Avian Influenza H7N9
Situation Analysis and Prevention
Dr. Tong Ka Io
2013.04.18
Spatial distribution

Shanghai municipality

Zhejiang province: Hangzhou, Huzhou, Jiaxing

Anhui province: Xuzhou, Haozhou

Jiangsu province: Nanjing, Suqian, Suzhou, Wuxi,
Rugao, Zhenjiang, Yaozhou, Changshou, Jiangying,
Yancheng, Kunshan

Henan province: Kaifeng, Zhoukou, Zhengzhou

Beijing municipality
Spatial distribution
Spatial
distribution
Beijing
04.11~ 1 case 0 death
Henan
04.06~ 3 cases 0 death
Jiangsu
03.19~ 21 cases 3 deaths
Anhui
03.09~ 3 cases 1 death
Shanghai
02.19~ 32 cases 11 deaths
Zhejiang
03.07~ 27 cases 2 deaths
Interpersonal distribution
Of the first 87 cases

Ÿ ge range = 2~87y, median = 63y, elder people more
A
common, only 3 child cases with milder clinical
presentations

M:F = 2.4:1

Occupational exposure to birds in at least 19 cases,
retired people account for 44 cases, none HCW

It was said that most fatal cases were male smokers
Suspect clusters
1)
Shanghai Li’s family

55y son became ill on 11th Feb, with severe
pneumonia, died on 28th Feb, no sample
collected for H7N9 testing

87y father became ill on 19th Feb, with severe
pneumonia, died on 4th Mar, H7N9 PCR positive

69y son became ill on 19th Feb, with milder
clinical course, H7N9 PCR negative,
retrospective serological test positive
Suspect clusters
2)
Jiangsu Zhang’s family

32y daughter became ill on 21st Mar, H7N9 PCR
positive

Her father had been ill before, H7N9 tests
negative
Suspect clusters
3)
Shanghai Gu’s
family

52y wife became ill
on 27th Mar, died
on 3rd Apr, H7N9
PCR positive

56y husband
became ill on 1st
Apr, H7N9 PCR
positive
Hypothetical mixing of avian flu viruses from east Asia
migratory birds and east China ducks and chickens.
Animal and environment testing

Since 20th Mar, animal facilities around human
cases in Anhui, Jiangsu and Shanghai had been
checked, with no animal illness found.

Until 3rd Apr, agricultural departments of
Shanghai, Jiangsu, Zhejiang, and Anhui did not
have specific testing agents for H7N9.
Animal and environment testing

As of 16th Apr, provincial and national AI
reference laboratories had collected a total of
84444 samples, covering 473 live poultry
markets, 32 slaughterhouses, 896 farms, 79 wild
bird habitats, 36 pig slaughterhouses, and 137
environmental sampling spots. Tests for 47801
samples had been concluded, yielding only 39
positive results (0.05%), of which 38 were poultry
and environment samples from live markets of
Shanghai, Anhui, Zhejiang and Jiangsu, 1 was
from wild pigeon from Nanjing, Jiangsu.
Positive tests
Date
Sampling sites
Positive rate
04.04 Shanghai Huhuai Market ?/?
04.05 Shanghai live markets
04.06
Zhejiang Hangzhou
Bangsheng Market
Farms and live markets
04.10 in Jiangsu, Zhejiang and
Anhui province
04.16
Suspect samples from
Jiangsu and Zhejiang
19/738(2.6%)
5/12(41.7%)
14/2099(0.7%)
5/12/?
Positive samples
Shanghai Huhuai Market
Pigeon
Huhuai Market
Chicken, environment
Jingchuan Market
Chicken, environment
Fengzhuang Market
Chicken, pigeon,
environment
Zhejiang Hangzhou Bangsheng
Market
Environment
Zhejiang Huzhou Zhebei Market
Duck
Anhui Hefei Huishangcheng
Market
Duck
3 markets in Jiangsu
Chicken
Jiangsu Nanjing
Wild pigeon
Zhejiang Huzhou Zhebei Market
Chicken
Zhejiang Huzhou Daoxiang Market
Chicken
Negative tests
Date
04.02
~04.09
Location
Shanghai natural
preservation district and
zoos
Shanghai farms
Sample
quantity
Tests
Migratory and wild birds
229
H7 gene
Animals
366
AI common
PCR
04.01~04.11
Farms, parks, wild bird
Chickens, pigs, ducks,
habitats and supermarkets gooses, pigeons, crows,
in 16 districts of Beijing
wild birds, animal
products
5609
?
04.14
Gucheng villange in Beijing Poultry
61+
95
Virology+
Serology
End of Mar
~04.17
35 pig farms and 11 pig
slaughterhouses in
Shanghai, Anhui, Zhejiang,
and Jiangsu
2050+
2000
Virology+
Serology
Pigs
Ducks along the bank of Changjiang river
may be all infected
Source of H7N9 virus may be the migratory birds
in Changjiang river mouth
H7N9 continuously evolves, hard to predict risk
The virus is still searching for a more compatible combination
Risk assessment
1.
The reassortment of avian influenza viruses had
occurred, probably in East China
2.
The reassorted virus massively go across the
animal-human boundary to infect human
3.
The virus is low pathogenic for birds and highly
pathogenic for human
4.
Up to the moment, there is no evidence that the virus
further go across the boundary to sustained humanto-human transmission, though limited human-tohuman transmission can not be excluded
Avian influenza dynamics
Phase 1
Bird-to-bird transmission
Phase 2
Bird-to-human transmission &
limited human-to-human transmission
Phase 3
Widespread
human-to-human transmission
H7N9
H1~H16
Avian disease surveillance,
prevention and control
Minimizing human exposure
Detection and isolation of
human cases
Ensuring care for patients
Slowing down spread
Risk assessment
5.
It is probably that the virus spreads beyond East
China to Central and North China by migratory birds,
which infect local Poultry and the latter infect human
6.
Comparing with H5N1, H7N9 infection in poultry
seems more widespread and persistent, constituting
a greater threat for human
7.
At this moment, it is impossible to precisely predict
if the virus will come to Macao, or how (birds or
human?), but preparedness is necessary
Animal-animal line of defense

Separate poultry with migratory birds and wild
birds

Separate water fowls and land fowls

Separate poultry from different regions

Separate infected poultry with other poultry
Significant measures taken in Macao

All local poultry farms eliminated

Raising poultry prohibited

Importation of live water fowls prohibited

Management in the source, surveillance,
separation, and double quarantine for poultry
provided from inland to Macao

Culling of all live poultry before the live markets
close everyday
Animal-human line of defense

Biosafety measures for poultry industry. In case
of animal epidemic, handling infected poultry
under strict protection

General people avoiding contact with live poultry
or presenting in places with live poultry, washing
hands after contact with raw poultry meat or egg,
eating poultry meat or eggs thoroughly cooked

According to situational, government adopting
appropriate risk management measures in sites
for poultry wholesale, sale, or watching
Human-human line of defense

Raising people’s alert for prompt seeking medical
advice if severe acute respiratory illness develops

Raising HCW alert, strengthening surveillance
system, building laboratory capacity, testing acute
respiratory patients with travel, poultry or patient
contact history, and patients with pneumonia of
unknown cause, for early detection of cases

Strengthening infection control in medical facilities.
Early isolation and treatment of detected cases

Tracing and health management of close contacts of
cases