[AI] Avian Flu Daily thread 03.13.05

[LMonty911]

Yesterday's thread is here:

http://www.timebomb2000.com/vb/showthread.php?t=142609


Commentary

Efficient Feline to Feline Transmission of Bird Flu
http://www.recombinomics.com/News/03120503/H5N1_Efficient_F2F.html

[font=Arial,Helvetica]Recombinomics Commentary[/font]
March 12, 2005

>> Probable Tiger-to-tiger Transmission of Avian Influenza H5N1, R. Thanawongnuweche et al <<

The article titled above will be published in the May issue of Emerging and Infectious Diseases. Its conclusion is reflected in the title. The article describes the bird flu epidemic among tigers at the Sri Racha Tiger Zoo in Thailand last summer. The zoo held 441 Bengal tigers at the start of the epidemic and eventually 147 died, 45 from H5N1 infections and 102 from euthanization because of the advanced state of their H5N1 infection. The epidemic had a bimodal distribution of onset dates. Small numbers of tigers died daily initially, followed by a large surge, consistent with tiger to tiger transmission.

The epidemic began with a small number of H5N1 infected chickens fed to the tigers. The details will be in the publication on how many tigers ate the chickens, when they were quarantined, and when Tamiflu treatment was initiated. However, it is clear that one third of the tigers died, and the case fatality rate in those that were infected may be much closer to 100% than the 33% for the entire population. The epidemic provides a sobering picture of how well H5N1 transmits and how ineffective the control measures are. The details will clearly highlight inadequate pandemic preparedness planning. These plans take an optimistic view of case fatality rates and effectiveness of antiviral medicines in halting an H5N1 pandemic.

Although the details have not been published, the sequences of isolates from tigers have been published. The sequences of the HA, NA, NS, PB2 genes of the tigers (A/tiger/Chonburi/Thailand/CU-T3/04(H5N1) and A/tiger/Chonburi/Thailand/CU-T7/04(H5N1) are very similar to the sequences of isolates from a tiger and leopard (A/tiger/Suphanburi/Thailand/Ti-1/04(H5N1) and A/leopard/Suphanburi/Thailand/Leo-1/04(H5N1) that were infected in a nearby zoo in the early part of 2004. These sequences do not contain human reassorted genes, yet the H5N1 was very efficiently transmitted to a large number of tigers quarantined in the zoo.

However, the sequences are also closely related to other avian isolates in Thailand as well as the sequences from the mother of the index case frequently cited as the best example of human-to-human transmission of H5N1. The sequences are also closely related to other human isolates from Thailand and Vietnam. The isolates can be used to experimentally infected domestic cats under controlled laboratory settings, and these infections are also transmitted cat to cat.

Thus, feline isolates closely related to human isolates are efficiently transmitted cat to cat, domestic and wild, and do not require additional genetic changes or human reassorted genes.

Reassurances that human isolates do not contain human influenza genes do not address efficient mammal-to-mammal transmission seen at the zoo and lab.

The recent clustering of human bird flu cases in Thai Binh is cause for concern. The familial clusters are bimodal, a strong indicator of human-to-human transmission. Moreover, the extended transmission chain involving both family members and health care workers are indications that human-to-human transmission is becoming more efficient. There is no evidence that human reassortants are required for improved efficiencies.

H5N1 has evolved over the years to broaden both host ranges and tissue tropism in the absence of any reported human reassortment. Thus, repeated assurances on the lack of human reassortment or failure to acquire a human receptor binding domain means little.

H5N1 has evolved into a virus associated with a high case fatality rate and extended human to human transmission in the absence of these genetic changes.

 

[LMonty911]

Institute develops preventative vaccine against new flu
Sunday, March 13, 2005 at 10:13 JST
TOKYO — Researchers at the National Institute of Infectious Diseases in Tokyo have developed a preventative vaccine against a new type of flu which is likely to originate from bird flu, informed sources said on Saturday.

The sources said researchers have already proved the effectiveness of the vaccine, which was developed by using the H5N1 type virus of avian flu, on animals. (Kyodo News)

http://www.japantoday.com/e/?content=news&id=330630

 

[LMonty911]

http://www.latimes.com/features/hea...mn?coll=la-health-medicine&ctrack=2&cset=true

 

[LMonty911]

Scientists slams UK bird flu plans
13/03/2005

A leading scientist has attacked the government's preparations to deal with a potential human bird flu pandemic.

Professor Hugh Pennington, president of the Society for General Microbiology, said more than two million Britons could die if there was a contagious outbreak of the deadly avian flu in the UK.

The scientist told the Independent on Sunday that a pandemic was both imminent and inevitable, adding: "If the virus moves into people there will be no stopping it. It will be here before we know it."

