Confirmation of Sarcocystis jamaicensis sarcocysts in IFN-gamma gene knock out mice orally inoculated with sporocysts from red-tailed hawk (Buteo jamaicensis)

Authors: Dubey, Jitender; CERQUEIRA-CEZAR, CAMILA - Non ARS Employee; MURATA, FERNANDO - Non ARS Employee; Mowery, Joseph; SCOTT, DAVID - Carolina Raptor Center; ROSYPAL, ALEXA - Johnson C Smith University; LINDSAY, DAVID - Virginia-Maryland Regional College Of Veterinary Medicine (VMRCVM)

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/4/2018
Publication Date: 2/22/2019
Citation: Dubey, J.P., Cerqueira-Cezar, C., Murata, F., Mowery, J.D., Scott, D., Rosypal, A., Lindsay, D. 2019. Confirmation of Sarcocystis jamaicensis sarcocysts in IFN-gamma gene knock out mice orally inoculated with sporocysts from red-tailed hawk (Buteo jamaicensis). Journal of Parasitology. 105(1):143-145. https://doi.org/10.1645/18-148
DOI: https://doi.org/10.1645/18-148

Interpretive Summary: 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 confirm that immunodeficient (knock out) mice can serve as experimental intermediate hosts for Sarcocystis jamaicensis of red tailed hawk; KO mice fed sporocysts from the feces of naturally infected hawk developed neurological signs and mature sarcocysts were found in their muscles. The results will be of interest to biologists, zoo veterinarians, and parasitologists, and help search for the natural intermediate host of S. jamaicensis.

Technical Abstract: Here, we report confirmation of sarcocysts of Sarcocystis jamaicensis in an experimental intermediate host, IFN-' gene knockout (KO) mice orally inoculated sporocysts from its natural definitive host, red-tailed hawk (RTH). A RTH submitted to the Carolina Raptor Center, Huntersville, North Carolina, was euthanized because it could not be rehabilitated and released. Fully sporulated sporocysts from intestinal scrapings of the RTH were orally fed to 2 laboratory-reared outbred Swiss Webster mice (SW) (Mus musculus) and to 2 KO mice. The sporocysts were infective for KO mice, but not to SW mice. Both SW mice remained asymptomatic, and neither schizonts nor sarcocysts were found in their tissues when euthanized on day 54 post-inoculation (PI). The KO mice developed neurological signs,and were necropsied between 38 or 54 days PI. Schizonts/merozoites were found in both KO mice euthanized and they were confined to the brain. The predominant lesion was meningoencephalitis. Microscopic sarcocysts were found in muscles of both KO mice. When viewed with light microscopy, the sarcocyst wall appeared thin (<1 'm thick) and smooth. By transmission electron microscopy, the sarcocyst wall classified as “type 1j”. Ultrastructural details of sarcocysts are described.