Is H7N9 Spreading from Human to Human in China?

[Shannon Bennett]

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

I find the pig/water scenario as an unlikely source of the infection myself but, it cannot be ruled out completely. As to the dead pig dumping timeline, if the number of pigs at first was small then we probably would not have read of the the first

animals disposed of in the river. It is my understanding that dumping dead pigs into rivers is a fairly common practice. Furthermore, I have never heard of a flu virus that could not be killed with chlorine bleach. So, the river as a focus for infections

is problematic. And, I too am well aware of a veracity problem with information coming out of China

.

I was unable through a 45 minute search to find any reliable sources indicating rodents as vectors for influenza. Interesting thought though. It is my understanding that mice used for testing for research have all been genetically altered.



Flu is usually passed as droplets and inhaled deep into lung tissue. So the most likely avenue is to have someone breathe the same air you are breathing. Transmission can also occur by touching contaminated surfaces then touching a mucus

membrane. As some of the victims rarely left their places of abode is is highly unlikely they came into very close contact with either uncooked chicken or pork. That brings us back to the conclusion that H2H is the most likely culprit. Albeit with a

virus that hasn't yet overcome the obstacles for easy transmission.

 

[curiosity]

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

Yes, I agree, major city connections to Shanghai.

One thing I don't understand is why does the WHO say with near conviction that there is no evidence of H2H transmission? Particularly when the outbreak is so unusual?

This is not comparable to the H5 event in Hong Kong in 97 where a few cases were detected over a much smaller geographic area with coinciding sick/dying birds. This event is not even comparable to the H1N1 event where multiple severe cases with unknown disease were detected in Mexico City AND two cases were located in separate US geographical areas. This event is more like a combination of both over a large area - how could they know or what evidence do they have that indicates it is NOT an efficient transmission between humans?

It seems more major cities would be on increased alert if WHO guidance at least included the plausibility it could be H2H spread - or simply that they don't know and until they do, be cautious!

 

[Nika]

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

I am guessing that if the WHO were to advise possible H2H that would trigger very expensive and widespread public health response plans. They probably do not want to go there any time soon.

 

[curiosity]

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

Right after I posted the last article, I read the WHO link post re: FAQ update. The WHO is now indicating there is a possibility for person to person transmission.

From the WHO FAQ:

7. How did people become infected with the influenza A(H7N9) virus?

Some of the confirmed cases had contact with animals or with an animal environment but the virus has not thus far been found in animals. It is not yet known how these persons became infected. The possibility of animal-to-human transmission is being investigated, as is the possibility of person-to-person transmission.

12. Is the general population at risk from the influenza A(H7N9) virus?

We do not yet know enough about these infections to determine whether there is a significant risk of community spread. This possibility is the subject of epidemiological investigations that are now taking place

 

[Catbird]

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

Bingo

until this pierces the veil and is found in a Western country we cant possibly say anything with certainty - well except that we certainly do not have the full story

(sadly lets hope it shows up in a competent country like Germany because then the transparency will be considerably better)

I think that we also need to be very vigilant in searching for any suggestion that a health care worker is ill. That's especially true because the earliest cases were apparently treated without use of isolation or protective gear. If any cases show up, that's going to take this to a whole 'nother level.

 

[curiosity]

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

What "evidence" must be present to determine human to human infection has occurred? Does anyone know of a standard or guideline for this?

We are all looking for (and have found some) items that suggest H2H spread, but are there any 'pertinent negatives' we are missing that would suggest H2H spread is NOT occuring?

I imagine the media is being excessively scrutinized in the affected areas and will not be printing articles about increased respiratory infections at hospitals or overcrowded ERs.

 

[Shannon Bennett]

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

Clustering of cases between close familiy, friends and co-workers. And a large number of health care workers coming down with the disease. Later swamped emergency rooms.

 

[Laidback Al]

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

Clustering of cases between close familiy, friends and co-workers. And a large number of health care workers coming down with the disease. Later swamped emergency rooms.

Shannon is correct. Unfortunately, we don't know if China will release such information in a timely manner. Remember that what lead to the reporting of the first case was a cluster of illnesses in a Shanghai hospital in early March. However, only one of the individuals was reported to have contracted H7N9.

 

[AlaskaDenise]

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

There is an additional possibility that springs to mind: vermin. Again, H7N9 infected pigs or other dead animals that had washed ashore would have been fed upon, and vermin are pervasive in cities and buildings and could be a spread vector.

...shades of early H5N1!

A post by IOH states that the M segment has the S31N change. An H9N2 2012 Brambling M segment sample also has that change. They are sometimes kept as pets (shades of early H5N1 also).

.

 

[Pathfinder]

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

This is a copy of excerpts of an article that I put in the H7N9 discussion thread earlier today.

...
"We speculate that when this virus is maintained in poultry the disease will not appear, and similar in pigs, if they are infected, so nobody recognizes the infection in animals around them, then the transmission from animal to human may occur," said Dr. Masato Tashiro, director of the World Health Organization's influenza research centre in Tokyo and one of the specialists who studied the genetic data. "In terms of this phenomenon, it's more problematic."

This behaviour is unlike the virus's more established relative, the virulent H5N1 strain, which set off warnings when it began ravaging poultry across Asia in 2003. H5N1 has since killed 360 people worldwide, mostly after close contact with infected birds.

"In that sense, if this continues to spread throughout China and beyond China, it would be an even bigger problem than with H5N1 in some sense, because with H5N1 you can see evidence of poultry dying, but here you can see this would be more or less a silent virus in poultry species that will occasionally infect humans," said University of Hong Kong microbiologist Malik Peiris, who also examined the information.
...

http://www.cbc.ca/news/health/story/...-flu-h7n9.html

 

[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?