Evaluating the role of heart rate variability in monitoring stress and sleep quality among nurses in the aftermath of the COVID-19 pandemic.

AIM: To assess heart rate variability (HRV) as a measure to assess job stress and sleep quality among nurses in the post-COVID-19 period. BACKGROUND: The COVID-19 pandemic significantly affected nurses, with heightened job stress and impaired sleep quality impacting their well-being and effectiveness in patient care. HRV could offer insights for supporting strategies in the pandemic aftermath. DESIGN: A quantitative cross-sectional study. METHODS: This study involved 403 clinical nurses recruited from a teaching hospital in Taiwan. Data on job stress, work frustration, sleep quality and HRV were collected and analysed. RESULTS: Among the nurses surveyed during the COVID-19 pandemic, 72.7% reported poor sleep quality (PSQI = 9.369). Job stress emerged as a strong predictor of work frustration. High stress levels and poor sleep quality were correlated with significantly decreased HRV, indicating a potential physiological impact of stress on the nurses' health and well-being. CONCLUSIONS: HRV is a valuable and cost-effective measure for monitoring and managing nurses' well-being in the post-COVID-19 era. Targeted interventions can be implemented to support nurses' overall performance and promote their well-being by identifying those at high risk of job stress and poor sleep quality.

Kudoa tanakai n. sp. (Myxozoa: Myxosporea: Multivalvulida), a new kudoid species with spheroid myxospores from the scalpel sawtail (Actinopterygii: Prionurus scalparum) from western Japan.

We describe a new kudoid species, Kudoa tanakai n. sp., in the scalpel sawfish, Prionurus scalprum (Actinopterygii: Acanthuriformes: Acanthuridae), from the natural water around western Japan. The plasmodia were filamentous, localized in pseudocysts in the myofibers of the trunk muscles. The occurrence of plasmodia in the trunk muscle showed no site preference. Its myxospores were spheroid, measuring 6.6-7.6 (7.0) µm by 5.8-6.9 (6.3) µm in apical view (width) and 5.7-6.6 (6.2) in length (n = 30), with four shell valves and a corresponding number of spheroid polar capsules. Shell valves lacked apical protrusions, but scanning electron microscopy revealed that one of the four shell valves had two semi-lunar flaps at its apical terminus. Nucleotide sequencing of the small and large subunit ribosomal RNA genes of the present isolate showed phylogenetic affinities to kudoid species characterized by spheroid myxospores, such as K. musculoliquefaciens, K. hemiscylli, and K. carcharhini, but was molecularly and morphometrically distinct from these and other kudoid species. For direct comparison, Kudoa hemiscylli was collected from the Pacific spadenose shark, Scoliodon macrorhynchos (Elasmobranchii: Carcharhiniformes: Carcharhinidae), in the South China Sea off Guangdong Province, China, and the myxospore surface of the species was observed using scanning electron microscopy. Our study describes the new host and distribution record of this kudoid species originally described from a variety of elasmobranchs in the Australian Coral Sea.

New coccidian Eimeria iyoensis n. sp. (Apicomplexa: Eucoccidiorida: Eimeriidae) in farmed ring-necked pheasants (Phasianus colchicus L.) in Ehime, Japan.

Eight Eimeria spp. (Apicomplexa: Eimeriidae) have been isolated from the ring-necked pheasant (Phasianus colchicus Linnaeus), native to the temperate zone of Asia and eastern regions of Europe. Enteric coccidiosis has become a major issue associated with the breeding of farmed pheasants for game bird release or meat production. In this study, 35 fecal samples were collected from two-to-three-month-old ring-necked pheasants from four pheasant-rearing farms in Ehime Prefecture, Japan. Microscopic examination using a saturated sugar solution technique detected numerous subspherical oocysts from the samples of one farm and ellipsoidal Eimeria phasiani Tyzzer, 1929 oocysts from the three other farms. The subspherical oocysts were artificially sporulated and measured 18.6 µm by 15.7 µm with a 1.18 shape index (n = 150). Each oocyst contained four 10.7 µm × 5.8 µm sporocysts (n = 30) and one coarse refractile polar granule; no micropyle or residua were detected. Each sporocysts contained two sporozoites with one large and one small refractile body and sparsely distributed residua. The complete, 1,443-bp cytochrome c oxidase subunit I gene (cox1) of this isolate exhibited low sequence identity with published Eimeria spp. sequences including E. phasiani that was previously recorded in the same area. Meanwhile, the oocyst morphology most closely resembled that of Eimeria tetartooimia Wacha, 1973, but with distinct refractile polar granules and sporocyst residua. The available GenBank cox1 sequence of E. tetartooimia exhibited a sequence identity of < 94.5% with the study isolate. Here, the coccidian isolate identified in this study represents a new Eimeria iyoensis n. sp. capable of infecting ring-necked pheasant.

