Identifying the true drivers of abrupt changes in ecosystem state with a focus on time lags: Extreme precipitation can determine water quality in shallow lakes.

A better understanding of abrupt ecosystem changes is needed to improve prediction of future ecosystem states under climate change. Chronological analysis based on long-term monitoring data is an effective way to estimate the frequency and magnitude of abrupt ecosystem changes. In this study, we used abrupt-change detection to differentiate changes of algal community composition in two Japanese lakes and to identify the causes of long-term ecological transitions. Additionally, we focused on finding statistically significant relationships between abrupt changes to aid with factor analysis. To estimate the strengths of driver-response relationships underlying abrupt algal transitions, the timing of the algal transitions was compared to that of abrupt changes in climate and basin characteristics to identify any synchronicities between them. The timing of abrupt algal changes in the two study lakes corresponded most closely to that of heavy runoff events during the past 30-40 years. This strongly suggests that changes in the frequency of extreme events (e.g., heavy rain, prolonged drought) have a greater effect on lake chemistry and community composition than do shifts in the means of climate and basin factors. Our analysis of synchronicity (with a focus on time lags) could provide an easy method to identify better adaptative strategies for future climate change.

Increased winter drownings in ice-covered regions with warmer winters.

Winter activities on ice are culturally important for many countries, yet they constitute a high safety risk depending upon the stability of the ice. Because consistently cold periods are required to form stable and thick ice, warmer winters could degrade ice conditions and increase the likelihood of falling through the ice. This study provides the first large-scale assessment of winter drowning from 10 Northern Hemisphere countries. We documented over 4000 winter drowning events. Winter drownings increased exponentially in regions with warmer winters when air temperatures neared 0°C. The largest number of drownings occurred when winter air temperatures were between -5°C and 0°C, when ice is less stable, and also in regions where indigenous traditions and livelihood require extended time on ice. Rates of drowning were greatest late in the winter season when ice stability declines. Children and adults up to the age of 39 were at the highest risk of winter drownings. Beyond temperature, differences in cultures, regulations, and human behaviours can be important additional risk factors. Our findings indicate the potential for increased human mortality with warmer winter air temperatures. Incorporating drowning prevention plans would improve adaptation strategies to a changing climate.

Combined impact of pesticides and other environmental stressors on animal diversity in irrigation ponds.

Rice paddy irrigation ponds can sustain surprisingly high taxonomic richness and make significant contributions to regional biodiversity. We evaluated the impacts of pesticides and other environmental stressors (including eutrophication, decreased macrophyte coverage, physical habitat destruction, and invasive alien species) on the taxonomic richness of freshwater animals in 21 irrigation ponds in Japan. We sampled a wide range of freshwater animals (reptiles, amphibians, fishes, mollusks, crustaceans, insects, annelids, bryozoans, and sponges) and surveyed environmental variables related to pesticide contamination and other stressors listed above. Statistical analyses comprised contraction of highly correlated environmental variables, best-subset model selection, stepwise model selection, and permutation tests. Results showed that: (i) probenazole (fungicide) was a significant stressor on fish (i.e., contamination with this compound had a significantly negative correlation with fish taxonomic richness), (ii) the interaction of BPMC (insecticide; also known as fenobucarb) and bluegill (invasive alien fish) was a significant stressor on a "large insect" category (Coleoptera, Ephemeroptera, Hemiptera, Lepidoptera, Odonata, and Trichoptera), (iii) the interaction of BPMC and concrete bank protection was a significant stressor on an "invertebrate" category, (iv) the combined impacts of BPMC and the other stressors on the invertebrate and large insect categories resulted in an estimated mean loss of taxonomic richness by 15% and 77%, respectively, in comparison with a hypothetical pond with preferable conditions.

Hepatitis A in a human immunodeficiency virus-infected patient: Impending risk during the Tokyo Olympic Games in 2020.

