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Concept: Kumamoto Prefecture


Kikai submarine caldera to the south of the Kyushu Island, SW Japan, collapsed at 7.3 ka during the latest supereruption (>500 km3 of magma) in the Japanese Archipelago. Multi functional research surveys of the T/S Fukae Maru in this caldera, including multi-beam echosounder mapping, remotely operated vehicle observation, multi-channel seismic reflection survey, and rock sampling by dredging and diving, provided lines of evidence for creation of a giant rhyolite lava dome (~32 km3) after the caldera collapse. This dome is still active as water column anomalies accompanied by bubbling from its surface are observed. Chemical characteristics of dome-forming rhyolites akin to those of presently active small volcanic cones are different from those of supereruption. The voluminous post-caldera activity is thus not caused simply by squeezing the remnant of syn-caldera magma but may tap a magma system that has evolved both chemically and physically since the 7.3-ka supereruption.

Concepts: Rhyolite, Kumamoto Prefecture, Japan, Kagoshima Prefecture, Volcanology, Caldera, Volcano, Lava


Field investigations and seismic data show that the 16 April 2016 moment magnitude (Mw) 7.1 Kumamoto earthquake produced a ~40-kilometer-long surface rupture zone along the northeast-southwest-striking Hinagu-Futagawa strike-slip fault zone and newly identified faults on the western side of Aso caldera, Kyushu Island, Japan. The coseismic surface ruptures cut Aso caldera, including two volcanic cones inside it, but terminate therein. The data show that northeastward propagation of coseismic rupturing terminated in Aso caldera because of the presence of magma beneath the Aso volcanic cluster. The seismogenic faults of the 2016 Kumamoto earthquake may require reassessment of the volcanic hazard in the vicinity of Aso volcano.

Concepts: Japan, Fault, Lava, Kumamoto Prefecture, Mount Aso, Kagoshima Prefecture, Volcano, Earthquake


Severe methylmercury poisoning occurred in Minamata and neighboring communities in Japan during the 1950s and 1960s, causing what is known as Minamata disease. Although an increase in stillbirths and a reduced male proportion at birth (i.e., reduced sex ratio) have been reported, no studies have evaluated the impact of exposure on an entire set of infant and birth outcomes. We therefore evaluated the temporal trends of these outcomes in the Minamata area from 1950 to 1974. We focused on the spontaneous/artificial stillbirth rate, crude fertility rate, male proportion at birth, male proportion among stillbirths, and infant mortality. We obtained the number of stillbirths, live births, and infant deaths in Minamata City and Kumamoto Prefecture (as a reference) from 1950 to 1974. After plotting annual figures for each outcome, we divided the study period into five intervals and compared them between Minamata City and Kumamoto Prefecture using the chi-squared test. We observed a slightly increased spontaneous stillbirth rate and decreased artificial stillbirth rate in Minamata City, followed by a reduced crude fertility rate. The crude fertility rates in Minamata City during the period 1955-1965 were significantly lower compared with those in Kumamoto Prefecture (p < 0.001). An increase in the male proportion among stillbirths was observed, corresponding to a reduction in the proportion of males at birth in the late 1950s. The impact on infant mortality was equivocal. These descriptive analyses demonstrate a severe regional impact of methylmercury exposure on a series of birth outcomes in the Minamata area.

Concepts: Population, Sex, Kumamoto Prefecture, Methylmercury, 1950s, Stillbirth, Fertility, Demography


Two major earthquakes struck Kumamoto Prefecture in Japan in April 2016. Disaster response was immediately provided, including disaster medical services. Many hospitals were damaged and patients needed immediate evacuation to alternative facilities. The hospital bed capacity of Kumamoto Prefecture was overwhelmed, and transportation of more than 100 patients was needed. Hospital evacuation was carried out smoothly with the coordinated efforts of multiple agencies. The overall operation was deemed a success because patients were transported in a timely manner without any significant adverse events. Upon repair of facilities in Kumamoto Prefecture, patients were returned safely to their previous facilities. The management of inpatients after this natural disaster in Kumamoto Prefecture can serve as a model for hospital evacuation with multi-agency coordination in the future. Future efforts are needed to improve interfacility communications immediately following a natural disaster. (Disaster Med Public Health Preparedness. 2017;0:1-5).

