Avian Influenza H7N9 Situation Analysis and Prevention

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Avian Influenza H7N9Situation Analysis and
Prevention

• Dr. Tong Ka Io
• 2013.04.18

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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

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Spatial distribution
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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
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Interpersonal distribution

• Of the first 87 cases
• ?Age range 287y, median 63y, elder people
  more common, only 3 child cases with milder
  clinical presentations
• MF 2.41
• 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

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Suspect clusters

• Shanghai Lis 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

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Suspect clusters

• Jiangsu Zhangs family
• 32y daughter became ill on 21st Mar, H7N9 PCR
  positive
• Her father had been ill before, H7N9 tests
  negative

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Suspect clusters

• Shanghai Gus 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

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

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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.

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Positive tests
Date Sampling sites Positive rate Positive samples Positive samples
04.04 Shanghai Huhuai Market ?/? Shanghai Huhuai Market Pigeon
04.05 Shanghai live markets 19/738(2.6) Huhuai Market Chicken, environment
04.05 Shanghai live markets 19/738(2.6) Jingchuan Market Chicken, environment
04.05 Shanghai live markets 19/738(2.6) Fengzhuang Market Chicken, pigeon, environment
04.06 Zhejiang Hangzhou Bangsheng Market 5/12(41.7) Zhejiang Hangzhou Bangsheng Market Environment
04.10 Farms and live markets in Jiangsu, Zhejiang and Anhui province 14/2099(0.7) Zhejiang Huzhou Zhebei Market Duck
04.10 Farms and live markets in Jiangsu, Zhejiang and Anhui province 14/2099(0.7) Anhui Hefei Huishangcheng Market Duck
04.10 Farms and live markets in Jiangsu, Zhejiang and Anhui province 14/2099(0.7) 3 markets in Jiangsu Chicken
04.16 Suspect samples from Jiangsu and Zhejiang 5/12/? Jiangsu Nanjing Wild pigeon
04.16 Suspect samples from Jiangsu and Zhejiang 5/12/? Zhejiang Huzhou Zhebei Market Chicken
04.16 Suspect samples from Jiangsu and Zhejiang 5/12/? Zhejiang Huzhou Daoxiang Market Chicken
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Negative tests
Date 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
04.0104.11 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
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Ducks along the bank of Changjiang river may be
all infected
Source of H7N9 virus may be the migratory birds
in Changjiang river mouth
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H7N9 continuously evolves, hard to predict
risk The virus is still searching for a more
compatible combination
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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

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Avian influenza dynamics
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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
H1H16
Avian disease surveillance, prevention and
control
Minimizing human exposure Detection and
isolation of human cases
Ensuring care for patients Slowing down spread
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Risk assessment

1. 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
2. Comparing with H5N1, H7N9 infection in poultry
   seems more widespread and persistent,
   constituting a greater threat for human
3. 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

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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

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• 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

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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

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Human-human line of defense

• Raising peoples 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