Volume 27, Number 12—December 2021
Trichinella spiralis [tri·kuh·neh′·luh spr·a′·luhs]
Trichinella is derived from the Greek words trichos (hair) and ella (diminutive); spiralis means spiral. In 1835, Richard Owen (1804–1892) (Figure 1) and James Paget (1814–1899) (Figure 2) described a spiral worm (Trichina spiralis)‒lined sandy diaphragm of a cadaver. In 1895, Alcide Raillet (1852–1930) renamed it as Trichinella spiralis because Trichina was attributed to an insect in 1830. In 1859, Rudolf Virchow (1821–1902) described the life cycle. The genus includes many distinct species, several genotypes, and encapsulated and nonencapsulated clades based on the presence/absence of a collagen capsule (Figure 3).
The smallest, viviparous nematode or pig parasite has sylvatic and domestic cycles and causes trichinellosis or trichinosis. Transmission occurs through the consumption of meat infected with pathogenic cysts, encasing larvae (Figure 4). Human-to-human transmission has not been reported.
- Campbell WC. History of trichinosis: Paget, Owends and the discovery of Trichinella spiralis. Bull Hist Med. 1979;53:520–52.
- Centers for Disease Control and Prevention. Trichinellosis: general information [cited 2021 May 11]. https://www.cdc.gov/parasites/trichinellosis/gen_info/faqs.html
- Gottstein B, Pozio E, Nöckler K. Epidemiology, diagnosis, treatment, and control of trichinellosis. Clin Microbiol Rev. 2009;22:127–45.
- Observations on. Trichina spiralis. Boston Med Surg J. 1860;63:294–8.
- Zarlenga D, Thompson P, Pozio E. Trichinella species and genotypes. Res Vet Sci. 2020;133:289–96.