Enormous risk described.

A new scientific article in the Chinese Science Bulletin talks of there being a high risk of a continuing and severe outbreak of H7N9 in the future. It extrapolates from the first 91 cases (today's case count is at 128), using a mathematical formula that could be heavily influenced by the appearance of decent numbers of mild cases - should testing find mild cases of course. 

Given the variation seen among many aspects of the different influenza viruses of recent years, I'm inclined to maintain my wait-and-see attitude a little longer before stocking the pantry.

Authorities considering human-to-human spread in Hunan?

crofsblogs reports on a news article quoting the Hunan Provincial Health Department will be setting up isolation wards in medical institutions to cater for fever and H7N9 influenza cases (allowing for interpretation of machine translation). 

This suggests to me that Hunan is expecting more cases and that they might be worried about human-to-human spread.

Son of Shandong's 1st H7N9 case positive for H7N9.

No evidence for human-to-human (h2h) transmission though. No evidence against it being the cause either of course. See my comments from the 18th regarding the first reported H7N9 case and family cluster. They still apply. 

Incubation time being surreptitiously the same as the (presumed) incubation period means nothing. Two people completely geographically isolated could have the the same gap between onsets and the second case would obviously not have been infected by the first. 

Even if the sequences of the two viruses are very similar, that does not prove h2h transmission. Chances are that many of the H7N9s will have very similar sequences reflecting that they have originated form the same animal (or human) source at some point.

What does this mean? 

It doesn't mean the sky is falling - contacts, by their very nature share things. In a family you often share (inhale, have land in your eyes etc) aerosolized (virus-laden) droplets as well as common surfaces contaminated by with those aerosols, when you have an acute virus infection. Coughing and sneezing do that. 

But you also share common tasks. 

There is so far no clear evidence of direct Dad to Son (or Son to Dad) transmission here (there is a timing issue that is intriguing)- the father and son may have simply shared the same airspace (I think its pretty safe to say this is transmitted through the air in some form) with an animal host during contact, handling, butchery, cleaning etc. Despite testing of animals to date finding very few have detectable H7N9 infections.

Guangdong creates a buffer against H7N9 entering Hong Kong.

Destruction of poultry in Guangdong province, the last province between Hong Kong and an inexorable march of H7N9-infected eastern Chinese provinces, has someFluTrackers noting that H7N9 may already be in Guangdong. 

UPDATE: An H7, but not H7N9.

Hunan province is number 10.

A 64-year old woman was the first case reported for the province of Hunan (1,km south-west of Shanghai, population >65,000,000). This province is adjacent (west) to Jiangxi, now reporting 5 cases (2 added tonight). 

There are now 10 provinces or municipalities having reported positive cases of H7N9 originating from within their borders.

Welcome to the end of the fourth week of H7N9.

And what a week its been.

There are now 122 H7N9 lab confirmed cases including an asymptomatic boy and an imported (to Taiwan from China) case. The numbers have risen from around 108 to 125 and the deaths from 13 to 23. More people have been discharged from hospital as well and the Case Fatality Rate/Ratio is sitting fairly steady at around 19%. A comment was made that official case reports would only appear once per week, but Provincial/Municipal numbers seem to still be coming out. Much has been made about age and sex. 

In the cases this past week, older males have borne the brunt of H7N9 infection.

Holes keep appearing in the amount of data coming out about each patient and as I write this (its 10pm and FluTrackers have already added more cases) there are at least 14 missing dates of onset, 54 dates of hospital admission (granted, some were not admitted, but only a small number), 2 dates of discharge, a number of occupations and the date of 1 (?Jiangsu) fatality in a state of flux. 

Despite that, so far no new cases have been reported, that have a date of onset in Week 4. That will probably change with newer provinces coming online and the diagnostic lag still being 9 days on average (having remained at 8-9 days since Week #2).

Fujian province reports its first H7N9 case

This completes the provinces surrounding the highly active Zhejiang province.