Acute hepatitis A is caused by hepatitis A virus (HAV), which spreads through contaminated food or water or person-to-person contact, and has been epidemic among men who have sex with men (MSM) since 2018 in Tokyo. The majority of these patients have been found to be seropositive for human immunodeficiency virus (HIV) and contracted hepatitis A through sexual contact. We cared for an HIV-positive patient with fulminant hepatitis A while on antiretroviral therapy at our hospital. Hepatitis A vaccine should be aggressively promoted for HIV-positive MSM.

Clinically Infrequent Arcanobacterium haemolyticum Bacteremia Complicated by Foot Decubitus Ulcer: An Educational Reminder for Primary Care Physicians.

An 81-year-old Japanese man with no history of diabetes mellitus was admitted to our hospital for a fever with a new ulcerative lesion on the left heel. Blood cultures on admission grew Arcanobacterium haemolyticum in aerobic bottles. He was therefore diagnosed with A. haemolyticum bacteremia and osteomyelitis complicated with foot decubitus ulcer. He was successfully treated with intravenous antibiotic therapy and debridement of the left heel. Our case and literature review show that it is important to recognize that A. haemolyticum is a systemic causative pathogen in immunocompetent patients in primary care practice.

Development of polymyalgia rheumatica during hospitalization and diagnosis based on history taking by physical and occupational therapists.

Polymyalgia rheumatica (PMR) is frequently reported in the outpatient setting and presents with pain, morning stiffness, mild fever, and fatigue. However, the clinical course of PMR during hospitalization is unknown. We report a case of PMR that developed during hospitalization. PMR diagnosis should begin with an evaluation of core inclusion and exclusion criteria. However, when examining elderly patients, retrieving symptom information from the patient or their family is often difficult, especially during prolonged hospitalization. History taking by physical and occupational therapists or by other health care professionals is paramount in the symptomatic diagnoses of inpatients.

Landscape- and Local-Scale Actions Are Essential to Conserve Regional Macrophyte Biodiversity.

Regional-scale pond diversity is supported by high variation in community composition. To effectively and efficiently conserve pond regional diversity, it is essential to recognize the community types in a focal region and the scales of the factors influencing the occurrence of respective community types. Based on a flora survey and GIS analysis of 367 ponds in western Japan, we developed a multinomial regression model that describes the relationship between aquatic macrophyte community type (based on cluster analysis) and five environmental factors that differ in the spatial scale at which they operate (i.e., landscape or local scale) and origin (i.e., natural or anthropogenic). A change in topographic configuration resulted in a transition of the community types with high species richness. Increasing urban and agricultural area around ponds resulted in a decrease in species-rich community occurrence; an increase in urban area increased the probability of a pond having no macrophytes, whereas that of paddy field increased the probability of a pond having only a few macrophytes. Pond surface area and proportion of artificial embankment significantly defined the pond community: greater embankment proportions increased the probability of ponds having few or no macrophytes. Our results suggest that conserving regional pond biodiversity will require actions not only at a local scale but also at a sufficiently large spatial scale to cover the full gradient of topographic configurations that influence the macrophyte species composition in ponds.

Bottom-up linkages between primary production, zooplankton, and fish in a shallow, hypereutrophic lake.