Concepts: Patient, Tokyo, Health care, Kyūshū, Prefectures of Japan, Hospital, Japan, Kumamoto Prefecture


Between 1932 and 1968, industrial wastewater containing methylmercury (MeHg) and other mercury (Hg) compounds was discharged directly into Minamata Bay, Japan, seriously contaminating the fishery. Thousands of people who consumed tainted fish and shellfish developed a neurological disorder now known as Minamata disease. Concentrations of total mercury (THg) in recent fish and sediment samples from Minamata Bay remain higher than those in other Japanese coastal waters, and elevated concentrations of THg in sediments in the greater Yatsushiro Sea suggest that Hg has moved beyond the bay. We measured stable Hg isotope ratios in sediment cores from Minamata Bay and the southern Yatsushiro Sea, and in archived fish from Minamata Bay dating from 1978 to 2013. Values of δ(202)Hg and Δ(199)Hg in Yatsushiro Sea surface sediments were indistinguishable from those in highly contaminated Minamata Bay sediments, but distinct from and non-overlapping with values in background (non-contaminated) sediments. We conclude that stable Hg isotope data can be used to track Minamata Bay Hg as it moves into the greater Yatsushiro Sea. In addition, our data suggest that MeHg is produced in bottom sediments and enters the food web without substantial prior photodegradation, possibly in sediment porewaters or near the sediment-water interface.

Concepts: Kumamoto Prefecture, Bay of Bengal, Shellfish, Lake, Mercury poisoning, Methylmercury, Mercury, Minamata disease


A case of zoonotic onchocercosis has been found in a resident who lived in Iizuka City, Fukuoka Prefecture, Japan for some time. A 24-year-old male developed a painful nodule on the middle finger of his right hand. The nodule was surgically removed from the vagina fibrosa tendinis of the finger at Beppu Medical Center, Beppu City, Oita Prefecture in 2012. The causative agent was identified as a female Onchocerca dewittei japonica based on its histopathological characteristics. The identity of the filarioid has been confirmed by sequencing the cox1 gene. The present study indicates that the zoonotic onchocercosis caused by O. dewittei japonica has been concentrated in northeast Kyushu.

Concepts: Saga Prefecture, Kumamoto Prefecture, Middle finger, Prefectures of Japan, Japan, Fukuoka Prefecture, Kyūshū, Ōita Prefecture


Background/Aims: Central nervous system germ cell tumors (CNS-GCTs) are relatively rare. While their incidence was thought to be higher in East Asia than the USA, recent evidence suggests the difference between Japan and the USA is not statistically significant. The aim of this study was to determine the rate of pediatric primary CNS-GCTs in Kumamoto prefecture, Japan. Methods: We surveyed 6,615 new cases of primary intracranial tumors diagnosed in Kumamoto prefecture between 1989 and 2011. Among these, 251 (3.8%) occurred in patients younger than 15 years. The age-adjusted incidence rates were calculated by the direct method using 5-year age groupings; the incidence in the total Japanese population in the year 2000 was the standard. Results: During the 23-year period, 70 cases of primary GCT were diagnosed. Of these tumors, 31 (44.3%) arose in patients aged between 0 and 14 years (22 boys, 9 girls). Their tumor location was pineal in 45.2%; the other sites were nonpineal. There were more germinomas (64.5%) than nongerminomas (35.5%) in this group. The age-adjusted annual incidence rate was 0.45 cases (boys: 0.64, girls: 0.28) per 10(5) children. At 2.29, the ratio of CNS-GCTs was higher in these boys than girls. Our data showed higher rates than data from CBTRUS 2012 (0.18/10(5)), SEER 2008 (0.15/10(5)) and Germany (0.10/10(5)). Conclusions: Our survey showed that the incidence of primary CNS-GCTs in children was higher in Kumamoto prefecture than in the USA and other Western countries, suggesting that racial backgrounds play a role. © 2014 S. Karger AG, Basel.

Concepts: United States, Kumamoto Prefecture, Brain, Germ cell tumor, Brain tumor, Nervous system, Central nervous system, Japan


Byssochlamys spectabilis no. 5 (anamorph Paecilomyces variotii no. 5) (NBRC109023) was isolated from a soil sample in 2001 in Kumamoto Prefecture, Japan. This fungus is highly resistant to formaldehyde. Here, we report a draft genome sequence of P. variotii no. 5; this draft was produced with the intent of investigating the mechanism of formaldehyde resistance. This is the first report of the genome sequence of any Paecilomyces species.

Concepts: Gene, Kyūshū, Prefectures of Japan, Archaea, Paecilomyces lilacinus, Paecilomyces, Human Genome Project, Kumamoto Prefecture