Download Confirmed H5N1 case

‫انفلوانزای فوق حاد مرغی‬
‫اداره کل دامپزشکی استان اصفهان‬
‫‪INFLUENZA‬‬
‫& ‪CLINICAL FINDINGS‬‬
‫‪CASE DETECTION‬‬
‫مركز بهداشت استان اصفهان‬
‫گروه مبارزه با بيماريها‬
Definition of flu
• Definition might be different according to Flu alert status
• Classic definition:
1)Fever
2)Cough or sore throat
3) One of the following items:
• malaise( ill appearance?)
• Neck pain (calf tenderness?) (muscle pain)
• Shivering
• Mucosal irritation
• Hx of contact to suspicious flu case
• Definition during pandemic:
Illness with both of the following:
1)T>38 c
2)cough,sore throat,or dyspnea
Transmission
• Human influenza is transmitted by
inhalation of infectious droplets and
droplet nuclei, by direct contact, and
perhaps, by indirect (fomite) contact, with
self-inoculation onto the upper respiratory
tract or conjunctival mucosa
• Evidence is consistent with bird-to-human,
possibly environment-to-human, and
limited, nonsustained human-to-human
• No significant risk related to eating or
preparing poultry products or exposure to
persons with influenza A (H5N1) disease
• Exposure to ill poultry and butchering of
birds were associated with seropositivity
for influenza A (H5N1).
• Most patients have had a history of direct
contact with poultry, although not those
who were involved in mass culling of
poultry
Potential Modes:
• Oral ingestion of contaminated water
during swimming and direct intranasal or
conjunctival inoculation during exposure to
water
• Contamination of hands from infected
fomites and subsequent self-inoculation
How do humans get “bird flu” ?



