Antigenic relationship between Pythium insidiosum de Cock et al. 1987 and its synonym Pythium destruens Shipton 1987.

Antigens and rabbit-antisera from holotypes of Pythium insidiosum and P. destruens were prepared to elucidate their antigenic relationship. The antigens and rabbit-antisera of P. insidiosum as well as P. destruens used as a reference system showed that both shared three precipitin bands in common. The antigen and rabbit-antisera of P. destruens and P. insidiosum used as a reference system against other strains isolated from humans and animals with pythiosis, also showed three precipitin bands in common. When we used sera taken from horses with proven pythiosis against antigens of P. insidiosum and P. destruens, six common bands were observed. We concluded that the etiologic agent of pythiosis is a single species P. insidiosum, and could be identified by serologic methods.