Content continues after advertisement

Research Note: Heterobilharzia americana

Clinician's Brief (Capsule)

Parasitology

|August 2016

Sign in to Print/View PDF

Heterobilharzia americana, a schistosomal trematode, is endemic in the coastal southern United States; most cases occur in Texas and Louisiana. Definitive hosts are dogs, raccoons, and other mammalian species; lymnaeid freshwater snails are intermediate hosts. The adult parasites reside in mammalian mesenteric veins. They release their eggs, which migrate to the intestines and are excreted in the feces. Once in freshwater, the eggs release ciliated miracidia, which penetrate the mantle of snails. The miracidia mature into cercariae in the snails before being released. Free-swimming cercariae then re-infect mammalian hosts by penetrating intact skin and migrating to the mesenteric veins. Aberrant migration can cause infection of the liver and other organs, which can cause granulomatous inflammation and fibrosis. H americana infections typically cause GI signs (eg, decreased appetite, weight loss, vomiting, diarrhea) and occasionally cause dermatitis or coughing from migration through the skin and lungs. Approximately half of reported cases have hypercalcemia of unknown cause. 

A fecal sodium chloride sedimentation is usually necessary to diagnose this infection. Polymerase chain reaction is also available to test feces, liver, and intestinal biopsies. If samples are available, eggs and parasites can be found on histopathology of affected tissues. In this case report, an H americana diagnosis was made via cytology of fine-needle aspirates of the patient’s liver. The authors concluded that cytology is a useful, accurate tool for diagnosing canine schistosomiasis.

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Clinician's Brief may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.

Podcasts

Clinician's Brief:
The Podcast
Listen as host Alyssa Watson, DVM, talks with the authors of your favorite Clinician’s Brief articles. Dig deeper and explore the conversations behind the content here.
Clinician's Brief provides relevant diagnostic and treatment information for small animal practitioners. It has been ranked the #1 most essential publication by small animal veterinarians for 9 years.*

*2007-2017 PERQ and Essential Media Studies

© 2023 Educational Concepts, L.L.C. dba Brief Media ™ All Rights Reserved. Terms & Conditions | DMCA Copyright | Privacy Policy | Acceptable Use Policy