In-vitro Susceptibility of FMD Virus Serotype A Endemic in KPK, Pakistan

Foot and Mouth Disease virus (FMDV) serotype A is considered to be antigenic ally diverse among various geographical locations leading to diverse patterns of resistance and sensitivity. This phenomenon is posing high risks to global trade. This is the first study to quantify the effects of different physical factors (temperature, pH, UV and gamma irradiation) affecting the infectivity of FMDV serotype A.The infectivity of virus was calculated in term of tissue culture infectivity dose-50 (TCID-50) and plaque forming units (PFU). Virus in suspension (6×10 6 particles/ml) was treated using Cobalt-60 source in BHK-21 cell line grown in 96 well plates. The virus showed complete inactivation on 3, 5, 9 and 11 pH and 10kGy dose of gamma irradiations. The results revealed that increase in temperature (both moist and dry heat) and UV light as well as increase in time of exposure with same dose of UV irradiations significantly decreased the infectivity of virus ( p< 0.05). These physical factors are a better alternate for virus inactivation than chemicals, which are toxic for the health and accumulate in the animal products. It is recommended that viral strains should be analyzed for their susceptibility to these physical methods. They could also be combined with thermal inactivation to further improve virus inactivity to obtain virus free products.