New insight into testing and epidemiology of infection.

In an excellent new article in the Lancet, Chen and colleagues explain testing (sensitive real-time RT-PCR for M, H7 and H9 targets; culture on MDCK (canine) cells to grow virus) describing result from throat and sputum samples from 4 patients.

They associate human cases directly to epidemiologically linked chickens (also tested quail, pigeons and ducks) samples from "wet" market (traditional live animals with on-site butchery - water used to clean up).

H7N9 cases in China to be reported weekly instead of daily.

Well that will let the guys at FluTrackers get some more sleep. Mike at Avian Flu Diary(who could probably do with some sleep too) notes it might not have a real impact on provincial reports but time will tell. The info is nestled at the bottom of this report.

This is a real shame for the public who have been getting access to some great real-time data break-downs, assemblies and interpretations from the flublogians. 

Realistically, its not like we're entitled to these detailed data from China. It all takes work (and workers) to compile, release the number and organize and hold the official press conferences etc...but in the age of "always on" and instant internet gratification...I think we feel that is how it should be.

We would feel entitled to the information if it were a story about a terrorist act or the latest comings and goings of a public figure or personality, or sports scores. Its been nice to see something as important as the emergence of a new human pathogen receiving the attention it has...at least so far.

Three hospital workers test negative.

Despite contact, and some confusion over whether they were or were not wearing personal protective equipment, they are H7N9 negative. So the upper respiratory tract infections (UTRIs; acute signs and symptoms including headache, perhaps a temperature, runny nose, sneezing, cough etc) they manifested after being in contact are due to another virus. Might be interesting to know which one(s). 

Presumably Taiwan already screens for whatever it is as part of a standard "respiratory virus panel". Thanks to ClaireW for the link.

Shanghai looks for antibodies to H7N9 in healthy people!

..and I say WOO-HOO! This is an important step forward. Looking among the currently healthy for past exposure to H7N9 will tell us a lot.

These results will start to unravel how long this virus has been circulating in Shanghai (it takes a couple of weeks to "seroconvert"; show a jump in specific antibody levels in the blood; looking in any older paired sera repositories would be great too) and also how many cases, beyond the one child so far reported, of moderate, mild or asymptomatic infection there could have been. 

Increasing that denominator is a great way to put the ability of H7N9 to cause severe illness in much clearer perspective.

Jiangxi tests positive for H7N9.

Given its proximity to Zhejiang its not too surprising that a case has been reported here-still to be confirmed by central testing. 

However, I don't know of a provincial/municipal announcement that didn't get confirmed so the odds are good that a confirmation is forthcoming After a quiet yesterday, Zhejiang also has a couple more H7N9 cases to report.

Returning to the issue of H7N9 and its skewed presentations in the sexes.

I wrote about this on the 22.04.13 but forgot to mention that there are no accompanying descriptions of the societal roles of males and females in these areas, or in general. 

The skewing may reflect a bias towards the males simply because they could be more involved in activities that increase their risk of exposure to the influenza A(H7N9) virus host or its environmental source.

A note on case fatality risk, rate or ratio (CFR)

..used in a couple of charts on the H7N9 page. This uses numbers based on very limited testing, publicly available data, recovered case numbers or understanding of the acquisition, transmission and clinical presentations associated with avian influenza A(H7N9) virus. 

It is very early days yet however I think this number gives you an idea of our understanding at the moment. It will undoubtedly change in the coming days, weeks and years. To be pedantic, the CFR relies uses the number of discharges/recovered cases as the denominator for the CFR. However, that will sensationally inflate the result. 

The CFR is often considered most useful at the end of an epidemic/pandemic, but less so when data-in-hand is limited such as during the early days of many outbreaks. Keeping in mind that some will take the CFR and multiply it by the world's population as an estimate of how many would die if the virus reached pandemic levels, I don't believe that approach is the best way to present the CFR metric for the emergence of a novel virus (usually first identified by the worst of the clinical presentations that will eventually be attributed to the virus). 

