- 1. AVIAN INFLUENZA ( BIRD FLU ) Dr. INDRAJEET KUMAR Department
of Community Medicine
2. Emerging & re-emerging disease Emerging diseases are
those infectious disease which have shown increase in frequency in
the last two decades or which threaten to increase in near future.
e.g: AIDS, SARS, bird flu, swine flu etc. Re-emerging diseases are
those infectious disease which were previously easily controlled by
antibiotics and chemotherapeutic agents are now appearing in
epidemic form. e.g; malaria, tuberculosis, typhoid. 3. FACTORS
RESPONSIBLE FOR EMERGENCE AND RE-EMERGENCE OF INFECTIOUS DISEASE
Unplanned and under-planned urbanization. Overcrowding and rapid
urbanization. Poor sanitation. Inadequate public health
infrastructure. Resistance to antibiotics. Increased exposure of
humans to vectors and reservoirs of infection. Rapid and intense
international travel. 4. AVIAN INFLUENZA BIRD FLU Avian influenza
or bird flu is a contagious disease caused by viruses that normally
infect only birds and less commonly pigs. 5. epidemiology Agent.
Host. Environment. Mode of transmission. Incubation Period. 6.
Agent: 1. Agent proper: 2. Reservoir: 3. Infectious material: 4.
Period of infectivity: 7. Agent 1. AGENT PROPER: :- Avian influenza
virus type-A (orthomyxoviridae family) sub-type: H5N1 :- Killed by
heat at 60*c for 30min and by common disinfectants such as 5%
formalin, iodine etc. :- can survive in contaminated manure for
3months in cold climate. 2. RESERVOIR: Wild aquatic birds &
migratory birds. e.g siberian crane, 3. INFECTIOUS MATERIAL: Saliva
and faeces of birds. 4. PERIOD OF INFECTIVITY: 10days. 8. Host
factor All age group is susceptible but it is serious in children
& elderly persons above 65yrs. HIGH RISK GROUP :- workers
handling poultry in farms and markets. :- those involved in culling
activity. :- veterinary and health worker. :- family members of
these workers. 9. Environmental factors Usually in winter &
rainy season Overcrowding favours droplet transmission. INCUBATION
PERIOD: Seasonal influenza: 48 72hrs Avian influenza: 2 7days 10.
Mode of transmission BIRDS TO BIRDS by inhalation of faecal matter
or droplets. by feco-oral transmission. BIRDS TO HUMAN through
inhalation when in contact with live infected poultry. NO EVIDENCE
OF HUMAN TO HUMAN TRANSMISSION 11. Clinical features IN BIRDS
Clinical signs may include:- ruffled feathers, soft shelled eggs,
sudden drop in egg production, diarrhoea, edema , cyanosis &
swelling of head, eyelids etc. respiratory distress & increased
death losses in a flock. IN HUMAN BEINGS:- typical influenza like
symptoms (like fever, cough, sore throat, muscle aches) :-
pneumonia, :- acute respiratory distress . 12. SPREAD WITHIN A
COUNTRY: :- from one poultry to another by contaminated dust and
soil, airborne, contaminated equipment, vehicles, feed, cages or
clothing, especially shoes can carry them from farm to farm. :-
feet and bodies of animals e.g: rodents and flies which act as
mechanical carrier. :- droppings from infected wild birds can
introduce the virus into both commercial and backyards poultry. :-
spread from wet market. SPREAD FROM ONE COUNTRY TO ANOTHER :-
through international trade in live poultry. :-through migratory
birds, including wild waterfowl eg. wild ducks, sea birds and shore
birds. 13. Laboratory diagnosis SAMPLES a. Nasopharyngeal secretion
b. Oro pharyngeal(OP) Swab/ Throat swab c. Paired serum. A.
