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Fowl glioma-inducing virus (FGV), which belongs to avian leukosis virus (ALV) subgroup A, induces fowl glioma. This disease is characterized by multiple nodular gliomatous growths of astrocytes and has been previously reported in Europe, South Africa, Australia, the United States and Japan. FGV and FGV variants have spread to ornamental Japanese fowl, including Japanese bantams (Gallus gallus domesticus), in Japan. However, it is unclear how and where FGV emerged and whether FGV is related to the past fowl glioma in European countries. In this study, the prevalence of FGV in European, Asian and Japanese native chickens was examined. FGV could not be isolated from any chickens in Germany and Asian countries other than Japan. Eighty (26%) out of 307 chickens reared in Japan were positive by FGV-screening nested polymerase chain reaction and 11 FGV variants with an FGV-specific sequence in their 3′ untranslated region were isolated. In addition, four other ALVs lacking the FGV-specific sequence were isolated from Japanese bantams with fowl glioma and/or cerebellar hypoplasia. These isolates were considered to be distinct recombinant viruses between FGV variants and endogenous/exogenous avian retroviruses. These results suggest that the variants as well as distinct recombinant ALVs are prevalent among Japanese native chickens in Japan and that FGV may have emerged by recombination among avian retroviruses in the chickens of this country. [ABSTRACT FROM PUBLISHER]

Evaluating the potential involvement of wild avifauna in the emergence of highly pathogenic avian influenza H5N1 (hereafter H5N1) requires detailed analyses of temporal and spatial relationships between wild bird movements and disease emergence. The death of wild swans (Cygnus spp.) has been the first indicator of the presence of H5N1 in various Asian and European countries; however their role in the geographic spread of the disease remains poorly understood. We marked 10 whooper swans (Cygnus cygnus) with GPS transmitters in northeastern Mongolia during autumn 2006 and tracked their migratory movements in relation to H5N1 outbreaks. The prevalence of H5N1 outbreaks among poultry in eastern Asia during 2003-2007 peaked during winter, concurrent with whooper swan movements into regions of high poultry density. However outbreaks involving poultry were detected year round, indicating disease perpetuation independent of migratory waterbird presence. In contrast, H5N1 outbreaks involving whooper swans, as well as other migratory waterbirds that succumbed to the disease in eastern Asia, tended to occur during seasons (late spring and summer) and in habitats (areas of natural vegetation) where their potential for contact with poultry is very low to nonexistent. Given what is known about the susceptibility of swans to H5N1, and on the basis of the chronology and rates of whooper swan migration movements, we conclude that although there is broad spatial overlap between whooper swan distributions and H5N1 outbreak locations in eastern Asia, the likelihood of direct transmission between these groups is extremely low. Thus, our data support the hypothesis that swans are best viewed as sentinel species, and moreover, that in eastern Asia, it is most likely that their infections occurred through contact with asymptomatic migratory hosts (e.g., wild ducks) at or near their breeding grounds. [ABSTRACT FROM AUTHOR]

Background: The global spread of the highly pathogenic avian influenza H5N1 virus has stimulated interest in a better understanding of the mechanisms of H5N1 dispersal, including the potential role of migratory birds as carriers. Although wild birds have been found dead during H5N1 outbreaks, evidence suggests that others have survived natural infections, and recent studies have shown several species of ducks capable of surviving experimental inoculations of H5N1 and shedding virus. To investigate the possibility of migratory birds as a means of H5N1 dispersal into North America, we monitored for the virus in a surveillance program based on the risk that wild birds may carry the virus from Asia. Results: Of 16,797 birds sampled in Alaska between May 2006 and March 2007, low pathogenic avian influenza viruses were detected in 1.7% by rRT-PCR but no highly pathogenic viruses were found. Our data suggest that prevalence varied among sampling locations, species (highest in waterfowl, lowest in passerines), ages (juveniles higher than adults), sexes (males higher than females), date (highest in autumn), and analytical technique (rRT-PCR prevalence = 1.7%; virus isolation prevalence = 1.5%). Conclusion: The prevalence of low pathogenic avian influenza viruses isolated from wild birds depends on biological, temporal, and geographical factors, as well as testing methods. Future studies should control for, or sample across, these sources of variation to allow direct comparison of prevalence rates. [ABSTRACT FROM AUTHOR]