Effects of food availability and climate on the activity budget of Shortridge's langur (Trachypithecus shortridgei) in the Drung Valley, Gaoligong Mountains, China.

Food availability and climate represent environmental factors that affect species' social behavior, ranging patterns, diet, and activity budget. From August 2012 to September 2013, we examined the effects of seasonal changes in food availability, temperature, and rainfall on the diet and behavioral ecology of Shortridge's langur (Trachypithecus shortridgei) an Endangered primate species inhabiting moist evergreen broadleaf forests in the Eastern Himalayas. Our field site represents the northernmost latitudinal distribution of this species. Data were collected using scan sampling at 10 min intervals, and analyzed based on generalized linear models. The results indicate that the langurs experienced two feeding peaks (9:00 and 17:00) and two traveling peaks (10:00 and 19:00) during each day. Periods of rest, mainly occurred between 10:00 and 13:00, and overnight. Feeding accounted for 38.5% of the daily activity budget, followed by resting (35%), traveling (24.5%), and socializing (2%). During periods when young leaves were most available, the langurs increased feeding time on young leaves (35% vs. 4%). During periods of maximum fruit availability, the langurs decreased total time spent feeding (36.6% vs. 40.4%), devoted more time to traveling (28.1% vs. 21%), and increased time spent consuming fruit (49.1% vs. 11.8%). During the winter, the langurs increased their consumption of mature leaves (44.5%) and reduced time spent traveling (20.2% vs. 25.4%). Overall, time spent resting was greatest in the spring (47.5%), time spent feeding was greatest during the summer (51.1%), and time spent in traveling was greatest in the autumn (33.2%). The frequency of social interactions remained relatively constant throughout the year. Foraging effort was greatest in the summer, when fruits dominated the diet. Like other species of temperate langurs, T. shortridgei devoted less time to resting, more time to feeding, and was characterized by a greater year-round foraging effort than tropical/subtropical langurs.

Factors influencing terminal cancer patients' autonomous DNR decision: a longitudinal statutory document and clinical database study.

OBJECTIVE: Much of our knowledge of patient autonomy of DNR (do-not-resuscitate) is derived from the cross-sectional questionnaire surveys. Using signatures on statutory documents and medical records, we analyzed longitudinal data to understand the fact of terminal cancer patients' autonomous DNR decision-making in Taiwan. METHODS: Using the medical information system database of one public medical center in Taiwan, we identified hospitalized cancer patients who died between Jan. 2017 and Dec. 2018, collected their demographic and clinical course data and records of their statutory DNR document types, letter of intent (DNR-LOI) signed by the patient personally and the consent form signed by their close relatives. RESULTS: We identified 1,338 signed DNR documents, 754 (56.35%) being DNR-LOI. Many patients had the first DNR order within their last week of life (40.81%). Signing the DNR-LOI was positively associated with being under the care of a family medicine physician prior to death at last hospitalization and having hospice palliative care and negatively associated with patient age ≥ 65 years, no formal education, having ≥ 3 children, having the first DNR order to death ≤ 29 days, and the last admission in an intensive care unit. CONCLUSIONS: A substantial proportion of terminal cancer patients did not sign DNR documents by themselves. It indicates they may not know their actual terminal conditions and lose the last chance to grasp time to express their life values and wishes. Medical staff involving cancer patient care may need further education on the legal and ethical issues revolving around patient autonomy and training on communicating end-of-life options with the patients. We suggest proactively discussing DNR decision issues with terminal cancer patients no later than when their estimated survival is close to 1 month.