Nutrient supply is a key bottom-up control of phytoplankton primary production in lake ecosystems. Top-down control via grazing pressure by zooplankton also constrains primary production and primary production may simultaneously affect zooplankton. Few studies have addressed these bidirectional interactions. We used convergent cross-mapping (CCM), a numerical test of causal associations, to quantify the presence and direction of the causal relationships among environmental variables (light availability, surface water temperature, NO3 -N, and PO4 -P), phytoplankton community composition, primary production, and the abundances of five functional zooplankton groups (large cladocerans, small cladocerans, rotifers, calanoids, and cyclopoids) in Lake Kasumigaura, a shallow, hypereutrophic lake in Japan. CCM suggested that primary production was causally influenced by NO3 -N and phytoplankton community composition; there was no detectable evidence of a causal effect of zooplankton on primary production. Our results also suggest that rotifers and cyclopoids were forced by primary production, and cyclopoids were further influenced by rotifers. However, our CCM suggested that primary production was weakly influenced by rotifers (i.e., bidirectional interaction). These findings may suggest complex linkages between nutrients, primary production, and rotifers and cyclopoids, a pattern that has not been previously detected or has been neglected. We used linear regression analysis to examine the relationships between the zooplankton community and pond smelt (Hypomesus nipponensis), the most abundant planktivore and the most important commercial fish species in Lake Kasumigaura. The relative abundance of pond smelt was significantly and positively correlated with the abundances of rotifers and cyclopoids, which were causally influenced by primary production. This finding suggests that bottom-up linkages between nutrient, primary production, and zooplankton abundance might be a key mechanism supporting high planktivore abundance in eutrophic lakes. Because increases in primary production and cyanobacteria blooms are likely to occur simultaneously in hypereutrophic lakes, our study highlights the need for ecosystem management to resolve the conflict between good water quality and high fishery production.

Frequent Community Use of Antibiotics among a Low-Economic Status Population in Manila, the Philippines: A Prospective Assessment Using a Urine Antibiotic Bioassay.

The widespread unregulated use of antibiotics without medical consultation contributes to the burden of antibiotic resistance in Southeast Asian countries. This study investigated antibiotic use before hospital consultation. In a prospective observational study from February 2, 2015, to July 2, 2015, we enrolled febrile patients attending the emergency room in San Lazaro Hospital, Manila, the Philippines. A urine sample was collected and a bioassay was used to detect antibiotic activity in urine using Bacillus stearothermophilus (ATCC7953), Escherichia coli (ATCC25922), and Streptococcus pyogenes (ATCC19615). Patients or caregivers reported their medication history, clinical information, and socioeconomic status. During the study period, 410 patients were enrolled. The median (interquartile range) age was 14 (7-23) years and 158 (39%) reported prior antibiotic use, predominantly a beta-lactam antibiotic. A total of 164 (40%, 95% confidence interval [CI]: 35-45) patients were urine bioassay positive with any of three organisms. The Bacillus assay was the most sensitive, detecting 162 (99%, 95% CI: 96-100) cases. Among bioassay positive patients, dengue (N = 91, 55%, 95% CI: 48-63) was the most frequent diagnosis, followed by other viral infections, including measles, rubella, and mumps (N = 17, 10%, 95% CI: 6-16). Patients with a positive bioassay were significantly more likely to be from the lowest-income group (adjusted odds ratio [AOR]: 1.7; 95% CI: 1.1-2.6) and required hospital admission (AOR: 2.1; 95% CI: 1.3-3.5). Unnecessary antibiotic use for febrile illnesses before hospital consultation is common in a low-income, highly populated urban community in Manila. Education targeting this group should be implemented to reduce unnecessary antibiotic use.

Predators regulate prey species sorting and spatial distribution in microbial landscapes.

The role of predation in determining the metacommunity assembly model of prey communities is understudied relative to that of interspecific competition among prey. Previous work on metacommunity dynamics of competing species has shown that sorting by habitat patch type and spatial patterning can be affected by disturbances. Microcosms offer a useful model system to test the effect of multi-trophic interactions and disturbance on metacommunity dynamics. Here, we investigated the potential role of predators in enhancing or disrupting sorting and spatial pattern among prey in experimental landscapes. We exposed multi-trophic protist microcosm landscapes with one predator, two competing prey, two patch resource types, and localized dispersal to three disturbance regimes (none, low, and high). Then, we used variation partitioning and spatial clustering analysis to analyse the results. In contrast with previous experiments that did not manipulate predators, we found that patch type did not structure prey communities very well. Instead, we found that it was the distribution of the predator that most strongly predicted the composition of the prey community. The predator impacted species sorting by (1) preferentially consuming one prey, thereby acting as a strong local environmental driver, and by (2) indirectly magnifying the impact of patch food resources on the less preferred prey. The predator also enhanced spatial signal in the prey community because of its limited dispersal. Our results indicate that predators can strongly influence prey species sorting and spatial patterning in metacommunities in ways that would otherwise be attributed to stochastic effects, such as dispersal limitation or demographic drift. Therefore, whenever possible, predators should be explicitly included as separate explanatory factors in variation partitioning analyses.

