Development of two rapid lateral flow test strips for detection of foot-and-mouth disease virus SAT 1 and SAT 3

Foot-and-mouth disease (FMD) is a highly contagious disease that affects cattle, sheep, goats, pigs, and over 70 species of wildlife. FMD continues to be a major economic concern for livestock productivity in many countries. FMDV has seven serotypes O, A, Asia 1, C, and Southern Africa Territories (SAT) 1, 2, and 3. Although SAT 1, and SAT 3 outbreaks are not as common as serotypes O, A, Asia 1, and SAT 2, outbreaks have also been reported. The recent outbreaks of SAT 1 occurred in Cameroon, Zimbabwe, South Africa, and Uganda, while most recent SAT 3 occurred in Namibia in 2019. The development of rapid and easy-to-perform FMDV detection tests is critical to control the outbreak and spread of FMD. The current project has produced monoclonal antibodies (mAb) against FMDV serotypes SAT 1, and SAT 3. Using these mAbs, two lateral flow immunochromatographic (LFI) strip tests for the detection of FMDV SAT 1, and SAT 3 have been developed. SAT 1 strip test detected 14 out of 15 SAT 1 field isolates. The SAT 3 strip test detected all four SAT 3 isolates tested, but the signal is weak for UGA 10/97 and showed no cross-reactivity with other FMDV serotypes. The diagnostic specificities of the SAT 1 and the SAT 3 tests are 100 %, which are higher than double antibody sandwich (DAS) ELISA. The diagnostic sensitivity of the SAT 1 test strip is lower than that of DAS ELISA, while the diagnostic sensitivity of the SAT 3 test strip is similar to that of DAS ELISA. The first reported SAT 1 and SAT 3 strip test combined with the previously developed SAT 2 strip test can be used for quick diagnosis in endemic countries in Africa. Rapid identification of FMDV serotypes is critical for disease control and vaccine selection. Also, these strip tests can be used in the laboratory to quickly screen samples from the field.