Protozoal polyradiculoneuritis

From Dog

Protozoal polyradiculoneuritis is an uncommon neurological disease of dogs characterized by neuropathy due to protozoan parasites.

This disorder, which occurs primarily in young pups, involve parasite-induced neuritis of peripheral nerves and skeletal muscle neuromuscular junctions which results in progressive paralysis, myositis and muscular rigidity of the hindlimbs.

Causes include:

Clinically affected pups usually present with progressive stiffness, paresis with muscle wasting, hyporeflexia and extensor rigidity, usually of the pelvic limbs. Neural reflexes are often diminished.

This protozoal myositis syndrome has also been reported in older dogs with cauda equina syndrome due to neosporosis, resulting in tail flaccidity and faecal and urinary incontinence[4].

Blood tests may reveal elevated creatinine kinase and CSF analysis may show leucocytosis and elevated protein levels[5] indicative of a disseminated encephalomyelitis[6].

A presumptive diagnosis is based on demonstration of anti-Neospora or anti-Toxoplasma antibodies in serum and response to antimicrobial therapy.

Treatment is usually successful with clindamycin or trimethoprim/sulfadiazine.

In pups with pelvic limb rigidity, the prognosis is guarded due to extensive nerve damage.


  1. Wouda W et al (1993) Neospora caninum as a cause of lameness symptoms in young dogs. Tijdschr Diergeneeskd 118(12):397-401
  2. Vashisht K et al (2005) Naturally occurring Sarcocystis neurona-like infection in a dog with myositis. Vet Parasitol 133(1):19-25
  3. Paciello O et al (2009) Canine inflammatory myopathy associated with Leishmania Infantum infection. Neuromuscul Disord 19(2):124-130
  4. Saey V et al (2010) Neuritis of the cauda equina in a dog. J Small Anim Pract 51(10):549-552
  5. Cuddon P et al (1992) Neospora caninum infection in English Springer Spaniel littermates. Diagnostic evaluation and organism isolation. J Vet Intern Med 6(6):325-332
  6. Wolf M et al (1991) The clinical diagnosis of protozoal myositis syndrome (Neospora caninum) of puppies. Tierarztl Prax 19(3):302-306