Radiocesium Transfer in Forest Insect Communities after the Fukushima Dai-ichi Nuclear Power Plant Accident.

To understand radiocesium transfer in the forest insect food web, we investigated the activity concentrations of radiocesium in forest insects in the Fukushima and Ibaraki Prefectures approximately 1.5-2.5 years after the Fukushima Dai-ichi Nuclear Power Plant. We analyzed 34 species of insects sampled from 4 orders and 4 feeding functional groups (herbivore, carnivore, omnivore, and detritivore) from three sites in each prefecture. 137Cs activity concentrations were lowest in herbivorous species and were especially high in detritivorous and omnivorous species that feed on forest litter and fungi. Radiocesium activity concentrations in any given species reflected the degree of contamination of that species' primary food sources since radiocesium activity concentrations were found to be the lowest in leaves and grass and the highest in litter, bark, and fungi. This study confirmed that litter and other highly contaminated forest components such as fungi, decaying wood, bryophytes, and lichens serve as sources of 137Cs transfer into the forest insect community.

Bacteremic renal stone-associated urinary tract infection caused by nontypable Haemophilus influenzae: A rare invasive disease in an immunocompetent patient.

Haemophilus species are known to colonize the upper respiratory tract and can cause infections. However Haemophilus influenzae has been rarely described as a cause of genitourinary tract infection. We report a 44-year-old nonimmunocompromised Japanese man with bacteremic pyelonephritis caused by a nontypable H. influenzae associated with a left ureteral calculus. The organism was isolated from both blood and urine cultures. Treatment consisted of 14 days of intravenous ceftriaxone and oral amoxicillin one after than other and insertion of a left ureteral stent. After discharge, he underwent extracorporeal shock wave lithotrity for the left ureteral calculus. He had no recrudescence of the symptoms. H. influenzae should be considered as a genitourinary pathogen among patients with certain risk factors such as anatomical or functional abnormality of genitourinary tract. Collaboration between clinicians and microbiology laboratory personnel is essential for correct identification of the organism and appropriate therapy for genitourinary tract infections due to this organism.

Phylogeographic insights into the invasion history and secondary spread of the signal crayfish in Japan.

Successful invasion by nonindigenous species is often attributed to high propagule pressure, yet some foreign species become widespread despite showing reduced genetic variation due to founder effects. The signal crayfish (Pacifastacus leniusculus) is one such example, where rapid spread across Japan in recent decades is believed to be the result of only three founding populations. To infer the history and explore the success of this remarkable crayfish invasion, we combined detailed phylogeographical and morphological analyses conducted in both the introduced and native ranges. We sequenced 16S mitochondrial DNA of signal crayfish from across the introduced range in Japan (537 samples, 20 sites) and the native range in western North America (700 samples, 50 sites). Because chela size is often related to aggressive behavior in crayfish, and hence, their invasion success, we also measured chela size of a subset of specimens in both introduced and native ranges. Genetic diversity of introduced signal crayfish populations was as high as that of the dominant phylogeographic group in the native range, suggesting high propagule pressure during invasion. More recently established crayfish populations in Japan that originated through secondary spread from one of the founding populations exhibit reduced genetic diversity relative to older populations, probably as a result of founder effects. However, these newer populations also show larger chela size, consistent with expectations of rapid adaptations or phenotypic responses during the invasion process. Introduced signal crayfish populations in Japan originate from multiple source populations from a wide geographic range in the native range of western North America. A combination of high genetic diversity, especially for older populations in the invasive range, and rapid adaptation to colonization, manifested as larger chela in recent invasions, likely contribute to invasion success of signal crayfish in Japan.

