Transcript HPAI: Clinical Signs

AVIAN INFLUENZA (AI)
BIRD FLU
Czech University of Life Sciences
Česká Zemědlská Univerzita v Praze
Institute of Tropics and Subtropics
MVDr.Joseh Holejšovský PhD
(former General Director of SVA and
Chief Veterinary Officer of the C R
Viral Classification
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Family: Orthomyxoviridae
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Genus: Influenza
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Virions (virus particles) are 80
to
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120 nm in diameter
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May be filamentous
 Influenza A virus causes
human, swine, equine, avian,
and marine mammal influenza
and is the type associated with
pandemic disease in humans.
THEORETICAL KNOWLEDGE
1. VIROLOGY
2. EPIZOOTHOLOGY
3. CLINICAL SIGNS
4. GROSS LESIONS
For influenza A viruses, there are 16 different HA antigens
(H1 to H16) and 9 different NA antigens (N1 to N9).
Only subtypes H5 and H7 of influenza A virus recently defined as highly
pathogenic AI (HPAI) that have caused AI in poultry.
The virus envelope has
spike like projections of
glyco-proteins, which have
hemagglutinin (HA) and
neuraminidase (NA) activity;
these characteristics are
used to subtype the A, B,
and C viruses.
Subtype A is most important
virus causing serious
outbreaks.
Avian Influenza (AI) can be divided into
Highly Pathogenic Avian Influenza (HPAI) and
Low Pathogenic Avian Influenza (LPAI).
Highly pathogenic H5 and H7 virus causes HPAI.
• HPAI is one of the List A animal diseases both for World
Organisation for Animal Health (OIE) but not LPAI.
● HPAI causes very high mortality in chicken, but not LPAI.
● Waterfowl plays very important role of reservoir.
• Persisting LPAI virus in chicken population might change
its pathogenicity and become HPAI virus.
• No evidence showing that LPAI H5N2 virus can infect
humans.
Low Pathogen AI
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Mild or no clinical signs in poultry
Decreased egg production
Mild respiratory signs: cough, sneeze
Feces, ocular, oral and nasal secretions
Bird-to-bird or contaminated equipment
Diagnosis:
– Virus isolation
– Serology
Source: AVIAN INFLUENZA / “BIRD FLU”,
Avian Influenza
• Numerous subtypes
• HxNx: 16 Hs and 9 Ns
– Theoretically 144 combinations
– Antigens on the virus surface
• Few have human health impact
– H5N1, H7N2, H7N3, H7N7, H9N2
– Most no more than conjunctivitis
Distribution of subtypes
HA a NA by species
• HA Human H1,H2, H3, (H5, H7, H9)
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Pig H1, H3
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Horse H3, H7, tuleň H4
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Birds 1-16
• NA Human N1, N2, N8
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pig N1, N2
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Horse N7, N8, tuleň N7
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Birds N1-9
Migrační cesty
Water fowls and migratory birds
are the most potential agents to transmit the virus.
These birds do not get infected but they are healthy carriers and shed
virus through their feces (droppings)
and other body secretions.
Influenza: Seasonal, HPAI, Pandemic
Seasonal Influenza
Highly
Pathogenic
Pandemic Influenza
Avian Influenza
Exposure
from persons
infected
infected birds
with the usual
circulating
from persons
infected
with a new virus
subtype
subtype, strains
may vary
Clinical
fever, respiratory
signs
Manifestatio
ns
and symptoms that shortness of
may
breath
or may not
progress
sustained fever
>380C
dry, nonproductive
fever, respiratory
signs,
severity to be
determined
Influenza: Seasonal, HPAI, Pandemic
Seasonal Influenza
Highly Pathogenic
Pandemic Influenza
Avian Influenza
Etiology
Influenza A (H3N2,
H1N1)
Influenza B
Pathogenic to
humans:
H5N1, H7N7
A new subtype
mutated H5N1
capable of
human- to -human
transmission
Incubation
Period
2 to 3 days
3 days
(range 1 to 7 days)
(range 2 to 4 days)
?
