Anti-CAEV 28 kDa capsid protein monoclonal antibody, clone 37D3

Maedi-visna virus (MVV) is a lentivirus of sheep, causing slowly progressive interstitial pneumonia and encephalitis(1). The primary target cells of MVV in vivo are considered to be of the monocyte lineage(2). Certain strains of MVV can replicate in other cell types, however(3,4). The green fluorescent protein is a commonly used marker for studying lentiviruses in living cells. We have inserted the egfp gene into the gene for dUTPase of MVV. The dUTPase gene is well conserved in most lentivirus strains of sheep and goats and has been shown to be important in replication of CAEV(5). However, dUTPase has been shown to be dispensable for replication of the molecular clone of MVV used in this study both in vitro and in vivo(6). MVV replication is strictly confined to cells of sheep or goat origin. We use a primary cell line from the choroid plexus of sheep (SCP cells) for transfection and propagation of the virus(7). The fluorescent MVV is fully infectious and EGFP expression is stable over at least 6 passages(8). There is good correlation between measurements of TCID50 and EGFP. This virus should therefore be useful for rapid detection of infected cells in studies of cell tropism and pathogenicity in vitro and in vivo(8).

The objective of the present study was to identify the occurrence of caprine arthritis encephalitis virus (CAEV) infection in dairy goat farms with intensive system in Minas Gerais State. Five properties were evaluated, totaling 1072 animals, being 48 males and 1024 females of different ages and breeds (Toggenburg, Saanen and Alpine). The diagnostic method used was the agar gel immunodiffusion (AGID) test, to detect antibodies anti-CAEV, which is the diagnostic test recommended by World Organization for Animal Health - OIE. The occurrence of anti-CAEV antibodies in the properties was 49.5% (531/1072), however varied according to the farm. The anti-CAEV antibodies detection varied according to the property: Farm 1 = 69.6% (156/224); farm 2 = 41.5% (47/113); farm 3 = 40.3% (63/156); farm 4 = 24.6% (18/73) and farm 5 = 48.8% (247/506). Of the total sampled males, 14.5% (7/48) were serologically positive. According to the results, there is a high occurrence rate of CAEV-seropositive animals in Minas Gerais, which has one of the largest Brazilian dairy goat herds. Therefore, it is essential to adopt strategies for CAE control, such as a routine of diagnostics tests in the properties and the separation of healthy from infected goats. The elimination of positive breeding goats in the properties is also a measure of control, because it has been shown that these are an important route of CAEV transmission in dairy farms.