Featured Research

from universities, journals, and other organizations

Bird Flu: Current Evaluation Of Risks To Humans From Avian Influenza Virus Following Recent Reports

Date:
July 21, 2004
Source:
World Health Organization
Summary:
In the last two weeks, avian influenza appears to have re-emerged in poultry in several countries in Asia. These outbreaks could either be new outbreaks of Highly Pathogenic Avian Influenza A(H5N1) virus or a continuation of the outbreaks first reported earlier in the year.

In the last two weeks, avian influenza appears to have re-emerged in poultry in several countries in Asia. These outbreaks could either be new outbreaks of Highly Pathogenic Avian Influenza A(H5N1) virus or a continuation of the outbreaks first reported earlier in the year. These events, in addition to two new research reports -- about the virus becoming increasingly pathogenic and becoming more widespread in birds in the region -- fuel the World Health Organization's concern about the threat the virus poses to human health.

WHO has been concerned about this virus, influenza A(H5N1), because of its threat to humans both in farm settings in Asia and its greater, potentially global risk. Several countries in Asia have witnessed this virus crossing the species barrier, moving from infected chickens or ducks directly into humans in three documented outbreaks since 1997. These direct human infections have produced severe and sometimes fatal outcomes. Moreover, the virus has the potential to acquire the ability to spread easily from human to human, and thus, trigger a global influenza pandemic.

Now, two research reports have added to our understanding of this virus. First, members of China's Ministry of Agriculture and colleagues reported in a paper published last week in the Proceedings of the National Academy of Sciences that the virus appears to be widespread in domestic ducks in southern China. Further, the scientists found that the virus is causing increasingly severe disease. However, these trials were done in mice and may not have a direct implication for humans.

This week, the journal Nature published a report which indicates domestic and wild birds in the region may have contributed to the increasing spread of the virus and suggests that the virus is gaining a stronger foothold in the region. These observations suggest that control of the virus may be even more difficult than thought in the spring.

Effective risk management tools exist to control outbreaks of influenza A(H5N1) when they are detected in poultry operations. China, for example, was quick to employ these tools last week when an outbreak was discovered in Anhui province. These risk management measures include the culling of infected and exposed birds, stringent biosecurity measures and vaccination. While this approach can still take months or even years to contain the virus completely, these methods have been effective in the past.

However, tools to assess the risk to human health are less well developed. While recent reports indicate the virus has been present consistently in the environment for the last several years, it has still not acquired the ability to infect humans easily. Why? Is there something about this virus which resists this development? Given the recent reports, WHO urges and offers assistance that such risk assessment activities, including surveillance in animals and humans, and strain analysis, be undertaken as soon as possible.

More knowledge of the virus could be acquired if WHO had full access to all virus isolates and clinical specimens from recent outbreaks. All H5N1 viruses are not the same, and how they differ could provide important insights. For example, the work reported in Nature suggests that the Indonesian avian influenza virus, while belonging to the genotype of viruses seen in Viet Nam and Thailand, is also distinct. What, if any, impact does this difference have? With this information, public health planners would know that they are confronting the same virus in all of the recent outbreaks in Asia. This is another set of the many questions that need to be answered imperatively.

Pandemic preparedness activities started by WHO in the wake of the outbreaks reported earlier this year continue. Less than two weeks ago, WHO hosted a meeting in Kuala Lumpur with experts from 13 countries and areas of the Asia-Pacific region. Among other activities, the meeting participants were provided with a WHO preparedness self-assessment tool. WHO is collaborating with scientists and the pharmaceutical community on a global surveillance system to monitor changes in the virus's susceptibility to known antivirals. Finally, pandemic vaccine development continues. Two vaccine manufacturers, both based in the United States, have produced a supply of trial vaccine which will be tested for safety and efficacy in humans.

In summary, recent developments suggest that:

• the virus is more widespread than previously thought and found in wild birds, and therefore it may be more difficult to eliminate.

• virus isolates and specimens from all recent outbreaks need to be shared with the WHO laboratory network to monitor the circulating viruses and to assess the adequacy of the current pandemic vaccine strain.

• as control measures are strengthened, national governments are encouraged to provide human influenza vaccinations to culling workers.

• all people, especially culling workers, exposed to infected birds need to be provided with antivirals.

• human trials of experimental influenza pandemic vaccines should be accelerated.

• while early identification of avian influenza cases in humans is difficult, stepped up surveillance for the early detection of the disease in humans is essential.

The risk of emergence of a new human pandemic virus will remain as long as the avian influenza virus exists in the environment. WHO's concern and activities continue at a high level following recent reports. Because the H5N1 threat is unlikely to be resolved in the shortterm, WHO is working with other international agencies, including the Food and Agricultural Organization (FAO), and World Organization for Animal Health (OIE), to monitor events.


Story Source:

The above story is based on materials provided by World Health Organization. Note: Materials may be edited for content and length.


Cite This Page:

World Health Organization. "Bird Flu: Current Evaluation Of Risks To Humans From Avian Influenza Virus Following Recent Reports." ScienceDaily. ScienceDaily, 21 July 2004. <www.sciencedaily.com/releases/2004/07/040721084503.htm>.
World Health Organization. (2004, July 21). Bird Flu: Current Evaluation Of Risks To Humans From Avian Influenza Virus Following Recent Reports. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2004/07/040721084503.htm
World Health Organization. "Bird Flu: Current Evaluation Of Risks To Humans From Avian Influenza Virus Following Recent Reports." ScienceDaily. www.sciencedaily.com/releases/2004/07/040721084503.htm (accessed July 22, 2014).

Share This




More Plants & Animals News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Michigan Plant's Goal: Flower and Die

Michigan Plant's Goal: Flower and Die

AP (July 22, 2014) An 80-year-old agave plant, which is blooming for the first and only time at a University of Michigan conservatory, will die when it's done (July 22) Video provided by AP
Powered by NewsLook.com
San Diego Zoo Welcomes New, Rare Rhino Calf

San Diego Zoo Welcomes New, Rare Rhino Calf

Reuters - US Online Video (July 21, 2014) An endangered black rhino baby is the newest resident at the San Diego Zoo. Sasha Salama reports. Video provided by Reuters
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins