Paralysis Worm

(Gurltia paralysans)

Gurltia paralysans is a unique metastrongyloid nematode that causes paralysis in cats in South America.

Parasite species: Gurltia paralysans
Common name: Paralysis worm
Hosts: Wild and domestic felids
Pre-patent period: Unknown
Location in the host: Veins of the spinal cord subarachnoid space and parenchyma
Distribution: South America
Transmission route: Predation of paratenic hosts (possibly lizards, rodents, and birds) or intermediate hosts (possibly terrestrial slugs or snails)
Zoonotic: Unknown


South America.

Clinical signs

Clinical signs reported in G. paralysans-infected cats include chronic and progressive ambulatory paraparesis or paraplegia, pelvic limb ataxia, pelvic limb proprioceptive deficit, hyperactive patellar reflexes, pelvic limb muscle atrophy, tail trembling, tail atony, diarrhoea, weight loss, urinary and faecal incontinence [1]. Some cats may die from this infection.


Gurltia paralysans eggs and larvae are not typically found in faecal samples of domestic cats. The infection is usually diagnosed based on neurological signs and the exclusion of other possible causes of feline myelopathies. Imaging tools (radiography, computed tomography) may be useful in this way. Nonetheless, many cases are only confirmed by finding adult worms during post-mortem examination. A semi-nested PCR assay has been developed to detect G. paralysans DNA, but this assay has not yet been validated using blood or faecal samples.


To date, no therapy has been proven effective against G. paralysans infection in cats.

Prevention and Control

Owners should be advised to prevent cats from hunting and eating potential paratenic and intermediate hosts.

Public health considerations

Zoonotic potential of G. paralysans is unknown.


[1] Muñoz P, Hirzmann J, Rodriguez E, Moroni M, Taubert A, Gibbons L, Hermosilla C, Gómez M. Redescription and first molecular characterization of the little known feline neurotropic nematode Gurltia paralysans (Nematoda: Metastrongyloidea). Vet Parasitol Reg Stud Rep. 2017;10:119-125.