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
Abstract:The Japanese rock ptarmigan, Lagopus muta japonica, inhabits the alpine zone of mountainous areas at 3000 m above sea level. Since L. m. japonica 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 Eimeria spp. are considered to have a negative impact on Japanese rock ptarmigan populations, the ecological interactions between the parasites and their hosts have not… Show more
“…In the present study, infection rates were in accordance with previous findings although examined numbers were small ( Table 2 ). Morphologies of the two type oocysts in our study were almost identical to those of E. uekii and type B as described previously ( Kamimura and Kodama, 1981 ; Ishihara et al, 2006 ; Matsubayashi et al, 2018b ). Although we could determine the phylogenetic positions of these isolates and type B was characterized as E. raichoi , sporulated oocysts of E. uekii and type B were similar to those of E. muta and E. rjupa from Iceland.…”
Section: Discussionsupporting
confidence: 85%
“…and type B was included in turkey Eimeria spp. Based on these findings and those from previous studies ( Ishihara et al, 2006 ; Matsubayashi et al, 2018b ), we propose type B of Eimeria from Japanese rock ptarmigans as E. raichoi , as described below. Fig.…”
Section: Resultssupporting
confidence: 66%
“…Thus far, two types of Eimeria have been reported in wild Japanese rock ptarmigans. Their prevalence increases up until August (summer) and then decreases as the temperature decreases until November (winter) ( Ishihara et al, 2006 ; Matsubayashi et al, 2018b ). In the present study, infection rates were in accordance with previous findings although examined numbers were small ( Table 2 ).…”
Section: Discussionmentioning
confidence: 99%
“…Recently, Eimeria infections were reported to be associated with a decrease in overall body condition and an increase in mortality in rock ptarmigans ( L. m. islandorum ) in Iceland ( Stenkewitz et al, 2016 ). Although two types of Eimeria parasites, namely E. uekii and type B, highly infect the Japanese rock ptarmigan ( Kamimura and Kodama, 1981 ; Ishihara et al, 2006 ; Matsubayashi et al, 2018b ), molecular analyses of these parasites have not been conducted. In the present study, we genetically examined E. uekii and type B to determine their precise phylogenic positions and classifications.…”
Thus far, two types of Eimeria parasites (E. uekii and type B) have been morphologically identified in wild Japanese rock ptarmigans, Lagopus muta japonica. Although high prevalences were reported for these parasites, genetic analyses have not been conducted. We first clarified the phylogenetic positions of two eimerian isolates using genetic analyses of 18S rRNA and mitochondrial cytochrome c oxidase subunit I gene regions. Consequently, of 61 samples examined, 21 and 11 samples were positive for E. uekii and type B, respectively. Additionally, the infection rate increased in the summer. Molecular analyses revealed both Eimeria isolates formed their own clusters; E. uekii was included in clades of chicken Eimeria and type B was include in clades of turkey Eimeria. Based on our findings in this study and previous data, we herein propose type B as E. raichoi. These genetic data will be helpful to conduct detailed classification and understand the impact of these parasites for conservation of endangered Japanese rock ptarmigans.
“…In the present study, infection rates were in accordance with previous findings although examined numbers were small ( Table 2 ). Morphologies of the two type oocysts in our study were almost identical to those of E. uekii and type B as described previously ( Kamimura and Kodama, 1981 ; Ishihara et al, 2006 ; Matsubayashi et al, 2018b ). Although we could determine the phylogenetic positions of these isolates and type B was characterized as E. raichoi , sporulated oocysts of E. uekii and type B were similar to those of E. muta and E. rjupa from Iceland.…”
Section: Discussionsupporting
confidence: 85%
“…and type B was included in turkey Eimeria spp. Based on these findings and those from previous studies ( Ishihara et al, 2006 ; Matsubayashi et al, 2018b ), we propose type B of Eimeria from Japanese rock ptarmigans as E. raichoi , as described below. Fig.…”
Section: Resultssupporting
confidence: 66%
“…Thus far, two types of Eimeria have been reported in wild Japanese rock ptarmigans. Their prevalence increases up until August (summer) and then decreases as the temperature decreases until November (winter) ( Ishihara et al, 2006 ; Matsubayashi et al, 2018b ). In the present study, infection rates were in accordance with previous findings although examined numbers were small ( Table 2 ).…”
Section: Discussionmentioning
confidence: 99%
“…Recently, Eimeria infections were reported to be associated with a decrease in overall body condition and an increase in mortality in rock ptarmigans ( L. m. islandorum ) in Iceland ( Stenkewitz et al, 2016 ). Although two types of Eimeria parasites, namely E. uekii and type B, highly infect the Japanese rock ptarmigan ( Kamimura and Kodama, 1981 ; Ishihara et al, 2006 ; Matsubayashi et al, 2018b ), molecular analyses of these parasites have not been conducted. In the present study, we genetically examined E. uekii and type B to determine their precise phylogenic positions and classifications.…”
Thus far, two types of Eimeria parasites (E. uekii and type B) have been morphologically identified in wild Japanese rock ptarmigans, Lagopus muta japonica. Although high prevalences were reported for these parasites, genetic analyses have not been conducted. We first clarified the phylogenetic positions of two eimerian isolates using genetic analyses of 18S rRNA and mitochondrial cytochrome c oxidase subunit I gene regions. Consequently, of 61 samples examined, 21 and 11 samples were positive for E. uekii and type B, respectively. Additionally, the infection rate increased in the summer. Molecular analyses revealed both Eimeria isolates formed their own clusters; E. uekii was included in clades of chicken Eimeria and type B was include in clades of turkey Eimeria. Based on our findings in this study and previous data, we herein propose type B as E. raichoi. These genetic data will be helpful to conduct detailed classification and understand the impact of these parasites for conservation of endangered Japanese rock ptarmigans.
“…Previously, we reported the high prevalence of two species of Eimeria , E. uekii and E. raichoi , which are protozoan parasites belonging to phylum Apicomplexa, and have high prevalence in Japanese rock ptarmigans (41.7%, 57.5%, 34.3% and 38.5% in 2006, 2007, 2016 and 2017, respectively) ( Matsubayashi et al, 2018a , 2018b ). Further, developing zoites of Eimeria spp.…”
Japanese rock ptarmigans,
Lagopus muta japonica
, are classified as an endangered species in Japan and are found only in the Japanese Alps. The number of birds has decreased in the last half century and cage protection projects have been undertaken as
in situ
conservation strategies (one of the projects for the recovery plan of Japanese rock ptarmigan) in the mountains. During the period with cage protections, some chicks died and two
Eimeria
spp.,
E. uekii
and
E. raichoi
, were identified in the chicks. Here, we examined the soil within the cages and in the surrounding environment to assess potential sources of infection between July to August 2020. We found high numbers of oocysts in the cages, especially at the back sides where the ptarmigan family frequently congregated, but soils in other areas outside the cages were less contaminated or not contaminated at all. The time required for more than 50% of the oocysts to sporulate at 15, 20 and 25 °C for
E. uekii
was 20, 11, and 5 h, respectively, and 72, 48 and 18 h, respectively, for
E. raichoi
. Our results cast some doubt that coprophagia by chicks is the source of infection because chicks consumed fresh cecal feces (approximately within 1 h) as far as we know, and instead, the protected chicks might be directly or indirectly infected by oocysts in soils or the environment.
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