| Adult
Trichuris
vulpis
are 40-70 mm long and consist of a long, slender anterior portion and a thick posterior third. They commonly inhabit the cecum of dogs where they are firmly attached to the wall, with their anterior end embedded in the mucosa. Thick-shelled eggs with bipolar plugs are passed in the feces and become infective in 2-4 wk in a warm, moist environment. Although eggs may remain viable in a suitable environment for up to 5 yr, they are susceptible to desiccation. The life cycle
is direct. After infective eggs are ingested, the larvae develop in the jejunal wall, and the adults mature in the cecum in ~11 wk. They may remain for up to 16 mo.
|
| No signs are seen in light infections, but as the worm burden increases and the inflammatory (and occasionally hemorrhagic) reaction in the cecum becomes more pronounced, weight loss and diarrhea become evident. Fresh blood may be seen in the feces of heavily infected dogs, and anemia occasionally follows. |
|
Trichuris
infections rarely are seen in cats in North America but may occasionally be associated with clinical signs similar to those described for dogs. |
| Treatment and Control: |
| The eggs are susceptible to desiccation; therefore, by maintaining cleanliness and eliminating moist areas, the risk of infection in dogs can be reduced considerably, although
T
vulpis
infections can be difficult to control. For anthelmintic treatment of dogs, licensed compounds include fenbendazole, flubendazole, mebendazole, milbemycin, and the combination formulations praziquantel/pyrantel/febantel, pyrantel/febantel, and pyrantel/oxantel (Table:
Drugs with Approved Activity Against Intestinal Helminths of Dogs and Cats). Treatment should be repeated 3 times at monthly intervals because of the long prepatent period. Finally, milbemycin oxime, milbemycin/lufenuron, and
diethylcarbamazine/oxibendazole, when administered for heartworm prevention, are also approved for control of
T
vulpis
infections. |
| Effective therapy has yet to be described for
Trichuris
infections in cats. If required, treatment should be attempted on an experimental basis using a compound with licensed activity against
T
vulpis
. |
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