Whipworms: Clinical Pathology Notes - PDF

CLINICAL PATHOLOGY I – Lecture Whipworms Species o Trichuris vulpis: Common whipworm of dogs o T. campanula, T serrata, T felis: “Whips” are rare in cats o T. trichiura: Whipworm of humans Adults o Located in cecum and colon o Long, thin cra...

CLINICAL PATHOLOGY I – Lecture Whipworms Species o Trichuris vulpis: Common whipworm of dogs o T. campanula, T serrata, T felis: “Whips” are rare in cats o T. trichiura: Whipworm of humans Adults o Located in cecum and colon o Long, thin cranial end (embedded in mucosa) and thick caudal end (free in lumen of intestine) results in whip-like appearance o Approximately 1.75 to 3 inches long Ova o Football shaped, yellow-brown o Double opercula (plural); “operculum” is singular (sometimes also called “polar plugs”) o Unembryonated ova mature to embryonated ova in 2 to 4 weeks and become infective o Infective ova are highly resistant to desiccation and can survive up to 5 years in environment Distribution: In US, mostly a problem in southeastern part of country d/t very moist climate Life Cycle o Direct o Adults live in cecum and colon producing thousands of unembryonated ova o Ova passed in feces, develop embryos after 2 – 4 weeks in moist soil o Embryonated ova are infective o Embryonated ova are ingested o Larvae hatch in small intestine (through operculum) but ONLY if ingested o Larvae move to large intestine, burrow into mucosa of cecum and colon, mature, and begin producing ova o Prepatent period ~ 3 months Clinical Signs o Typically, signs are mild, but if infestation is severe o Puppies: Diarrhea, dehydration, emaciation, death o Adult dogs: Chronic, intermittent diarrhea with bright red blood (BRB) and mucus (ie, “large bowel diarrhea”) Diagnosis o Fecal flotation with characteristic ova o Diagnosis can be difficult, as females produce ova intermittently o If whips are suspected, perform 1 fecal/day for 4 consecutive days before declaring patient “NOO” o Ova are heavy (SG ~ 1.15) -- wait minimum of 20 minutes to provide sufficient time to float Use of Sheather’s solution may increase sensitivity of test 12/3/2024 1  o Occasionally, heavy larval infestations will produce clinical signs, but ova will not be detected in feces -- diagnosis is made through response to treatment o Reinfestations are common d/t highly resistant eggs -- check fecal samples every 3 months Treatment** o Fenbendazole: PO for three consecutive days; repeat monthly for three months o Milbemycin oxime: PO monthly o Moxidectin: Topically monthly Environmental Control o Pick up feces regularly o Impervious kennel floors allow for disinfection and desiccation:  Bleach at 1% concentration: Also kills hookworm larvae  Steam sterilization: Also kills ascarid ova o Grass or soil: Sunlight; permits complete desiccation of ova Public Health Concerns o Although there are reports in medical literature of human infestations with T vulpis, these reports lack sufficient validation to consider T vulpis a zoonotic parasite at this time 12/3/2024 2