The spread of highly pathogenic H5N1 avian influenza into Asia, Europe, and Africa has resulted in enormous impacts on the poultry industry and presents an important threat to human health. The pathways by which the virus has and will spread between countries have been debated extensively, but have yet to be analyzed comprehensively and quantitatively. We integrated data on phylogenetic relationships of virus isolates, migratory bird movements, and trade in poultry and wild birds to determine the pathway for 52 individual introduction events into countries and predict future spread. We show that 9 of 21 of H5N1 introductions to countries in Asia were most likely through poultry, and 3 of 21 were most likely through migrating birds. In contrast, spread to most (20/23) countries in Europe was most likely through migratory birds. Spread in Africa was likely partly by poultry (2/8 introductions) and partly by migrating birds (3/8). Our analyses predict that H5N1 is more likely to be introduced into the Western Hemisphere through infected poultry and into the mainland United States by subsequent movement of migrating birds from neigh- boring countries, rather than from eastern Siberia. These results highlight the potential synergism between trade and wild animal movement in the emergence and pandemic spread of pathogens and demonstrate the value of predictive models for disease control. [ABSTRACT FROM AUTHOR]

Considers preparations essential in the prevention of an avian influenza pandemic. Damages caused by the avian flue pandemic; Statistics on avian flu cases in Asian countries as of October 26, 2005; Initiatives implemented to prevent the spread of avian influenza.

The spread of highly pathogenic avian influenza HSN1 viruses across Asia in 2003 and 2004 devastated domestic poultry populations and resulted in the largest and most lethal H5N1 virus outbreak in humans to date. To better understand the potential of HSN1 viruses isolated during this epizootic event to cause disease in mammals, we used the mouse and ferret models to evaluate the relative virulence of selected 2003 and 2004 H5N1 viruses representing multiple genetic and geographical groups and compared them to earlier HSN1 strains isolated from humans. Four of five human isolates tested were highly lethal for both mice and ferrets and exhibited a substantially greater level of virulence in ferrets than other H5N1 viruses isolated from humans since 1997. One human isolate and all four avian isolates tested were found to be of low virulence in either animal. The highly virulent viruses replicated to high titers in the mouse and ferret respiratory tracts and spread to multiple organs, including the brain. Rapid disease progression and high lethality rotes in ferrets distinguished the highly virulent 2004 H5N1 viruses from the 1997 H5N1 viruses. A pair of viruses isolated from the same patient differed by eight amino acids, including a Lys/Glu disparity at 627 of PB2, previously identified as an H5N1 virulence factor in mice. The virus possessing Glu at 627 of PB2 exhibited only a modest decrease in virulence in mice and was highly virulent in ferrets, indicating that for this virus pair, the K627E PB2 difference did not have a prevailing effect on virulence in mice or ferrets. Our results demonstrate the general equivalence of mouse and ferret models for assessment of the virulence of 2003 and 2004 H5N1 viruses. However, the apparent enhancement of virulence of these viruses in humans in 2004 was better reflected in the ferret. [ABSTRACT FROM AUTHOR]

With more than 100 million birds either dead from infection or culled, the present outbreak of avian influenza in Asia is unprecedented in size. The virus is capable of transmitting to man, causing lethal infections, but as yet the virus does not easily transmit from human to human. However, there is a substantial risk of either re-assortment of virus (combination of avian and human influenza), or adaptation of the influenza virus to humans. If this happens we may be on the verge of a new influenza pandemic with grave consequences both for human health and the world economy. The present situation stresses the importance of good surveillance and updated pandemic plans in all countries. [ABSTRACT FROM AUTHOR]

Summarizes information about the human infections and avian outbreaks in Asia during December 2003-February 2004 and provides recommendations to guide influenza A (H5N1) surveillance, diagnosis and testing in the U. S. Total human avian influenza A infections reported in Vietnam as of February 9; Analysis of viruses; Recommended laboratory testing procedures.

