2. History
• “Influenza” epidemics of acute, rapidly spreading
catarrhal fevers of humans. highly lethal, systemic
disease
• Befor 1870s to 1981, Influenza virus was known
by various names including
• fowl plague (most common),
• fowl pest,
• peste aviaire,
• Geflugelpest,
• typhus exudatious gallinarium,
3. • fowl disease
• fowl or bird grippe
Caustive agent :
• family Orthomyxoviridae,
• genus Influenzavirus
• negative-sense RNA
4.
5. Economic Significance
Economic losses depending upon :
• strain of virus
• species of bird infected
• number of farms involved
• control methods used
• eradication strategies
6. • 1990s H9N2 subtype in commercial poultry
• 2003, H5N1 HPAI become endemic in village
poultry (ducks)
7. History In twentieth century I.V was
reported
• Switzerland
• Russia
• Great Britain
• Egypt,
• China,
• Japan,
• Brazil
• Argentina
8. In mid-twentieth century, I.V
diagnosed
• Europe
• Russia
• North Africa
• Middle
• East Asia
• South America
• North America
9. Eradication of I.V in United States.
• Quarantine
• depopulation
• cleaning
• disinfection
10. Circulating Influenza Strains and
Pandemics in The 20th Century
1920 1940 1960 1980 2000
H1N1
H2N2
H3N2
1918: “Spanish Flu” 1957: “Asian Flu” 1968: “Hong Kong Flu”
20-40 million deaths 1-4 million deaths 1-4 million deaths
11.
12.
13.
14. History of HPAI in the
Americas in the last 30 years
• HPAI is considered a foreign animal disease
in the Americas
• Five HPAI outbreaks have occurred in the
Americas in the 1990s
– Pennsylvania 1983-84 (17 million birds)
– Mexico 1994-95 (Millions of birds)
– Chile 2002 (2 million birds)
– Canada 2004 (17 million birds)
– Texas 2004-Molecular definition of HPAI only
(5,000 birds)
15. H5N1 Asian “Bird Flu”
• The HPAI H5N1 Asian lineage was first detected in
China in 1996 with the Goose/Guangdong/1/96 isolate
• This isolate had a unique multi-basic aa cleavage site
and was highly pathogenic for chickens
• 1997 Hong Kong poultry and human H5N1 viruses had
same H5 gene but different internal genes
• 1999 Hong Kong goose viruses were most similar to
Guangdong/96 virus
• 2001 Korean quarantine station isolate (from China) 4
genes like Guangdong/96 including HA and four unique
genes
• 2001 Hong Kong H5N1 viruses with 5 distinct
combinations of genes observed (same HA)
16.
17. Incubation Period
• Incubation period :is the time period lapses
b/w infection and appearance of its clinical
signs
• Short incubation period (18-72 hour)
• H5N1 HPAI virus from Mongolia producted
clinical signs within 24 hrs.
18. Morphology
• diameter from 80–120 nm
• Filamentous
• surface covered by two types of glycoprotein
projections (10–14 nm in length and 4–6 nm
in diameter):
• 1) rod-shaped hemagglutinin (HA){H1…..H17}
• 2)mushroom-shaped neuraminidase
(NA){N1……N9}
19. Chemical Composition
Influenza virius are composed of :
• 0.8–1.0% RNA,
• 5–8% carbohydrate
• 20% lipid (phospholipids, but small amounts
of cholesterol and glycolipid).
• 70% protein
20. Susceptibility to Chemical and
Physical Agents
• Physical Agents : can inactivate Influenza
viruses.
• Heat
• extremes of pH
• hypertonic conditions
• dryness
21. Organic Solvents &Disinfectants
• Chemical Agents : influenza virus have lipid
envelopes, it is inactivated by organic solvents
and detergents
• aldehydes
• beta-propiolactone,
• binary ethylenimine.
• sodium desoxycholate
• sodium dodecylsulfate
27. Incidence and Distribution
Most frequent reports of Influenza viruses has
been
• free-flying bird
• aquatic birds (ducks andgeese)
which are considered the biological and genetic
reservoirs of all I.V.
