Characterization of the stunting syndrome agent: Physicochemical properties

Stunting syndrome is an enteric disease of turkeys causing diarrhea, reduce d weight gain, poor feed efficiency, and maldigestion. The etiologic agent is a newly identified, but unclassified, virus termed the stunting syndrome agent (SSA). The SSA is a pleomorphic, enveloped virus ranging from 60 to 95 nm in diameter. The objectives of this study were to characterize the ph ysicochemical properties of SSA. SSA hemagglutinated rat erythrocytes at 4 C and room temperature. Treatment of SSA with ether resulted in loss of inf ectivity. SSA was resistant to pH changes between pH 3.0 and pH 9.0 at 37 C for 1 hr. The virus was inactivated at pH greater than or equal to 10. SSA was resistant to treatment with trypsin, chymotrypsin, pancreatin, phospho lipase C, and sodium deoxycholate. Treatment of SSA with trypsin, chymotryp sin, and pancreatin resulted in enhanced viral infectivity. The viral genom e extracted from purified SSA was sensitive to RNAse treatment. Using oligo d(T)(16-18) and random hexamers as primers, the SSA genome was amplified u sing the reverse transcription-polymerase chain reaction conditions but was not amplified using polymerase chain reaction conditions. The enrichment o f viral genome was achieved following poly-A(+) selection. These studies pr ovide evidence that the SSA is a positive-sense, single-stranded RNA virus having many characteristics (stability at acidic pH, resistant to proteolyt ic enzymes and bile salt) consistent with other enveloped enteric viruses.