New records of three commercial fish hosts for two Unicapsula spp. and Kudoa megacapsula (Myxozoa: Myxosporea: Multivalvulida).

Infections caused by multivalvulid myxosporeans belonging to genera Unicapsula and Kudoa (Cnidaria: Myxozoa) occasionally affect commercial marine fish species. Postmortem myoliquefaction caused by a variety of Kudoa spp., including K. thyrsites, and unsightly cyst or pseudocyst formation, caused by K. amamiensis, U. muscularis, and other kudoid species, negatively affect commercial values of fillets. However, multivalvulid infections are often latent and imperceptible in the market. Biodiversity, host range, and epidemiology remain to be explored. Here, myxosporean infection was detected in four commercial fish species from southern China, using morphological and molecular analyses. Three Unicapsula spp. (U. pyramidata in Nemipterus japonicus; U. pflugfelderi in Dentex angolensis transported from the Eastern Central Atlantic Ocean, off West African coast; and U. aequilobata in Decapterus macarellus) and Kudoa megacapsula in Nemipterus virgatus were observed to form pseudocysts in the myofibers of the host trunk muscles. All fish hosts identified here, except for U. pyramidata, are new records. Kudoa megacapsula was morphologically characterized by gigantic, cruciform myxospores with four wing-like shell valves morphologically comparable to previous Japanese records of the same species in aquaculture facilities, acquiring fly from China or Korea (Sphyraena pinguis and Seriola quinqueradiata, respectively). Molecular analyses established the conspecificity of the present Chinese isolate with previously recorded Japanese isolates. To our knowledge, for the first time, a partial large subunit ribosomal RNA gene sequence of K. megacapsula was obtained, showing close phylogenetic relationships with Kudoa spp. harboring cruciform myxospores, such as K. thyrsites, K. gunterae, K. whippsi, and K. lateolabracis.

Identification of a new species, Unicapsula aequilobata n. sp., and Unicapsula seriolae (Myxozoa: Myxosporea: Multivalvulida) in carangid fish from the South China Sea.

An examination of 18 fishes caught in the South China Sea detected two Unicapsula spp. in the myofibers of the trunk muscles of carangid fishes: Unicapsula aequilobata n. sp. in the Japanese scad, Decapterus maruadsi, and Unicapsula seriolae in the yellowstripe scad, Selaroides leptolepis. They formed thin filamentous pseudocysts of 0.9-2.0 (mean 1.4) mm by 0.03-0.06 (0.04) mm (n = 5) and 0.9-3.4 (2.1) mm by 0.02-0.05 (0.04) mm (n = 12), respectively. Myxospores of U. aequilobata n. sp. are composed of three equal shell valves and measured 6.7-8.5 (7.3) µm in length and 7.1-8.8 (7.6) µm in width, and contained a prominent polar capsule (PC) 3.2-3.8 (3.6) µm in diameter (n = 18) and two rudimentary PCs. A nucleotide sequence (5127 bp) of the ribosomal RNA gene (rDNA) array was obtained for the genetic characterization of this new species. Based on morphological and phylogenetic criteria, we erect U. aequilobata n. sp. as the sixteenth species in the genus Unicapsula. Nucleotide sequences of the 18S and 28S rDNA obtained from U. seriolae from the yellowstripe scad were almost identical (99.6-100% or 99.0-99.6%, respectively) to those from fish found in the seawaters around Australia and Japan. Consequently, this is a new host and geographical distribution records for U. seriolae. In addition, we illustrated the predicted secondary structure of the available 5.8S rDNA sequences of multivalvulid species, including those obtained from U. aequilobata n. sp., to assess the significance of interspecific nucleotide variations in this short rDNA unit.

Icariin reduces Glu-induced excitatory neurotoxicity via antioxidative and antiapoptotic pathways in SH-SY5Y cells.

