Prevalence of sarcocysts in the muscles of raptors from a rehabilitation center in North Carolina

Authors: ROSYPAL, ALEXA - Johnson C Smith University; SCOTT, DAVID - Carolina Raptor Center; Dubey, Jitender; LINDSAY, DAVID - Virginia-Maryland Regional College Of Veterinary Medicine (VMRCVM)

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/31/2018
Publication Date: 1/22/2019
Citation: Rosypal, A., Scott, D., Dubey, J.P., Lindsay, D. 2019. Prevalence of sarcocysts in the muscles of raptors from a rehabilitation center in North Carolina. Journal of Parasitology. 105:11-16. https://doi.org/10.1645/18-139.
DOI: https://doi.org/10.1645/18-139

Interpretive Summary: The life cycle of Sarcocystis species is heteroxenous (2-host) with carnivores being the definitive host and herbivores serving as intermediate hosts in predator-prey relationships. Raptors (eagles, hawks, falcons, and owls), are apex predators and are not consumed routinely by other carnivores making the occurrence of sarcocysts in their muscles unusual. Recent reports of sarcocysts in eagles and owls with Sarcocystis encephalitis suggests that this condition maybe becoming more frequent and S. falcatula has been implicated as the agent of encephalitis in Golden and Bald eagles as well as Great horned owls. The present study was done to determine the prevalence of sarcocysts of Sarcocystis species in the muscles of raptors from the Southeastern United States. Pectoral and heart muscle from 204 raptor patients from the Carolina Raptor Center, Huntersville, North Carolina were tested for the presence of Sarcocystis species using histology. Only a few sarcocysts were seen in sections of pectoral muscle from 39 of 204 raptors (19.1%) and hearts from 9 that also had sarcocysts in their pectoral muscle. Two structural types of sarcocysts composing thin-walled (1 im; 62%) or thick-walled (>2 im, 38%) were seen. Statistical analysis of raptor age and gender was done by Fishers exact test on samples from raptors with 20 or more samples per group. The prevalence of sarcocysts and age (2 yr or more) was significant for Red-shoulder hawks (P=0.022) and Cooper’s hawks (P=0.028). Sarcocyst prevalence in male raptors from these groups evaluated statistically were always less than females. Prevalence in female Redtailed hawks (42.1%) was significantly greater than males (6.7%) using Fishers exact test (P=0.046). Examination of case histories from the 39 sarcocyst positive raptors did not reveal an association with sarcocysts in raptor pectoral or heart muscle and in a diagnosis of encephalitis. Additional studies are needed to determine the epidemiology and relationships of Sarcocystis species that use raptors as intermediate hosts and the importance of Sarcocystis spp. in the overall wellbeing of raptors in their natural environments.

Technical Abstract: Toxoplasma and Sarcocystis are related single celled parasites of livestock and humans. While Toxoplasma has long been recognized to cause neurologic disease in many warm-blooded hosts, several species of Sarcocystis also cause a variety of disorders in livestock, pets, and wild animals and some of them are zoonotic. Neurological sarcocystosis simulating toxoplasmosis has been reported in raptors, including eagles. Additionally, raptors are definitive hosts (reservoirs) of several species of Sarcocystis that cause fatal pneumonia in several species of birds. In the present investigation, the authors report prevalence of Sarcocystis in muscles of raptors. The results will be of interest to biologists, zoo veterinarians, and parasitologists, and help diagnosis of sarcocystosis.