Through close contact with infected birds
e.g. breathing in particles from their
droppings
Rare for bird flu to infect humans
Limited evidence of human-tohuman transmission to date
according to WHO
‫نحوه انتقال ويروس آنفلوآنزای طيور به انسان‬
‫‪ ‬تماس مستقيم و نزديک انسان با پرنده آلوده‬
‫‪ ‬انتقال ويروس آنفلوآنزا از طريق خوردن گوشت‬
‫پرنده آلوده بصورت پخته ميسر نمی باشد ولی‬
‫توصيه ميگردد از خوردن گوشت و تخم مرغ آلوده‬
‫بصورت نيم پز اجتناب گردد‪.‬‬
‫پاندميهای جهانی آنفلوآنزا در قرن بيستم‬
Credit: US National Museum of Health and
Medicine
1918:
1957:
1968:
“Spanish Flu”
“Asian Flu”
“Hong Kong Flu”
20 - 40 million deaths
A(H1N1)
1 - 4 million deaths
1 - 4 million deaths
Clinical findings .1
Classic signs
&symptoms :
• Sudden onset
• Incubation:1-2 days
• Dominancy of
systemic s&s at the
onset: fever,
headache,chilly sens.
,shaking chills
,myalgia,
anorexia,perspiration
• Eye s&s
• URI s&s
Clinical findings .2
Uncomplicated course:
• Persistence of
systemic s&S FOR 3
DAYS
• Cough become more
prominent & can
continue for a few
days after stopping
the fever
• A few wks
convalescence
Differences of findings in pediatric
age group
More common features in pediatric patients:
• More sudden onset
• Anorexia
• Abd. Pain & GI s&s
• Very high fever
• Cervical LNP
• Specially in younger kids: non obvious
respiratory s&s
• Newborn period: like sepsis
• Febrile convulsion
COMPARISON OF FINDINGS IN ADULTS VS CHILDREN(%)
SYMPTOMS
CHLDREN
ADULTS
Sudden onset
66
46
Myalgia
33
62
Nasal discharge
67
82
Sneezing
38
67
Abd pain
31
0
Vomiting
26
7
Cervical LNP
38
8
Animals and Highly
Pathogenic Avian
Influenza
Clinical Signs
•
•
•
•
•
•
•
Incubation period: 3-14 days
Birds found dead
Drop in egg production
Neurological signs
Depression, anorexia,
ruffled feathers
Combs swollen, cyanotic
Conjunctivitis and respiratory signs
Post Mortem Lesions
•
•
•
•
Lesions may be absent with
sudden death
Severe congestion of
the musculature
Dehydration
Subcutaneous
edema of head
and neck area
Post Mortem Lesions
•
•
•
•
Nasal and oral cavity discharge
Petechiae on serosal surfaces
Kidneys severely congested
Severe congestion of
the conjunctivae
‫عالئم بيماري‬
‫‪‬‬
‫‪‬‬
‫‪‬‬
‫‪‬‬
‫‪‬‬
‫‪‬‬
‫‪‬‬
‫‪‬‬
‫‪‬‬
‫‪‬‬
‫شروع ناگهاني بيماري‬
‫تلفات بدون نشاني (حالت برق گرفتگي)‬
‫افزايش فزاينده تلفات حتي تا ‪%100‬‬
‫عالئم تنفسي حاد‬
‫گسترش سريع بيماري در گله‬
‫سيانوره شدن تاج و ريش و ساق پا‬
‫ترشحات چشمي و بيني‬
‫كاهش اشتها‬
‫عالئم عصبي‬
‫اسهال‬
‫تورم تاج و ريش‬
‫خونريزيهای زير جلدی‬
‫خونريزی نای‬
Differential Diagnosis
•
•
•
•
•
•
•
Virulent Newcastle disease
Avian pneumovirus
Infectious laryngotracheitis
Infectious bronchitis
Chlamydia
Mycoplasma
Acute bacterial diseases
− Fowl
cholera, E. coli infection
Diagnosis
•
•
Clinically indistinguishable from
virulent Newcastle Disease
Suspect with:
− Sudden
death
− Drop in egg production
− Facial edema, cyanotic combs
and wattles
− Petechial hemorrhages
•
Virology and serology necessary for
definitive diagnoses
Diagnosis
•
Laboratory Tests
− HP
AI is usually diagnosed by
virus isolation
•
Presence of virus confirmed by
− AGID
− ELISA
− RT-PCR
•
Serology may be helpful
Avian Influenza
in Humans
Avian Flu
1)Fever
&
2)at least one of the following items:
 Sore throat
 Headache
 Conjunctivitis
 Dyspnea
&
3)At least one of the following epidemiologic clues:
 Hx of contact to dead bird during preceding 10 days
 Hx of contact to confirmed human case of avian flu, during
preceding 10 days
 Hx of contact to suspicious environmental area during
preceding 10 days
 Hx of occupational contact in the lab during preceding 10 days
 Positive inf A virus detection without knowing it’s subtype














Initial symptoms
High fever >38.c
Headache
Myalgia
Watery diarrhea
Abdominal pain
Vomiting
Cough
Sputum
Sore throat
Bleeding nose and gums
Rhinorrhea
Shortness of breath
Conjunctivitis(Rarely)
Clinical Stages of AI in humans
Recovery
in 30%
of cases
Exposure
Incubation
Period
Prodromal Stage Lower Respiratory
3 days,
range 2-4
days
0-1 days
1-7 days
high fever (above
38 °C), cough and
shortness of
Breath
early dyspnea
crackles
rapid progress to
respiratory
distress respiratory failure
Stage
Most
cases have
died in spite
of ventilatory
support after
about 10
days
Avian flu characteristics.1

Lower respiratory tract manifestations





dyspnea
Respiratory distress ,tachypnea, and
inspiratory crackles are common.
Radiographic changes include diffuse, multifocal ,or
patchy infiltrates; interstitial infiltrates; and segmental or
lobular consolidation with air bronchograms.
Radiographic abnormalities were present a median of 7
days after the onset of fever in one study
Pleural effusions are uncommon.
primary viral pneumonia ,usually without bacterial super
infection
Avian flu characteristics:2




Progression to respiratory failure
Manifestations of the acute respiratory
distress syndrome (ARDS)
Multiorgan failure with signs of renal
dysfunction
Ventilator-associated pneumonia,
pulmonary hemorrhage, pneumothorax,
pancytopenia, Reye's syndrome, and
sepsis syndrome without documented
Mortality in avian flu





