ELISA Effective in FMD Diagnosis
The use of Enzyme-linked Immunosorbent Assay (ELISA) was found to be effective and extremely valuable for diagnosing, monitoring and for the surveillance of foot and mouth disease in the Philippines. Specifically, the assay is useful in the fast detection and diagnosis of FMD suspect cases and in the measurement of antibodies agains FMD virus (FMDV) in serum samples from all animals either vaccinated or infected.
This was revealed in a study conducted by scientists form FMD Laboratory, Philippine Animal Health Center (PAHC) of the Bureau of Animal Industry (BAI). According to Dr. Blesilda C. Verin, a veterinarian and Rosalinda M. Arvesu a medical technologist who led the team of researchers, ELISA should now be the standard test for diagnosis monitoring, and surveillance of FMD in the country. It will also be used for potency testing of FMD imported vaccines.
It was only in 1975 that FMD diagnosis in the country was started. The test most commonly used then was the conventional Complement Fixation Test (CFT) and the Mouse Inoculation Test (MIT). However, both tests were found to be far less sensitive and specific as compare to ELISA(Cainglet et al 1991).
For years the World Reference Laboratory (WRL) for FMD carried out serological tests for the country. However, these were done on a minimal basis and proved to be costly for the government. In 1991 a comparative study between CFT and ELISA showed that the latter was more specific and sensitive in the diagnosis of FMD.
This event led to a collaborative project in 1995 between PAHC, BAI, and Food and Agriculture Organization/ International Atomic Energy Agency (FAO/IAEA) on the use of ELISA technology for FMD diagnosis , and concluded that the assay should now be the standard test for both FMD diagnosis and serology. In the study, 522 epithelial samples and 4401 serum samples were tested starting in 1995 to 1998. Using 522 samples, results showed that 17.9% were found negative and 84.78% were found positive for sero-types O and C. Within four years, 62 representative samples were sent to the World Reference Laboratory for FMD confirmation diagnosis. Out of 62 samples , 87% were diagnosed positive. Serum samples received were either for diagnosis, surveillance, post vaccination titre and for the FAO/IAEA external quality assurance program.
FMD virus is one of the vesicular diseases of pigs , cattle and other cloven-footed animals. While it was proven that FMD-infected meat has no harmful effects on humans if consumed, this can greatly affect the livestock industry, and has its economic impact reminiscent of the 1995 FMD scare which caused meat prices to dive in Luzon
Source: BAR Today Jan mar 2001 issue, Thea Kristina M. Pabuayon
(adapted from the “Use of Enzyme Linked Immunosorbent Assay (ELISA) for the Diagnosis and Monitoring of FMD in the Philippines” by Dr. B. C. Verin and R.M. Arvesu. For more information please contact Dr. Verin and RM Arvesu at tel. 9282177 and 925-4343 respectively)