Is H7N9 Spreading from Human to Human in China?

[Roehl_JC]

Re: Is H7N9 Spreading from Human to Human in China?

There may be more mild cases going unreported, but the current genotype of H7N9 includes genes that make it probable that H2H transmission is going on.
It has the same genes that were recorded in H5N1 including D225G and Q226L and the PB2 E627K gene that heralds deeper lung penetration and higher pathogenicity in mammals. It may have been in wild birds or in caged poultry for some time before somehow establishing itself in the early cases in China. I don't dismiss the reports of 10,000 dead swine thrown into the river around Shanghai, but I think there'd be huge numbers of human cases if that was the vector of transmission.
And the fact that cases are now reported from Hangzhou to Shanghai to Nanjing, all eastern China cities close to one another makes H2H transmission more likely especially with cluster early case links within families. If so, we should see a breakout soon in Hong Kong or other regions. The good news is that spring has come and that may reduce other stressor factors such as cold and smog contributing to the breakout scenario of people being stuck indoors in close proximity as much.
It's all speculation at this juncture, but thanks to FluTrackers and the collegiality of today's scientific communities and medical staffs, word will get out if it has gone H2H. Good luck to everyone in the meantime.
Thanks to Sharon and Al and Alaska Denise and Shannon and Emily and Giuseppe and Vibrant and all you wonderful reporters for keeping the world aware of developments.

[Shannon Bennett]

Re: Is H7N9 Spreading from Human to Human in China?

This isn't evolving the way the H5N1 virus did. We had to wait days weeks and even monthes for a new case. How is it possible that a virus never before seen in humans has now shown up with 14 probable cases and several possible cases in a

matter of a few days? Asymptomatic chickens plays a huge role. Without the usual culling of sick and dying chickens the virus was able to spread throughout a wide area while lying hidden from view. An unknown intermediate host also not dying

in vast numbers further obscures the viral progression. Reading the sequencing charts is beyond my ability but, what I can discern is there are a few posibilites officials are targeting. We still cannot rule out pigs and pigeons are also implicated.

Pigeons, also know as sky rats, are everywhere. Pigs if found to be the culprits can be culled, pigeons, on the other hand, cannot.



We have also seen our first pediatric case. This child appears to have only a mild case and is recovering at last report. What is alarming with this case is that her mother is in critical condition. (case #3 on the chart) This implies both the start of

a cluster and the possibility of a lot more mild cases we know nothing about. A large number of silent cases does reduce the know cfr but also implies that this disease is a done deal. Frankly, I am uncomfortable with either hypothisis. The deaths

attributed to this disease are not found in the normal list of who dies and who lives. Healthy adults within the ages of 20-50 rarely succumb to flu. Novel flu, which this is, always incurs a higher cfr in the 18-55 year-old population than those that

have circulated for years. In any case the next few weeks should be......interesting.

[Nika]

Re: Is H7N9 Spreading from Human to Human in China?

I know this might be crazy talk but does anyone have a sense for how many people - who were exposed to these cases - are being held for observation and or have mild illness officially related or not?

[Shannon Bennett]

Re: Is H7N9 Spreading from Human to Human in China?

Nika, on the first day the Chinese reported following 800 close contacts. Until a few minutes ago they stated none had appeared sick. A few minutes ago Sharon linked a report of one person exhibiting symptoms who is now in isolation.

[Nika]

Re: Is H7N9 Spreading from Human to Human in China?

Got it, thnx!

[Vibrant62]

Re: Is H7N9 Spreading from Human to Human in China?

One thought occurs to me.

If we assume for a moment that H2H transmission is not happening (or at least not widely or easily or in a sustained manner) we are still left with a high number of new cases in a very short timeframe.

Whether the vector is pigs or chickens (or pidgeons) when you bear in mind high exposure rates viz a vis H5N1 outbreaks in the past and relatively low infection rates in humans, then IF this is an animal to human transmission, then the virus must be highly infectious regardless.

That does not bode well, especially if the animal source proves hard to eradicate.

[AlaskaDenise]

Re: Is H7N9 Spreading from Human to Human in China?

.........That does not bode well, especially if the animal source proves hard to eradicate.

Given that today they found it in pigeons (which are being culled in Shanghai markets) and that there are 300,000 Chinese with racing pigeons - it would indeed be hard to eradicate. Also, if it in in the racing pigeon population, they race across international borders!

.

[Shannon Bennett]

Re: Is H7N9 Spreading from Human to Human in China?

Vibrant, that is the conundrum. What is infecting these people. There has to be a hell of a lot of unseen human cases or an animal carrier we have yet to identify. What do these diverse people all have in common that puts them in harms way? The actual number of cases is not high today but, the scary thought is what is it going to be next week? Is this exponential? Even linear is frightening if we have identified most of the victims. What is the actual cfr? What is the actual infection rate (RO). How fast can we get a culprit so we can stop this before we have a pandemic on our hands? I, and you no doubt, wait with baited breath.

[Roehl_JC]

Re: Is H7N9 Spreading from Human to Human in China?

(Reuters) - China said it was mobilizing resources nationwide to combat a new strain of bird flu that has killed six people, as Japan and Hong Kong stepped up vigilance and the United States said it was closely monitoring the situation.

All of the 14 reported infections from the H7N9 bird flu strain have been in eastern China and at least four of the six dead are in the financial hub of Shanghai, a city of 20 million people.

The strain does not appear to be transmitted from human to human but authorities in Hong Kong raised a preliminary alert and said they were taking precautions at the airport. Vietnam banned imports of Chinese poultry.

