Physical Factors Affecting in Vitro Replication of Foot and
Mouth Disease Virus
(Serotype “O”)
Muhammad Taslim Ghori*, Khushi Muhammad and Masood Rabbani1
Department of Microbiology, 1University Diagnostic
Laboratory, University of Veterinary and Animal Sciences, Lahore,
Pakistan; *Present address: University College of Veterinary &
Animal Sciences, The Islamia University of Bahawalpur, Bahawalpur
*Corresponding author:
tasleemghauri@yahoo.com
Abstract
Effect of physical factors (temperature, pH and UV light) on replicating ability
of “O” type of Foot and Mouth Disease (FMD) virus on Baby Hamster Kidney (BHK)
cell line was determined. The freshly grown FMD virus containing 106
units of tissue culture infective dose (TCID50) was divided into
aliquots. Each of the 9 virus aliquots was exposed to 37, 57 or 77°C
for 15, 30 or 45 minutes, respectively. Each of the 5 virus aliquots was mixed
with MEM-199 maintenance medium having pH 3, 5, 7, 9, or 11. Similarly, each of
the 3 aliquots having
1 mm
depth of the medium was exposed to ultraviolet light (252.7 nm wavelength: one
foot distance) for 15, 30 or 45 minutes.
Each of the virus aliquot exposed to either of the temperature, pH or
ultraviolet light (UV) for either of the interaction time was inoculated to 8
wells of the 96-well cell culture plate containing complete monolayer of BHK
cell line. One row of 8 wells served as virus control and other row of 8 wells
served as control for monolayer of the BHK-21 cell line. The plates were
incubated at
37°C
for 48 hours. It was observed that temperature of 57 and 77°C
inactivated the virus within 15 minutes. The virus when admixed in the MEM-199
maintenance medium having pH 3, 5, 9 or 11, of the medium inactivated the virus
while pH 7 did not show any detrimental effect on its survival. The ultraviolet
light for 15, 30 or 45 minutes showed undetectable effect on survival of the
virus as either of the virus aliquot exposed to the UV light for either of the
interaction time showed cytopathogenic effects (CPE). It was concluded that the
temperature of
57°C
or higher for 15 minutes, acidic pH (below 5) or basic pH (more than 9) may
inactivate the FMD virus.