The fatality rate among hospitalized
patients has been high
The overall rate is probably much lower in
patients older than 13 years of age
The case fatality rate was 89 percent
among those younger than 15 years of
age in Thailand.
Death has occurred an average of 9 or 10
days after the onset of illness.
Most patients have died of progressive
Laboratory findings
1.
leukopenia particulary lymphopenia
2.
mild –to-moderate thrombocytopenia
3.
mild-to-moderate elevated
Aminotransferase levels
Some laboratory Findings in avian
flu



Marked hyperglycemia
Elevated creatinine levels
Death was associated with decreased
leukocyte, platelet ,and particularly,
lymphocyte counts at the time of
admission .
Radiographic changes :

Diffuse ,multifocal , or patchy
infiltrates interstitial infiltrates and
segmental or lobular consolidation
with air bronchograms

Pleural effusions are uncommon
Radiological Findings
Virologic diagnosis
1.
Viral
isolation(pharyngeal>nasal)
2.
RT – PCR
3.
Rapid antigen test
When do you suspect to flu in a
case?
Very important key findings:
 Characteristics of fever
 Toxic appearance at presentation+/ Body pain+/
Avian flu has many clinical similarities but
the key point is the epidemiologic
evidences
CASE DEFINITIONS

Person under investigation
A person whom public health authorities have decided to investigate for possible H5N1 infection.

Suspected H5N1 case
A person presenting with unexplained acute lower respiratory illness with fever (>38 ºC ) and cough,
shortness of breath or difficulty breathing.
AND
One or more of the following exposures in the 7 days prior to symptom onset:
a. Close contact (within 1 meter) with a person (e.g. caring for, speaking with, or
touching) who is a suspected, probable, or confirmed H5N1 case;
b. Exposure (e.g. handling, slaughtering, defeathering, butchering, preparation for
consumption) to poultry or wild birds or their remains or to environments contaminated by
their faeces in an area where H5N1 infections in animals or humans have been suspected
or confirmed in the last month;
c. Consumption of raw or undercooked poultry products in an area where H5N1 infections
in animals or humans have been suspected or confirmed in the last month;
d. Close contact with a confirmed H5N1 infected animal other than poultry or wild birds
(e.g. cat or pig);
e. Handling samples (animal or human) suspected of containing H5N1 virus in a laboratory
or other setting.
CASE DEFINITIONS


Probable H5N1 case (notify WHO)
Probable definition 1 :
A person meeting the criteria for a suspected case
AND
One of the following additional criteria:
a. infiltrates or evidence of an acute pneumonia on chest
radiograph plus evidence of respiratory failure (hypoxemia, severe
tachypnea)
OR

b. positive laboratory confirmation of an influenza A infection but
insufficient laboratory evidence for H5N1 infection.
Probable definition 2 :
A person dying of an unexplained acute respiratory illness who is
considered to be epidemiologically linked by time, place, and
exposure to a probable or confirmed H5N1 case.
CASE DEFINITIONS

Confirmed H5N1 case (notify WHO)
A person meeting the criteria for a suspected or probable case
AND
One of the following positive results conducted in a national, regional or
international influenza laboratory whose H5N1 test results are accepted by
WHO as confirmatory:
a. Isolation of an H5N1 virus;
b. Positive H5 PCR results from tests using two different PCR targets, e.g.
primers specific for influenza A and H5 HA;
c. A fourfold or greater rise in neutralization antibody titer for H5N1 based
on testing of an acute serum specimen (collected 7 days or less after
symptom onset) and a convalescent serum specimen. The convalescent
neutralizing antibody titer must also be 1:80 or higher;
d. A microneutralization antibody titer for H5N1 of 1:80 or greater in a
single serum specimen collected at day 14 or later after symptom onset and
a positive result using a different serological assay, for example, a horse red
blood cell haemagglutination inhibition titer of 1:160 or greater or an H5specific western blot positive result.
‫انفلوانزای فوق حاد مرغی‬
‫اداره کل دامپزشکی استان اصفهان‬