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380.e2 Gastric Parasites

Gastric Parasites Client Education
Sheet
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DIAGNOSIS
○ Ivermectin: may be effective at 0.2 mg/kg
BASIC INFORMATION
PO (dog, cat); not for use in ivermectin-
Definition Diagnostic Overview sensitive breeds (p. 638).
Nematode gastric parasites affecting dogs and A presumptive diagnosis is made for individuals • Anthelminthics for O. tricuspis
cats with a chief complaint of vomiting that resolves ○ Fenbendazole 50 mg/kg/d PO for 3 days,
with anthelmintic treatment; alternatively, or
Epidemiology diagnosis may follow demonstration of parasites ○ Pyrantel 20 mg/kg PO, repeat in 2-3
SPECIES, AGE, SEX (endoscopic or microscopic). weeks
Physaloptera spp infect dogs and cats, and
Ollulanus tricuspis infects cats. There is no age Differential Diagnosis Possible Complications
or sex predisposition. Other causes of vomiting (p. 1294) Fenbendazole is not labeled for use in cats but
is safe at doses up to 250 mg/kg q 24h for 9
RISK FACTORS Initial Database days. Adverse reactions (e.g., systemic vasculitis,
• Dogs and cats that habitually ingest inter- Initial diagnostic tests are aimed at ruling out bone marrow suppression) to fenbendazole
mediate (e.g., crickets, beetles, cockroaches) other causes of vomiting. occur rarely.
or transport hosts (e.g., rodents, snakes) are • CBC, serum biochemistry profile, and uri-
at greater risk for Physaloptera spp infection. nalysis: usually normal, although peripheral PROGNOSIS & OUTCOME
• Multi-cat households are a risk factor for eosinophilia occurs rarely
Ollulanus spp infection. Ollulanus spp were • Fecal flotation: usually negative. Rarely, the The prognosis for complete resolution of
the second most common gastrointestinal translucent eggs of Physaloptera spp may be chronic vomiting is excellent. Reinfection with
parasite found in feral cats in Denmark. identified. Physaloptera spp is very likely due to repeated
• Abdominal imaging (radiographs and ingestion of intermediate and transport hosts.
CONTAGION AND ZOONOSIS ultrasound): normal Treatment of all cats in a household for O.
Neither is a zoonotic parasite. Ollulanus is • Ollulanus spp may be seen on microscopic tricuspis should eliminate the parasite.
spread from cat to cat. One report from Japan exam of vomitus.
described O. tricuspis infection in two dogs PEARLS & CONSIDERATIONS
that had been on long-term glucocorticoids Advanced or Confirmatory Testing
and ate cat vomitus. • For otherwise healthy animals with chronic Comments
vomiting unexplained by initial testing, an • During gastroscopy, the presence of small
GEOGRAPHY AND SEASONALITY anthelminthic trial is warranted before erosions or pinpoint hemorrhages on the
Worldwide proceeding to invasive diagnostic testing. gastric mucosa should prompt a careful
• Gastroscopy (p. 1098) is the only method inspection for Physaloptera spp.
Clinical Presentation to reliably identify Physaloptera spp in the • The elusive nature of the parasites, minimal
HISTORY, CHIEF COMPLAINT stomach. severity of clinical signs, and expense of
Chronic vomiting is the chief complaint for ○ These very small parasites are often found endoscopy warrant an anthelmintic trial
both infections. A good appetite is usually in low numbers and are easy to miss. before advanced testing. Gastric parasites
retained. Weight loss is insignificant with • Ollulanus spp can also be identified on may still be found after a failed anthelmintic
Physaloptera spp infections, but cats with microscopic exam of squash or touch preps trial.
Ollulanus spp infection may have chronic weight of gastric mucosal biopsies (endoscopic
loss. Clinical signs may be present from a few or surgical) or on histologic evaluation of Prevention
days to many months. Other than vomiting, biopsies (less reliable). • Block access to intermediate or transport
infected animals typically act normally. hosts (difficult).
TREATMENT • Use of a monthly heartworm preventive
PHYSICAL EXAM FINDINGS that contains pyrantel may be beneficial in
No significant physical exam abnormalities but Treatment Overview management of dogs with continued access
cats may be thin. Parasite removal causes rapid resolution of to intermediate or transport hosts.
vomiting.
Etiology and Pathophysiology Technician Tips
Physaloptera spp, most commonly Physaloptera Acute General Treatment When dispensing fenbendazole granules,
rara: range in length from 1 to 6 cm, although • Mechanical removal of Physaloptera spp remember that a 1-g packet contains only
most are 1-2 cm. resolves clinical signs. 222 mg of fenbendazole. The 1-g packet
• Subclinical infections are thought to occur • Anthelminthics for Physaloptera spp used to treat a 10-pound animal equates to
in many animals, but chronic vomiting due ○ Pyrantel 5 mg/kg PO (dog), 20 mg/kg 50 mg/kg.
to gastritis or penetration of parasite into the PO (cat). Using a higher dosage in dogs
gastric wall is the typical disease presentation. (10-15 mg/kg) and repeating in 2-3 weeks SUGGESTED READINGS
O. tricuspis: size range is 0.7-1 mm long. may yield a higher response rate.
• Ollulanus may induce gastric irritation ○ Fenbendazole 50 mg/kg/d PO for 3 days Guilford WG, et al: Chronic gastric diseases: parasitic
and inflammation or, in severe cases, (dog, cat) is reportedly effective. This gastritis. In Guilford WG, et al, editors: Strombeck’s
Small animal gastroenterology, ed 3, Philadelphia,
chronic fibrosing gastritis; infections can author uses 75 mg/kg/d PO for 5 days 1996, Saunders, pp 285-286.
be inapparent. in dogs along with pyrantel at 7.5 mg/ Kato D, et al. The first report of the ante-mortem
• Direct life cycle: infection from eating kg PO, once. Repeat this protocol in 3 diagnosis of Ollulanus tricuspis infection in two
vomitus containing larvae weeks. dogs. J Vet Med Sci 77:1499-1502, 2015.

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