Anthelmintic therapies for Parafilaroides decorus pneumonia in California sea lions
- Lungworm
- Parasites
- Pathology
- Medicine
Abstract
Infection with the lungworm Parafilaroides decorus is ubiquitous among young California sea lions (CSL; Zalophus californianus), and high infection intensity is a significant cause of pulmonary pathology, respiratory distress, morbidity, and mortality. Anthelmintics are a common treatment for stranded CSL exhibiting clinical evidence of pneumonia in the rehabilitation setting. To evaluate the clinical efficacy of anthelmintics in reducing larval lungworm fecal output, 55 stranded pup and yearling CSL were treated with either parenteral moxidectin or oral fenbendazole and compared with a group that did not receive an anthelmintic. Clinical disease scoring initially revealed 1 animal to not have disease, 37 animals to have mild to moderate disease, and 17 animals to have severe disease secondary to P. decorus infection. Initial posttreatment fecal recheck scored animals as improved (n ¼ 30), unchanged (n=14), worsened (n=2), or dead (n=9). There was no difference between treatment groups and changes in clinical scores on the basis of clinical signs, nor was there a difference between treatment groups and change of P. decorus presence. There is insufficient evidence to indicate that oral fenbendazole or subcutaneous moxidectin is superior for parasitic pneumonia therapy due to P. decorus in CSL.
Kane, L. P., Field, C. L., Hortensius, L. M., Rios, C., McClain, A. M., Whitmer, E. R., Simeone, C., Dennison, S., Zabrodski, M. W., & Duignan, P. (2025). Anthelmintic therapies for Parafilaroides decorus pneumonia in California sea lions (Zalophus californianus). Journal of Zoo and Wildlife Medicine, 56(3), 515–524.
Meet The Experts
{"image":"\/People\/Portrait\/cara-field.jpg","alt":"Cara Field","title":"Cara Field","text":"Director, Conservation Medicine","link_url":"https:\/\/www.marinemammalcenter.org\/person\/cara-field","link_text":"Read Bio"}
{"image":"\/People\/Portrait\/cropped-images\/PD_Gray whale Pacifica_IMG_0552-0-0-1270-992-1775170630.jpeg","alt":"Padraig Duignan","title":"P\u00e1draig Duignan","text":"Senior Director, Research Pathology","link_url":"https:\/\/www.marinemammalcenter.org\/person\/padraig-duignan","link_text":"Read Bio"}
{"image":"\/People\/Portrait\/cropped-images\/carlos-rios-0-180-1160-906-1605722153.jpg","alt":"Carlos Rios","title":"Carlos Rios","text":"Associate Director, Pathology and Diagnostics","link_url":"https:\/\/www.marinemammalcenter.org\/person\/carlos-rios","link_text":"Read Bio"}
{"image":"\/People\/Portrait\/lian-hortensius.jpg","alt":"Lian Hortensius","title":"Lian Hortensius","text":"Director, Animal Data Science","link_url":"https:\/\/www.marinemammalcenter.org\/person\/lian-hortensius","link_text":"Read Bio"}
{"image":"\/People\/Portrait\/cropped-images\/emily-whitmer-0-226-3018-2357-1622227790.jpg","alt":"Emily Whitmer","title":"Emily Whitmer","text":"Clinical Veterinarian","link_url":"https:\/\/www.marinemammalcenter.org\/person\/emily-whitmer","link_text":"Read Bio"}
Related Publications
{"image":"\/Animals\/Patients\/California sea lions\/csl-by-bill-hunnewell-c-the-marine-mammal-center-1.jpg","alt":"California sea lion eating a fish","title":"New Technique for Diagnosing Lung Parasite Infections in Sea Lions","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/new-technique-for-diagnosing-lung-parasite-infections-in-sea-lions","label":"Research Paper"}
{"image":"\/Animals\/Patients\/Elephant seals\/cropped-images\/es-by-bill-hunnewell-c-the-marine-mammal-center-3-2-1214-3454-3512-1600891002.jpg","alt":"northern elephant seal","title":"Diagnostic Tests for Lungworm-Infected Northern Elephant Seals","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/diagnostic-tests-for-lungworm-infected-northern-elephant-seals","label":"Research Paper"}
{"image":"\/Animals\/Wild\/Humpback whale\/cropped-images\/humpback-whale-sea-lions-photo-c-bill-hunnewell-190-2-2774-2167-1659123832.jpg","alt":"humpback whales and California sea lions feeding","title":"Aquatic Mammals","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/aquatic-mammals","label":"Research Paper"}
{"image":"\/Animals\/Patients\/Guadalupe fur seals\/2021\/cropped-images\/gfs-skyrocket-by-bill-hunnewell-c-the-marine-mammal-center-noaa-permit-18786-2-112-1667-1302-1625765450.jpg","alt":"Guadalupe fur seal Skyrocket","title":"Vasculitis and Thrombosis due to the Sea Lion Lungworm in a Guadalupe Fur Seal","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/vasculitis-and-thrombosis-due-to-the-sea-lion-lungworm-in-a-guadalupe-fur-seal","label":"Research Paper"}
Vasculitis and Thrombosis due to the Sea Lion Lungworm in a Guadalupe Fur Seal
Read MoreRecent News
{"image":"\/Animals\/Patients\/California sea lions\/2024\/d-california-sea-lionsin-treatment-for-domoic-acidsausalito72624photo-by-giancarlo-rulli-c-the-marine-mammal-center.jpg","alt":"California sea lions","title":"SF GATE: Sick, disoriented sea lions are washing up on California beaches","link_url":"https:\/\/www.marinemammalcenter.org\/news\/sf-gate-sick-disoriented-sea-lions-are-washing-up-on-california-beaches","label":"In the News","date":"2026-09-01 10:39:22"}
SF GATE: Sick, disoriented sea lions are washing up on California beaches
September 1, 2026
Read More{"image":"\/Animals\/Wild\/Sea otter\/cropped-images\/sea-otter-shutterstock-118-0-2496-1950-1604015482.jpg","alt":"sea otter eating clams","title":"What Do Sea Otters Eat? And Other Otter Trivia","link_url":"https:\/\/www.marinemammalcenter.org\/news\/what-do-sea-otters-eat-and-other-otter-trivia","label":"News Update","date":"2026-09-01 02:00:00"}
{"image":"\/People\/Action\/Volunteers\/h-california-sea-lion-transportdomoic-acidslo-countydomoic-acid80524photo-by-giancarlo-rulli-c-the-marine-mammal-center.jpg","alt":"Volunteers transporting a California sea lion","title":"An Update on Domoic Acid Poisoning on the California Coast","link_url":"https:\/\/www.marinemammalcenter.org\/news\/an-update-on-domoic-acid-poisoning-on-the-california-coast","label":"News Update","date":"2026-08-28 02:00:00"}
{"image":"\/Places\/Sausalito\/cropped-images\/sausalito-front-view-by-dan-friedman-c-the-marine-mammal-center-894-0-2040-1466-1601846127.jpg","alt":"front view of The Marine Mammal Center","title":"Explore The Marine Mammal Center\u2019s Exhibits","link_url":"https:\/\/www.marinemammalcenter.org\/news\/explore-the-marine-mammal-centers-exhibits","label":"In the News","date":"2026-08-26 02:00:00"}