Excessive glutamate (Glu) can lead to significant effects on neural cells through the generation of neurotoxic or excitotoxic cascades. Icariin (ICA) is a main active ingredient of Chinese Medicine Berberidaceae epimedium L., and has many biological activities, such as antiinflammation, antioxidative stress, and anti-depression. This study aims to evaluate the effect of ICA on Glu-induced excitatory neurotoxicity of SH-SY5Y cells. The cell viability assay was evaluated by the CCK-8 assay. The apoptosis, reactive oxygen species (ROS), and mitochondrial membrane potential were assessed by flow cytometry. Intracellular Ca2+ concentration was determined by using the fluorescent probe Fluo-3. Protein expression was detected by western blotting analysis. ICA can significantly enhance the SH-SY5Y cell viability reduced by Glu. At the same time, ICA can significantly reduce apoptosis, ROS, nitric oxide (NO) levels, and intracellular Ca2+ concentration, and significantly inhibit the increase of mitochondrial membrane potential. In addition, ICA significantly increased the expression of P47phox and iNOS, decreased p-JNK/JNK, p-P38/P38, Bax/Bcl-2, active caspase-3, and active caspase-9. These results indicate that ICA may reduce the excitatory neurotoxicity of Glu-induced SH-SY5Y cells through suppression of oxidative stress and apoptotic pathways, suggesting that ICA could be a potential therapeutic candidate for neurological disorders propagated by Glu toxicity.

Phylogenetic characterisation of seven Unicapsula spp. (Myxozoa: Myxosporea: Multivalvulida) from commercial fish in southern China and Japan.

The myxozoan genus Unicapsula Davis, 1924 (Myxosporea: Multivalvulida: Trilosporidae) is characterized as having one functional polar capsule (PC) and two rudimentary PCs in a three-valved myxospore. The plasmodia of Unicapsula spp. grow either in the myofibres or in the gills, oesophageal walls and urinary organs of marine fish. Few studies have investigated the taxonomy of Unicapsula spp. including the type species Unicapsula muscularis. Accordingly, the taxonomy of the genus was explored in the present study by using 15 new isolates of seven Unicapsula spp. (U. muscularis, U. galeata, U. andersenae, U. pyramidata, U. pflugfelderi, and two new species) that had formed pseudocysts in the trunk myofibres of commercial fish collected in southern China and Japan from November 2015 to January 2019. Two new species Unicapsula trigona n. sp., and Unicapsula motomurai n. sp. exhibited unique myxospore morphologies (semi-triangular and spherical myxospores, respectively) and 18S and 28S rDNA sequences that were distinct from those of the other Unicapsula spp. Phylogenetic analysis of the 18S and 28S rDNA sequences confirmed the monophyletic status of Unicapsula.

Phylogenetic relationships of three Kudoa spp. with morphologically similar myxospores (K. iwatai, K. lutjanus, and K. bora), with the redescription of K. uncinata and K. petala and description of a new species (K. fujitai n. sp.) in fishes in the South China Sea.

Members of the myxozoan genus Kudoa (Myxosporea: Multivalvulida: Kudoidae) are characterized as having four or more shell valves in a myxospore, with a corresponding number of polar capsules. Certain Kudoa spp. are critical pathogens in fish, causing postmortem myoliquefaction, unmarketable fish musculature due to unsightly macroscopic cysts, and reduced aquaculture production due to the outbreaks of neurological symptoms or cardiac diseases. Molecular genetic techniques have enabled the differentiation of Kudoa spp. with morphologically similar myxospores. In the present study, we employed integrated taxonomic approaches on five Kudoa spp. forming cysts between the trunk muscle myofibers (K. bora from Osteomugil perusii and K. lutjanus from Acanthopagrus latus), or cysts in the gallbladder wall (K. petala from Sillago sihama), and pseudocysts in the trunk muscle myofibers (K. uncinata from Nuchequula nuchalis and K. fujitai n. sp. from O. perusii). These four host fishes, which originated in the South China Sea, were purchased in the wet markets in Zhanjiang City, Guangdong Province, China, between August 2016 and April 2018. We have redescribed the four Kudoa spp. (K. bora, K. lutjanus, K. petala, and K. uncinata) on which little data are available after their original descriptions. Particularly, genetic characterization of K. bora and K. lutjanus, which are known to have myxospores morphologically similar to those of K. iwatai, was performed based on the nuclear ribosomal RNA gene and partial mitochondrial DNA genes such as cytochrome c oxidase subunit I and small and large ribosomal genes, demonstrating the validity and independence of these three kudoid species. We also provide description of a new species-K. fujitai n. sp.-in the present study. Application of integrated taxonomic approaches to known species characterized solely based on morphological criteria, as well as unknown species (e.g., K. fujitai n. sp. in the present study), contributes to better understanding of the biodiversity of Kudoa and multivalvulid myxosporeans.

