Avian Influenza H7N9Situation 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

Shanghai02.19~ 32 cases 11 deaths

Zhejiang03.07~ 27 cases 2 deaths

Anhui03.09~ 3 cases 1 death

Jiangsu03.19~ 21 cases 3 deaths

Henan04.06~ 3 cases 0 death

Beijing04.11~ 1 case 0 death

Interpersonal distributionOf 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

Suspect clusters1) 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 clusters2) Jiangsu Zhang’s family

32y daughter became ill on 21st Mar, H7N9 PCR positive

Her father had been ill before, H7N9 tests negative

Suspect clusters3) 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 testsDate Sampling sites Positive rate Positive samples

04.04 Shanghai Huhuai Market ?/? Shanghai Huhuai Market Pigeon

04.05 Shanghai live markets 19/738(2.6%)

Huhuai Market Chicken, environment

Jingchuan Market Chicken, environment

Fengzhuang Market Chicken, pigeon, environment

04.06 Zhejiang Hangzhou Bangsheng Market 5/12(41.7%) Zhejiang Hangzhou Bangsheng

Market Environment

04.10Farms and live markets in Jiangsu, Zhejiang and Anhui province

14/2099(0.7%)

Zhejiang Huzhou Zhebei Market Duck

Anhui Hefei Huishangcheng Market Duck

3 markets in Jiangsu Chicken

04.16 Suspect samples from Jiangsu and Zhejiang 5/12/?

Jiangsu Nanjing Wild pigeon

Zhejiang Huzhou Zhebei Market Chicken

Zhejiang Huzhou Daoxiang Market Chicken

Negative testsDate Location Sample quantity Tests

04.02 Shanghai natural preservation district and zoos

Migratory and wild birds 229 H7 gene

~04.09 Shanghai farms Animals 366 AI common PCR

04.01~04.11 Farms, parks, wild bird habitats and supermarkets in 16 districts of Beijing

Chickens, pigs, ducks, gooses, pigeons, crows, 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

Pigs 2050+2000

Virology+Serology

Source of H7N9 virus may be the migratory birds in Changjiang river mouth

Ducks along the bank of Changjiang rivermay be all infected

H7N9 continuously evolves, hard to predict riskThe virus is still searching for a more compatible combination

Risk assessment1. 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

Avian influenza dynamics

Phase 1Bird-to-bird transmission

Phase 2Bird-to-human transmission &

limited human-to-human transmission

Phase 3Widespread

human-to-human transmission

Avian disease surveillance, prevention and control

Minimizing human exposure Detection and isolation ofhuman cases

Ensuring care for patients Slowing down spread

H1~H16

H7N9

Risk assessment5. 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