Coenurosis, also known as caenurosis, coenuriasis, gid or sturdy, is a parasitic infection that develops in the intermediate hosts of some tapeworm species (Taenia multiceps, T. serialis, T. brauni, or T. glomerata). It is caused by the coenurus, the larval stage of these tapeworms. The disease occurs mainly in sheep and other ungulates, but it can also occur in humans by accidental ingestion of tapeworm eggs. Adult worms of these species develop in the small intestine of the definitive hosts (dogs, foxes and other canids), causing a disease from the group of taeniasis. Humans cannot be definitive hosts for these species of tapeworms. History
The texts of Hippocrates describe a nervous disease of sheep consistent with the symptoms of gid, comparing its symptoms to epilepsy and describing the accumulation of bad-smelling fluid in the brain. However, it was only in the 1600s that clearer behavioural and necropsy descriptions were recorded, including the chacteristic brain cysts and early surgical methods of removal. The cause of these cysts was identified as an animal parasite in 1780 by Nathanael Gottfried Leske and Johann August Ephraim Goeze.
It was shown that the parasite could be transferred across species to and from dogs by Karl Theodor Ernst von Siebold and Friedrich Küchenmeister in the 1850s and the species was identified as Taenia multiceps (then called Coenurus cerebralis) in 1890.Coenurosis in humans is rare and was not diagnosed until the twentieth century, with the first recorded cases by each Taenia species being: T. multiceps in 1913, T. glomerate in 1919, T. serialis in 1933, and T. brauni in 1956. Life cycle
The eggs of T.multiceps, T. glomerate, T. serialis, and T. brauni are shed in the feces of infected hosts into the environment. The eggs are then ingested by an intermediate host, where the eggs hatch in intestines and release oncospheres. Oncospheres are the larval form of tapeworms that contain hooks for attaching to the host’s tissues. The oncospheres continue to move through the bloodstream of the intermediate host until they find suitable organs to inhabit. The oncospheres can bind to the eyes, the brain, skeletal muscle, and subcutaneous tissue. Once the oncospheres reach their destination, they take about three months to develop into coneuri. Coenuri are white, fluid filled structures that are 3-10 centimeters in diameter. Coenuri have a collapsed membrane and several protoscolices on the interior. The coenuri cysts found in the central nervous system have multiple cavities, and those that are not have only one cavity. The disease is transferred to the definitive host when the host digests the tissue of the intermediate host.