Identification of four new Kudoa spp. (Myxozoa: Myxosporea: Multivalvulida) in commercial fishes collected from South China Sea, Atlantic Ocean, and Bering Sea by integrated taxonomic approach.

Members of the myxosporean genus Kudoa are defined as having a myxospore with four or more shell valves (SVs) and a corresponding number of polar capsules (PCs). Here, we employed integrated taxonomic approaches to four kudoid isolates from Acentrogobius chlorostigmatoides and Konosirus punctatus from the South China Sea, off Guangdong, Pentanemus quinquarius from the Southeast Atlantic Ocean, off West African coast, and Atheresthes stomias from the Bering Sea, off Alaska, and concluded that all these kudoids were novel species, named Kudoa acentrogobia n. sp., Kudoa guangdongensis n. sp., Kudoa iidae n. sp., and Kudoa aburakarei n. sp., respectively. Kudoa guangdongensis n. sp., forming pseudocysts in the trunk muscle myofibers of K. punctatus, had large-sized tripod myxospores with three wing-like SV extensions and three PCs (one prominent PC and two rudimentary PCs). Phylogenetic analyses based on the 18S and 28S ribosomal RNA gene (rDNA) demonstrated its affinity to the genus Kudoa, not to Unicapsula characterized by a myxospore with one prominent PC and two rudimentary PCs, suggesting the atypical nature of this new species in the context of myxospore morphology. Three other kudoid isolates had four SVs and PCs in a semi-quadrated, ray-like, or cruciform myxospore, respectively, forming pseudocysts in the trunk muscle myofibers. Kudoa iidae n. sp. forming pseudocysts in the muscles of P. quinquarius from Southeast Atlantic Ocean had unique myxospores with ray-like form, showing close morphological resemblance to Kudoa rayformis, which were recorded from the muscle of Scomberomorus sierra from the Pacific Ocean off Panama. These two species had a phylogenetic relationship of morphological convergence, evolving separately in different sea areas. It is fairly difficult to differentiate K. acentrogobia n. sp. and K. aburakarei n. sp., prevalent in their host fishes, from kudoid species with similar myxospore morphology (e.g., Kudoa nova and Kudoa thyrsites, respectively), but distinct in phylogeny from known Kudoa spp. Combined taxonomic identification of multivalvulid myxosporeans based on both morphological criteria of isolated myxozoans and their molecular characterization could disclose their real biodiversity and phylogeny.

Utilization and medical costs of outpatient rehabilitation among children with autism spectrum conditions in Taiwan.

BACKGROUND: We examined the utilization of rehabilitation resources among children with autism spectrum condition (ASC), a neurodevelopmental condition, in Taiwan. METHODS: We derived from the National Health Insurance Research Database of Taiwan data pertaining to 3- to 12-year-old children for the period 2008-2010. Based on diagnoses executed in accordance with the International Classification of Diseases, Ninth Revision, Clinical Modification, we classified these data into the ASC and non-ASC groups and analyzed them through multiple linear regression model, negative binomial model, independent sample t testing, and χ2 testing. RESULTS: Compared with the non-ASC group, the ASC group exhibited higher utilization of rehabilitation resources. Because hospitals are constrained by overall expenditure limits, expenditure on rehabilitation resources has plateaued, preventing any increase in the utilization of rehabilitation resources. In our ASC group, preschool-aged children significantly outnumbered (p < 0.001) school-aged children. When stratified by the hospital level, district hospitals reported the highest utilization (p < 0.001). When stratified by region, the highest utilization was in Taipei, whereas the lowest was in the East region (p < 0.001). The total annual cost, average frequency of visits, utilization of rehabilitation resources, and average cost were all affected by such elements as patient demographics, hospital type and location (p < 0.001). CONCLUSIONS: For improving treatment outcomes among children with ASC and decreasing treatment expenditure, policies that promote the timely ASC detection and treatment should be implemented.