A Case of Fascioliasis Treated Successfully Without Sequelae in a Japanese Expatriate Living in Jakarta.

A 46-year-old Japanese female expatriate living in Jakarta presented with intermittent fever lasting for a month. Although she was considered at low risk of Fasciola spp. infection because she lived in an upper-class residential area of the city, the patient presented with eosinophilia after consuming organic raw vegetables; in addition, contrast-enhanced computed tomography detected microabscesses in a tractlike pattern in the liver. These findings led to an early diagnosis of fascioliasis, which was successfully treated without sequelae. In any patient with a history of consuming raw vegetables, fascioliasis should be suspected regardless of where the patient has lived.

Visibility from roads predict the distribution of invasive fishes in agricultural ponds.

Propagule pressure and habitat characteristics are important factors used to predict the distribution of invasive alien species. For species exhibiting strong propagule pressure because of human-mediated introduction of species, indicators of introduction potential must represent the behavioral characteristics of humans. This study examined 64 agricultural ponds to assess the visibility of ponds from surrounding roads and its value as a surrogate of propagule pressure to explain the presence and absence of two invasive fish species. A three-dimensional viewshed analysis using a geographic information system quantified the visual exposure of respective ponds to humans. Binary classification trees were developed as a function of their visibility from roads, as well as five environmental factors: river density, connectivity with upstream dam reservoirs, pond area, chlorophyll a concentration, and pond drainage. Traditional indicators of human-mediated introduction (road density and proportion of urban land-use area) were alternatively included for comparison instead of visual exposure. The presence of Bluegill (Lepomis macrochirus) was predicted by the ponds' higher visibility from roads and pond connection with upstream dam reservoirs. Results suggest that fish stocking into ponds and their dispersal from upstream sources facilitated species establishment. Largemouth bass (Micropterus salmoides) distribution was constrained by chlorophyll a concentration, suggesting their lower adaptability to various environments than that of Bluegill. Based on misclassifications from classification trees for Bluegill, pond visual exposure to roads showed greater predictive capability than traditional indicators of human-mediated introduction. Pond visibility is an effective predictor of invasive species distribution. Its wider use might improve management and mitigate further invasion. The visual exposure of recipient ecosystems to humans is important for many invasive species that spread with frequent instances of human-mediated introduction.

Infective endocarditis caused by Streptococcus gallolyticus subspecies pasteurianus and colon cancer.

A 56-year-old man presented to our department with a 2-month history of fever and chills. He had received a mitral valvuloplasty 3 years ago. He had been administered levofloxacin for 2 months. We discontinued levofloxacin and repeated the blood cultures. Bacterial blood cultures were positive and transoesophageal echocardiography revealed vegetation attached to the posterior mitral leaflet. We started the patient on intravenous antibiotic therapy for infectious endocarditis by Streptococcus gallolyticus subspecies pasteurianus. A colonoscopic screening revealed adenomatoid intracellular carcinoma. Previous studies have reported a weak association between colorectal cancer and Streptococcus bovis biotype II/2, which includes S gallolyticus subspecies pasteurianus; however, the rate is notably higher than the rate of colorectal cancer as indicated by positive faecal occult-blood test results. We conclude that colonoscopies should be routine while scanning for colorectal cancer in all patients with S bovis bacteraemia, regardless of the subspecies.

A case of subacute infective endocarditis and blood access infection caused by Enterococcus durans.

