Psorosperm (from the Greek ψωρα itch and σπερμα seed) is a former name of a number of parasitic protozoa that produce cystlike or sporelike structures in the tissue of hosts. The term is now essentially obsolete.
- Some that affect vertebrate hosts are now called coccidia.
- Others, such as the cause of pébrine in silkworms, are now recognized as microsporidians, and some are myxosporidians.
- The genus Psorospermium (which includes the species Psorospermium haeckeli) itself is a parasite of crayfishes, and belongs to an enigmatic group of unicellular organisms that some biologists think may be related to the common ancestors of animals and fungi.[1]
J. Müller introduced the term in German (as Psorospermien) in 1841.[2][3]
Psorosperm was at one point believed to be the cause of Darier's disease.[4][5]
"Psorospermiasis" is classified under 136.4 in ICD-9.[6]