Dave Weidner
08-07-2007, 09:54 PM
http://www.cdc.gov/eid/content/13/8/1139.htm
Interesting Points to ponder from this article.
1) We show that several studies demonstrate that such prolonged, intense exercise leads to immunosuppression and that migratory performance is negatively affected by infections. These findings make it unlikely that wild birds can spread the virus along established long-distance migration pathways. However, infected, symptomatic wild birds may act as vectors over shorter distances, as appears to have occurred in Europe in early 2006.
2) We agree with Yasué et al. (5), who considered data on which migratory birds are considered responsible for long-distance spread of HPAI (H5N1) to be incomplete, inadequate, and often incorrect.
3) Relevant findings published in ecologic or physiologic journals are also easily missed by the scientists who deal most closely with avian influenza. An additional problem is that many important phenomena in avian movements are not well researched, e.g., movements caused by cold weather and migratory connectivity.
4) We argue that the considerable physiologic stresses of long-distance flights cast some doubts on the assumption that migratory birds are capable of spreading HPAI (H5N1) on a continental and transcontinental scale.
5) The hypothesis that migratory birds can transport HPAI (H5N1) over long distances rests on the assumption that some infected, virus-shedding wild birds show no or only mild symptoms and migrate long distances unhampered. There has been no direct test of this assumption, but several findings from ecologic immunology and exercise physiology studies are not compatible with this conjecture.
6) No convincing evidence has yet shown that infected, asymptomatic wild birds can or do carry influenza virus along established, seasonal long-distance migration routes.
7) This finding suggests that ducks may act as asymptomatic carriers. However, it remains unclear whether free-living, migratory wild ducks facing stressors such as food shortages or long flights are as immunocompetent as their laboratory counterparts or whether virus evolution takes the same course under such conditions. The commercial movement of asymptomatically infected domestic ducks, often for pest control reasons and over longs distances, could be a mechanism of spread.
I found point 7 most interesting and relates to my discussion with Phil Robertson as to why I am against using Duck Stamp money to fund the propogation and release of domestic ducks for sport.
Interesting Points to ponder from this article.
1) We show that several studies demonstrate that such prolonged, intense exercise leads to immunosuppression and that migratory performance is negatively affected by infections. These findings make it unlikely that wild birds can spread the virus along established long-distance migration pathways. However, infected, symptomatic wild birds may act as vectors over shorter distances, as appears to have occurred in Europe in early 2006.
2) We agree with Yasué et al. (5), who considered data on which migratory birds are considered responsible for long-distance spread of HPAI (H5N1) to be incomplete, inadequate, and often incorrect.
3) Relevant findings published in ecologic or physiologic journals are also easily missed by the scientists who deal most closely with avian influenza. An additional problem is that many important phenomena in avian movements are not well researched, e.g., movements caused by cold weather and migratory connectivity.
4) We argue that the considerable physiologic stresses of long-distance flights cast some doubts on the assumption that migratory birds are capable of spreading HPAI (H5N1) on a continental and transcontinental scale.
5) The hypothesis that migratory birds can transport HPAI (H5N1) over long distances rests on the assumption that some infected, virus-shedding wild birds show no or only mild symptoms and migrate long distances unhampered. There has been no direct test of this assumption, but several findings from ecologic immunology and exercise physiology studies are not compatible with this conjecture.
6) No convincing evidence has yet shown that infected, asymptomatic wild birds can or do carry influenza virus along established, seasonal long-distance migration routes.
7) This finding suggests that ducks may act as asymptomatic carriers. However, it remains unclear whether free-living, migratory wild ducks facing stressors such as food shortages or long flights are as immunocompetent as their laboratory counterparts or whether virus evolution takes the same course under such conditions. The commercial movement of asymptomatically infected domestic ducks, often for pest control reasons and over longs distances, could be a mechanism of spread.
I found point 7 most interesting and relates to my discussion with Phil Robertson as to why I am against using Duck Stamp money to fund the propogation and release of domestic ducks for sport.