Download Statutory Reporting of “Variant Influenza A(H3N2) ”

Surveillance
And
Epidemiology
Branch
監測及流行病學處
本署檔號
Our Ref.
: (57) in DH SEB CD/8/27/1 Pt.19
17 August 2012
Dear Doctor,
Statutory Reporting of “Variant Influenza A(H3N2) ”
Recently in the United States, a significant increase in the number of
infections with influenza A(H3N2) variant [A(H3N2)v] has been reported. In
order to prepare in advance for possible importations of this infection into
Hong Kong and their consequences, there is public health justification to
strengthen the surveillance of this type of influenza to enable effective public
health preventive and control measures be implemented locally. It is considered
necessary to amend the Prevention and Control of Disease Ordinance (Cap.
599) to include “variant influenza A(H3N2)” in the list of scheduled infectious
diseases, with effect from 17 August, 2012.
Influenza A virus infections are common in pigs, but these viruses are
generally different from those circulating among human. Swine influenza A
viruses can occasionally cause human infections. These viruses are called
“variant viruses” when people are infected with them. Human infections with
variant influenza viruses usually occur in people with exposure to infected pigs
(e.g. workers in the swine industry, children near pigs at a fair).
In 2011, a new A(H3N2)v virus that had acquired the matrix or M gene
from influenza A(H1N1)pdm09 [A(H1N1)pdm09] virus was detected in the
United States. Such viruses are expected to test positive for influenza A, and
variably for different subtype markers.
衞生防護中心乃衞生署
轄下執行疾病預防
及控制的專業架構
The Centre for Health
Protection is a
professional arm of the
Department of Health for
disease prevention and
control
In the United States, while a total of 12 cases infected with this new
A(H3N2)v were reported in 2011, increasing number of infections have been
reported since July 2012. As of 10 August, the United States Centers for
Disease Control and Prevention (USCDC) reported 166 cases, of which 153
cases were reported recently in July and early August 2012. Most of the cases
were mild and self-limited, presenting with symptoms and signs of influenza
and most cases have recovered. USCDC has not received any report of deaths
香港九龍亞皆老街 147C 號 3 樓
3/F, 147C Argyle Street, Kowloon, Hong Kong
-2-
associated with variant influenza A(H3N2), and there have been two confirmed
hospitalizations with variant influenza A(H3N2) so far in 2012. Both patients
have recovered and have been discharged. Of the 138 reported cases for
which demographic information was available, 128(93%) occurred in persons
aged <18 years, and 10(7%) occurred in adults. Limited serologic studies
conducted in the United States to date indicate that children would have little to
no immunity to this virus, whereas adults may have some cross-protective
immunity. No sustained community transmission of A(H3N2)v has been
observed yet. However, it is possible that this A(H3N2)v could gain increased
capacity for efficient and sustained human-to-human transmission because
influenza viruses are constantly evolving.
So far, no human infection with this A(H3N2)v has been reported outside
the United States. However, with the frequent international travel, it is possible
that an imported case of variant influenza A(H3N2) may occur in Hong Kong.
To detect these cases early, medical practitioners are reminded to notify the
Department of Health any suspected cases of variant influenza A(H3N2)
fulfilling the reporting criteria (see attached) and collect relevant respiratory
specimens. The Public Health Laboratory Services Branch of the Centre for
Health Protection (CHP) has the ability to diagnose these cases.
Please report suspected cases to the Central Notification Office (CENO)
of CHP via fax (2477 2770) using the reporting form attached, phone (2477
2772) or CENO On-line (http://ceno.chp.gov.hk/). Please also call our
Medical Control Officer at 7116 3300 a/c 9179 outside office hour for prompt
investigation. The case definition of variant influenza A(H3N2) is attached in
Appendix for your reference. The reporting form and the case definition are
also available on CENO On-line website.
May I take this opportunity to thank you for your continuous support in
combating infectious disease in Hong Kong.