Risk of dementia in patients with primary insomnia: a nationwide population-based case-control study.

BACKGROUND: To investigate the association between primary insomnia and dementia using a Taiwanese population-based database. METHODS: This case-control study involved a subset of Taiwan's National Health Insurance Research Database of reimbursement claims. We included 51,734 patients who were diagnosed with primary insomnia from 2002 to 2004 as the test group and 258,715 nonprimary insomnia participants aged 20 years or older as the reference group. We excluded patients under 20 and those with depression, post-traumatic stress disorder, and/or sleep disorders caused by organic lesion(s), drugs, or alcohol. We used a Cox proportional hazards model to assess the primary insomnia on the risk of developing dementia after adjusting for sociodemographic characteristics and comorbidities. RESULTS: The primary insomnia cohort had a higher prevalence of diabetes, dyslipidemia, hypertension, coronary heart disease, chronic liver disease, and chronic kidney disease at baseline. After adjusting for select comorbidities, primary insomnia remained a significant predisposing factor for developing dementia, and was associated with a 2.14-fold (95% confidence interval, 2.01-2.29) increase in dementia risk. We also found a higher risk of dementia in younger patients. CONCLUSIONS: Taiwanese patients with primary insomnia, especially those under 40, had a higher risk of developing dementia than those without primary insomnia.

3D Target Localization of Modified 3D MUSIC for a Triple-Channel K-Band Radar.

In this paper, a modified 3D multiple signal classification (MUSIC) algorithm is proposed for joint estimation of range, azimuth, and elevation angles of K-band radar with a small 2 × 2 horn antenna array. Three channels of the 2 × 2 horn antenna array are utilized as receiving channels, and the other one is a transmitting antenna. The proposed modified 3D MUSIC is designed to make use of a stacked autocorrelation matrix, whose element matrices are related to each other in the spatial domain. An augmented 2D steering vector based on the stacked autocorrelation matrix is proposed for the modified 3D MUSIC, instead of the conventional 3D steering vector. The effectiveness of the proposed modified 3D MUSIC is verified through implementation with a K-band frequency-modulated continuous-wave (FMCW) radar with the 2 × 2 horn antenna array through a variety of experiments in a chamber.

3D-Subspace-Based Auto-Paired Azimuth Angle, Elevation Angle, and Range Estimation for 24G FMCW Radar with an L-Shaped Array.

In this paper, a three-dimensional (3D)-subspace-based azimuth angle, elevation angle, and range estimation method with auto-pairing is proposed for frequency-modulated continuous waveform (FMCW) radar with an L-shaped array. The proposed method is designed to exploit the 3D shift-invariant structure of the stacked Hankel snapshot matrix for auto-paired azimuth angle, elevation angle, and range estimation. The effectiveness of the proposed method is verified through a variety of experiments conducted in a chamber. For the realization of the proposed method, K-band FMCW radar is implemented with an L-shaped antenna.

Dual Channel S-Band Frequency Modulated Continuous Wave Through-Wall Radar Imaging.

This article deals with the development of a dual channel S-Band frequency-modulated continuous wave (FMCW) system for a through-the-wall imaging (TWRI) system. Most existing TWRI systems using FMCW were developed for synthetic aperture radar (SAR) which has many drawbacks such as the need for several antenna elements and movement of the system. Our implemented TWRI system comprises a transmitting antenna and two receiving antennas, resulting in a significant reduction of the number of antenna elements. Moreover, a proposed algorithm for range-angle-Doppler 3D estimation based on a 3D shift invariant structure is utilized in our implemented dual channel S-band FMCW TWRI system. Indoor and outdoor experiments were conducted to image the scene beyond a wall for water targets and person targets, respectively. The experimental results demonstrate that high-quality imaging can be achieved under both experimental scenarios.

Long-Range Drone Detection of 24 G FMCW Radar with E-plane Sectoral Horn Array.

