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Оглавление

Balantidium

BASICS

DEFINITION/OVERVIEW

Balantidium is a large ciliated protozoal organism that resides within the gastrointestinal tract. The trophozoite is elliptical in shape and ranges in size from 30–300 × 25–120 μm. It is densely covered with cilia along its surface. At the tapered front end lies the cystostome (mouth). Cysts have a thick wall, spherical in shape, and have a kidney bean‐shaped macronucleus. Balantidium testudinis is a species commonly reported in turtle species. They are typically found in herbivorous reptiles. It is debated whether these organisms are considered commensal within reptiles.

ETIOLOGY/PATHOPHYSIOLOGY

Transmission is through the fecal–oral route.

Cysts are ingested and then undergo excystation in the intestinal tract.

Trophozoites inhabit the large colon and replicate by binary fission.

Trophozoites undergo encystation in which infective cysts are formed and then excreted in feces.

Balantidium sp. are facultative parasites and only become pathogenic when other virulence factors such as hyaluronidase are present.

This then allows them to penetrate the intestinal mucosa and cause extensive hemorrhage and necrosis.

Balantidium is generally limited to the large intestinal tract.

In severe infections, the protozoal organisms migrate to the liver and cause abscessation.

SIGNALMENT/HISTORY

No age or sex predisposition

CLINICAL PRESENTATION

Diarrhea

Tenesmus

Inappetence

Weight loss

RISK FACTORS

Husbandry

Improper husbandry

Others

Immunocompromised animals with active parasitic/bacterial infections are more predisposed for the protozoan to become pathogenic.

DIAGNOSIS

DIFFERENTIAL DIAGNOSIS

Nyctotherus sp.

DIAGNOSTICS

Microscopic evaluation of fresh fecal material to visualize trophozoites and cysts.

SAF technique can be used for better visualization.

The addition of iodine will stain the contents of the cysts, making them more visible.

PATHOLOGICAL FINDINGS

Hemorrhagic necrotizing colitis

TREATMENT

APPROPRIATE HEALTH CARE

N/A

NUTRITIONAL SUPPORT

N/A

CLIENT EDUCATION/HUSBANDRY RECOMMENDATIONS

Practice proper hygiene

Wash fruits and vegetables before being fed

House infected animals separately

MEDICATIONS

DRUG(S) OF CHOICE

Metronidazole 50 mg/kg PO q24h for 7 days

Nimorazole 125 mg/kg PO q24h for 4 days

Tetracyclines 5–10 mg/kg q24h for 5–8 days

PRECAUTIONS/INTERACTIONS

N/A

FOLLOW‐UP

PATIENT MONITORING

Recheck feces on a routine basis

EXPECTED COURSE AND PROGNOSIS

Treatment should only be started if clinical disease is observed.

MISCELLANEOUS

COMMENTS

N/A

ZOONOTIC POTENTIAL

Balantidium coli is the only known species to infect humans.

SYNONYMS

N/A

ABBREVIATIONS

SAF = sodium acetate acetic acid formalin

INTERNET RESOURCES

De Bosschere H, Roels S. Balantidium sp. and Nyctotherus sp.: Two common members of the digestive‐tract flora in Mediterranean tortoises. Tortoise Trust. https://www.tortoisetrust.org/articles/balantidium.htm

Divers SJ. Parasitic Diseases of Reptiles. MSD Manual Veterinary Manual, June 2020. http://www.merckvetmanual.com/exotic‐and‐laboratory‐animals/reptiles/parasitic‐diseases‐of‐reptiles