Submitted to: Colombiana de Ciencias Pecuarias
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2006
Publication Date: 5/31/2006
Citation: Grubman, M.J. 2006. New approaches to control foot-and-mouth disease: antivirals and novel vaccines. Colombiana de Ciencias Pecuarias. 19: 341-346. Interpretive Summary: Foot-and-Mouth Disease Virus (FMDV) causes an economically devastating disease of cloven-hoofed animals. Vaccines produced by chemical inactivation of virus are available, but there are concerns about their safety, about the ability to serologically distinguish vaccinated animals from infected animals, and about their inability to induce protection prior to 7 days postvaccination. In the event of an FMD outbreak in a disease-free country such as the U.S., it is necessary to induce immediate protection to control disease spread. A possible alternative approach to develop safe, effective FMD vaccines is to produce viral subunit vaccines which do not contain infectious FMDV and lack the genetic information for a number of viral nonstructural proteins. Thus, production of this vaccine does not require expensive high-containment manufacturing facilities, can be made in the U.S., which currently prohibits work with infectious FMDV on the mainland, and animals inoculated with this marker vaccine can readily be differentiated from infected animals using diagnostic assays employing the viral nonstructural proteins not present in the vaccine. In addition, we have previously shown that the antiviral agent type I interfern can rapidly inhibit FMDV replication. Therefore, the use of both an FMDV subunit vaccine and type I interferon can result in rapid protection and clear distinction between vaccinated and infected animals. In this manuscript, I discuss the development of a human adenovirus expression vector that contains a noninfectious portion of the FMDV genome. One inoculation of this vector is able to induce a protective response in swine and cattle when challenged by direct infection with virulent FMDV 7 days postvaccination. Furthermore, swine given one inoculation of an adenovirus vector containing type I interferon are protected when challenged one day postvaccination. These results demonstrate that this novel combination control strategy addresses the concerns of FMD-free countries with the current FMD disease control approach and also can potentially be used in the final stages of FMD eradication campaigns in countries where the disease is enzootic.
Technical Abstract: Foot-and-Mouth Disease (FMD) is a highly contagious viral-induced disease of cloven-hoofed animals that results in serious economic consequences in affected countries that have a significant international livestock trade. Currently, disease control measures include inhibition of susceptible animal movement, slaughter of infected and susceptible in-contact animals, disinfection, and possibly vaccination with an inactivated whole virus antigen. However, there are a number of problems with use of the current vaccine in outbreaks in countries which have been previously free of FMD. As a result, countries which vaccinate face a longer delay in regaining FMD-free status than countries which do not vaccinate but rather slaughter all infected or susceptible in-contact animals. Researchers have been attempting to develop both new FMD vaccines to overcome the limitations of the current inactivated vaccine as well as methods to more rapidly induce a protective response. In this manuscript, I discuss the most effective new FMD vaccines and novel antiviral strategies that are currently being examined.