You won't see that usage on VDU, you will see the "rolling" version though. The US CDC definition is useful here.

One of the most lethal influenza viruses.

Well of course that was going to be the quote picked up by the world's press from comments made by WHO Assistant-Director-General, Health Security and Environment, Dr Keiji Fukuda.

H7N9 is not the only game in town.

Three HCWs who looked after the first H7N9 exported case have developed upper respiratory tract(URTs) infections somewhere during the 15-days between illness onset and lab confirmation. It is well worth noting that H7N9 is not the only virus that can cause URTs.

There are over 200 endemic human "respiratory viruses" that have been associated with URTs including the rhinoviruses (160 of them alone), coronaviruses, adenoviruses, enteroviruses, parainfluenzaviruses, influenza viruses, metapneumovirus, respiratory syncytial virus and bocavirus. Working out what causes a patient's URT is a challenging task, especially when more than one of these viruses can be detected by PCR in a patients airway sample at the same time. 

Differential diagnoses (testing for all the things that may cause the same clinical appearance) is interesting in times of an outbreak. Keep an eye on these HCWs - they could be an important canary in the dark H7N9 mine we've been stumbling about in so far.

H7N9 transported outside mainland China.

The first case of H7N9, has been reported reported in Taiwan marking its first known departure from the borders of mainland China. It seems that the 53-year old businessman imported it from somewhere on the mainland - he visited Suchou city in Jiangsu province, traveling out via Shanghai. He reportedly did not have any live birds or poultry.

There is now a risk of new cases emerging from close/regular/healthcare worker (HCW) contacts (n=138) he had (also also those during travel although he was pre-symptomatic and possibly not shedding), in the 3 three days he spent in Taiwan before showing signs of illness and at the medical facilities where he visited and was eventually admitted. If human-to-human transmission can happen, this will be the first chance to see it spread under the auspices of a different government. Four HCWs have cleared the suspected 7-day incubation period without symptoms while 3 HCWs have "developed" upper respiratory infections.

The patient did not seem to respond to Tamiflu but his infection was well advanced and beyond the recommended 48-hour commencement time (Tamiflu was started 16.04.13, about a week after first symptoms). His condition on 20.04.13 required intubation to manage respiratory failure.

The only upside to this "release" is that we may see and hear about some prospective testing which is sorely needed. Thanks to ClaireW and Jason Gale for the heads up.

Hepatitis B rears its tiny ugly head in the Taiwan case.

Apparently the 53M was also hepatitis B (HepB) positive as were 2/3 cases described in detail in the recent NEJM manuscript (see H7N9 page). 

Is there an association between HepB virus/viral disease and H7N9 or are these co-detections just coincidence due to high prevalence of HepB infection in China (suggested here)?

Market closure the key?

Is the closure of Shanghai's wet animal markets to thank for the precipitous drop in H7N9 cases from Shanghai from around mid-April? 

Back in 13.04.13 I mentioned we still had a few days to see if there was any impact based on the diagnostic testing lag of 10-12 days. Dr Kelso of the WHO influenza-A team thinks the drop and the market closures could be linked.

WHO panel wraps up visit.

"The primary focus of the investigation is to determine whether this is in fact spreading at a lower level among humans. But there is no evidence for that so far except in these very rare instances," said the WHO panel.

So presumably there are no signs or symptoms of disease spreading within these clusters. It is remains unclear from this visit whether the spread of the virus can be ruled out among these cases. Realistically (and pedantically), its very likely that the virus entered the airways and eyes of close contacts during sneezing, coughing etc. It just didn't cause obvious signs or self-reported symptoms of disease as a result of that challenge. 

Presumably the virus lacks something when replicating in humans that it has when coming from the suspected animal source, which allows it to cause disease in humans. Or that other theory - it can infect humans and cause mild and subclinical disease. 

