In 6 months, 1 billion dead in avian flu?

Aquamarine

http://www.mosnews.com/news/2004/10/28/pandemic.shtml

Others are more optimistic:
http://www.theglobeandmail.com/servl...enceandHealth/

Not that I understand how they get these optimistic number since avian flu has had a fatality of about 70% of those infected.

russ_watters

Well, where does the Russian agency get 70%? I'd be more inclined to believe 1% - its "only" the flu.

[google...]HERE appears to be the source: One danger here is sample size - the 30% was 6 out of 18 (from another site). With that small of a sample, you can get a sample bias.SOME THINGS to remember about the flu - it kills roughly 36,000 people a year in the US and 90% are over age 65. I'm having trouble finding a death rate - probably because a significant fraction of cases go unreported.

Aquamarine

Many comments from a physician on Avian flu:
http://www.recombinomics.com/whats_new.html

His view on pandemic potential:
http://www.recombinomics.com/pandemic_potential.html

Aquamarine

But the WHO and CDC quotes much lower number and hopefully are more correct. Unless they are conservative and wants to avoid a panic.

The worst flu until now was probably the flu of 1918, which killed 20-50 million. A flu of similar severity could kill many more since world population has increased 3-4 times since that. But maybe better knowledge can give more effective countermeasures today. Hopefully vaccination could protect those in rich countries several months after an outbreak. There are some expensive anti-virals that also may help, especially as profylax, but also only a very small number of people initially. Probably restricted to health care professionals.

Large number of cases could overwhelm at least the health care system and maybe also other parts of society, for example food distribution. Especially from panic.

niman

The case mortality rate in the 70-80% is pretty solid. There were human cases in Vietnam and Thailand at the beginning of this year, and then another wave over the summer. All data sets have case mortaility rates in the 70-80% range.

The key question concerns human to human transmission. If the H5N1 virus just picks up the abilty to recognize human receptors via recombination

http://www.recombinomics.com/viral_evolution.html

the virus can acheive a high transmission rate and maintain the high case fatality rate (which is much higher than seen in the 1918 flu pandemic).

CDC and WHO are being VERY conservative (and optimistic) by assuming that the case fatality rate would fall from 70% to 1%.

Aquamarine

Welcome Niman.

Do you think it would be possible to quickly produce large amounts of a vaccine after an outbreak with new technologies? Assuming that the government will simply ignore all the usual hurdles like extensive safety testing and patent rights, if they slow the process?

http://www.upmc-biosecurity.org/misc/flu/vaccine.html
http://www.ncbi.nlm.nih.gov/entrez/q..._uids=11803087

arildno

We shouldn't hold on to a too bleak perspective on this, as long as we steel ourselves to endure some harsh measures in the event of a pandemic without functional vaccines:

One tends to forget that tuberculosis in the Western world was successfully combated without really efficient vaccines:

What the health authorities did, was wide-spread use of quarantining infected individuals, and, by being efficient in this, were largely successful of containing outbreaks at manageable levels.

(Tuberculosis remains, however, one of the most widespread diseases today, particularly in 3rd world countries with inefficient local health authorities&restricted access to vaccines/antibiotics.)

If our health authorities (surgeon generals and the like) dare to implement the sufficient restrictions on peoples' movement (i.e, freedom), such a pandemic can be kept in check, even if we at present lack efficient medicines to combat the plague directly.

niman

The technologies exist not only for stockpiling vaccines, but also for predicting new isolates before they emerge

http://www.recombinomics.com/vaccine_development.html

but its easier to do on paper than scale up to make billions of vaccines.

Aquamarine

Influenza is a nightmare to try to quarantine. If I remember correctly an comparison between SARS and influenza, someone holding a lecture might infect a person right next to him with SARS. He might infect everybody listening in a large room with influenza.

Here is a map of the spread of the 1918 epidemic. Click on maps:
http://history1900s.about.com/gi/dyn...e%2Findex.html

Today everything will go much quicker because of airplanes and cars. But I expect that closing of schools, public meetings, entertainment centers and so on will be tried. But that were also tried in 1918 but then there were also many mass gatherings after the war and when the soldiers returned. It will not be possible to stop people from meeting at work and in shops.

Here is an interesting paper that seem to indicate that very strong quarantine might be effective. (I have only read the free abstract):
http://www.pnas.org/cgi/content/abst...?view=abstract

niman

The effectiveness of quarantine really depends of the organism. For SARS quarantine may have helped because peak levels of virus shedding was several days after symptoms (and seasonal factors may have played a fairly major role).

Flu can move around pretty quickly and there are some major issues regarding under devloped contires and rural areas

http://www.recombinomics.com/flu_laos_cambodia.html

I think flu, if human to human transmission is efficient, will be very tough to control by quarantine.

Aquamarine

The government seems to have similar thoughts :
http://www.sciencedaily.com/releases...1116153511.htm

iansmith

I just want to add that one simple sanitary measure was responsible for the decrease of the level of transmission of TB and other infectious microorganism. This measure is called pasteurization. Prior to pasteurization, milk was one of the major infection vector. The Cow TB could be pass to human by milk. This is a major problem in the underdeveloped countries.

The same thing can be applied to influenzae. The major cause of outbreak is bad sanitition at the farm level. Duck pass influenzae to pig or human, human or pig exchange the virus. Sanitation would the best way to go for now because most of the transmission is done via the duck-human path.

Aquamarine

How about killing all ducks? Setting a reward for each killed duck would be quite effective. We can keep some tucked away in zoos. Sure, they are probably important in the ecosystems for eating insects or something similar but that would seem to be a small price for stopping this catastrophe. Not to mention that they are also the silent carriers of the ordinary yearly flu which kills tens of thousands each year in the US alone.

iansmith

Killing all the duck might be an over-reaction. Duck are asymptomic carriers, except with some recent cases.

The problem with chinese farming is that the duck and the pigs are in close contact and the hygene level is below any statisfactory standard. The problem does not really exist in the americas and europe. The solution would be for the chinese government to educated their farmer and change their pratice. The pandemic will not occur if those simple rules are followed.

Aquamarine

The farmers in southeast Asia are still very poor and it may not be possible for them to separate their free-ranging tame birds from wild ducks. That and education would take a long time. Killing the ducks could be done quickly.

niman

Much has been made of pigs as a "mixing vessel". However, H5N1 has evolved considerably and it is not clear that a mammalian mixing vessel is required for H5N1 to acheive human to human transmission.

The most prevelent serotype in Asia is H9N2 and some H9s already have human receptor binding sequences. Moreover, some H5N1 isolates from dead patients grow assymptomatically in ducks, and the ducks excrete high levels of virus.

Thus, a dual infection involving H9N2 and H5N1 in birds could generate a recombinant with the high case mortality associated with H5N1 and human recptor binding properties seen in H9N2

http://www.recombinomics.com/H5N1_H9N2.html

Thus, a pandemic strain can evolve without pigs, humans, or high density farms and a little recombination can go a long way

http://www.recombinomics.com/pandemic_potential.html

tumor

Global pandemic will finish us all, not nukes.