The article focuses on several medical misconceptions related to the spread of avian flu in Asia. Poultry owners believe that avian flu affect only sick chickens. Government misinterprets that the outbreaks can be prevented by quickly vaccinating poultry animals through inexpensive drugs. This could prevent the outbreak but will not eliminate it. Culling is recommended followed by vaccinating to eliminate avian flu. Public often misunderstand seasonal flu with avian flu. They wrongly believe that influenza vaccine could prevent people from avian flu.

Reports on the outbreaks of highly pathogenic avian influenza A among poultry in Cambodia, China, Indonesia, Japan, Laos, South Korea, Thailand, and Vietnam from December 2003 through February 2004. Summary of information about the human infections and avian outbreaks in Asia; Provision of recommendations to guide influenza A surveillance, diagnosis, and testing in the United States.

The article reflects on the bird flu epidemic. The H5N1 avian influenza strain became known in 1997. It has infected birds, pigs and housecats and has since killed millions of poultry in various outbreaks in Asia. Although interventions have been developed, the question on the world's preparednes in addressing the pandemic is still doubted. Therefore, health communicators are urged to present facts about bird flu cases to governments and policy makers to better educate the public on the appropriate measures needed.

This article reports that Asian poultry countries are experimenting with a novel strategy to control avian influenza. Fearful that a deadly flu epidemic could be brewing in Asia, some countries are stockpiling drugs, preparing pandemic flu plans, and ratcheting up vaccine production. As these efforts kick into overdrive, animal experts are grappling with the other half of the bird flu equation: the birds. Specifically, they are debating whether a relatively untested strategy of mass vaccination of chickens and other poultry against avian flu will do more harm than good in warding off a human pandemic. INSET: Asia Struggles to Keep Humans and Chickens Apart.

Focuses on the decision of the U.S. government to ban bird imports from Southeast Asian countries to protect poultry and humans from the possible spread of avian influenza. Estimated number of birds imported by the U.S.; Terms of the restrictions.

Reports that the avian influenza epidemic has affected huge populations of domestic and migratory birds across Asia, resulting to concerns that the virus could mutate into a dangerous human pathogen. Control program proposed by the United Nations Food and Agricultural Organization, World Organization for Animal Health and World Health Organization to help countries eradicate the disease; Goal of avoiding a pandemic; Concern over the possible coinfection with human and avian viruses.

The article discusses spread of bird flu in Asia. Public-health officials and lab researchers are engaged in a frantic battle to contain the escalating outbreak of bird flu in Asia, and to minimize the risk of it developing into a human flu pandemic. The first cases of apparent human-to-human transmission of the avian flu virus were reported in Vietnam, heightening public-health concerns. As officials struggle to contain the avian outbreak by orchestrating the massacre of chicken flocks, researchers around the world are preparing the way for the mass production of a vaccine that could help to contain a human pandemic.

The article reports on the widespread of avian influenza in fowls in some nations in Asia. According to the author, India was the latest nation to be affected by the outbreak of bird flu which the existence of virus has detected in 13 districts in the eastern state in West Bengal. Experts have attributed the outbreak to the smuggling of poultry from Bangladesh and inadequate culling initiatives. Meanwhile, the epidemic in Indonesia has become worst due to the increasing number of deaths. Swapan Jana, secretary of the Society for Social Pharmacology, stated that poor hygiene, close contact between human beings and poultry, and lack of proper medical care are some factors that contribute human death.

The article reports on the mutation risk brought by bird flu virus that has killed hundreds of people since the outbreak of highly pathogenic avian influenza A (H5N1) remerged in Asia in 2003. According to president of world animal health body OIE Bernard Vallat, there is no basis to say that H5N1 will not mutate even if the said virus is extremely stable. He added that countries where the disease is endemic which includes Indonesia. Egypt, and to a lesser extent Nigeria that could serve as reservoirs for the bird flu virus.

