00297nam a2200109Ia 4500008004100000022001800041040001100059245002400070260006600094300001700160300001000177251112s9999||||xx |||||||||||||| ||und||  a1-55581-038-1  aCNCLSA 0aJournal of Virology  cJuly, 1993bAmerican Society for MicrobiologyaWashington, DC  aP. 3703-5712  bV. 69