Yours faithfully,
(Dr SK CHUANG)
Consultant Community Medicine (Communicable Disease)
Centre for Health Protection
Department of Health
-3-
Appendix
Variant Influenza A(H3N2) (Effective on 17 August, 2012)
Description
Influenza A viruses that are different from those circulating among human are
called “variant viruses” when people are infected with them. Human infections
with influenza A(H1N1) variant [A(H1N1)v], A(H3N2)v and A(H1N2)v
viruses determined to be of swine origin have been occasionally reported. In
the United States, increasing number of infections with A(H3N2)v with the
influenza A (H1N1)pdm09 virus M gene have been reported since July 2011,
mostly in people with direct exposure to pigs (e.g. workers in the swine
industry, attendants to agricultural fairs). Most cases presented with
symptoms and signs of influenza (fever, cough, runny nose, sore throat, muscle
aches). Limited human-to-human transmission of A(H3N2)v had been
identified but sustained and efficient community transmission of A(H3N2)v
has not yet been detected.
Case Definition
Laboratory Criteria
One of the following positive results reported by a reference laboratory z
nucleic acid detection for specific A(H3N2)v genome; OR
z
isolation of an A(H3N2)v; OR
z
seroconversion or four-fold rise in A(H3N2)v specific antibodies.
Confirmed Case
A clinically compatible illness fulfilling the laboratory criteria.
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Reporting criteria for suspected variant influenza A(H3N2)
Reporting criteria
An individual fulfilling both the Clinical Criteria AND Epidemiological
Criteria should be reported to CHP for further investigation.
Clinical Criteria
z
z
z
person with acute respiratory illness, characterized by fever
(temperature >38oC) and cough and/or sore throat, OR
person with pneumonia, OR
person died of unexplained acute respiratory illness
Epidemiological Criteria
z
History of recent contact (7 days before onset of illness) with
„ swine in the United States or areas with known variant influenza
A(H3N2); OR
„ patient with variant influenza A(H3N2)
FORM 2
PREVENTION AND CONTROL OF DISEASE ORDINANCE
(Cap. 599)
Notification of Infectious Diseases other than Tuberculosis
Particulars of Infected Person
Name in English:
Name in Chinese:
Age / Sex:
I.D. Card / Passport No.:
Telephone No.
(Home) :
Residential address:
(Mobile) :
Name and address of workplace / school:
(Office / school / others):
Job title / Class attended:
Hospital / Clinic sent to (if any):
Hospital / A&E No.:
Disease [“9”] below Suspected / Confirmed on ______ / _______ / _________ (Date: dd/mm/yyyy)
□
Acute poliomyelitis
□
Amoebic dysentery
□
Anthrax
□
Bacillary dysentery
□
Botulism
(H3N2), Influenza A (H5),
□
Scarlet fever
□
Chickenpox
Influenza A (H7), Influenza A (H9)
□
Severe Acute Respiratory
□
Chikungunya fever
□
Japanese encephalitis
□
Cholera
□
Legionnaires' disease
□
Community-associated methicillin-resistant
□
Leprosy
Staphylococcus aureus infection
□
Leptospirosis
□
Smallpox
□
Creutzfeldt-Jakob disease
□
Listeriosis
□
Streptococcus suis infection
□
Dengue fever
□
Malaria
□
Tetanus
□
Diphtheria
□
Measles
□
Typhoid fever
□
Enterovirus 71 infection
□
Meningococcal infection
□
□
Food poisoning
□
Haemophilus influenzae
□
Rabies
type b infection (invasive)
□
Relapsing fever
□
Hantavirus infection
□
Rubella and congenital
□
Influenza A (H2), Variant Influenza A
rubella syndrome
Syndrome
□
Shiga toxin-producing
Escherichia coli infection
(invasive)
Typhus and other rickettsial
diseases
Number of persons known to be affected:
□
Mumps
□
Viral haemorrhagic fever
Place and district of consumption
(e.g. “XX Restaurant in Mongkok”):
□
Paratyphoid fever
□
Viral hepatitis
□
Plague
□
West Nile Virus Infection
□
Psittacosis
□
Whooping cough
□
Q fever
□
Yellow fever
Date of consumption:
Notified under the Prevention and Control of Disease Regulation by
Dr. ______________________________ of ___________________________Hospital / Clinic / Private Practice
(Full Name in BLOCK Letters)
____________________________Ward / Unit / Specialty on ______ / _______ / ________ (Date: dd/mm/yyyy)
Telephone No.: ________________
Remarks:
DH 1(s)(Rev. August 2012)
Fax No.: ___________________
___________________________
(Signature)