USDA scientists are claiming an important breakthrough in the battle against foot-and-mouth disease, the most economically devastating livestock disease in the world. Researchers at the USDA's Foreign Animal Disease Research Unit have identified the primary site where the virus that causes FMD begins infection in cattle. USDA says the discovery could lead to development of new vaccines to "control and potentially eradicate FMD."
Veterinary medical officer Jonathan Arzt, research leader Luis Rodriguez and microbiologist Juan Pacheco found that after just six hours of exposure to the FMD virus through the nasal passages, the virus selectively infects cells at the back of the cow's throat.
"Because we have determined the actual route the FMD virus takes in infected cattle, we can now begin to target the virus-host interaction in an effort to develop better vaccines and biotherapeutic countermeasures against the disease," Arzt said.
Although the U.S. has not had an FMD outbreak since 1929, the disease is still considered a serious threat. Epidemics of the disease in previously FMD-free countries have the potential to cause billions of dollars in economic losses related to eradication efforts and trade bans.
Though vaccines have already been developed that offer temporary immunity for livestock, there is no universal FMD vaccine. Because there are seven different types of FMD viruses and more than 60 subtypes, existing vaccines must be highly specific and matched to the type and subtype present in the area of an outbreak. Blocking the initial site of infection may be the most effective way to achieve complete protection.
The findings have allowed Arzt and his colleagues to answer some basic, yet long-standing mysteries regarding how the FMD virus first invades and spreads in susceptible cattle. The scientists now are conducting further research to answer questions about why particular cells are susceptible, and how the initial infection site can be blocked. The research was published in the November issue of Veterinary Pathology.
