Avian Influenza H7N9 epidemiological situation analysis and lines of defense

1. Avian Influenza H7N9
Situation Analysis and Prevention
Dr. Tong Ka Io
2013.04.18

3. 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

4. Spatial distribution

5. 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

6. Interpersonal distribution
Of the first 87 cases
 ŸAge range = 2~87y, median = 63y, elder people more
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

8. 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

9. 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

10. 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

12. Hypothetical mixing of avian flu viruses from east Asia
migratory birds and east China ducks and chickens.

13. 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.

14. 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.

15. Positive tests
Date Sampling sites Positive rate Positive samples
04.04 Shanghai Huhuai Market ?/? Shanghai Huhuai Market Pigeon
Huhuai Market Chicken, environment
Jingchuan Market Chicken, environment
04.05 Shanghai live markets 19/738(2.6%)
Chicken, pigeon,
Fengzhuang Market
environment
Zhejiang Hangzhou Zhejiang Hangzhou Bangsheng
04.06 5/12(41.7%) Environment
Bangsheng Market Market
Zhejiang Huzhou Zhebei Market Duck
Farms and live markets
Anhui Hefei Huishangcheng
04.10 in Jiangsu, Zhejiang and 14/2099(0.7%) Duck
Market
Anhui province
3 markets in Jiangsu Chicken
Jiangsu Nanjing Wild pigeon
Suspect samples from
04.16 5/12/? Zhejiang Huzhou Zhebei Market Chicken
Jiangsu and Zhejiang
Zhejiang Huzhou Daoxiang Market Chicken

16. Negative tests
Date Location Sample quantity Tests
04.02 Shanghai natural Migratory and wild birds 229 H7 gene
preservation district and
zoos
~04.09 Shanghai farms Animals 366 AI common
PCR
04.01~04.11 Farms, parks, wild bird Chickens, pigs, ducks, 5609 ?
habitats and supermarkets gooses, pigeons, crows,
in 16 districts of Beijing wild birds, animal
products
04.14 Gucheng villange in Beijing Poultry 61+ Virology+
95 Serology
End of Mar 35 pig farms and 11 pig Pigs 2050+ Virology+
~04.17 slaughterhouses in 2000 Serology
Shanghai, Anhui, Zhejiang,
and Jiangsu

17. Ducks along the bank of Changjiang river
may be all infected
Source of H7N9 virus may be the migratory birds
in Changjiang river mouth

19. H7N9 continuously evolves, hard to predict risk
The virus is still searching for a more compatible combination

20. 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 human-
to-human transmission, though limited human-to-
human transmission can not be excluded

21. Avian influenza dynamics

22. Phase 1 Phase 2 Phase 3
Bird-to-bird transmission Bird-to-human transmission & Widespread
limited human-to-human transmission human-to-human transmission
H7N9
H1~H16
Avian disease surveillance, Minimizing human exposure Ensuring care for patients
prevention and control Detection and isolation of Slowing down spread
human cases

23. 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

24. 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

25. 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

26. 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

27. 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