In Japan, airports have put up posters at entry points warning all passengers from China to seek medical attention if they have flu-like symptoms.

A total of 14 people in China have been confirmed to have contracted H7N9, all in the east of the country. One of the cases was a four-year-old child, who was recovering, the official Xinhua news agency said.

Hong Kong authorities said six people had died.

Authorities in Shanghai also discovered the H7N9 virus in a pigeon sample taken from a traditional wholesale market, Xinhua added, believed to be the first time the virus has been discovered in an animal in China since the outbreak began.

In the United States, the White House said it was monitoring the situation and the Centers for Disease Control and Prevention (CDC) said it had started work on a vaccine if it was needed. It would take five to six months to begin commercial production.

But the groundwork is being laid.

The virus has been shared with World Health Organization (WHO) collaborating centers in Atlanta, Beijing, London, Melbourne and Tokyo, and these groups are analyzing samples to identify the best candidate to be used for the manufacture of vaccine - if it becomes necessary.

Any decision to mass-produce vaccines against H7N9 flu will not be taken lightly, since it will mean sacrificing production of seasonal shots.

That could mean shortages of vaccine against the normal seasonal flu which, while not serious for most people, still costs thousands of lives.

Sanofi Pasteur, the world's largest flu vaccine manufacturer, said it was in continuous contact with the WHO through the International Federation of Pharmaceutical Manufacturers and Associations (IFPMA), but it was too soon to know the significance of the Chinese cases..."

link to source:

http://www.reuters.com/article/2013/04/05/us-birdflu-china-idUSBRE93201G20130405

So now they have an animal vector possibility and a 6th death recorded. I still think there's some significance to the way the CDC and WHO are now stepping up monitoring of this potential new human flu...and also there's significance in the way China has ordered testing gear and PCR kits to be deployed for it, I do reckon there's H2H underway in at least 3 E. China cities. IMHO

[curiosity]

Re: Is H7N9 Spreading from Human to Human in China?

Does anyone know if the contacts are being treated prophylactically with Oseltamivir or other antiviral? If they are/were, would this masque the capability of the virus to spread H2H?

[JimO]

Re: Is H7N9 Spreading from Human to Human in China?

According to the CDC, no confirmed cases have been detected in over 100 contacts tested. Of course, no information is provided as to which contacts were tested, whether they were symptomatic, or whether they have been treated.

My guess is that China is going to avoid producing any information that would confirm H2H transmission for as long as they possibly can. It might have to show up in Hong Kong or Japan before we'll know.

Does anyone know if the contacts are being treated prophylactically with Oseltamivir or other antiviral? If they are/were, would this masque the capability of the virus to spread H2H?

[curiosity]

Re: Is H7N9 Spreading from Human to Human in China?

Known:

Human cases of H7N9 previously undetected in humans
Quite a few cases detected in short period of time, some posthumously, without epidemiological link
Cases are in a substantial geographical area
H7N9 detected in chickens, pigeons, and the environment in Shanghai
No "Known" contacts or healthcare works are sick
Mammalian adaptation (unknown degree) apparent on genetic analysis

Unknown:

Reservoir
The case exposure type
How the case was exposed
The case exposure time

Possible causes:

1. Inefficient human to human spread (High efficiency = alot more cases, i.e., 20-30% infection rate in families)

and/or

2. Chicken/wild bird exposure - one would expect the sudden rate of case growth and the geographical spread would mean that the virus infections have been ongoing undetected for a good clip of time and we have only been able to identify the virus recently (second, of course to the undetected illness due to low pathogenicity in fowl)

and/or

3. Environmental exposure - food borne illness.

a. Infection at a farm distributing fresh (untreated, uncooked)
produce with environmentally infectious virus - presumably from
bird droppings?

b. Infection at a slaughterhouse distributing meat infected products to
population at large over wide geographical area

c. Infection at an egg distributer

Option 3 might explain the reason why retired folks and cooks are ill?

Any other possibilities besides Human to Human spread?

[Giuseppe]

Re: Is H7N9 Spreading from Human to Human in China?

H7 was not traced by animal health in China so far.

Previously, almost all H5N1 human Chinese cases had not obvious contacts with poultry.

OIE has received two notifications from China (today) about several samples of chicken, pigeons and from environment positive for H7N9.

The virus is on poultry but it is not clear how widespread.

There are some behavioral issues that are deserving to be investigated in China related to poultry and birds management by people.

The PLoS paper I suggested (from a renowned Canadian expert) may be useful in detecting through a simple stochastic algorithm the likelihood of a h2h spread.

I suspect we need to collect things and doing some calculation (as other need, WHO firstly...)

[AlaskaDenise]

Re: Is H7N9 Spreading from Human to Human in China?

According to the CDC, no confirmed cases have been detected in over 100 contacts tested. Of course, no information is provided as to which contacts were tested, whether they were symptomatic, or whether they have been treated...........

In an NPR interview today, Laurie Garrett stated that contacts are SELF REPORTING flu symptoms after a telephone contact. She points out that contacts might be reluctant to report symptoms since they could be held in quarantine.

Link to interview is in this post: http://www.flutrackers.com/forum/sho...d.php?t=203045

.

[curiosity]

Re: Is H7N9 Spreading from Human to Human in China?

http://www.iesingapore.gov.sg/wps/wcm/connect/c90ee28047827c64b661f79983497819/Distribution_Channel_Analysis_for_Convenience_food_in_China_2011_-_Article.pdf?MOD=AJPERES

An interesting analysis on food distribution in China- particularly because of the changes from "mom and pop" to large retailers like Wal Mart, KFC, McDonalds... in recent years with their economic growth.