Isolation and characteristics of an equine reovirus type 3 and an antibody prevalence survey to reoviruses in horses located in New York State

Reoviruses have been isolated from a number of species including human, bovine, feline, canine and equine. In most species they seem to produce mild to inapparent disease. We have isolated a reovirus type 3 from a foal with diarrhea. The virus designated the Ralph strain has been propagated in both the MA-104 and A-72 cell lines. The strain produced cytoplasmic inclusion bodies in these cell cultures. Tissue-cultured virus fixed complement in the presence of reovirus antibodies, but failed to do so in the presence of rotavirus antiserum. By electron microscopy the viral particle measured ±65 nm. The virus hemagglutinated pig erythrocytes, but not human O, human A, calf, cow, chicken or guinea pig erythrocytes. In the hemagglutination test there was complete reciprocal crossing between the Ralph strain and the NIH reovirus type 3, but there was no crossing with NIH reovirus types 1 and 2. A limited serological survey was completed on serum samples from New York State horses collected in 1976–1977 and 1981 using the hemagglutination-inhibition test. The percentage with antibodies to reovirus types 1, 2 and 3 for 1976–1977 was 24.5, 42.2 and 3.9% and in 1981, 8.8, 9.8 and 3.9%, respectively.