Prompt identification of the cases
is paramount to rapidly implement the control measures and for
5. Prevention and Control measures
Care and Management of the Cases
• Among Poultry birds
World Health Organization recommends culling of birds (burn or
burial) with spraying of disinfectants at the site of the
burial; as a measure to stay ahead of the battle to prevent the
spill over of this form of influenza into human populations.
Among Human Population
• Good supportive care including intensive therapy has been
shown to improve the prognosis.
• 2003-04 trivalent influenza vaccine (flu shots) OR
intranasally administered live, attenuated influenza vaccine (LAIV,
a nasal-spray flu vaccine) for chemoprophylaxis is available.
• Two classes of drugs are available. These are the M2
inhibitors (amantadine and rimantadine) and the neuraminidase
inhibitors (oseltamivir and zanimivir). These drugs have been
licensed for the prevention and treatment of human influenza in
some countries, and are thought to be effective regardless of
the causative strain.
Management of suspected human case
• Patients with suspected avian influenza symptoms should be
isolated and cared for using barrier-nursing techniques by
providing surgical mask to the patient.
• Detailed clinical, contact and travel history including
occurrence of acute respiratory diseases in contact persons
during the last 10 days.
• X-ray chest (CXR) and complete blood count:
If CXR is normal,
- discharge the patient with advice to seek medical care if
- improve personal hygiene and
- avoid public areas and transportation, confine at home until
• If CXR demonstrates unilateral or bilateral infiltrates with
or without interstitial infiltrations, see management of
Management of probable case
Hospitalize under isolation or cohorted with other avian
• Lab investigation to exclude known cause of atypical
- Complete blood picture
- Serology from blood samples
- Throat and/or nasopharyngeal swabs and cold agglutinin
- Bronchoalveolar lavage
• Specimens should be collected on alternate day and
investigated in the
laboratories with proper containment facilities (BL3)
• CXR as clinically indicated
• Treat as clinically indicated (symptomatic treatment)
- Broad spectrum antibiotics have not proven effective in
halting bird flu progression to date. Effectiveness of treatment
by M2 inhibitors and neuroaminadase inhibitors is under
Management of contact of suspected and probable cases
• Record name and contact in detail.
• Advice to seek medical assistance in the event of fever or
respiratory symptoms worsen.
- Immediately report to the health authority.
- Do not report to work until advised by the physician.
Minimize contact with family members and friends and avoid
Hospital Infection Control Guidance
• Strict adherence with barrier nursing of avian influenza
• Use precautions for airborne, droplet and contact
• Rapidly divert the patient reporting to health care facility
with flu-like symptoms to a separate area to minimize
transmission to others.
• Suspect case should wear surgical masks until avian influenza
• Isolate the patient and accommodate as follows;
- Negative pressure rooms with door closed
- Single room with their own bathroom facilities
- Cohort placement in an area with an independent air supply and
- Turn off air condition in a facility and open windows for good
- Patient under investigation for avian influenza should be
separated from those diagnosed with the syndrome
• Disposable equipments should be used. If devices are to be
reused, they should be sterilized with broad-spectrum
disinfectants (bactericidal, fungicidal or veridical) of proven
• Restrict movement of patient as much as possible. If
necessary, patient should wear surgical mask to minimize
dispersal of droplets.
• Visitors, staff, students and volunteers should wear N95 masks
on entering the room of the patient
• Hand washing before and after contact with any patient is the
most important hygienic measure in preventing the spread of
• Health Care Workers (HCWs) should wear gloves for all patients
handling and gloves should be changed after any contact with the
items likely to be contaminated with respiratory secretions.
• HCWs must wear protective eyewear or face shields or masks
during procedures where there is potential splashing,
splattering or spraying of blood or other body substances of the
patients suspected, probable or confirmed avian influenza.
• Standard precautions should be applied when handling any
clinical wastes. Gloves and protective clothing should be worn
while handling clinical waste bags and containers. Manual
handling should be avoided and clinical waste should be placed
in leak-resistant biohazard bags or containers labeled and
disposed of safely.
Safety measures for Poultry bird workers, cullers and poultry
Ensure that the cullers use the following protective items:
• N95 respirator masks are preferred. Standard well-fitted
surgical masks should be used if N95 respirators are not
• Protective clothing, preferably coveralls plus an impermeable
apron or surgical gowns with long cuffed sleeves that can be
either disinfected or discarded.
• Heavy duty rubber work gloves that may be disinfected
• Goggles/protective glasses;
• Rubber or polyurethane boots that can be disinfected or
protective foot covers that can be discarded
• Persons at high risk for severe complications of influenza
(e.g. the immuno-compromised, the over 60 years old, or people
with known chronic heart or lung disease) should avoid working
with affected chickens.
• All persons who have been in close contact with the infected
poultry should wash their hands frequently with soap and water.
Cullers and transporters should disinfect their hands after the
Epidemic Investigation Cell (EIC), NIH and Global Infectious
Disease Surveillance and Alert System Pakistan (GIDSAS), John
Hopkins University, USA
Public Health Division
National Institute of Health, Islamabad
Tel: 051- 9255237, 9255117, Fax: 051-9255099, 9255125