Influenza: Seasonal, HPAI, Pandemic
Seasonal Influenza
Highly Pathogenic
Pandemic Influenza
Avian Influenza
Who are at risk
young children,
persons
of complications
>50 y/o, persons with
1918 pandemic- young,
co-morbidities e.g DM,
otherwise healthy,
heart, lung, kidney
working population
disease,
were affected
children and adults
uncertain,
immunocompromised
Vaccine
yearly vaccine strains
none
none
Treatment
supportive, antiviral
supportive, antiviral
antiviral agent, if the
agent within the
agent within the 1st
new subtype is not
1st 2 days
2 days, but shows
resistant
Human Public Health
Implications
• High mortality of H5N1 to humans
• Emergence of a new influenza virus with
pandemic potential
-Efficient human to human transmission
-Vast majority of people have no
immunity
-No protective vaccine/ Inadequate
quantity of developed vaccines for the
world
-High number of cases and deaths
worldwide (pandemic)
Transmission to humans
• Close contact with infected birds and
through aerosols, discharges and
surfaces
• Virus is excreted in feces, which
dries, pulverized and inhaled
• Flapping of wings hasten
transmission
Stages of Avian and Pandemic
Preparedness
Stage 1: Avian influenza-free country
Stage 2: Avian influenza in domestic fowl
Stage 3: Avian influenza from poultry to
humans
Stage 4 - Human-to-human transmission
(pandemic influenza) in the country
Stage 1: Keeping Country Bird
Flu Free
Prevention of entry of the virus:
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Ban of all poultry and poultry products from AIinfected countries
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Border control
Ban on sale, keeping in captivity of wild birds
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Biosecurity measures
Standardized footbath
Confiscation and destruction of unlicensed cargo
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Surveillance of Poultry in Critical Areas
Influenza vaccination for all poultry workers,
handlers
STAGE 2: Avian Influenza in
Domestic Fowl
Individuals at risk
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Poultry handlers/workers
Sellers/ people in live chicken sale
Aviary workers/ Ornithologists
Cullers
People living near poultry farms
Any individual in close contact with
infected birds
STAGE 2: Avian Influenza in
Domestic Fowl
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Prevention of spread from birds-to birds:
early recognition and reporting, mass culling,
quarantine of affected area
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Prevention of spread from birds to humans:
human protection through proper handling of
infected birds, use of protective gear by
residents, poultry handlers, and response
teams
STAGE 2: Avian Influenza in
Domestic Fowl
Response to sick or dead birds
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Protection of exposed residents – gloves/ plastic
material in handling sick or dead birds, hand washing
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Personal protective equipment for cullers – caps,
masks, goggles, gowns
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Identification of exposed individuals and quarantine
for 7 days
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Reporting to the Health Emergency Response Team/
local health officer
STAGE 3- Avian Influenza in
Humans
Community response
• Patient: face mask, in a separate area or at
least 1 meter distance from other people
• Monitoring of contacts of the case
• Protection of caregiver : face mask and
goggles or eye glasses, hand washing, selfmonitoring for signs and symptoms
• Immediate transfer to the Referral Hospital
• Protection of the transporting team and
disinfection of vehicle
Strategic Approaches
Use of antiviral agents
• Infection control
• Quarantine of contacts
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Import ban
Border control
Wildlife Act
Early
recognition/
reporting
• Mass culling,
• Quarantine of
affected area
• Management of
public panic
• Early recognition/
reporting
• Proper handling
of birds
• Protective gear
• Management of
public panic
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Passenger entry-exit
management
Border control
Quarantine of
contacts
Isolation
Management of cases
Social distancing
Personal hygiene
Management of
public panic
HOGS
This is an example of a duck farm outside of North America. Notice that the ducks are
being raised outside. This means that they are free to comingle with migratory birds.
HOG
This poses a huge biosecurity risk. Also, The barn in the picture
is fullMANURE
of hogs. The
manure from the hogs is running out to where the ducks are living. This poses a risk as
the hogs, biologically, serve as a mixing vessel for disease organisms, which makes
genetic mutation much easier, ultimately contributing to the risk of a human pandemic.
Keep Your Distance
• Restrict access to your birds
– Gates, fences, locks
• No unnecessary visitors on your farm
• Keep your birds separated from wild game
birds or migratory waterfowl
HPAI: Clinical Signs
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Incubation Period
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Clinical signs
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Sudden death without signs
Lack of energy, appetite
Severe depression with ruffled feathersLoss of appetite ( reduced feed
consumption)
Severe drop in egg production
Edema of head and neck
Swollen and cyanotic combs and wattles
Discolored purple wattles, comb, legs
Petechial hemorrhages on internal membrane surfaces
Watery diarrhea that begins as bright green and progresses to white
Diffuse hemorrhage between hocks and feet
Nasal and ocular discharge
Coughing/sneezing
In-coordination and nervous signs
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3-7 days
Know the Warning Signs
of Infectious Bird Diseases
• Sudden increase in bird
deaths in your flock.
• Sneezing, gasping for air,
coughing, and. nasal discharge
• Watery and green diarrhea.
• Lack of energy and poor appetite.
Know the Warning Signs
of Infectious Bird Diseases
• Drop in egg production
or soft- or thin-shelled,
misshapen eggs.
• Swelling around the eyes, neck,
and head.
• Purple discoloration of the wattles,
combs, and legs (AI).
Know the Warning Signs
of Infectious Bird Diseases
• Tremors, drooping wings,
circling, twisting of the
head and neck, or lack of
movement (END).
Early detection is important to
prevent the spread of disease.
Respiratory Diseases
and HPAI
There are many causes
and is very common
Signs:
• Coughing
• Sneezing
• Discharge from the
eyes and nostrils
High Path AI
• Sudden death without clinical signs
Source: AVIAN INFLUENZA / “BIRD FLU”,
Depression and gasping were found in the six-week-old native chickens.
High Path AI
• Decreased activity and decreased feed
consumption
F.A.O.- Italy
Source: AVIAN INFLUENZA / “BIRD FLU”,
High Path AI
• Nasal discharge, coughing, sneezing
• Lack of coordination
• Diarrhea
F.A.O.- Italy
Source: AVIAN INFLUENZA / “BIRD FLU”,
Report Sick Birds
High Path AI
• Decreased egg production
• Soft-shelled or misshapen eggs
Source: AVIAN INFLUENZA / “BIRD FLU”,
High Path AI
• Swelling of head, eyelids, comb,
wattles and hocks
Source: AVIAN INFLUENZA / “BIRD FLU”,
Gross Lesions HPAI
• Vesicles and ulcers
on comb
• Facial edema
Source: AVIAN INFLUENZA / “BIRD FLU”,
Gross Lesions HPAI
• Hemorrhage throughout
internal body organs and
fat
Source: AVIAN INFLUENZA / “BIRD FLU”,
OIE, FAO
Gross Lesions HPAI
• Hemorrhage throughout
internal body organs
and fat
Source: AVIAN INFLUENZA / “BIRD FLU”,
Avian Influenza
• Highly transmissible viral disease
• Infects a wide variety of wild and
domestic birds
• Worldwide distribution
• 16 hemagglutinin and 9 neuraminidase
subtypes
• Clinical signs and lesions variable
Economic Impact of AI
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Mortality
Depopulation and disposal
Lost production
Cleaning and disinfection
Interstate movement restrictions
Trade restrictions