PCR DETECTION OF LENTIVIRAL GAG SEGMENT DNA IN THE WHITE BLOOD-CELLS OF SHEEP AND GOATS

A PCR assay for the detection of small ruminant lentiviral gag DNA (pr ovirus) in the white blood cells of sheep and goats was developed and compared with a serological test (AGIDT). A sample of the DNA prepared from the white blood cells in 3 ml of blood from 208 sheep and goats from 18 different hocks was subjected to PCR assay. One of 85 animals from flocks accredited under the Dutch national MVV/CAEV control progr amme was positive by PCR while none was positive by AGIDT. In infected flocks, the AGIDT appeared slightly more sensitive, but preliminary r esults show that the sensitivity of the PCR assay may be further impro ved by increasing the number of monocytes tested. The PCR assay, howev er, was clearly more sensitive in detecting animals in the early stage s of infection. With the use of a set of mixed primers and probes, the assay was able to detect the variety of CAEV and MVV strains occurrin g in the field.