Surveillance of species in wild Japanese rock ptarmigans, , and insight into parasitic seasonal life cycle at timberline regions of the Japanese Alps.

The Japanese rock ptarmigan, , inhabits the alpine zone of mountainous areas at 3000 m above sea level. Since is endangered due to a decline in the overall population, controlling infectious diseases such as those caused by protozoan parasites is a critical factor in the conservation of this species. Although spp. are considered to have a negative impact on Japanese rock ptarmigan populations, the ecological interactions between the parasites and their hosts have not yet been fully clarified. We therefore conducted seasonal surveys of the prevalence of spp. in Japanese rock ptarmigan populations. In addition, we recorded the ambient temperature in ptarmigan habitat and characterized the ability of eimerian isolates to acquire infectivity. spp. were detected in 217 of 520 (41.7%) Japanese rock ptarmigan fecal samples in 2006 and in 177 of 308 (57.5%) fecal samples in 2007. Specifically, we observed two types of oocysts characteristic of and type B. In adult birds and chicks, infection rates increased towards August (summer) and then decreased as the temperature decreased toward November (winter). Oocyst counts per gram (OPG) of feces peaked in August in adults and chicks, and OPG values were markedly higher in chicks than in adults. Isolated spp. oocysts sporulated at temperatures as low as 8 °C and remained viable after being stored at 4 °C for 6 months. Our findings suggest that spp. can complete their annual lifecycle in the cold timberline regions inhabited by the host, the Japanese rock ptarmigan, and that spp. infection is widespread in the bird populations examined.