The quickest way to resolve this question, a very important one for short-term and future containment of the virus, is to use PCR-based lab testing of contacts; look for virus in eye and upper airway swabs and, for a little bit, forget about being led by symptomatic illness alone.

Thanks to the reddit user

..who linked to the Cases and Deaths chart.

Two deaths and 5 new confirmations tip the numbers above 100

..avian influenza A(H7N9) cases. Nothing has changed since yesterday, apart from Zhejiang province now surpassing Shanghai municipality in the total number of cases reported and accelerating (see chart below) in case numbers at a very rapid rate.

Still, but a 3-digit number tends to sound more scary to some - so expect the media to carry big banner headlines akin to "100 cases of killer virus in three weeks!"

FluTrackers notes a new province has been added.

The H7N9 outbreak welcomes Shandong, about 870km north-west of Shanghai and 420km south of Beijing; population >95,000,000, of whom 1 (37M) is now confirmed as being H7N9-positive.

Given the rate of case reports from Zhejiang, I'm surprised we haven't heard from provinces further south such as Jiangxi or Fujian.

H7N9 and the tendency for males to predominate in case and fatality numbers.

The H7N9 graphs highlight that cases and deaths are occurring in males more than females. We often see more males than females in hospital presentations for acute respiratory illnesses. Why this is so is not known for certain.

Published research from Prof John Upham in Queensland, Australia shows a difference in the immune response to rhinovirus, the virus responsible for triggering most asthma attacks, between males and females in that females stronger response cleans up the virus, probably related to sex hormones. 

This was supported by research from Dr Scotland in London, United Kingdom who found that female mice had more white blood cells and that these were more effective and less over-reactive than male cells in responding to invaders. 

Perhaps this can be extended to influenzavirus infections also.

H7N9 and the skewed age issue.

We are reading much about the older than expected ages of those infected by H7N9 (current average case age of 58 years). Why? One school of thought is that the elderly have weaker, or perhaps "less experienced" immune defences. 

But there are many other risk factors for severe complications arising after influenzavirus infection including heart and other organ disease, things which may accumulate with age.

This shift is not uncommon among pandemic influenzaviruses - those settling in to a new host. Also worth noting: (1) seasonal influenza is commonly regarded as having its worst impact in those over 65 years of age, (2) influenza A(H5N1) virus (the other bird flu) has had its biggest impact in pre-adults and young adults (15-39)(3) the influenza A(H1N1)pdm virus (swine flu) had its greatest impact on children and young adults and(4) influenza A(H7N7) virus was confirmed in 89 people (average age 30 years among mostly workers culling chickens), mostly mild, including conjunctivitis.

That' a lot of diversity. Begs the question of whether we can predict too much about H7N9 until we've lived with it a bit longer.

Absence of evidence is not evidence of absence. Welcome to the end of the third week.

Three weeks since the WHO was notified of the newly emerged avian influenza A(H7N9) virus.

Today the case tally sits at 97 confirmation including 18 deaths, an asymptomatic case, three family clusters, no proven or sustained human-to-human transmission, no clear host in poultry or wild birds or pigs (all things that history or H7N9 genetic sequences indicate should be hosting infection).

The US CDC starts more gears turning.

US CDC asked local healthcare providers to keep an eye out for "signs of H7N9 flu". 

Rather than watch for feathers, this will entail being on the lookout for cases with influenza-like illness (ILI) among those who have themselves, or are in contact with someone who, recently traveled China who are influenzavirus-negative by standard laboratory testing methods. Rapid prescription of Tamiflu is recommended (within 48h). 

All commercially available influenzavirus tests on these cases should be disregarded because their ability to detect the new H7N9 is untested so the risk of false negatives is high.

