Foot and mouth virus traced within cells
In cattle, sheep, pigs and goats, Foot and mouth disease (FMD) causes fever, loss of appetite and painful vesicles (blisters) in the mouth and on the feet. The FMDV (FMD virus) is responsible for significant stock losses and consequent income reduction for the producer while stocks are culled, premises cleaned and herds rebuilt. As a result of the seriousness of FMD, extensive research has been focused on the pathology of the disease. Gaps in the knowledge regarding localisation of the actual virus prompted the FMD TROPISM project to research into where the virus is situated during the different stages of infection. Two phases are evident in the progression of the disease. Firstly, an acute phase when the antibody response is particularly important, followed by an asymptomatic persistent phase. If the virus persists after 28 days following initial exposure, the animal has carrier status, the phase which poses particular problems for vaccination programmes. Project partners at the Institute for Animal Health in the United Kingdom used Laser microdissection (LMD) combined with real-time Polymerase chain reaction (PCR) techniques to estimate levels of FMDV genetic material during the acute and persistent phases of the infection. The five layers of the epithelium in the foot, tongue and pharyngeal tissues as well as mucous gland and lymph node tissue were analysed. Exact location of viral RNA within the cell was also recorded. This way, the prime tissues invaded by the virus during establishment of infection were identified. Data from this research will aid future investigation into the status of infected animals in both the acute and carrier phases. Exactly how the virus targets epithelial cells in vivo can be determined which can be used to develop a non-immune control strategy based on anti-viral agents.
