At Qinghai Lake in China, where in 2005 alone, more than 6000 wild birds died, migrating birds are being tracked by satellite, part of a series of investigations that began after highly pathogenic avian influenza (H5N1 subtype) first swept the region in 2005. The studies aim to pinpoint the viral reservoir and the role that wild birds play in transmission. No reservoir has yet been found, but transmission routes have come into clearer focus.
For more than a decade there has been increasing interest in the use of nanotechnology and microarray platforms for diagnostic applications. In this report, we describe a rapid and simple gold nanoparticle (NP)-based genomic microarray assay for specific identification of avian influenza virus H5N1 and its discrimination from other major influenza A virus strains (H1N1, H3N2).
Results: Capture and intermediate oligonucleotides were designed based on the consensus sequences of the matrix (M) gene of H1N1, H3N2 and H5N1 viruses, and sequences specific for the hemaglutinin (HA) and neuraminidase (NA) genes of the H5N1 virus.
Viral RNA was detected within 2.5 hours using capture-target-intermediate oligonucleotide hybridization and gold NP-mediated silver staining in the absence of RNA fragmentation, target amplification, and enzymatic reactions. The lower limit of detection (LOD) of the assay was less than 100 fM for purified PCR fragments and 1000 TCID50 units for H5N1 viral RNA.
Conclusions: The NP-based microarray assay was able to detect and distinguish H5N1 sequences from those of major influenza A viruses (H1N1, H3N2).
The new method described here may be useful for simultaneous detection and subtyping of major influenza A viruses.
The Ministry raised the minimum level of anti-dumping duties it first announced in February this year. It will charge duties of between 50.3 percent and 105.4 percent on imports beginning Sept. 27, it said in a statement on its website on Sunday.
The chicken parts ruling comes on the heels of a U.S. congressional panel approval of a bill that would let the U.S. Department of Commerce apply countervailing duties to offset undervalued currencies, a bill targetted at China.
That bill, which stems from Congressional criticism of China for keeping its currency artificially low, will be voted on by the House next week, and critics fear it could further fuel Sino-U.S. trade tensions.
“The ruling is that there is a causal relationship between the U.S. dumping of broiler products and the losses suffered by domestic businesses,” the Ministry said.
Chicken wings and feet, virtually worthless in the U.S. market, are a delicacy in southern China. Many U.S. poultry producers count on the Chinese market to round out their profits.
Tyson Foods, an active investor and lobbyist in China, got the lowest duty of 50.3 percent, still higher than preliminary duties of 43.1 percent announced in February.
Other U.S. poultry producers who appealed the initial ruling found duties lowered. Keystone Foods will be assessed 50.3 percent and Pilgrim’s Pride Corp 53.4 percent, while Sanderson Farms and 31 other American companies face duties of 51.8 percent.
Other U.S. producers face a 105.4-percent duty, the Ministry said. The duties will be applied for five years.
“We’ve allowed U.S. chicken parts into our market for ten years but they don’t let our products in. This is an unequal trade situation,” Wang Xiulin, president of the Chinese Poultry Association, told Reuters.
“The anti-dumping ruling is unequivocally a good thing for our industry. It’s the American’s problem now to resolve this issue.”
U.S. poultry producers had lobbied hard for Chinese companies making cooked poultry to gain access to U.S. markets, after a Congressional ban on discussions of such imports following a series of deadly food safety scandals in China.
The World Trade Organisation in July ruled for China and against that ban, after Congress had already ended it under pressure from U.S. producers.
In late August, the Ministry of Commerce imposed anti-subsidy duties ranging from 4 percent to 30.3 percent on U.S. chicken products, after it concluded U.S. producers had received improper government subsidies and hurt the domestic industry.
U.S. chicken products acount for almost 90 percent of China’s imports. The additional duties could well fuel a return to rampant smuggling of chicken wings and feet, especially into southern China.
A new outbreak of the strain of bird flu that is deadly to humans has struck Ukraine after being kept under control for two years, veterinarians said on Friday.
Ukraine’s Veterinary Inspectorate said the outbreak was detected this week in the village of Rovnoye in the Crimean peninsula, the same region hit in late 2005.
A total of 153 birds died suddenly at a private firm where more than 25,000 poultry were kept.
“Yesterday, tests were concluded and DNA of the H5N1 virus was found,” a veterinary inspectorate spokesman, Anatoly Osadchi, told Reuters.
“The village has been sealed off, guards have been posted at entry points and a quarantine is in place. All the birds are being incinerated.”
