Information on Bird flu, from NEJM and W.H.O.

[bluedawg12]

From what I have read the concern for avian flu is that it has jumped species. Bird to human infection occurred from poultry workers.

Felids, tigers, got infected by eating infected poultry in zoos and by experimentation on domestic cats.

As of 9-29-05 NEJM article no human to human infection has occurred.

The concern is that the virus may mutate. There is speculation that anti-viral medications used on poultry in China may have hastened resistence and or mutation.

The infection is particularly lethal and death rate is high even among patients who receive hospital ICU care.

The medication currently recommended is an anti-viral called osletamivir, but concern about resistence to this medication has been raised.

If the virus mutated and became a pathogen that could be spread person to person early treatment with in 48 hours may reduce the seriousness of the infection. But patients with serious infection require ICU ventilator support- clearly a situation that could not be handled on a large scale.

Instead of catastrophizing, the government needs to make sure that there are sufficient doses of oseltamivir for early treatment with in 48 hours of symptoms.

The first outbreak of avian influenza A(H5N1) virus in humans occurred in Hong Kong in 1997. Infection was confirmed in 18 individuals, 6 of whom died. Infections were acquired by humans directly from chickens, without the involvement of an intermediate host. The outbreak was halted by a territory-wide slaughter of more than 1.5 million chickens at the end of December 1997. The clinical spectrum of H5N1 infection ranges from asymptomatic infection to fatal pneumonitis and multiple organ failure. Reactive hemophagocytic syndrome was the most characteristic pathologic finding and might have contributed to the lymphopenia, liver dysfunction, and abnormal clotting profiles that were observed among patients with severe infection.

Gastrointestinal manifestations, raised liver enzymes, renal failure unrelated to rhabdomyolysis, and pancytopenia were unusually prominent. Factors associated with severe disease included older age, delay in hospitalisation, lower-respiratory-tract involvement, and a low total peripheral white blood cell count or lymphopenia at admission
..........
World Health Organization. WHO interim guidelines on clinical management of humans infected by influenza A(H5N1). February 20, 2004. (Accessed September 2, 2005, at

http://www.who.int/csr/disease/avian_influenza/guidelines/Guidelines_Clinical%20Management_H5N1_rev.pdf

.........
http://www.who.int/csr/disease/influenza/globalagenda/en/index.html
Info at the WHO link.

..................
New England Journal of Medicine

Previous Volume 353:1374-1385 September 29, 2005 Number 13

Avian Influenza A (H5N1) Infection in Humans
The Writing Committee of the World Health Organization (WHO) Consultation on Human Influenza A/H5

“An unprecedented epizootic avian influenza A (H5N1) virus that is highly pathogenic has crossed the species barrier in Asia to cause many human fatalities and poses an increasing pandemic threat. ..Because many critical questions remain, modifications of these recommendations are likely...

>Animal to Human

In 1997, exposure to live poultry within a week before the onset of illness was associated with disease in humans, whereas there was no significant risk related to eating or preparing poultry products or exposure to persons with influenza A (H5N1) disease.6


Human to Human
Human-to-human transmission of influenza A (H5N1) has been suggested in several household clusters16 and in one case of apparent child-to-mother transmission (Table 3).20 Intimate contact without the use of precautions was implicated, and so far no case of human-to-human transmission by small-particle aerosols has been identified.
Serologic surveys in Vietnam and Thailand have not found evidence of asymptomatic infections among contacts.Recently, intensified surveillance of contacts of patients..and an increased number and duration of clusters in families in northern Vietnam,21 findings suggesting that the local virus strains may be adapting to humans.
However, epidemiologic and virologic studies are needed to confirm these findings.

Conclusions

Infected birds have been the primary source of influenza A (H5N1) infections in humans in Asia. Transmission between humans is very limited at present, but continued monitoring is required to identify any increase in viral adaptation to human hosts...
Despite recent progress, knowledge of the epidemiology, natural history, and management of influenza A (H5N1) disease in humans is incomplete. There is an urgent need for more coordination in clinical and epidemiologic research among institutions in countries with cases of influenza A (H5N1) and internationally. “ <
...........

[bluedawg12]

1. Avian Influenza A (H5N1) in 10 Patients in Vietnam

The New England Journal of Medicine
Volume 350:1179-1188 March 18, 2004 Number 12

Avian Influenza A (H5N1) in 10 Patients in Vietnam

"There was no definitive evidence of human-to-human transmission. Eight patients died, one patient has recovered, and one is recovering.

