Understanding how the virus is transmitted between hosts and farms can help prevent its spread.
Understanding the role of vectors – including dust, dander and feathers – and other factors in the transmission of HPAI in commercial poultry will be crucial to preventing the virus and ending the current outbreak.
Research has shown that feathers – and especially feather meat – can contain high levels of HPAI. Several French studies are focusing on the link between HPAI transmission and feather meat.
“During feather development, the cells inside the feather shaft are filled with virus,” said Erica Spackman, PhD, distinguished senior research scientist, Emerging and Exotic Avian Virus Diseases Unit, National Poultry Research Center, U.S. Department of Agriculture (USDA)-Agricultural Research Service (ARS). “The feather shaft appears to help protect it.”
She added that feathers are very light and appear to float in the air, although more research is needed to understand how long the virus remains in feathers before determining full transmissibility.
In the “What We Know About HPAIV Transmission” webinar, Spackman discussed several potential HPAI transmission pathways between hosts and poultry farms.
Host-Level Transmission
When most people think of HPAI transmission, they think of transmission at the host level.
Influenza A is a “panzootic” virus, meaning it can infect most species. Broiler chickens are not a natural host for influenza A because they shed the virus for shorter periods of time than ducks and other birds. However, the current strain circulating is much more likely to infect chickens and turkeys than previous outbreaks, Spackman said.
Environmental Transmission
When it comes to cross-species transmission of HPAI—between wild birds and commercial poultry or between poultry and dairy cattle—the environment may be a factor, although more research is needed before firm conclusions can be drawn either way, she noted.
Airborne transmission is a likely source of HPAI transmission, although it can be difficult to control and test for HPAI in air samples. So far, experimental data suggest that airborne transmission of HPAI between chickens is low. Absolute humidity may be important, Spackman added. Higher humidity slows virus transmission. Overall, preliminary research suggests that HPAI cannot spread very far outside poultry houses through airborne transmission.
HPAI is also unlikely to spread through soil, feed, water or feces. While HPAI can survive for a limited time on these objects, its infectivity appears to decline rapidly on all four. Water is the most likely vector, especially at warmer temperatures, Spackman said.
V.A (according to Feedstrategy)
Source: mard.gov.vn