Foot-and-mouth disease virus

Foot-and-mouth disease is caused by a virus from the picornavirus family. It is a very tiny particle – millions would fit on a pinhead. There are several different types of foot-and-mouth disease virus known as serotypes and multiple strains of the virus within each serotype. Each virus is made up of a sealed outer shell called capsid which is constructed from 4 main proteins – VP1, 2, 3, and 4. These proteins assemble to create subunits, five of these then joined together to form building blocks called pentamers. Together 12 of these building blocks make a complete capsid which incases the virus’s genetic material. All viruses have genetic material, some have DNA like us but the foot-and-mouth disease virus has a single strand of RNA. Foot-and-mouth disease virus infects cloven-hooved ‘two-toed’ animals such as cows, sheep, pigs, and goats. It also infects wild animals like buffalo. The virus may be inhaled and enters the cells of the tongue or respiratory system.  It can also enter through open sores and wounds. It invades the cell using a protein loop on VP1 to blind a receptor on the cell surface called integrin. These receptors grab the virus and draw it into the new cell. Once inside the cell, the virus breaks apart, releasing its RNA. The RNA then hijacks the cell’s machinery called ‘ribosomes’ to make two new strands of virus proteins. The first strand of protein is cut into pieces which reform to make the capsid pentamers. The second strand of protein is broken up and used to create more RNA. The capsid proteins then surround the RNA to create a new virus particle. Hundreds of thousands of these viruses are created. These virus particles then burst out of the cell, ready to infect new cells. Foot-and-mouth disease is highly contagious and can be passed from one animal to another by direct contact, or by contact with contaminated objects. When animals are infected with foot-and-mouth disease, their symptoms include fever, reduced appetite, and blisters on their feet, mouth, nose, and teats causing lameness and excess salavation. The disease may cause abortions in pregnant cows and can result in death though this is rare and mainly in the young. Foot-and-mouth disease is a major problem globally causing huge economic losses and threats to food security. It is constant in some countries but absent in others. Some countries vaccinate to prevent the disease from spreading but this approach has its own disadvantages. Current vaccines contain foot-and-mouth disease viruses that are inactivated, so they cannot cause infection. However, these vaccines are expensive to produce as they require special production facilities that can only protect against one serotype and need refrigeration. New synthetic vaccines that are being researched in Institutes contain a more stable version of the capsid and no genetic material. This means they would potentially be cheaper to produce because they don't need special facilities. They are easier to store and transport and could potentially protect against all serotypes. As well as research into the virus and future vaccines, the institute is the World Reference Laboratory for foot-and-mouth disease, playing an essential role in the diagnostics, surveillance, and control of the disease globally.