Balantidium spp

From Dog
Balantidium coli trophozoite[1]

Balantidium spp are a ciliated protozoan parasite of most mammals and part of the normal gastrointestinal flora.

Species which are pathogenic to dogs include:

  • Balantidium coli

Dogs are primarily affected with this parasite in association with gastrointestinal disease[2]. Infections are often attributed to close proximity to pigs[3], or co-infections with Trichuris vulpis[4].

Balantidium coli is widely epidemic among the pig population of the world. The adult resides in the large intestine and cecum. Cysts are expelled in feces and reinfect host via accidental ingestion. The parasite excysts in the host intestine. The parasite normally feeds upon fecal material, starch granules, and cell fragments. The ciliates often invade the mucosa and submucosa of the intestines and produce severe ulcers, that are often flask like in shape[5].

Clinically affected dogs usually present with abdominal pain, mucoid diarrhea and occasionally blood in stools associated with ulerative large bowel enteritis[6].

Diagnosis is based on coprological identification of motile trophozoites of direct smears or detection of cysts in floatation devices (e.g. Baermann).

Treatment is usually not required, although broad-spectrum parenteral antimicrobials such as clindamycin or metronidazole (30mg/kg daily for 1 - 2 weeks) may assist recovery.


  1. Oregon Gov
  2. Bailey WS & Williams, AG (1949) Balantidium infection in the dog. J Am Vet Med Assoc 114(865):238
  3. Hayes FA & Jordan HE (1956) Canine helminthiasis complicated with Balantidium species. J Am Vet Med Assoc 129(4):161
  4. Ewing SA & Bull RW (1966) Severe chronic canine diarrhea associated with Balantidium-Trichuris infection. J Am Vet Med Assoc 149(5):519-520
  5. Schuster, FL & Ramirez-Avila, L (2008) Current World Status of Balantidium coli. Clinical Microbiology Reviews 21(4):626-638
  6. Bowman, DD (2009) Georgis' parasitology for veterinarians. Elsevier Saunders, Missouri. 9th edn. pp:92