The inspectorate said the first six deaths were noted on Tuesday, followed by dozens more over the next two days.
The first outbreak of bird flu was detected in Ukraine in late 2005, in northern Crimea — a major stopping point on migratory bird routes. About 30 villages were affected at that time and tens of thousands of birds were destroyed.
Governments need to stockpile different sorts of flu drugs — not just Roche Holding AG’s Tamiflu — to counter the danger of resistance in a pandemic triggered by bird flu, British experts said on Wednesday.
The warning could boost demand for GlaxoSmithKline Plc’s inhaled medicine Relenza, which has been largely overlooked in favor of Roche’s more convenient pill.
Scientists analyzing the structure of a key flu virus protein found that both H5N1 and seasonal flu could develop resistance to Tamiflu, while still remaining highly susceptible to Relenza.
“What this research shows is that stockpiling any one drug to prepare for a potential H5N1 pandemic is unlikely to provide adequate cover,” said Steve Gamblin of the National Institute for Medical Research in London.
“In order not to be outflanked by the virus, it will be necessary to have stocks of both existing drugs.”
There is a also “a huge imperative” to develop further drugs since the best way to treat patients in the long term is likely to be a three- or four-pronged approach, similar to the multi-drug cocktails used to fight HIV and AIDS, Gamblin said.
A new influenza drug, peramivir, is being developed by Biocryst Pharmaceuticals Inc but it must be injected and it has not performed well in clinical trials. Two older flu drugs are available but flu viruses have quickly developed resistance to them, although some experts believe they may be useful in cocktails with newer drugs.
Both flu viruses and HIV have a high rate of mutation, which allows them to adapt to the treatments devised to tackle them.
To date, H5N1 remains mainly a virus affecting birds, although it has killed more than 200 people since 2003. But scientists say it is the most likely source of the next deadly flu pandemic in humans, since it may soon mutate into a form transmitted easily from person to person.
Tamiflu, known generically as oseltamivir, and Relenza, or zanamivir, target the viral protein neuraminidase, which helps release newly made viruses so that they can spread infection.
Using a technique called X-ray crystallography, Gamblin and colleagues examined the exact mutation in protein structure that can make some flu virus resistant to Tamiflu and showed the different nature of Relenza meant it was still effective.
Their results were published in the journal Nature.
The main seasonal flu virus circulating this year in the United States and Canada as well as parts of Europe has shown higher resistance to Tamiflu. But cases of resistance remain relatively rare.
Tamiflu, which was originally developed by Gilead Sciences Inc, had sales of 1.9 billion Swiss francs ($1.8 billion) in 2007, making it a major profit driver for the Swiss group. Relenza, which Glaxo licensed from Australia’s Biota Holdings Ltd, sold 262 million pounds ($510 million) last year.
Serum Institute of India resumes research on vaccine for bird flu that experts say could be more severe than H1N1
After launching a nasal spray vaccine for H1N1 virus, the Serum Institute of India in Pune have now begun research on a vaccine for another deadly killer — the H5N1 virus that causes avian influenza, commonly known as bird flu.
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| Crusader: Adar Poonawala, executive director of Serum Institute of India in Pune, launches a nasal spray vaccine for H1N1 virus. PIC/DATTA KUMBHAR |
A scientist, who was in Mumbai for the launch of the nasal vaccine, said, “We don’t want anyone to panic but H5N1 can be severe than swine flu and may affect more people.”
Work on the H5N1 vaccine had been put on hold, since the swine flu pandemic broke out.
H1N1 project director Rajiv Dhere confirmed the same.
“We were developing the H5N1 vaccine and had reached the clinical trial stage in March 2009 itself. Then swine flu struck and the WHO instructed us to concentrate on developing a vaccine for the problem in hand.
Therefore, we had to vacate the building where the H5N1 work was going on and dedicate that entire space to H1N1. Now, however, we are working on the H5N1 vaccine again,” said Dhere.
Avian influenza had briefly caused a stir when some cases were detected among poultry in West Bengal in January this year. However, no human cases had been detected.
Executive director at the institute, Dr S S Jadhav, said that clinical trials on animals would begin shortly. “We are also keenly working on developing a vaccine for swine flu that can be administered to children below the age of three. The present nasal spray is not suitable for children. There should be some progress by the end of this year,” said Jadhav.
A meeting in Vietnam has seen ministers from 70 countries reaffirm their commitment to battling H5N1 avian influenza into the future.
The Hanoi Declaration proposes increased communication between professionals and the public, strengthened public health and veterinary systems as well as improved international and regional cooperation.
