Osaka Prefecture University

Identifying a New Eimeria Parasite Named as “E. Raichoi” in Wild Japanese Rock Ptarmigans -Could Be a Great Contribution to Ptarmigan Conservation-

LastUpDate: July 20, 2018

Dr. Makoto Matsubayashi, Department of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Prof. Kazunari Murata and Dr. Sayaka Tsuchida, Academy of Emerging Sciences, Chubu University, Prof. Koichi Murata, College of Bioresource Sciences, Nihon University and other members of their research group performed a series of studies on Eimeria species in wild Japanese rock ptarmigan, one of the designated special natural monuments of Japan and of being on the red list of Japanese Red Data Book, to clarify that infection by Eimeria spp, prevalent parasites, could be a cause for increasing mortality rates of Japanese rock ptarmigan during breeding and growing period. They also clarified the phylogenetic positions and conducted molecular analysis for Eimeria parasites, and proposed a new species “E. Raichoi”, which was previously referred as type B.

Japanese rock ptarmigan is an endangered species that their population has decreased from 3,000 to less than 2,000 individuals since 1980. The issue is that the growth rate of the chicks is low, and it may be associated with Eimeria infection. Controlling such parasite infection could be a key for ensuring the survival of their population and conserving the species.

The research results were published in an online journal of International Journal for Parasitology: Parasites and Wildlife.

Vol 7, issue 2, titled: “Surveillance of Eimeria species in wild Japanese rock ptarmigans, Lagopus muta japonica, and insight into parasitic seasonal life cycle at timberline regions of the Japanese Alps.”

Vol 7, issue 3, titled: “Molecular identification of two Eimeria species, E. uekii and E. raichoi as type B, in wild Japanese rock ptarmigans, Lagopus muta japonica.”

Main point of research

Overview of research

For the purpose of conserving endangered wild Japanese rock ptarmigans and of identifying the associated causes for their decreased population, seasonal surveys of the prevalence of Eimeria spp. was conducted.

Results and findings

Two types of Eimeria, E. uekii and type B have been highly detected in the intestines of wild Japanese rock ptarmigans inhibited at the timberline regions throughout the areas extended over Toyama, Gifu, Nagano, and Niigata prefectures and Nagano, Yamanashi, and Shizuoka prefectures. Their prevalence and infection rates increased up to summer, when they most likely breed and grow.Additionally, the genetical analysis of Eimeria spp., clarified what was previously referred as type B as new. They were named “Eimeria Raicho”’. These parasites remained viable even after being stored at 4 °C for 6 months, and may be adapted to colder temperature to complete life cycle at the timberline regions.

Future contributions

These results will be a key to parasite control practice and will be a help to ensuring the conservation of Japanese rock ptarmigans.

Comment from Dr. Matsubayashi:

I have been involved with the researches of protozoan parasites for nearly twenty years. It will be the honor if my research contributes to the conservation of Japanese rock ptarmigans.

Research grant

A part of this study was supported by grants from the Life Science Center of Nihon University (to K. Murata), JSPS KAKENHI (Grant No. JP16510179) and the Environment Research and Technology Development Fund of Ministry of the Environment (No. 4-1604).


Department of Veterinary Science, Graduate School of Life and Environmental Sciences
Dr. Makoto Matsubayashi

E-mail matsubayashi[at] *Please change [at] to @.