Canis ISSN: 2398-2942

Isospora neorivolta

Contributor(s): David Lindsay

Introduction

Classification

Taxonomy

  • Phylum: Apicomplexa.
  • Class: Sporozoasida.
  • Family: Eimeriidae.
  • Genus: Isospora.
  • Species: neorivolta.

Active Forms

This article is available in full to registered subscribers

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

Resting Forms

This article is available in full to registered subscribers

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

Clinical Effects

Epidemiology

Habitat

  • Asexual stages are located primarily in the lamina propria near the tips of the villi of the posterior half of the small intestine of dogs, particularly the ileum. Gametocytes occur in the lamina propria and surface epithelium of the ileum and cecum.
  • Cystozoites occur in the parenteral tissues, probably the mesenteric lymph nodes and the abdominal viscera, of rats, mice, probably other herbivores and probably also the tissues of the dog.

Lifecycle

  • Intestinal development.
  • Oocysts.
  • Cystozoites in paratenic herbivorous hosts.
  • Cystozoites in tissues of dog.

Transmission

Direct lifecycle

  • Feco-oral transmission in kennel situations.
  • Development of the oocysts is very rapid, the prepatent period of infection is short and, as the biotic potential of Isospora is high, very large numbers of oocysts can build up rapidly to pathogenic levels.

Indirect lifecycle

  • Infection is derived by ingestion of cystozoites in the tissues of prey.
  • Numbers are unlikely to be sufficient to cause disease but this source of infection could maintain the lifecycle.

Reactivation of cystozoites in the dog

  • The presence of heavily infected animals continues to suggest that reactivation of cystozoites in immunosuppressed or stressed puppies may then initiate intestinal multiplication and so could be an important factor in causing disease.

Pathological effects

  • Some protective immunity and decreased susceptibility to infection with age probably does occur in regard to the intestinal stages.
  • No evidence for pathogenicity.
  • Mild congestion and infiltration of inflammatory cells have been seen in infected tissues.

Other Host Effects

  • Obligate, intracellular parasite lying within a parasitophorous vacuole.

Control

Control via animal

  • Remove animal from surroundings and so from the source of infection.
  • There is no clear evidence that common anticoccidials have real efficacy, but they may shorten the course of the disease and therefore could be administered.

Control via chemotherapies

  • Sulfadimethoxine is approved in the US for the treatment of coccidiosis. No products are licensed in the UK.
  • Toltrazuril and diclazuril seem the most likely candidates with proven efficacy againstIsospora suisin pigs but have been used only in very few dogs.
  • Trimethoprim/sulfadiazine Trimethoprim (30-60 mg/kg in larger dogs, half this for dogs <4 kg, administered daily for 6 days). Some toxicity has been reported.

Control via environment

  • The oocysts sporulate very rapidly and are very resistant.
  • Parasite control can be difficult due to the presence of both oocyst and rodent sources of infection, and the rapid multiplication of the parasite.
  • Remove feces frequently.
  • Wash pens well to remove oocysts.
  • Desiccation will kill oocysts over several days.
  • Ammonia disinfectants will be the most effective.

Diagnosis

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.
  • Lindsay D S, Dubey J P, Blagburn B L (1997) Biology of Isospora spp. from humans, nonhuman primates and domestic animals. Clin Microbiol Rev 10 (1), 19-34 PubMed.
  • Dubey J P & Mahrt J L (1978) Isospora neorivolta n. sp. from the domestic dog. J Parasitol 64 (6), 1067-1073 PubMed.

ADDED