The article offers information about the outbreaks of H5N1 bird flu or avian influenza. Poultry throughout Asia witnessed a high growth in the viral disease. This devastating disease is also increasing the death toll in human. Thailand, Vietnam, Japan, South Korea, Hong Kong, and Indonesia confirmed to have serious outbreaks of the disease in their poultry farms. The increase in outbreaks in Northern Hemisphere follows an established pattern. According to Les Sims, a veterinarian, the reason for the seasonality of the disease was not well understood. He further mentioned that free-flying birds might be the origin of the outbreaks in Japan and South Korea. Recently, a cluster of human H5N1 case were found by experts in Egypt.

This article comments on the global pandemic of the H5N1 strain of avian influenza. Avian H5N1 cases had been recorded in several countries in Asia, Europe and Africa, and human infections had been detected in Cambodia, China, Indonesia, Iraq, Thailand, Turkey and Vietnam as of mid-February 2006. According to virologists, H5N1 could undergo genetic reassortment in a person harboring both H5N1 and a variant more readily transmitted between humans. A probable way to reduce the risk that a human-adapted form of the disease will evolve is to minimize human exposure to the pathogen.

The article reports that after circulating in Asia since late 2003, In February, the H5N1 avian influenza virus jumped to Africa and spread through Europe, affecting 13 countries in a single month. It's unclear why the sudden jump has occurred.

This article details efforts to eliminate the avian flu. Donor nations met in China and pledged nearly $2 billion in order to combat H5N1 avian influenza and reduce the likelihood of a human pandemic. The World Bank estimated developing countries would need between $1.2 billion and $1.4 billion to take necessary measures against avian influenza. Turkey showed the first case of H5N1 influenza outside of Asia in January 2006. The article includes a chart that shows the cases and deaths from avian influenza around the world.

The article examines the spread of avian influenza, as Asian countries affected gathered to discuss preparedness for an avian flu pandemic. China, Indonesia and Turkey continued to report new cases of H5N1 avian flu infection. Funds to fight bird flu in both animal and human populations should get a boost from the International Pledging Conference on Avian and Human Pandemic Influenza in Beijing, China. The World Bank has announced global funding for countries battling avian flu. The European commission has also pledged money to fight bird flu.

This article reports that the H5N1 has devastated the Asian poultry industry and infected at least 100 people in roughly three successive waves, it has also been shown to infect several other mammal species. Because human-to-human transmission is still rare, the World Health Organization categorizes the current outbreak as a "phase 3" pandemic threat. Some 40 countries now have published plans to deal with a pandemic, varying from a few to many hundreds of pages. At least 18 countries have ordered stockpiles of oseltamivir, an anti-influenza drug, but the percentage of the population that would be covered varies widely by country. Roche, the drug's only supplier, is in negotiations with a dozen other countries; it may take years to fill all the orders. H5N1 infects an extraordinary variety of species. Its currently known animal hosts include west birds, ducks, house cats, chickens and pigs. Stages of pandemic are divided in to phases. In phase 1 no new influenza virus subtypes detected in humans. An influenza virus subtype that has caused human infection may be present in animals, but the risk for humans is considered low.

The article discusses the Asian governments' concern at the spread of deadly H5N1 avian influenza virus. The Thai government announced in February 2005 that it would join China and Indonesia in vaccinating select healthy ducks and chickens. Vietnam also is considering a vaccination program. Vaccinations can lessen the risk of influenza by reducing the birds’ chances of infection and minimizing the amount of virus shed through nasal secretions and feces by those that do become infected. But vaccinated chickens can still become infected while showing no symptoms of disease. For that reason, many countries, including Japan, one of Thailand’s biggest poultry markets, ban imports of vaccinated chickens. Countries therefore usually vaccinate poultry against influenza only as a last resort.

Reports on the possible re-emergence of the bird flu virus in Asia in January 2005. Preparations taken by the World Health Organization for mass infections caused by the virus; Development of a screening test that would detect bird flu in humans; Efforts of researchers to identify the genes in the genome sequence of chickens which are responsible for the transmission of the virus.

Focuses on the impact of the avian influenza epidemic in Asia on the condition of the international community in reference to a statement by the Food and Agriculture Organization of the United Nations and the Office International des Epizooties on September 27, 2004. Countries in Asia with recent outbreaks of avian influenza; Role of the wildlife, domestic ducks and pigs in the transmission of the virus; Recommendations of the organizations on how to control the outbreaks.