Exotis ISSN 2398-2985

Reptiles

Flagellate / ciliate infection

Contributor(s): Sarah Pellett, Robert Johnson

Introduction

  • Cause:
    • Flagellates: Hexamitia spp, Monocercomonoides spp, Proteromonas spp, Monocercomonas spp, Trichomonas spp and Giardia spp.
    • Ciliates: Balantidium spp and Nyctotherus spp.
  • Signs: often asymptomatic (most are non-pathogenic commensals). In excessive numbers, flagellates may cause anorexia, weight loss and diarrhea. The pathogenic flagellate Hexamita parva can cause fatal renal disease in tortoises. The ciliates, Balantidium spp and Nyctotherus spp are not known to cause clinical disease in reptiles.
  • Diagnosis: examination of a direct fecal smear to see the mobile trophozoite stage in ciliates and the flagella and undulating membranes in flagellates. Fecal flotation to observe cysts. Hexamita parva may be observed in chelonian urine. Definitive diagnosis is by detecting the parasite on renal biopsy.
  • Treatment: if required, ronidazole. Supportive therapy is essential. Alternatively, metronidazole can be prescribed.
  • Prognosis: varies depending on protozoal parasite present and host immune system.

Pathogenesis

Etiology

  • Ciliates:
    • Ciliated protozoa commonly seen are Balantidium spp and Nyctotherus spp.
    • Usually they do not cause disease.
  • Flagellates:
    • Flagellated protozoa seen are Hexamita spp, Trichomonas spp, Giardia spp, Leptomonas spp, Monocercomonoides spp, Proteromonas spp and Monocercomonas spp.
    • In small numbers, in immunocompetent animals, these are often commensals.
    • The pathogenic flagellate, Hexamita parva, can cause fatal renal disease in chelonians.

Predisposing factors

General

  • Ciliates:
    • Host immunosuppression.
    • Suboptimal environment which allows fecal-oral contamination.
  • Flagellates:
    • Host immunosuppression, often due to underlying disease.
    • Suboptimal environment which allows fecal-oral contamination.

Pathophysiology

  • Ciliates:
    • Direct life cycle.
    • Reproduce by sexual reproduction with conjugation of two ciliates and exchange of micronuclei.
    • The new ciliates then divide by binary fission.
    • Transmission by ingestion of an infective cyst.
    • Once ingested, it encysts within the small intestine. Trophozoites are produced.
    • Trophozoites colonize the large intestine, undergo replication and form new infective cysts.
  • Flagellates:
    • Direct life cycle.
    • Reproduction occurs asexually by binary fission.
    • Infection from ingesting an infective cyst.
    • For Hexamita parva, the flagellate normally is found in the lumen of the intestines. If it enters the biliary duct, or the urinary tract via the cloaca up the ureters to the kidneys, it may cause pathology.
    • Parasite encysts in the kidney.

Timecourse

  • Variable.

Epidemiology

  • Direct lifecycle.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Juan-Salles C, Garner M M, Nordhausen R W, Valls X, Gallego M & Soto S (2014) Renal flagellate infections in reptiles: 29 cases. J Zoo Wildl Med 45 (1), 100-109 PubMed.

Other sources of information

  • Divers S J (2018) Parasitic Diseases of Reptiles. MSD Manual Veterinary Manual. Website: www.msdvetmanual.com. Last accessed 12th June 2016.
  • Šlapeta J, Modrý D & Johnson R (2018) Reptile Parasitology in Health and Disease. In: Reptile Medicine and Surgery in Clinical Practice. Eds: Doneley R, Monks D, Johnson R & Carmel B. Wiley-Blackwell, UK. pp 425-39.
  • Hedley J (2012) Survey of Gastrointestinal Parasites in Tortoises in the United Kingdom. RCVS Diploma Thesis. Website: https://knowledge.rcvs.org.uk. Last accessed 12th June 2018.
  • Schneller P  Pantchev N (2008) Parasitology in Snakes, Lizards and Chelonians. Edition Chimaira, Frankfurt am Main.
  • Greiner E C & Mader D R (2006) Parasitology. In: Reptile Medicine and Surgery. 2nd edn. Ed; Mader D R. Elsevier, USA. pp 343-364.
  • Johnson J D (2004) Urogenital System. In: BSAVA Manual of Reptiles. 2nd edn. Eds: Girling S J & Raiti P. BSAVA, UK. pp 261-272
  • Klingenberg R J (2004) Parasitology. In: BSAVA Manual of Reptiles. 2nd edn. Eds: Girling S J & Raiti P. BSAVA, UK. pp 319-329.
  • Jacobson E R (1988) Use of Chemotherapeutics in Reptile Medicine. In: Exotic Animals. Eds: Jacobson E R & Kollias Jr G V. Churchill Livingstone, USA. pp 35-48.


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