Source: World Health Organization
(WHO)
Updated during December 2009
Appearing in April 2009, the novel strain of H1N1 (previously
called Swine Influenza) virus falls in the group of Influenza
A viruses. Thought to be reassorted in Swine, the virus
causes acute respiratory illness along with high-grade fever,
dry cough, headache, muscle and joint pains, sore throat,
runny nose and sometimes vomiting and diarrhoea. The infected
person can spread the virus to its close contacts from one
day prior to the appearance of symptoms to 7 days after
their disappearance.
Human-to-human
transmission is rapidly occurring and disease has already
affected more than 207 countries, territories and areas.
Although, the illness in the affected patients has mostly
been mild with mortality rate (1.3 %) comparable to seasonal
influenza yet the threat of its further genetic modification
to acquire more virulence cannot be ruled out. Due to its
rapid spread across the globe, WHO has declared global alert
level 6 meaning full-fledged pandemic.
Disease is
notifiable under IHR 2005 and any suspected patient along
with throat swab sample must be immediately reported to
NIH, Islamabad.
Infectious Agent:
Influenza-A (H1N1)
Incubation period:
The disease has an incubation period of 1-7 days.
Mode of transmission:
Disease can spread through droplets generated by coughing or sneezing of infected person or touching objects contaminated with patient's secretions.
Case Definitions:
Probable case of new influenza A (H1N1) virus infection
is defined as an individual with an influenza test that
is positive for influenza A, but is unsubtypable by reagents
used to detect seasonal influenza virus infection.
OR
An individual
with a clinically compatible illness or who died of an unexplained
acute respiratory illness who is considered to be epidemiologically
linked to a probable or confirmed case.
Confirmed
Case:
A confirmed case of new influenza A (H1N1) virus infection is defined as an individual with laboratory confirmed new influenza A (H1N1) virus infection by one or more of the following tests: -
 |
Real-Time
RT-PCR.
|
| |
Viral Culture.
|
| |
Four-Fold
rise in new influenza A (H1N1) virus specific neutralizing
antibodies.
|
Management:
|
|
The
goal of treatment is to alleviate the symptoms.
|
|
|
Antibiotics are not effective against viruses. |
|
|
Bed rest is advisable until the fever is subsided. |
|
|
A mild analgesic such as paracetamol 0.5 - 1 g every 4-6 hours usually relieves the headache and generalized pains and warm fluids help to relieve the discomfort of the symptoms. |
|
|
Pholcodine 5-10 mg 3-4 times daily may be used to suppress unproductive cough. |
|
|
Specific treatment of complications such as bronchitis and pneumonia may be necessary. |
|
|
Virus has been found sensitive to oselatmivir and zanamivir but resistant to amantadine and remantadine. WHO recommends that the treatment with antiviral drug oseltamivir should be administered as soon as possible after symptom onset as the benefits are greatest when administered within 48 hours. Oseltamivir (Tamiflu) 75 mg b d for 5 days preferably with in 48 hours of the beginning of infection for better response. |
Vaccination:
No vaccine is available as yet for H1N1 Novel virus strain
in Pakistan. The specific vaccine may be available soon.
Sample Collection & Transportation::
| |
Collect throat and nasal swabs and nasopharyngeal aspirates from patient and tracheal aspirate or broncho-alveolar lavage fluid from intubated patients place immediately in Viral Transport Medium (VTM).
|
| |
Collect 5 ml blood or serum for serology (acute and convalescent if possible).
|
| |
Transport specimens' bottles and tubes in upright position, secured in a screw cap container or in a rack in a transport box having enough absorbent paper around them to soak up all the liquid in case of spillage.
|
| |
Sample for virus isolation collected in VTM can be taken to lab within 4 days, kept at +4oC and frozen at -70oC if stored.
|
| |
In the absence of freezers or VTM, ethanol preserved swabs are a possible alternative. Storage of such specimens at 4oC (in a standard refrigerator) is better than at room temperature.
|
| |
Blood/serum samples should be frozen at -70oC for PCR and at -20oC or lower for antibody determination but can also be stored at +4oC for about one week.
|
| |
Specimens for influenza virus isolation should not be stored or transported in dry ice unless they are sealed, taped and double plastic-bagged as CO2 (dry ice) can rapidly inactivate the virus if it gains access to the specimens.
|
Prevention & Control Measures:
| |
Wash your hands thoroughly with soap and water.
|
| |
Avoid touching mouth and nose, close contact with ill people and crowded settings
|
| |
Improve ventilation in living places
|
| |
Practice good health habits including good sleep, nutritious food with plenty of fluids and physically active.
|
| |
Encourage sufferer to cover their faces with a mask or handkerchief when coughing and sneezing.
|
| |
Annual winter vaccination (Seasonal anti influenza vaccine) is recommended for patients suffering from chronic pulmonary, cardiac or renal disease.
|
| |
Infected patients should not travel.
|
| |
Younger and older people and pregnant women are at greater risk.
|
| |
Isolation of suspected patients
|
| |
Stockpiling of required medicine and logistics.
|
| |
Activation of district and provincial Influenza Committees / Task Forces.
|
Compiled
by: Epidemic Investigation Cell (EIC), Public
Health Laboratories Division (PHLD)
National
Institute of Health (NIH), Islamabad
Tel:
051-9255237, Fax: 051-9255575
|