28. Five distinct man-made ecosystems have been
identified that have impacted AI virus ecology
• 1) integrated indoor commercial poultry
• 2) range-raised commercial Poultry
• 3) live poultry markets
• 4) village, backyard and hobby flocks
• 5) bird collection and trading systems
30. Methods of Control
• infected flocks destroy them to prevent spread
to other flocks
• Vaccination
• Biosecurity
31. Laboratory Situation
• The Influenza viruses are relatively stable in
protein-containing solutions,but long-term
storage at –70°C or following lyophilization.
32. Field Situation
Influenza viruses are protected by :
• organic material…….such as nasal secretions
or feces
• Influenza virus in liquid manure for 105 days in
the winter
• in feces for 30–35 days at 4°C and for 7 days
at 20°C
33. Antigenic Variation of Strains—Drift
and Shift
• More antigenic variation in HA and NA due to
glycoproteins in nature
• Drift : Minor change HA and NA gene
• Shift : major change HA and NA gene
34. A H1N1 :new virus
• The 2009 H1N1 virus is a hybrid of swine,
avian and human strains
Influenza A (H1N1)
40. Pathotype
• pathogenicity : the ability to produce disease
Influenza virus classified into two pathotypes:
• low pathogenic Influenza(LPI)
• Highly pathogenic Influenza(HPI)
41. Low Pathogenicity Avian Influenza
Viruses
• Respiratory (coughing, sneezing, rales, rattles,
and excessive lacrimation)
• digestive, urinary, and reproductive
• organs.
• egg production
• some cases green diarrhea or “urine
42. High Pathogenicity Avian Influenza
Viruses
• neurological signs,
• depression,
• anorexia
• tremors of head and neck, inability to stand,
torticollis,
• opisthotonus
• cessation of egg production within six days
43. Infectious Process
• initial replication in respiratory epithelium
• virions invade in the submucosa
• entering capillaries
• replicates within endothelial cells
• Spreads via the vascular or lymphatic systems
• replicate in visceral organs, brain, and skin
44. Laboratory Host Systems
• Isolation and propagation Influenza viruses in
9–11-days-old embryonating chicken eggs
• Most inactivated vaccines produced by
cultivation in embryonating eggs.
45. Mechanism for LPI to HPI
• substitutions of non-basic with basic amino
acids
• insertions of multiple basic amino acid in
hemagglutinin cleavage site
• Insertion of basic and non-basic amino acids
from unknown source
• Non homologous recombination with inserts
that lengthen the proteolytic cleavage site but
which may or may not contain additional basic
amino acids
46. Diagnosis
A definitive diagnosis of AI :
• 1)Tissues
• swabs
• cell cultures
• embryonating egg
• 2)presumptive diagnosis by detecting
antibodies to AI virus.
47. Serology
Serologic tests are used to demonstrate the
presence of AI specific antibodies
• agar gel immunodiffusion or AGID
• ELISA
• HI
• HA
48. Vaccination
• Killed vaccine (inactivate virus & add adjuvent
• reverse genetic generate
• vaccine is given by subcutaneous or wing web
• 1 day post-hatchd AI vaccine
49. To Vaccinate or Not To Vaccinate
• Vaccines will prevent clinical disease, but not
infection
• Good vaccines, properly administered, can reduce
virus shedding from infected birds and reduce
chance of virus spread
• Vaccines will adversely affect export markets
• Costs of vaccination are not insignificant
• Bad vaccines may contribute to virus spread
50. Vaccination
• Proper vaccination programs must also
include good surveillance, education,
quarantines and animal movement controls
• Vaccination can be used to reduce the
susceptible population, and when used
with stamping out may be an effective tool
• Vaccination without the proper controls
may reduce disease, but will not eliminate
it
51. Treatment
• Not specific treatment
• Amantadine : reducing mortality(inhibit
coating of virus)
• antibiotic treatment
• Vit.C
• NSID(Disprine , pain killer )
• The use of human antiinfluenza drugs is
strongly discouraged.
