Psorosperm

Psorosperm (from the Greek ψωρα itch and σπερμα seed) is a name formerly given to a number of parasitic protozoa which produce cystlike or sporelike structures in the tissue of hosts, but now essentially obsolete.

• Some which affect vertebrate hosts are now identified as coccidia.
• Others, such as the cause of pébrine in silkworms, are now recognized as microsporidians, and some are regarded as 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 which some biologists think may be related to the common ancestors of animals and fungi.^[1]

The term was introduced in German (as Psorospermien) by J. Müller 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]

References

1. Ragan MA, Goggin CL, Cawthorn RJ, et al. (October 1996). "A novel clade of protistan parasites near the animal-fungal divergence". Proc. Natl. Acad. Sci. U.S.A. 93 (21): 11907–12. doi:10.1073/pnas.93.21.11907. PMC 38157. PMID 8876236.
2. Müller J. 1841: Über Psorospermien. Arch. Anat. Physiol. Wissensch. Med. 5: 477–496
3. Revere Randolph Gurley (1894). The Myxosporidia, or Psorosperms of fishes: and the epidemics produced by them. Govt. print. off. p. 72. Retrieved 10 April 2010.
4. "Arch Derm Syphilol -- Excerpt: KERATOSIS FOLLICULARIS (DARIER'S DISEASE) A VITAMIN A DEFICIENCY DISEASE, February 1941, PECK et al. 43 (2): 223".
5. F. J. Darier. De la psorospermose folliculaire végétante. Étude anatomo-pathologique d'une affection cutanée non décrite ou comprise dans le groupe des acnés sebacées, cornées, hypertrophiantes, des kératoses (ichtyoses) folliculaires, etc. Annales de dermatologie et de syphilographie, Paris, 1889, 10: 597-612.
6. "2009 ICD-9-CM Diagnosis Code 136.4 : Psorospermiasis".