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Biological/Public Health Threat (Human) – H7N9 (highly pathogenic avian influenza): Hubei Province, China

2016/03/15

AVIAN INFLUENZA, HUMAN (29): CHINA H7N9 (HUBEI) MODELING H7N9
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Published Date: 2016-03-14 19:58:36
Subject: PRO/AH/EDR> Avian influenza, human (29): China H7N9 (HU) modeling H7N9
Archive Number: 20160314.4092108

In this update:
[1] China (Hubei) H7N9
[2] Modeling seasonality of H7N9

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[1] China (Hubei) H7N9
Date: Mon 14 Mar 2016
Source: Xinhuanet News [edited]

A human infection of the H7N9 strain of avian flu has been reported in central China’s Hubei Province.

With severe pneumonia and sepsis, the patient has suffered multiple organ failure and is being treated in isolation, said the provincial health and family planning commission on Mon 14 Mar 2016.

The patient is a trader of live poultry and was formally diagnosed on Sun 13 Mar 2016, the commission said.

H7N9 was 1st reported to have infected humans in China in March 2013. It is most likely to strike in winter and spring.

From September 2015 to 1 Feb 2016, 44 H7N9 human cases, including 10 deaths, have been reported in China, 70 fewer cases than the same period a year ago, according to the National Health and Family Planning Commission.

The decrease of reported cases has been attributed to tougher control of live poultry markets.

Communicated by:
ProMED-mail
<promed@promedmail.org>

[FluTracker’s H7N9 line listing (http:flutrackers.com/forum/forum/china-h7n9-outbreak-tracking/143874-flutrackers-2013-16-human) currently shows 78 cases of H7N9 for the winter of 2015-16. This is the 2nd human case reported in Hubei since H7N9 emerged in China in 2013. Most of these infections have been associated with contact with infected poultry or contaminated environments (such as poultry markets) in China.

Hubei is a province of China located in the easternmost part of central China. It is located north of Dongting Lake. The provincial capital is Wuhan, a major transportation thoroughfare and the political, cultural, and economic hub of Central China. – Mod.LK]

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[2] Modeling seasonality of H7N9
Date: Thu 10 Mar 2016
Source: PLoS One [edited]

Lin Q, Lin Z, Chiu APY, He D (2016) Seasonality of Influenza A(H7N9) Virus in China–Fitting Simple Epidemic Models to Human Cases. PLoS ONE 11(3): e0151333. doi:10.1371/journal.pone.0151333

Abstract
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Background:
Three epidemic waves of influenza A(H7N9) (hereafter H7N9) human cases have occurred between March 2013 and July 2015 in China. However, the underlying transmission mechanism remains unclear. Our main objective is to use mathematical models to study how seasonality, secular changes and environmental transmission play a role in the spread of H7N9 in China.

Methods:
Data on human cases and chicken cases of H7N9 infection were downloaded from the EMPRES-i Global Animal Disease Information System. We modelled on chicken-to-chicken transmission, assuming a constant ratio of 10-6 human cases per chicken cases, and compared whether the model fit with the observed human cases. We developed 3 different modified Susceptible-Exposed-Infectious-Recovered-Susceptible models: (i) a non-periodic transmission rate model with an environmental class, (ii) a non-periodic transmission rate model without an environmental class, and (iii) a periodic transmission rate model with an environmental class. We then estimated the key epidemiological parameters and compared whether the model fit using Akaike Information Criterion and Bayesian Information Criterion.

Results:
Our results showed that a non-periodic transmission rate model with an environmental class provided the best model fit to the observed human cases in China during the study period. The estimated parameter values were within biologically plausible ranges.

Conclusions:
This study highlighted the importance of considering secular changes and environmental transmission in the modelling of human H7N9 cases. Secular changes were most likely due to control measures such as Live Poultry Markets closures that were implemented during the initial phase of the outbreaks in China. Our results suggested that environmental transmission via viral shedding of infected chickens had contributed to the spread of H7N9 human cases in China.