Conclusions Influenza A (H5N1) infection, characterized by fever, respiratory symptoms, and lymphopenia, carries a high risk of death. Although in all 10 cases the infection appears to have been acquired directly from infected poultry, the potential exists for genetic reassortment with human influenzaviruses and the evolution of human-to-human transmission. Containment of influenza A (H5N1) in poultry throughout Asia is therefore urgently required. "

[bluedawg12]

9. I am kicking this in case somebody wants this info.

:kick:

[bluedawg12]

2. Probable Person-to-Person Transmission of Avian Influenza A (H5N1)

The New England Journal of Medicine


Volume 352:333-340 January 27, 2005 Number 4

Probable Person-to-Person Transmission of Avian Influenza A (H5N1)
Results The index patient became ill three to four days after her last exposure to dying household chickens. Her mother came from a distant city to care for her in the hospital, had no recognized exposure to poultry, and died from pneumonia after providing 16 to 18 hours of unprotected nursing care. The aunt also provided unprotected nursing care; she had fever five days after the mother first had fever, followed by pneumonia seven days later. Autopsy tissue from the mother and nasopharyngeal and throat swabs from the aunt were positive for influenza A (H5N1) by RT-PCR. No additional chains of transmission were identified, and sequencing of the viral genes identified no change in the receptor-binding site of hemagglutinin or other key features of the virus. The sequences of all eight viral gene segments clustered closely with other H5N1 sequences from recent avian isolates in Thailand.

Conclusions Disease in the mother and aunt probably resulted from person-to-person transmission of this lethal avian influenzavirus during unprotected exposure to the critically ill index patient.

[bluedawg12]

8. This says "probable" that's why I am not convinced

that human 2 human transmission has been established thus far.

[phantom power]

3. A mutation for efficient human-to-human transmission is the danger.

So far, there have been a few instances of "single-chain" human-to-human transmissions. But it's likely that a strain will eventually evolve that transmits easily, and then these chains will grow in length, branch out, etc. At that point, a pandemic is possible if the outbreak cannot be contained.

[bluedawg12]

4. Thanks for the info. I think that the danger is real, I just don't trust

that fema-bearing varmit shrub to protect us.

Also, it seems that a vaccine is more unlikely than having anti-viral medications around in stock piles? Thoughts?

[phantom power]

5. Neither the vaccine nor anti-virals will be completely effective

It's probably easier to mass-produce something like tamiflu, simply because we already know how to make it. My understanding is that it's about 30% effective, and only if you take it immediately, or prior to infection.

Mass-production of vaccine for H5N1 has begun, however the catch is that whatever the pandemic strain turns out to be, it will be different than H5N1. So the vaccine will also be only partially effective against it. It's impossible to predict how different the final strain will be. The more different it is, the less effective the vaccine will be. On the other hand, any difference is also likely to imply a lower mortality rate. The pandemic strain will (most likely) have a lower mortality rate than H5N1, but how much lower is impossible to predict.

When/if the pandemic begins, it will be possible to create a vaccine specifically for that strain. Unfortunately, it takes many months to develop and mass-produce, so the initial pandemic will probably run it's course before there is vaccine. If we get lucky, they may contain it in Asia, long enough to develop a vaccine before it spreads to other continents. Not much consolation for Asia, though.

[bluedawg12]

6. The lag in vaccine production makes it less practical for treament

I would go with early treatment with the anti-viral medication.

[bluedawg12]

7. Are We Ready for Pandemic Influenza?

Good over view on what the government could be doing.


http://www.sciencemag.org/cgi/content/full/302/5650/1519?ijkey=f29848fa7c7eb0d31136ffae8fbf88eca9cc7530


Review

Are We Ready for Pandemic Influenza?
Richard J. Webby and Robert G. Webster*

"Antiviral Drugs

"A global influenza strategy would call for the stockpiling of influenza antiviral drugs

A sufficiently large supply of anti-influenza drugs

A vaccine matching the subtype of the emerging pandemic influenza strain

The preparation, testing (safety and clinical trials)

An improvement in the global influenza vaccine manufacturing capacity.


The conclusion of this analysis is inescapable: The world will be in deep trouble if the impending influenza pandemic strikes this week, this month, or even this year.
"