David Nabarro, the UN’s senior coordinator for avian and pandemic flu, told the Reuters news agency increased biosecurity was the key so as to avoid mid-size traders acting as avian flu transmission hubs.
Bird flu outbreaks have generally been dealt with by culling birds, but health authorities were now trying to look further up the supply chain, Mr Nabarro said.
Since 2003 the H5N1 strain of bird flu has infected a confirmed 493 people and killed 292, or nearly 60%. Most of the deaths have been in Asia. Almost all of these infections were believed to have taken place directly from birds to humans, but health experts fear it could mutate to a form that could be easily transmitted human-to-human, sparking a global pandemic.
“We are finding that if we have a much clearer understanding of the patterns of movement of the virus, and in particular build-up points, we can then do much more sophisticated control strategies that have less economic damage for poorer people and more impact,” Mr Nabarro told Reuters.
“It’s the medium-sized commercial poultry traders who have yet to introduce good quality biosecurity that are the ones on whom we are focusing most of our attention these days.”
There have been two sizeable clusters of human deaths from the disease so far – one in which eight family members died on the Indonesian island of Sumatra in 2006 and another in Turkey in which eight people were infected and four died.
In the Sumatra case, the virus went on for two generations and then stopped – a 37-year-old woman was believed to have infected her 10-year-old nephew, who went on to infect his father.
Another smaller probable case of human-to-human transmission occurred in Thailand in 2004, where a mother died after tending to her sick daughter for hours.
The conference in Hanoi brought together hundreds of officials from around the world.
Most people may not immediately make the connection between avian influenza and humans. Avian influenza is rare in humans. When it does infect a human, the virus often causes serious illness or death.
Avian influenza has been getting increasing worldwide attention from medical authorities. A new subtype of the virus called H5N1, which first infected chickens and then humans in Hong Kong in 1997, can cause disease with a high rate of mortality (death) in humans.
Bird flu is caused by a virus. There are several different subtypes of the virus that have been known to cause the condition in people, including H5N1, H7N7, and H9N2. The letters H and N in the subtype name stand for proteins found on the surface of the virus that are used to distinguish between different subtypes.
Pathogenicity is a measure of how likely a virus is to cause disease. In the case of the bird flu virus, it can have either low or high pathogenicity. Different subtypes of the virus cause either a mild form of the condition or an extremely contagious and highly dangerous form that spreads quickly.
Influenza viruses are constantly changing their genes. This process is called mutation. It can occur by one of two methods:
These genes determine whether the virus will cause a mild condition or a deadly condition in the infected person or animal. The bird flu virus that affects birds has at least 15 different subtypes and usually only affects the bird population. The most dangerous subtype is the H5N1 subtype.
When the virus is found in humans, it is said to have “jumped the species barrier.” This means that the virus has mutated in a way that allows it to cause the condition in humans. Because humans have no natural protection or immunity to the virus, they are likely to become ill very quickly and possibly die due to complications of the bird flu.
Bird to human transmission: Birds such as turkeys, geese, and domestic chickens come in contact with the virus from food, water, or particles contaminated with the virus. The virus can be shed in the droppings of migratory birds since they are natural carriers and is able to survive for 3 months in cool temperatures. It can also survive in water at 0°C for more than 30 days and at 22°C for up to 4 days. Transmission of the virus from birds to humans occurs when a person working closely with these animals inhales dust particles containing the virus or by other means.
In countries where live birds (e.g., chickens, geese, turkeys) are sold in markets along with pigs or raised near pigs, the possibility of the virus recombining with other subtypes is greater. This is because both human and avian viruses can infect pigs. If a pig is infected with both viruses at the same time, different parts of the avian and human viruses can mix with each other. Later, the avian virus that has picked up some genes from the human form of the influenza virus is able to more easily cause the condition in humans.
Human to human transmission: Whether the virus is able to move efficiently from person-to-person is under investigation.
Symptoms of the condition in birds depend on the form of the virus that infects a bird. A virus that is not highly pathogenic causes mild illness. This form of the condition produces ruffled feathers or a decrease in egg production in infected birds. The highly pathogenic form of the virus can kill so quickly that once the virus enters the bird, the bird may die the same day.
In humans, bird flu causes symptoms similar to the typical flu. People may complain of any of the following:
The symptoms usually appear within 1 to 5 days after contact with the virus. The condition is life-threatening because of the complications that can occur. These include viral pneumonia and respiratory distress. A mild eye infection may also be a symptom of the condition.
A doctor can perform tests that help identify the flu virus. If you have recently travelled to an area of the world where avian flu occurs and have any of the symptoms of the flu, you should see your doctor.