DETECTION OF ANTIGEN IN NASAL SECRETION 1. Rapid Test 2
.Immuno-fluorescence test 3. ELISA test 4. Polymerase Chain
Reaction (PCR) B. VIRUS ISOLATION C. SEROLOGICAL TEST IN PAIRED
SERUM SAMPLE One in acute phase and other in convalescent phase
collected at 15days interval. A 4 fold rise in Influenza A/H5 N1
specific antibody is diagnostic. DESIGNATED LABORATORIES:- 1. NICD
(National Institute of communicable diseases. 2. Virology section,
Dept. of Microbiology, AIIMS, Delhi 3. NICED (National Inst. Of
Cholera & Enteric dis.), Kolkata 14. COLLECTION &
TRANSPORTATION OF SAMPLES FROM HUMAN CASES OF AVIAN INFLUENZA
Samples should be collected preferably within 72hrs of illness and
sent to laboratory within 24hrs of collection. Teperature 2 8C
Sample is transported using the standard Triple Packaging System
(WHO) 1. Primary receptacle:- properly labeled, unbreakable,
sterile, screw capped with paraffin seal. Preferably a plastic
container. Each primary receptacle wrapped with enough absorbent
material. 2. Secondary receptacle:- a watertight (e.g-sealed
plastic bag) container. An item wise list of contents must be
enclosed between the secondary & tertiary packaging. 3.
Tertiary container:-Best is vaccine carrier with a bio-hazard sign
& address where to send is pasted on it. 15. BIO HAZARD LOGOS
16. CASE DEFINITION 1.SUSPECTED CASE OF INFLUENZA - A (H5N1):-
Features of Acute Respiratory Infection within seven days of a.
Contact with a confirmed case of influenza A (H5N1) during the
infectious period. Or b. Recent ( less than 1 week )visit to a
poultry farm OR other poultry contact in an area known to have
outbreak of influenza A (H5N1) Or c. having worked in a laboratory
that are processing samples from persons or animals that are
suspected to have influenza A ( H5N1) infection. 2. PROBABLE CASE
OF INFLUENZAA (H5N1) A Possible Case / Suspected Case AND Limited
laboratory evidence for influenza A (H5N1) OR No evidence for
another cause of disease. 3. CONFIRMED CASE OF INFLUENZAA (H5N1)
Suspected or Probable Case as given above with confirmed laboratory
evidence. e.g: Positive Viral Culture or PCR or IFA test or 4fold
rise in antibody titre in paired serum for H5N1 CONTACT CASE:- A
contact case of pandemic influenza is a person who had close (i.e
within one meter) contact with an infectious case or who has spent
more than 60 minutes in a confined space (such as aeroplane or an
enclosed room) with an infectious person. 17. MANAGEMENT OF AVIAN
INFLUENZA CASE GENERAL AND SUPPORTIVE TREATMENT:- 1. Hospitalize
and isolate cases. 2. Monitor vital signs. 3.Maintain airway,
breathing and circulation (ABC) 4.Maintain hydration, electrolyte
balance & nutrition. 5. Provide oxygen therapy when needed. 6.
Manage fever symptomatically with Paracetamol. SPECIFIC TREATMENT:-
1. Antiviral drugs:- Oseltamivir (Tamiflu):- adults>40kg. 75mg X
bid for 5 days Do not use aspirin, and corticosteroids
CHEMOPROPHYLAXIS:- Oseltamivir is the drug of choise Close
contacts:- 75mg once daily for at least 7days. Protection lasts for
only during the period of chemoprophylaxis Only c.i is known
hypersensitivity to the drug. 18. Prevention & control strategy
SOURCE LEVEL: 1. Systemic surveillance of avian influenza in
poultry & pigs. 2. Culling or Stamping out (rapid destruction)
of all infected or exposed birds. 3. Proper disposal of carcases
(dead birds) and faecal matters. ( by incineration or buried deep
2ft using lime & soil in 1:3 ratio) TRANSMISSION LEVEL: 1.
Bio-security practices: > absolute ban on movement of poultry
& its products. > closure of poultry or egg market in 10km
radius. 2. Quarantining the infected farm upto 3km radius. 19.
Prevention at host level Stringent sanitary measure (of self &
surrounding). Avoid contact with live animals in poultry &
market. Use of N95 mask or triple layered surgical mask.
Vaccination: 20. PERSONAL PROTECTION EQUIPMENT
