Canis ISSN: 2398-2942

Neosporosis

Synonym(s): Neospora caninum

Contributor(s): Stephen Barr, Bryn Tennant, SandyTrees

Introduction

  • First recognized as a disease of dogs in Norway in 1984.
  • Cause:Neospora caninum Neospora caninum similar protozoal parasite toToxoplasma gondii Toxoplasma gondii.
  • Signs: typically paresis and mortality mainly affecting young dogs (but can produce a wide variety of signs in dogs of all ages).
  • Diagnosis: serology, demonstration of parasites in tissues with specific staining. 5-17% of dogs in the UK are seropositive.
  • Treatment: appropriate antibiotics.
  • Prognosis: fair.
  • Widespread cause of abortion in dairy cattle.
  • No natural infections reported in cats or humans.

Pathogenesis

Etiology

Predisposing factors

General
  • Immunosuppression may re-activate subclinical infection.

Specific

  • Administration of corticosteroids can exacerbate acute and chronic neosporosis.

Pathophysiology

  • Ingestion of tissue cysts and tachyzoites may occur in dogs fed uncooked meat (beef) → rapid multiplication of tachyzoites → kills host cells → tissue cyst rupture → host reaction.
  • Mononuclear cell infiltration into CNS and spinal nerves suggests immune-mediated pathology.
  • Lesions include hypo- or demyelination and inflammatory response but exact mechanism of paralysis unknown.
  • Immunosuppression may reactivate latent infection.
  • N. caninumcan be transmitted transplacentally and is a possible cause of abortion/resorption or stillbirth.
  • As well as vertical transmission (placenta and colostrum) horizontal transmission is considered possible, perhaps via oocyte shedding in feces, although this does not occur in significant numbers except in immunocompromised dogs.
  • In cattle, prevalence of antibodies can be high, eg up to 35% in New Zealand, but abortion is probably triggered by an immunomodulating event, eg infection with bovine viral diarrhea virus.

Timecourse

  • Clinical signs do not usually occur until puppies are 3-5 weeks old.
  • Neurological signs may progress over days to months → dysphagia and death.
  • Myocarditis may present as sudden collapse or death.

Epidemiology

  • Transmission by ingestion and transplacentally.
  • Chronically infected bitches may show recurrent parasitemia without clinical signs.
  • Not all puppies in a litter may be affected.
  • Full lifecycle is not known. The only stages identified are tachyzoites and tissue cysts.

Diagnosis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Prevention

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Boyd S P, Barr P A, Brooks H W & Orr J P (2005) Neosporosis in a young dog presenting with dermatitis and neuromuscular signs. JSAP 46 (2), 85-88 PubMed.
  • Lorenzo V, Pumarola M & Siso S (2002) Neosporosis with cerebellar involvement in an adult dog. JSAP 43 (2), 76-79 PubMed.
  • Boydell P & Brogan N (2000) Horner's syndrome associated with Neospora infection. JSAP 41 (12), 571-572 PubMed.
  • Reichel M P (2000) Neospora caninum infections in Australia and New Zealand. Aust Vet J 78 (4), 258-261 PubMed.
  • Braund K G (1997) Idiopathic and exogenous causes of myopathies in dogs and cats. Vet Med 92 (7), 629-634 VetMedResource.
  • Barber J S & Trees A J (1996) Clinical aspects of 27 cases of neosporosis in dogs. Vet Rec 139 (18), 439-443 PubMed.
  • Dubey J P & Lindsay D S (1996) A review of Neospora caninum and neosporosis. Vet Parasitol 67 (1-2), 1-59 PubMed.
  • Ruehlmann D, Podell M, Oglebee M & Dubey J P (1995) Canine neosporosis - a case report and literature review. JAAHA 31 (2), 174-183 PubMed.

Other sources of information

  • Dubey J P (1992)Neospora caninum infections.In:Current Veterinary Therapy XI.Eds: R W Kirk & J D Bonagura. Philadelphia: W B Saunders. pp 263.


ADDED