In this work, a 24-GHz frequency-modulated continuous-wave (FMCW) radar system with two sectoral horn antennas and one transmitting lens antenna for long-range drone detection is presented. The present work demonstrates the detection of a quadcopter-type drone using the implemented radar system up to a distance of 1 km. Moreover, a 3D subspace-based algorithm is proposed for the joint range-azimuth-Doppler estimation of long-range drone detection. The effectiveness of the long-range drone detection is verified with the implemented radar system through a variety of experiments in outdoor environments. This is the first such demonstration for long-range drone detection with a 24-GHz FMCW radar.

Four Myxobolus spp. (Myxosporea: Bivalvulida) from the gill lamellae of common carp (Cyprinus carpio) and Japanese silver crucian carp (Carassius langsdorfii) in the western part of Japan, with the description of three new species (M. tanakai n. sp., M. paratoyamai n. sp., and M. ginbuna n. sp.).

Approximately three dozen Myxobolus spp. (Myxozoa: Myxosporea: Bivalvulida) have been described to parasitize the gills of carp of the genera Cyprinus and Carassius. Hitherto, these fish were often introduced to temperate waters worldwide as food and ornamental fish from Asia, their place of origin. The present study examined the myxosporean infection of seven common carp (Cyprinus carpio) and seven Japanese silver crucian carp (Carassius langsdorfii) collected from the Fushinogawa River around the university in Yamaguchi City, Japan, during the period April 2015 to October 2016. In total, four Myxobolus spp. were detected in the gill lamellae of Cy. carpio and Ca. langsdorfii, i.e., two species in each species of fish. The four species were characterized morphologically and genetically based on the 18S ribosomal RNA gene (rDNA). A new species, Myxobolus tanakai n. sp., from four individuals of Cy. carpio had an elongated pyriform spore (15.4-18.6 µm by 6.3-8.4 µm), resembling the spore shape of Myxobolus koi from Cy. carpio or Carassius auratus in Japan, China, and the USA, but bigger than it (13.2-15.6 µm by 6.6-7.8 µm). The new species formed a clade with M. koi but was distinct from any of the isolates of this species (nucleotide identities less than 98.6%). The second new species, Myxobolus paratoyamai n. sp., from a single Cy. carpio with its one prominent and one rudimentary polar capsule closely resembled the spore morphology of Myxobolus toyamai from Cy. carpio or Carassius gibelio in Japan, China, and the USA. However, the isolate formed a clade with Myxobolus longisporus from Cy. rubrofuscus in China rather than with M. toyamai isolates (nucleotide identities less than 97.9% with known species). Another new species, Myxobolus ginbuna n. sp., from two individuals of Ca. langsdorfii had similar-shaped spores to Myxobolus wulii, but the dimensions were smaller (11.7-13.9 µm by 8.5-9.8 µm vs. 17.6-18.5 µm by 8.9-10.0 µm). This new species formed a clade with M. wulii but was distinct from any of the M. wulii isolates from Ca. gibelio in China (nucleotide identities less than 99.1%). An additional species, Myxobolus pyramidis, from six individuals of Ca. langsdorfii was morphologically and genetically similar to the previous record from Ca. gibelio in China (99.6% nucleotide identity of the 18S rDNA). Two of these six individuals were mix-infected with M. ginbuna n. sp. This is a new host and geographical distribution record for M. pyramidis.

Incidence of three Kudoa spp., K. neothunni, K. hexapunctata, and K. thunni (Myxosporea: Multivalvulida), in Thunnus tunas distributed in the western Pacific Ocean.

