Isolation, molecular characterization, and in vitro schizogonic development of Sarcocystis sp. ex Accipiter cooperii from a naturally infected Cooper's hawk (Accipiter cooperii)

Authors: LINDSAY, DAVID - Virginia Tech; VERMA, SHIV - Non ARS Employee; SCOTT, DAVID - Carolina Raptor Center; Dubey, Jitender; DOHLEN, ALEXA - Johnson C Smith University

Submitted to: Parasitology International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/5/2016
Publication Date: 12/26/2016
Citation: Lindsay, D., Verma, S., Scott, D., Dubey, J.P., Dohlen, A.R. 2016. Isolation, molecular characterization, and in vitro schizogonic development of Sarcocystis sp. ex Accipiter cooperii from a naturally infected Cooper's hawk (Accipiter cooperii). Parasitology International. 66:106-111.

Interpretive Summary: Toxoplasma gondii is a single-celled parasite of all warm-blooded hosts worldwide. It causes mental retardation and loss of vision in children, and abortion in livestock. Cats are the main reservoir of T. gondii because they are the only hosts that can excrete the resistant stage (oocyst) of the parasite in the feces. Humans become infected by eating under cooked meat from infected animals and food and water contaminated with oocyst. Why some people become ill and even die from toxoplasmosis whereas others remain asymptomatic is largely unknown. The genetic characteristics of T. gondii strains are considered a factor in the pathogenesis on clinical disease. Both the prevalence of T. gondii infections and the severity of clinical toxoplasmosis are higher in children in Brazil than in USA and Europe. Repeated infections with different T. gondii strains are thought to be a factor for the severity of toxoplasmosis. The underlying mechanism for the parasite virulence is also not fully understood. Sexual recombination of T. gondii strains (that can occur only in intestine of cats) could enhance T. gondii virulence. Domestic livestock tend to harbor parasites of rather limited genetic diversity but that certain wildlife populations have been identified as reservoirs for more genetic diversity. In the present study the authors found for the first time that bobcats in total wilderness in Mississippi were infected with more than 1 strain of T. gondii. These data are important because they identify a focus of diversity in a remote wildlife population in the United States. The results will be useful for parasitologists, biologists, and epidemiologists.

Technical Abstract: Raptors serve as the definitive host for several Sarcocystis species. The complete life cycles of only a few of these Sarcocystis species that use raptors as definitive hosts have been described. In the present study, Sarcocystis species sporocysts were obtained from the intestine of a Cooper’s hawk (Accipiter cooperi) and were used to infect cell cultures of African green monkey kidney cells to isolate a continuous culture and describe asexual stages of the parasite. Two clones of the parasite were obtained by limiting dilution. Asexual stages were used to obtain DNA for molecular classification and identification. PCR amplification and sequencing were done at 3 nuclear ribosomal DNA loci; 18S rRNA, 28S rRNA, and ITS-1, and the mitochondrial cytochrome c oxidase subunit 1 (cox1) locus. Examination of clonal isolates of the parasite indicated a single species S. columbae was present in the Cooper’s hawk. Our results document for the first time that S. columbae occurs naturally in a definitive host in North America and that Cooper’s hawks (A. cooperi) are a natural definitive host.