Be sure to tell the doctor where you have visited and whether or not you were at a farm or open market with live animals.
There is no vaccine currently available to protect humans from bird flu, although one is under development. There are treatments to help those people with bird flu. M2 inhibitors (such as amantadine*) andneuraminidase inhibitors (such as oseltamivir and zanamivir) are the two classes of medication that are available. However, the World Health Organization (WHO) has found that the bird flu viruses in fatal cases in Vietnam are usually resistant to the use of M2 inhibitors.
Preventing the spread of bird flu is a global effort. Steps taken to prevent the disease or stop the spread of disease include:
There are ways to protect yourself from catching the bird flu. People who are travelling in areas where the bird flu has occurred need to take special precautions to reduce the chance of exposure to the bird flu virus. Keep these tips in mind when travelling:
New research has revealed that the swine flu virus can be spread through the eyes, underscoring the importance of personal hygiene to avoid the disease.
University of Hong Kong researchers compared the ability of swine flu H1N1 and the seasonal H1N1 and H3N2 flu viruses to replicate in cells and tissue samples from the human upper and lower respiratory tract and in the cells lining the surface of the eye.
It found that swine flu is more efficient than seasonal flu in infecting the eyes.
The study by the HKU departments of microbiology and pathology was published in the American Journal of Pathology.
“We found that pandemic H1N1 flu can actually infect and replicate in conjunctiva [the eyes] while the seasonal flu cannot,” said Michael Chan Chi-wai, research assistant professor of the department of microbiology.
“The public should be made more aware to wash their hands before rubbing their eyes. It is an important route for pandemic flu.”
The research also found that unlike bird flu H5N1, swine flu did not lead to a hyper-activation of the human cell cytokine response, a mechanism believed to contribute to the severity of bird flu H5N1 infection.
Cytokines are proteins secreted by the immune system.
So even if the lungs are infected by swine flu, it is usually mild, Chan said.
The researchers also found that the swine flu and seasonal flu viruses have comparable efficiency in replicating in the upper respiratory tract.
But at 33 degrees Celsius, swine flu replicates to higher levels in the bronchus, he added.
The findings indicate that swine flu differs from seasonal flu viruses in “subtle ways and these differences may explain why the pattern of illness it causes is not identical to that caused by seasonal flu,” the team said.
Meanwhile, Secretary for Food and Health York Chow Yat-ngok defended the effectiveness of the swine flu vaccine, saying people who came down with the disease had not been inoculated.
“This is already good proof [for the need of a vaccine]. It has actually proved that it works,” he said.
He insisted the vaccine supply is an insurance in case of need.
“The reason why we have the vaccine is to ensure that we have sufficient supply for all the patients who are in need.
“Obviously, we have sufficient supply for all the five at-risk groups in Hong Kong, plus some extra for people who are willing to take the vaccine,” he said.
“It is important that we have it in reserve and are able to use it if necessary.
“It is like insurance. It is like something you put there in case you need it.”
So far, 157,440 people have been vaccinated against swine flu.
Influenza A virus subtype H5N1, also known as “bird flu“, A(H5N1) or simply H5N1, is a subtype of the Influenza A virus which can cause illness in humans and many other animal species. A bird-adapted strain of H5N1, called HPAI A(H5N1) for “highly pathogenic avian influenza virus of type A of subtype H5N1″, is the causative agent of H5N1 flu, commonly known as “avian influenza” or “bird flu”. It is enzootic in many bird populations, especially in Southeast Asia. One strain of HPAI A(H5N1) is spreading globally after first appearing in Asia. It is epizootic (an epidemic in nonhumans) and panzootic (affecting animals of many species, especially over a wide area), killing tens of millions of birds and spurring the culling of hundreds of millions of others to stem its spread. Most references to “bird flu” and H5N1 in the popular media refer to this strain.
According to the FAO Avian Influenza Disease Emergency Situation Update, H5N1 pathogenicity is continuing to gradually rise in endemic areas but the avian influenza disease situation in farmed birds is being held in check by vaccination. Eleven outbreaks of H5N1 were reported worldwide in June 2008 in five countries (China, Egypt, Indonesia, Pakistan and Vietnam) compared to 65 outbreaks in June 2006 and 55 in June 2007. The “global HPAI situation can be said to have improved markedly in the first half of 2008 cases of HPAI are still underestimated and underreported in many countries because of limitations in countrydisease surveillance systems”. On December 21, 2009 the WHO announced a total of 447 human cases which resulted in the deaths of 263.