Foot and Mouth Disease Virus

Foot and mouth disease (FMDV) is an acute, febrile, highly contagious disease that occurs in cloven hoofed animals such as cattle, sheep, and pigs. The World Organization for Animal Health has classified foot-and-mouth disease as a Class A highly contagious disease in animals, which seriously endangers the healthy development of animal husbandry and the foreign trade of related products, and has a profound impact on the country's politics and economy.

Figure 1. The FMD virus.

Introductions

Foot and mouth disease (FMDV) is an acute, febrile, and contact infectious disease caused by the foot-and-mouth disease virus (FMDV) in ungulates. The most susceptible animals are cattle, water buffalo, pigs, camels, sheep, deer, etc. Wild animals such as yellow sheep, musk deer, wild boars, and bison are also susceptible to this disease. Cattle are most susceptible to this disease, while sheep have a low infection rate. Foot and mouth disease is prevalent in Asia, Africa, the Middle East, and South America, with sporadic cases in non-endemic areas as well. After the onset of foot-and-mouth disease, it is generally not fatal, but it can cause a large number of blisters on the mouth and hooves of infected animals, with high fever that does not subside, resulting in a sharp decrease in actual livestock production. In addition, there are individual variants of foot-and-mouth disease virus that can be transmitted to humans. Therefore, after each outbreak, only infected livestock can be slaughtered and collectively burned to prevent future problems. Due to its rapid spread, difficulty in prevention and control, and limited remedial measures, foot-and-mouth disease is known as the "number one killer" in animal husbandry.

Figure 2. Foot and Mouth Disease.

Molecular Mechanism of Foot-And-Mouth Disease Virus Pathogenesis

FMDV can bind to receptor molecules on the surface of host cells, enter cells through endocytosis, replicate and proliferate in the cytoplasm, and typically generate new infectious viral particles after 4-6 hours of infection. The first step in viral infection is the specific recognition of receptors. Studies have shown that integrin and heparan sulfate are receptors for FMDV In vitro experiments have shown that integrin αVβ1, αVβ3, αVβ5, αVβ6, and αVβ8 can recognize the RGD motif of FMDV capsid protein VP1. Among them, αVβ6 only exists in epithelial cells and is more easily bound to the virus in vivo compared to other receptors. However, it is still unclear which integrin plays a key role and the synergistic function between integrin proteins in the natural infection process of FMDV Heparin sulfate is a receptor utilized by FMDV during in vitro culture. Initially thought to be a receptor for certain O-type FMDV entering cells, it was later discovered that other serotypes of viruses such as A, C, Asia1, and SAT-1 can also use heparin sulfate as a cellular receptor.

Virus Prevention and Control

Animal diseases caused by foot-and-mouth disease can affect labor and reduce milk production. Generally, slaughter and destruction of corpses are used for disposal, causing serious losses to animal husbandry. Foot and mouth disease rarely infects humans, but when humans come into contact with or ingest contaminated livestock products, the foot-and-mouth disease virus can invade the human body through injured skin and oral mucosa. The characteristics of human hoof disease are sudden fever, large and clear blisters appearing in the mouth, throat, palms, and other areas. There is no effective treatment for these symptoms, which can naturally recover after 2-3 weeks without leaving scars. Therefore, the harm to human health is not significant.

Anti-FMDV Antibodies

FMDV Virus Antigens