2. History
⢠âInfluenzaâ 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: âSpanish Fluâ 1957: âAsian Fluâ 1968: âHong Kong Fluâ
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
â Pennsylvania 1983-84 (17 million birds)
â Mexico 1994-95 (Millions of birds)
â Chile 2002 (2 million birds)
â Canada 2004 (17 million birds)
â Texas 2004-Molecular definition of HPAI only
(5,000 birds)
15. H5N1 Asian âBird Fluâ
⢠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 80â120 nm
⢠Filamentous
⢠surface covered by two types of glycoprotein
projections (10â14 nm in length and 4â6 nm
in diameter):
⢠1) rod-shaped hemagglutinin (HA){H1âŚ..H17}
⢠2)mushroom-shaped neuraminidase
(NA){N1âŚâŚN9}
19. Chemical Composition
Influenza virius are composed of :
⢠0.8â1.0% RNA,
⢠5â8% 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 â70°C or following lyophilization.
32. Field Situation
Influenza viruses are protected by :
⢠organic materialâŚâŚ.such as nasal secretions
or feces
⢠Influenza virus in liquid manure for 105 days in
the winter
⢠in feces for 30â35 days at 4°C and for 7 days
at 20°C
33. Antigenic Variation of StrainsâDrift
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 âurine
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
9â11-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.