Transcript Systemic Hi Disease in Children`s Hospital

Avian Influenza
15 subtypes of influenza in birds most
pathogenic H5, H7
waterfowl (wild duck) are the natural
reservoir of avian influenza virus
domestic poultry (chicken, turkey)
are susceptible to epidemic
fatal
pigs can infected with avian and mammalian
influenza virus
Influenza Virus
Family Orthomyxoviridae
Genus Influenzavirus A, B
Avian influenza
H1
15
N1
9
All highly pathogenic avian influenza
is Influenza A; Subtype H5, H7
Human influenza
H 1, 2, 3
N 1, 2
History of “Human Avian-Flu
Year
1997
1999
2003
2003
2004
2004
28 Jan 2004
country
strain
Hong Kong
H5N1
Hong Kong
Netherland
Hong Kong
Vietnam
Thailand
H9N2
H7N7
H5N1
H5N1
H5N1
outcome
(case/death)
18/6
2/0
83/1
2/1
18/6
3/2
Resistance to Physical and
Chemical Action
Temperature
: Inactivate 56๐c in 3 hours
60๐c in 30 min
pH
: Inactivated by acid pH
Chemicals
: Inactivated by oxidizing agent
Sod. Dodecyl sulfate
Lipid solvents
b propiolactone
Disinfectant
: Inactivated by formalin, lodine compound
Survival
: long period in tissus, feces, water
Transmission of Avian-Flu
1. Direct contact with secretion esp. feces
of poultry
2. Indirect contact from feed, water, equipment
clothing
3. Human-to-human :- possible but low risk
(CID 2002; 34:558-564)
Clinical Forms of Human Avian-Flu
1. Asymptomatic
2. Mild URI
3. Severe pneumonia
4. Multiple organ failure
(CID 2002; 34:558-564)
Clinical Features of Human Avian-Flu
Fever
Headache
Malaise
Myalgia
Sorethroat
Cough
Runny rose
Conjunetivitis
Diarrhea
Severe Pneumonia
ARDS
Organ failure
Clinical Manifestations of Severe
H5N1 Infection
No predictor of progression of disease
Bacterial superimposed pneumonia were
unlikely to be the causes
Manifestation of severe disease
- primary viral pneumonia
- lymphopenia
- impaired liver function
- impaired renal function
- prolonged clotting time
H5N1 Infection in Hong Kong 1997
(18 cases)
Characteristic
Mean age (yr)
M:F
Pneumonia
GI symptom
mean WBC
Lymphocytopenia
Pancytopenia
Renal failure
Mild
(N=7)
3
5:2
0
2
11,200
0
0
0
Severe
(N=11)
26
3:8
11
8
3,900
11
2
4
18 Human Avian-Flu in HK 1997
18 cases
Mild URI
7 cases
Pneumonia
11 cases
Survived
5 cases
died
6 cases
(ARDS, organ failure)
Postmortem finding in 2 patients
Both reactive hemophagocytic syndrome
lung-hemorrhage, fibrinous exudate no viral
inclusion
renal tubular necrosis
liver fatty change
RT-PCR for H5N1 found in renal tissue,
bone marrow, spleen, liver
Cytokine-driven conditions
hemophagocytic syndrome
reactive
Lab. Diagnosis of “Human AvianFlu”
1. Culture (Madin-Darby canine kidney cells) Cytopathic effect
prelim. using H5 specific RT-PCR
or immunostaining with monoclonal antibody
2. H5 specific RT-PCR
3. Rapid test :- IFA from NP, endotracheal
:- antigen detection
4. Serodiagnosis :- NT in paired serum
Treatment of Avian-Flu
1. Supportive care :- Ventilator support when
needed
2. Antiviral agents eg. Amantadine, Rimantadine,
Zanamivir, Oseltamivir etc
(Antiviral agents is the most effective when given within
2 days of onset, but don’t know in Avian Flu)
Influenza Antiviral Medications
Chemoprophylaxis
:- Amantadine, Rimantadine,
Oseltamivir
70-90% efficacy in healthy adult
Treatment
:-
high risk group eg. nursing home,
hospital
(same as above),
Zanamivir x 5 days
treat within 2 days after onset
reduce symptoms, shorten time
by 1-2 days, less contagious to
other
Antiviral Drug for Influenza
Amantadine Rimantadine
Virus
Administration
Treatment
A
A
Oral
Oral
>1 y of age
>13 y of age
>1 y of age
>1 y of age
Zanamivir Oseltamivir
A and B
A and B
Inhalation
>7 y of age
Oral
>1 y of age
indications1
Prophylaxis
Not licensed >13 y of age
indications1
Adverse effects Central nervous Central nervous Bronchospasm Nausea,
system, anxiety
1
Licensed ages.
system, anxiety
vomiting
Daily Dosage Oseltamivir
(Tamiflu®) in Children
For Prophylaxis and Treatment
Weight
< 15 kg ; Oseltamivir 30 mg, bid x 5d.
16-23 kg ; Oseltamivir 45 mg, bid x 5d.
24-40 kg ; Oseltamivir 60 mg, bid x 5d.
> 40 kg ; Oseltamivir 75 mg, bid x 5d.
Vaccine for Avian-Flu
Influenza vaccine do not protection
against H5N1
No H5N1 vaccine available
Vaccine composition change every year
(antigenic drift)
Prevention of Avian-Flu for
Health Care Worker
Same as SARS measure
1. Isolation room
2. PPE (as SARS is more than enough)
3. disinfectants of material
Risk of H5N1 Infection among HCWs
Exposed to H5N1 patients, HK.
Characteristics
Exposed
(N=217)
Non-Exposed
(N=309)
Median age
No (%) of nurses,
doctor
No (%) with
poultry exposure
No (%) H5N1
antibody-positive
30
171 (79)
29
234 (76)
0.1
0.2
121 (56)
190 (61)
0.2
8* (4)
2 (0.7)
(JID 2000; 181:344-8)
* all were contact without protection because late diagnosis and
severe illness
* 2 cases of seroconversion
P
0.01
Prevalence of H5 antibody-positive
individuals in cohorts, stratified
by poultry exposure
Cohort
n
No. of antibody-positive
individuals/total (%)
Exposed
Not exposed
to poultry
to poultry
5/24 (21)
1/21 (5)
P
.13
Household contacts
45a
Tour group members
26
1/16 (6)
0/10 (0)
.62
exposed
23
0/9 (0)
0/14 (0)
NA
Not exposed
24
0/3 (0)
0/21 (0)
NA
Coworkers
(JID 1999; 180:1763-70)
Factors Influenzing HCW Acquired
H5N1 from Patient
1. Severity of patient - quantity of virus
2. No. of days from admission to diagnosis
3. Infection - control practice - droplet
precaution
(human to human unlikely to occur, if occur it is
asymptomatic)
History of Human Influenza
Hong Kong Flu
H3N2
Asian Flu
H2N2
Spanish Flu
Russian Flu
H1N1
1918
H1N1
1957
1968
year
1977
Influenza Pandemics :could it occur ?
Pandemic influenza 3-4 times/century
(1st 1918-1919 : 2nd 1957-1958
: 3rd 1968-1969)
more human infected with human
(H1, H2, H3) and avian influenza
“mixing vessel”
pandemic
expert suspect pandemic occur soon
Thank you