Halicephalobus gingivalis

Halicephalobus gingivalis is a free-living saprophagous nematode species identified and named in 1954 by Stefanski. It is a facultative parasite of horses, invading the nasal cavity, and sometimes numerous other areas, where it produces granulomatous masses. On rare occasion, it can infect humans as well, in whom it is invariably fatal. Based on studies performed on infected horses in Florida, the parasite is associated with swampland environments. These worms are dioecious, with female and male organs having been found in separate individuals. Eggs and immature larvae have been found in tissue samples, indicating an asexual reproductive cycle , and free-living males have been found in soil environments, indicating that sexual reproduction also occurs. The site of entry for the parasite is thought to be through breaks in the skin or through mucous membranes. This nematode is now distributed worldwide, as cases of equine infections have been found in Canada, Florida, the Nordic regions, and Arabian horses alike.