A variety of tunas of the genus Thunnus are consumed daily in Japan as sliced raw fish (sashimi and sushi). The consumption of fresh sliced raw fish, i.e., unfrozen or uncooked, can sometimes cause food poisoning that is manifested by transient diarrhea and vomiting for a single day. One of the causes of this type of food poisoning has been identified as live Kudoa septempunctata (Myxosporea: Multivalvulida) in the olive flounder (Paralichthys olivaceus). Furthermore, raw slices of fresh tunas are highly suspected to be a possible causative fish of similar food poisoning in Japan. In the present study, we conducted a survey of kudoid infections in tunas (the yellowfin tuna Thunnus albacares, the Pacific bluefin tuna Thunnus orientalis, and the longtail tuna Thunnus tonggol) fished in the western Pacific Ocean off Japan and several East Asian countries and characterized morphologically and genetically the kudoid myxospores in pseudocysts or cysts dispersed in the trunk muscles. Pseudocysts of solely Kudoa hexapunctata were identified in the Pacific bluefin tuna (four isolates), whereas in the yellowfin tuna (21 isolates) pseudocysts of Kudoa neothunni and K. hexapunctata were detected at a ratio of 15:6, respectively, in addition to cyst-forming Kudoa thunni in five yellowfin tunas. In the trunk muscles of six longtail tunas examined, pseudocysts of K. neothunni (all six fish) and K. hexapunctata (two fish) were densely dispersed. The myxospores of K. neothunni found in these longtail tunas had seven shell valves and polar capsules (SV/PC) instead of the more common six SV/PC arranged symmetrically. Nucleotide sequences of the 18S and 28S ribosomal RNA gene (rDNA), some with the internal transcribed spacer regions as well, of K. hexapunctata and K. neothunni from the three Thunnus spp., including the seven-SV/PC morphotype, were very similar to previously characterized nucleotide sequences of each species, whereas the 18S and 28S rDNA of four isolates of K. thunni from yellowfin tunas showed a range of nucleotide variations of 99.0-99.9% identity over 1752-1763-bp long partial 18S rDNA and 97.4-99.9% identity over 797-802-bp long partial 28S rDNA. Therefore, this rather high variation of the rDNA nucleotide sequences of K. thunni proved to be contrary to the few variations of K. neothunni and K. hexapunctata rDNA nucleotide sequences. The present study provides a new host record of the longtail tuna for K. neothunni and K. hexapunctata and reveals a high prevalence of the seven-SV/PC myxospore morphotype of K. neothunni in this tuna host.

New host records of monacanthid fish for three Kudoa spp. (K. septempunctata, K. thyrsites, and K. shiomitsui) prevalent in the olive flounder (Paralichthys olivaceus), with the description of K. parathyrsites n. sp. from a black scraper (Thamnaconus modestus).

Kudoa septempunctata (Myxosporean: Multivalvulida) is known as a cause of foodborne disease associated with consumption of raw flesh of the olive flounder (Paralichthys olivaceus). Knowledge of its life cycle, particularly alternate annelid hosts and reservoirs or susceptible fish hosts in natural waters, may facilitate disease control in aquaculture farms. Our recent survey of myxosporean infection in monacanthid fish in natural waters around Japan revealed infection with three kudoid species prevalent in the olive flounder, i.e., K. septempunctata, Kudoa thyrsites, and Kudoa shiomitsui. Of the 51 black scrapers (Thamnaconus modestus) examined, five fish were infected: two fish with K. septempunctata and three with K. thyrsites. One of the fish infected with K. septempunctata was also infected with a K. thyrsites-like species. One of the 17 threadsail filefish (Stephanolepis cirrhifer) and two of four unicorn leatherjackets (Aluterus monoceros) were parasitized with K. shiomitsui. Three modest filefish (Thamnaconus modestoides) had no kudoid infection. K. septempunctata from a black scraper fished in the Inland Sea of Japan off Yamaguchi had 6-8 (predominantly 7) shell valves/polar capsules, whereas K. septempunctata found in another black scraper from the Sea of Japan off Tottori had 5 or 6 (predominantly 6). However, the two isolates displayed identical 18S and 28S ribosomal RNA gene (rDNA) nucleotide sequences, which were also identical to the isolates from the olive flounder. K. thyrsites from the Inland Sea of Japan off Yamaguchi and Sea of Japan off Tottori and K. shiomitsui from the Sea of Japan off Shimane and western Pacific Ocean off Kochi were also morphologically and genetically characterized. They were found to be coincident with the previous reports from olive flounders. Furthermore, the K. thyrsites-like species found in a black scraper from the Inland Sea of Japan off Yamaguchi was morphologically and genetically characterized; a new species, Kudoa parathyrsites n. sp., is erected for this species. The relationships of the new species with K. thyrsites and related species as well as those of K. shiomitsui with Kudoa pericardialis and related species parasitizing the pericardium are briefly discussed.