Oesophageal-pharyngeal Fluid Research Articles

Improved techniques for the detection of foot-and-mouth disease virus in carrier cattle.

A cup probang was used to collect oesophageal-pharyngeal fluid specimens from cattle carriers of foot-and-mouth disease (FMD) virus (Type A). The specimens were assayed for virus content by inoculation of primary calf kidney cell cultures in prescription bottles and in Povitsky bottles for assay of greater volumes. The efficiency of the techniques was improved by treating the specimens with trichlorotrifluoroethane (TTE) prior to assay. With the TTE-treatment, bacterial and fungal contaminants were virtually eliminated and FMD virus apparently was reactivated from neutralizing antibodies or other inhibitors. Aliquot specimens stored at −20° C for more than 2 months did not have an appreciable loss in titer when the TTE treatment was used. Specimens with 50% glycerin added maintained their original virus titers during prolonged storage at −20° C.