Abstract
California sea lions (Zalophus californianus) are routinely tested for infection with canine heartworm (Dirofilaria immitis) prior to introduction into a captive environment.2 No known cases of D. immitis have been reported in wild sea lions; however, positive D. immitis antigen test results are common in sea lions tested at The Marine Mammal Center. Acanthocheilonema odendhali is a common cause of microfilaremia in California sea lions and is evident when conducting routine differential examination of blood.1 Thirty-five incidental cases of microfilaremia were observed at The Marine Mammal Center in 2011. The objective of this study was to collect pilot data to investigate a possible association between positive results on a heartworm antigen test and microfilaremia due to A. odendhali infection. Ten serum samples from sea lions were submitted to Antech Diagnostics for ELISA antigen test for D. immitis. Five negative control samples collected from neonatal pups and five samples from animals with microfilaremia, confirmed microscopically on blood smear, were submitted. All five of the control samples returned negative results while four out of five of the microfilaremic samples were positive for D. immitis. These data indicate a possible association between infection with A. odendhali and a false positive result on the canine heartworm test while supporting the need for further investigation.
Acknowledgements
The author would like to thank Lauren Rust, Carlos Rios, and Frances Gulland, and the staff and volunteers of The Marine Mammal Center for their assistance with this project.
* Presenting author
+ Student presenter
Literature Cited
1. Dailey M. D. 2001. Parasitic Diseases. In: Gulland F. M. D, Dierauf L. A, editors. CRC Handbook of Marine Mammal Medicine. Boca Roca (Fl): CRC Press. p. 357–374.
2. Woodford M. H. 2000. Quarantine and health screening protocols for wildlife prior to translocation and release into the wild. Jointly Published: Gland, Switzerland: The IUCN Species Survival Commission's Veterinary Specialist Group. Paris, France: The Office International des Epizooties (OIE). The United Kingdom: Care for the Wild. Switzerland: The European Association of Zoo and Wildlife Veterinarians. Available from http://digitalcommons.unl.edu