A mutation musing

A collaborative report (by Dutch and Chinese contributor) published yesterday from Eurosurveillance shows that 5/7 H7N9 strains from humans, birds and the environment have an amino acid change in the HA gene called Q226L (the normal" glutamine [Q] found at amino acid position 226 has "mutated" to a Leucine[L]). 

In the past, this change has been associated with binding of influenzavirus to a receptor molecule called alpha(2,6,)-linked sialic acid, which is found in the human upper respiratory tract. 

A virus that is happy to replicate in the upper airways, one of the first ports of call for inspired virus-laded droplets, is going to have a good ability to spread by the aerosol route. [I include the eyes in here - but they may considered anatomically separate and the true first point of contact with virus-laden aerosols as they are probably open more than the mouth. 

Other influenza viruses have been shown, by testing of eye swabs, to cause conjunctivitis at this site and common cold viruses can enter the airways through the tear duct. 

More info on Q226L can be found here and here

Good read.

I highly recommend this Editorial over at crofsblogs. 

Adds a little context to some exaggerated headlines over the past three weeks and looks at the emergence of a novel virus from a...different angle.

The 15-person strong "influenza A-team"...

...have arrived in China to examine, understand and advise on the avian influenza A(H7N9) virus situation in Shanghai and Beijing. 

The comment that "with perhaps rare exceptions, people are not getting sick from other people. Of the many hundreds of people who were in close contact with the H7N9 patients, all the care-givers, neighbors, family members, and so on, there are only a very few cases where these contacts have become ill as well." exemplifies the search for symptomatic illness. 

However there is still an opportunity to test the contacts using sensitive laboratory methods. 

These results will be very important for ruling out (or in) the potential for stealthy H7N9 spread among people without predetermined clinical signs and symptoms.

Despite a dodgy serology test...

..not my interpretation, tweet from WHO's Gregory Hartl, it seems that at least one son of this outbreak's first reported H7N9 case (Case #1, 87M) has been confirmed as also being H7N9 positive. 

What does this mean? 

It doesn't mean the sky is falling - contacts, by their very nature share things. In a family you often share (inhale, have land in your eyes etc) aerosolized (virus-laden) droplets as well as common surfaces contaminated by with those aerosols, when you have an acute virus infection. 

Coughing and sneezing do that. But you also share common tasks. There is so far no clear evidence of direct Dad to Son (or Son to Dad) transmission here (there is a timing issue that is intriguing)- the father and son may have simply shared the same airspace (I think its pretty safe to say this is transmitted through the air in some form) with an animal host during contact, handling, butchery, cleaning etc. 

Despite testing of animals to date finding very few have detectable H7N9 infections.

How to solve a problem like transmission?

Perhaps once Prof Ron Fouchier can get the virus into his ferret model he should be able to definitively answer whether avian influenza A(H7N9) can be transmitted via the airborne route and the real impact of the much discussed mutations found in H7N9 over recent weeks. He will also look at the virus by infecting rhesus macaques and African green monkeys.

Shanghai still has the highest case load..

...but Zhejiang has surpassed Jiangsu to take second most active spot for H7N9.

Looking like Shanghai contributed 6 cases overnight.

However, dates are scant and patchy so I have not further updated the charts yet. I'm hoping for some clear data later in the day. 

New retrospective test results have appeared - these comprise serological data for two cases (seroconversion to influenzavirus can take 12-21d which may vary further in the elderly or those with immunocompromise) and culture isolations for two cases as well as two deaths. 

Why PCR did not pick up the H7N9 in the cases from which virus was isolated? Unclear and surprising.

Editor's Note #3

Increasing calls to reduce paranoia and stop overstating the likelihood of pandemic. 

Hopefully VDU doesn't add to the blather too much - collecting only verified observations of interest is the name of its game on this page. 

Opinions are mine alone and I hope they don' extend beyond hard data...too much.

VDU's Editor in Chief comments...