Medical experts have predicted that around one in four people in Britain could be affected by a flu pandemic, with 50,000 being killed if contingency plans are not implemented. However, Professor Pennington believes this is overly optimistic and has compared the situation to complacency over BSE a decade ago.

"They (the government) hope that by the time they have to spend money the problem will have gone away," he said.

The H5N1 bird flu virus has killed 47 people in Asia and experts believe it could mutate into a strain easily transmitted in humans that could kill millions of people worldwide. There is, as yet, no evidence of sustained person-to-person transmission of the virus.

The government has ordered enough anti-viral drugs to treat about one quarter of the population, which will be delivered over the next two years.

Former Health minister Edwina Curry has called on the government to heed Professor Pennington's warning.

She told BBC One's Breakfast with Frost: "If I were the health minister I would have a meeting tomorrow morning and I would be vaccinating people, for example, in the Health Service by the end of the week. I would rather be ready."

Yesterday Vietnamese health officials revealed that a 41-year-old nurse who had cared for a bird flu victim in the country's northern Thai Binh province had contracted the disease, increasing fears that it is beginning to spread from person to person. She is the second nurse in a week to have gone down with the flu.

http://www.dehavilland.co.uk/webhost.asp?wci=default&wcp=NationalNewsStoryPage&ItemID=13017456&ServiceID=8&filterid=10&searchid=8

 

[LMonty911]

http://www.thanhniennews.com/healthy/?catid=8&newsid=5546

Vietnam nurse tested negative of bird flu

Vietnam has successfully tested bird flu vaccine on poultryA female nurse suspected to have bird flu has been tested negative of the disease, Vietnamese health officials announced Sunday. [font=arial, helvetica, sans-serif]Test results provided by the Center for Tropical Diseases in Hanoi showed the nurse was free of H5N1, the deadly strain of the avian influenza, said Vietnam’s Central Institution of Sanitation and Epidemiology on March 13.[/font]

[font=arial, helvetica, sans-serif]The nurse, who worked in a hospital in the Red River Delta province of Thai Binh, was previously thought to be infected and hospitalized for treatment.[/font]

[font=arial, helvetica, sans-serif]Another male nurse, also infected with bird flu 4 days ago after having direct contact with infected patients, has shown signs of improvement, doctors said.[/font]

[font=arial, helvetica, sans-serif]The institution is now carrying out extensive search on how the virus gets circulated in the province of Thai Binh, where a number of people were found eaffected by the disease.[/font]

 

[LMonty911]

Fear of bird flu pandemic grows as more humans infected
13 Mar 2005

http://www.medicalnewstoday.com/printerfriendlynews.php?newsid=21169

Health officials around the world look on anxiously as Vietnamese officials confirm another person has come down with bird (avian) flu - this time a nurse who had been attending a bird flu patient. This is the second nurse in less than a week.

Experts worry that the virus could mutate, become transmissible from human to human - resulting in a worldwide pandemic.

Countries are already beginning to build up national stocks of antivirals - the UK has 14m of them in the form of Tamiflu (an antiviral drug).

About two thirds to three quarters of bird flu patients die.

What is Bird Flu?

Bird flu or avian influenza is an infectious disease of birds ranging from mild to severe form of illness. All birds are thought to be susceptible to bird flu, though some species are more resistant to infection than others. Some forms of bird flu can cause illness to humans.

What causes bird flu?

Bird flu is caused by different subtypes of influenza A virus affecting chickens, ducks and other birds Viruses which cause mild disease can mutate into viruses that can cause serious disease (highly pathogenic).

To date, all outbreaks of the highly pathogenic form have been caused by Influenza A /H5N1 virus, the only subtype that cause severe disease in humans.

How is bird flu transmitted in chickens and other birds?

-- Direct contact with discharges from infected birds, especially feces and respiratory secretions

-- Contaminated feed, water, cages equipment, vehicles and clothing

-- Clinically normal waterfowl and sea birds my introduce the virus into flocks

-- Eggs from infected hens can break and contaminate incubators

Birds that survive infection excrete virus for at least 10 days, orally and in feces. Highly pathogenic viruses can survive for long periods in tissue, water and the environment, especially when temperatures are low.

How do outbreaks of bird flu spread within the country?

1. Domestic birds can get the infection when they:

-- roam freely

-- share water supply with wild birds

-- use a water supply that might be contaminated by infected droppings

2. Contaminated equipment, vehicles, feeds, cages, or clothing, especially shoes can carry the virus from farm to farm

3. Wet markets where live chickens and other birds are sold under crowded and sometimes unsanitary conditions

How is bird flu transmitted to humans?