BACKGROUND: Infection by Enterococcus durans (E. durans) is very rare; reported cases are often preceded by therapy or an immunosuppressed state, including infective endocarditis, urinary tract infection, or wound infection. A few reported cases of infective endocarditis exist, with no reports describing involvement of blood access infection. CASE PRESENTATION: The patient is an 83-year-old man who had been undergoing hemodialysis for 8 years due to renal failure caused by diabetic nephropathy. He developed infective endocarditis and blood access infection/infective aneurysm due to Enterococcus durans; these conditions were treated with the antibiotic regimen of ampicillin + gentamicin. There have been only a few reported cases of infective endocarditis caused by E. durans, and to our knowledge, this is the first report of blood access infection. CONCLUSIONS: We have experienced a case of concurrent infective endocarditis and blood access infection/infective aneurysm caused by E. durans. This is the world's first reported case of blood access infection/infective aneurysm by E. durans.

Effects of pond draining on biodiversity and water quality of farm ponds.

Farm ponds have high conservation value because they contribute significantly to regional biodiversity and ecosystem services. In Japan pond draining is a traditional management method that is widely believed to improve water quality and eradicate invasive fish. In addition, fishing by means of pond draining has significant cultural value for local people, serving as a social event. However, there is a widespread belief that pond draining reduces freshwater biodiversity through the extirpation of aquatic animals, but scientific evaluation of the effectiveness of pond draining is lacking. We conducted a large-scale field study to evaluate the effects of pond draining on invasive animal control, water quality, and aquatic biodiversity relative to different pond-management practices, pond physicochemistry, and surrounding land use. The results of boosted regression-tree models and analyses of similarity showed that pond draining had little effect on invasive fish control, water quality, or aquatic biodiversity. Draining even facilitated the colonization of farm ponds by invasive red swamp crayfish (Procambarus clarkii), which in turn may have detrimental effects on the biodiversity and water quality of farm ponds. Our results highlight the need for reconsidering current pond management and developing management plans with respect to multifunctionality of such ponds. Efectos del Drenado de Estanques sobre la Biodiversidad y la Calidad del Agua en Estanques de Cultivo.

Individual and combined suppressive effects of submerged and floating-leaved macrophytes on algal blooms.

Shallow lakes and ponds are often characterised either by clear water with abundant submerged macrophytes or by turbid water with abundant phytoplankton. Blooms of toxic filamentous blue-green algae (cyanobacteria) often dominate the phytoplankton community in eutrophic lakes, which threatens ecological functions and biodiversity of freshwater ecosystems. We studied a simple lake model in order to evaluate individual and combined suppressive effects of rooted submerged and rooted floating-leaved macrophytes on algal blooms. Floating-leaved plants are superior competitors for light, whereas submerged plants absorb and reduce available phosphorus in a water column that rooted floating-leaved plants exploit to a lesser extent. We found that mixed vegetation that includes both submerged and floating-leaved plants is more resistant than vegetation comprised by a single plant type to algal invasion triggered by phosphorus loading. In addition, competitive exclusion of submerged plants by floating-leaved plants may promote an algal bloom. These predictions were confirmed by the decision tree analysis of field data from 35 irrigation ponds in Hyogo Prefecture, Japan.

Hydrologic connection between ponds positively affects macrophyte alpha and gamma diversity but negatively affects beta diversity.

Connections between habitat patches can positively influence the number of species in respective patches, providing a basis for preferentially conserving interconnected patches. However, from a regional perspective, it is not known whether conserving multiple sets of interconnected habitat patches would include more species (i.e., show higher gamma diversity) than conserving multiple, unconnected, solitary patches. We studied aquatic macrophytes in 15 sets of unidirectionally interconnected ponds and 19 unconnected ponds and also tested whether alpha and beta diversity, expressed as the number of species and dissimilarity in species composition, respectively, differed between connected and unconnected ponds. We found that gamma diversity was higher in connected ponds than in unconnected ponds, even after controlling for surface area. This resulted from a higher alpha diversity in connected ponds, despite lower beta diversity. These results suggest that connections between habitat patches positively influence diversity at both local and regional scales. When the total surface area available for conservation is limited, interconnected habitat patches should be preferentially conserved.