... in an article by Jason Gale, Editor, Bloomberg News, picked up by crofsblogs and on ProMED too in the AVIAN INFLUENZA, HUMAN (47): CHINA H7N9 UPDATE update.

The old question of how much do we trust PCR?

Over at FluTrackers, expert virology communicator (the virology blog), picornavirologist and teacher Prof Vincent Racaniello reiterates a point that hasn't been mentioned much with respect to the H7N9 emergence. 

"Conclusions about etiology are more difficult to determine if viral sequences are detected by PCR in the absence of clinical symptoms". In other words its important to consider the much greater sensitivity of PCR compared to old culture-based diagnostics, in the context of false positives (environmental or laboratory cross-contamination) and what a weak H7N9-positive might practically mean. 

A good seroconversion still can't be beat in these cases!

IMHO - experienced diagnostic labs should have long ago dealt with this issue. PCR has been in use as the "gold standard" for years. 

In a situation like the one ongoing, I assume that all H7N9 positives are being suitably confirmed using follow-up confirmatory testing using previously established protocols.

(waaaay) Down the track...

..it will also be interesting to see whether the H7N9 circulation had an unusual impact on "seasonal" respiratory viruses like parainfluenzaviruses (PIVs), enteroviruses (EVs) and rhinoviruses (HRV) which reportedly, like influenzavirus, can peak in Beijing and Shanghai around May (Ren et al., Clin Microbiol Infect 2009;p1146-; Wang et al. J Clin Virol 2010;p211-)

A new question...

...to mull over: Have viral co-infections and bacterial super-infections been sought, or excluded, in the H7N9 fatalities to date (some mention the 3 cases NEJM article)? 

What contribution do they make, along with existing co-morbidities, in the deaths of the 14 (as of 15.04) H7N9-positive cases?

Editor's Note #2.

Just a note of sincere thanks and a fair serving of awe to the tireless (perhaps sleepless) efforts of the dedicated guys at FluTrackers (Sharon Sanders, EiC) and the Avian Flu Diary (Mike Coston), and Crofs blogs for help and generous hat tips (see #7137 and others) that have kept VDU fed over the past couple of weeks.

Asymptomatic H7N9 case detected.

Multiple reports of the first asymptomatic case in a 4-year old male (4M) living across the street from the previously H7N9-POS, 7F. This may demystify a lot of H7N9 confusion as well as seriously increase the threat level for H7N9 spread...a stealth virus not only in poultry but humans is a new game. 

As I've suggested earlier, the widespread use of sensitive molecular detection methods, not just on the cases with the most severe clinical signs and symptoms, is absolutely essential to detect mild or asymptomatic cases of infection. The use of PCR in this way seems to have done just that. 

I'll keep a close eye on this story but I suspect it will result in a drastic change to the landscape of detection numbers and epidemiology. 

Symptoms alone tell only a small part of the story of any respiratory virus. This may strengthen the case for H7N9 having been in the community for much longer than the pneumonia cases officially commencing back in Feb, suggest.

Three more cases and a death.

The latter of a 77F previously H7N9 POS. Numbers of new notifications are surprisingly low after the weekend's flurry.

Editor's Note #1

A new format for the Cases Chart is being tried out to help me cope with the increasing analysis. 

Check out the other H7N9 charts of province, age, sex and mortalities all at the H7N9 page.

Biggest single H7N9 notification day?

Today saw a remarkable 11 H7N9 confirmations added including 2 new deaths and a new province (Henan; population >94,000,000) added to the list. FluTrackershas all the details...although many cases do not have full details; the best quality data come from Shanghai, Beijing and Henan at the moment. 

Cases jump to 60 with 13 deaths but the Case Fatality Rate remains steady at 22%. 

No sustained human-to-human transmission has been identified yet.

New H7N9 cases bring tally to 43

Another 5 H7N9 confirmations including a new death (n=11). Total of 43 cases - looks like 5/day is the new rate...an increase over time.