Communicated by:
ProMED-mail
<promed@promedmail.org>

[This study extends the models built on the 1st 2 waves of H7N9 transmission in China to include the 3rd wave. Note that secular variation of a time series is its long-term non-periodic variation. Gaps identified in the model indicate that more research is needed to determine environmental transmission routes of H7N9 in China.

Maps of China can be found at http://www.sacu.org/maps/provmap.png and http://healthmap.org/promed/p/155. – Mod.LK]

See Also

Avian influenza, human (28): China (SH ex AH) H7N9 20160311.4086680
Avian influenza, human (27): China (GD) H7N9 20160310.4083565
Avian influenza, human (25): China (HK ex JS) H7N9, WHO update, epi-virol. study 20160223.4044829
Avian influenza, human (24): China (GD,SD) H7N9 20160219.4035682
Avian influenza, human (22): China (ZJ) nosocomial co-transm H7N9 & H1N1, 2014 20160213.4017431
Avian influenza, human (21): China (GD) hospital cluster, H7N9, 2015 20160212.4014491
Avian influenza, human (20): China H7N9 update 20160207.4002127
Avian Influenza, human (19): China H7N9 20160205.3997868
Avian influenza, human (18): China, H7N9, H5N6, CHP report 20160205.3995719
Avian influenza, human (17): China (GD,HN) H7N9, CDC guidance 20160129.3977245
Avian influenza, human (10): China (JS) H7N9 20160113.3933423
Avian influenza, human (09): China update H7N9 20160112.3929801
Avian influenza, human (08): China update H7N9 20160111.3928027
Avian influenza, human (06): China H7N9 20160109.3923182
Avian influenza, human (01): China (JX,SH) H7N9 20160101.3905900
2015
—-
Avian influenza, human (136): China (GD) H7N9 20151226.3893014
Avian influenza, human (135): Algeria (TB) comment, RFI 20151223.3885144
Avian influenza, human (134): Egypt (PS) susp 20151223.3886176
Avian influenza, human (130): China (AH, HN) H9N2 20151217.3867941
Avian influenza, human (129): China, H7N9 20151212.3857995
Avian influenza, human (128): China (ZJ) H7N9 20151210.3854497
Avian influenza, human (127): China (GD) H7N9 20151124.3815415
Avian influenza, human (126): China (ZJ) H7N9 nosocomial transmission, susp 20151120.3806724
Avian influenza, human (125): China (ZJ) H7N9, 4th wave H7N9 20151118.3801312
Avian influenza, human (124): China, H7N9 20151109.3779443
Avian influenza, human (123): China (ZJ) H7N9 new cases 20151020.3728683
Avian influenza, human (122): China (ZJ) 4th wave H7N9 20151017.3723789.
Avian influenza, human (121): China (ZJ) H7N9, travel advisory 20151009.3703391
Avian influenza, human (120): Bangladesh, H9N2 20150923.3666519
Avian influenza, human (119): China (Hong Kong) 2014, H7N9 epidemiological study 20150804.3556142
Avian influenza, human (118): CDC H5 virus risk assessment 20150731.3548675
Avian influenza, human (117): United States risk 20150724.3534053
Avian influenza, human (116): China, H7N9, WHO 20150718.3520026
Avian influenza, human (115): human-animal interface, SA status comments 20150718.3520025
Avian influenza, human (114): China (YN) H5N6 20150712.3504427
Avian influenza, human (111): China H7N9 20150616.3443129
Avian influenza, human (110): China H7N9 20150524.3382639
Avian influenza, human (109): novel viruses, virulence, H5N8 20150523.3380732
Avian influenza, human (107): WHO assessment 20150521.3376485
Avian influenza, human (106): novel viruses, virulence unknown 20150520.3375592
Avian influenza, human (103): China H7N9 20150514.3363072
Avian influenza, human (102): China H7N9 20150510.3353745
Avian influenza, human (101): China (AH) 20150506.3345785
Avian influenza, human (99): China H7N9 retrospective analysis 20150504.3340899
Avian influenza, human (98): China (JX) H7N9 20150502.3336779
………………………………………….lk/msp/mpp

Source:
A ProMED-mail post
ProMED-mail is a program of the International Society for Infectious Diseases

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