Bird flu is transmitted to humans from direct or indirect contact with infected wild ducks and chickens through infected aerosols, discharges and surfaces.

A person handling or taking care infected chickens or came near or inside a poultry or market where there are sick chickens can inhale the particles from dried discharges or feces with the bird flu virus.

Discharges can get in contact with the nose or eyes of a person handling infected chickens.

There is no reported case of bird flu in humans after handling dressed chicken. Since the virus is easily inactivated by heat, one does not get bird flu from thoroughly cooked chicken meat.

To date, there is no evidence of human-to-human transmission.

Written by Christian Nordqvist, Editor, Medical News Today

 

[LMonty911]

http://www.recombinomics.com/News/03130501/PP_Detection.html

Bird Flu Pandemic Preparedness Detection Issues

[font=Arial,Helvetica]Recombinomics Commentary[/font]
March 13, 2005

>>Vietnamese health officials said Saturday they suspect a second nurse who cared for a bird flu patient has contracted the disease that's killed 46 people across the region.<<

The increased efficiency of human-to-human transmission of H5N1 in Thai Binh province has focused attention on pandemic preparedness. However the scandalously poor monitoring of H5N1 and the lack of a definition of the diseases it causes creates significant problems in control and preparedness areas. The decrease in transparency linked to the spread of H5N1 is cause for concern, as is he misinformation of human-to-human transmission.

Bird flu cases have been narrowly defined and many clear cases have been actively excluded because of a lack of testing and a lack of sensitivity of the tests that are run. This has led to a significant under-reporting of cases at all levels and a narrowly focused vaccine plan, which increases the likelihood of the development of an ineffective vaccine.

Although WHO has recently indicated that the definition of H5N1 diseases will be expanded, there was evidence in January of 2004 in Thai Binh that H5N1 would cause a spectrum of clinical diseases. Prior investigations of H5N1 cases in 1997 as well as infections in wild and domestic birds clearly showed that multiple versions of H5N1 could infect the same host, resulting in broad tissue tropisms and both reassorted and recombined viruses.

The results from a familial cluster in Thai Binh in January of 2004 demonstrated that these earlier observations could be extended to the 2004 H5N1 infecting large numbers of patients in Vietnam and Thailand. The infections generated a very high case fatality rate and the familial cluster clearly demonstrated that a comprehensive approach was required.

The cluster showed human-to-human transmission, dual infections, and distinct clinical presentations with a 100% fatality rate. Instead of initiating a comprehensive program, the human-to-human transmission was discounted, most recently by the fact that the two H5N1 isolates detected in the sisters were different.

The index case for the cluster had just been married and developed typical bird flu symptoms. No samples were collected but when his two sisters, who had cared for him, also fell ill on the same day and were admitted to the hospital in the same day, samples were collected. Initial test results were inconclusive, but the sisters subsequently tested positive and died the same day, although one had a respiratory symptoms while the other had a gastrointestinal illness. Sequencing showed identified differences between the two H5N1 isolates.

Although these results were consistent with several examples of multiple H5N1 strains infecting the same animal and producing various clinical symptoms, the WHO adopted a narrow case definition that focused on the respiratory disease. They also adopted a rigorous case definition that required multiple tests and excluded cases such as the index case, because on no sample collection. This approach reduced the number of cases and clusters, which lead to significant undercounts.

Recently, publication of the detection of H5N1 in another case that did not present with classical symptoms, as well as the death of a sibling, raised questions about the narrow WHO definition. The concerns were increased when samples from additional atypical patients also tested positive for H5N1. However, the concerns related to these cases were compounded by false negative results on samples from these patients. In four of seven instances the re-tests were positive, but negative results on three of the retests raised sensitivity issues.

Thus, the current status of H5N1 in Vietnam and nearby countries is unclear because of the lack of testing coupled with false negatives.

However, the most recent cases from Thai Binh appear to have reduced fatality rates in association with increased transmission efficiencies. There are now at least four patients that are linked, two of whom are health care workers. The transmission chain extends over a three week period, which is markedly longer than more limited familial transmissions described earlier

The high case fatality rate facilitated the identification of cases. A lower case fatality rate would allow atypical cases to more easily be confused with other diseases, such as cholera, dengue fever, and typhoid, common misdiagnoses in the 1918 flu pandemic.

Transparency issues have complicated the monitoring issues. The cases in the south were well covered in media reports, but WHO was not officially notified until recently. Moreover, there has been no news on cases in the south since the beginning of February. Thus testing, contact tracing, and reporting all remain highly suspect in Vietnam, although similar problems may be present in Thailand and Indonesia as well as other countries.

Thus, the mere presence of H5N1 in endemic areas is uncertain, creating significant issues for control as well as identification of relevant isolates with genetic changes.