Tapeworms: rabbit as the definitive host

 

Esther van Praag, Ph.D.

 

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Warning: this file contains pictures that may be distressing for some persons.

Cestodes

Several species of flat segmented worms, or tapeworms, can infest wild or domestic rabbits and wild lagomorph species like the American cottontail rabbit or hares, and develop into mature reproducing tapeworms.  They include:

ˇ     Monoecocestus americanus, the porcupine tapeworm;

ˇ     Ctenotaenia ctenoides;

ˇ     Cittotaenia variabilis, the rabbit tapeworm;

ˇ     Mosgovoyia pectinata americana or M. perplexa;

Tapeworm infestation is rare in pet rabbits, and essentially caused by Cittotaenia variabilis.

The life cycle of these worms is not well understood to these days. It is believed that infected arthropods like oribatid mites (mites living in the soil) transmit the rabbit tapeworm Cittotaenia variabilis. The rabbit ingest the mites while grazing or eating contaminated hay. The larval form will develop in the abdomen and the liver. Adult stages are found in the intestine. It measures up to 1 cm wide, and can reach as long as 20 cm. 

Cittotaenia variabilis is characterized by a scolex (head) with 4 suckers that will attach to the intestinal wall.

Clinical signs

If the number of tapeworm is small, no clinical signs are observed. In case of severe infection, there may be signs of, diarrhea, bloat, ileus, and severe pain. The rabbit may grow slowly; appear abnormally thin, in spite of a normal appetite. 

Proglottis (reproductive segments) can be found among the feces:

Portion of a flat worm - possibly Cittotaenia variabilis, found among the fecal dropping of a pet rabbit.

This rabbit is fed fresh dandelion and broadleaf plantain from the field, where wild contontails can be observed.

Picture : Wei in Massachusets (USA)

Rarely, the worm can be found to stick out of the anus.

Upon necropsy, ulceration may be is observed at the attachment site of the worm onto the intestinal wall.

The tapeworms affecting rabbits are not zoonotic and can therefore not be transmitted to humans after contact with contaminated fecal material or proglottis.

Treatment

Praziquantel

10 mg/kg

PO

5-10 mg/kg

SC, IM

Niclosamide

100 mg/kg

PO

to understand the meaning of the abbreviations, click here.

The rest of the tapeworm has been expelled after treatment with praziquantel

Fecal material and mucus surround the expelled worm. Picture: Wei

Good sanitation of the living environment of the rabbit is also necessary.

Acknowlegement

Many thanks to Wei in Massachusetts (USA) for sharing this rare finding in her rabbit Bunbun and her permission to use the pictures.

Further information:

Manning et al. The biology of the laboratory rabbit. 2nd ed. London, UK, 1994.

Sadler KC. Common diseases and Parasites of Cottontails, Missouri Dept. of Conservation.

Pinto RM, et al. Helminths of rabbits (Lagomorpha, Leporidae) deposited in the Helminthological Collection of the Oswaldo Cruz Institute. Rev. Bras. Zool. 2004, v. 21, n. 3, pp. 599-604.

Soltysiak Z, Bednarski M, Piekarska J. Wagrzyca watroby królika. Medycyna Wet. 2007, 63:1255-1257.

 

 

  

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