Given the approx 12-d gap between onset and test confirmation, it will still be a few days before we see an impact, if any, of Shanghai market closures and even more time for an impact from poultry culls.

H7N9 in Beijing

A new location for H7N9 - Beijing (population >20,000,000) has reported 1st case of H7N9. 

Testing results were turned around in only 1 day - great job!

Another 5 cases

Another 5 cases this evening (Down Under time that is) from three sites. Total at 49 cases. 

One case (56M, Shanghai, Case #47) is the husband of a formerly H7N9-positive deceased woman (Case #13) - is this the first data to support human-to-human transmission of H7N9 or is it two independent avian infections that just happen to be married? 

Earlier throat swabs on this case were H7N9 NEG

Influenza A(H7N9) update

Another 5 H7N9 confirmations including a new death.

H7N9 update...

Another existing case, 35F (Case #3) has died. The CDC has activated an "emergency center", simply helps support the response to the outbreak in China

Influenza A(H7N9) in a 4-year old boy

 The recovered 4M has now been discharged from hospital! 

The first case to do so. 

H7N9 detection now at 33 - 5 new confirmations tonight!

Birds are a rare duck with H7N9 infection...

Very few bird samples have tested positive for H7N9 (20 of 738 samples from Shanghai market birds).

Time to look beyond poultry?

Male suffer most from H7N9 infection?

An existing H7N9 case, 83M, has died. 

This is the 8th death from H7N9 infection from 24 cases. 

87.5% of deaths have been male.

WHO on H7N9 diagnostic tool...

WHO post details on a new H7N9-specific reverse transcriptase real-time PCR (RT-rtPCR). Method PDF here.

H7N9 adds 4 cases...

Four more H7N9 cases reported bringing tally to 28.

Peramavir for H7N9 and more detections confirmed...

19th and 20th cases of confirmed influenza A(H7N9). 

Peramivir, a new intravenous drug, is designed to target both influenza A and B viruses. Developed by US-listed biotech BioCryst Pharmaceuticals, it has been fast-tracked by Chinese FDA. 

The US CDC developing a candidate virus seed strain.

Are H7N9 case contacts being tested or just observed?

No epidemic linkage found between any of the H7N9 cases to date, and no "abnormality" among any of 621 close contacts. 

Sounds like contacts are not being subjected to laboratory testing.

21st H7N9 case reported...

21st laboratory-confirmed case of influenza A virus H7N9 reported [thanks to FluTrackers].

H7N9 in Shanghai...

7th H7N9 death, 64M retiree from Shanghai.

First new death from infection initiated after the WHO notification date.

Two new positive cases also. See time line for the 24 H7N9 cases so far

H7N9 and a range of birds...

Influenza A H7N9 now found in pigeons, quail (at live poultry market in Huangzhou [NOT - see update. Ed. 16.04.13]) and chickens (subclinical disease).

Live animal market bans...

17th and 18th cases of confirmed influenza A(H7N9) but all cases described as isolated with no spread from infectees to contacts.

Shanghai, Huangzhou and Nanjing ban live animal markets.

H7N9 and poultry culls...

14th H7N9 case and a 5th death. 

Poultry culls underway (>20,500 chickens, ducks, geese and pigeons). 

Virus found in pigeon samples at a Shanghai market.

H7N9 in a 10th case...

10th confirmed H7N9 case, 67M.

More on H7N9 here.

New H7N9 cases...

Four new influenza A virus H7N9 bird flu cases, no new deaths, from the Jiangsu province (N of Shanghai, NE of Anhui province). 

See more on influenzavirus here

Dead pigs in a river...

How does the death of thousands of pigs found in the Huangpu river, relate to the H7N9 cases?

Does it relate at all (or was it due to porcine circovirus? PCV is not commonly a symptomatic infection in pigs)?

Could there be another, as yet undiscovered agent involved that is common to both outbreaks? Good job for NGS!