The Growth Zones of Test Plates in Four Spatangoid Echinoid Species: Irregular Pattern.

Whether the growth zone found in the coronal plate of echinoids can be used as a chronometer to estimate the age of individuals is controversial. In spatangoid echinoids, it is not known whether the growth zone formation occurs annually. In this study, the growth zone formation process was examined in four spatangoid species from natural conditions. In Nacospatangus alta and Brissus agassizii, the formation of a dark zone indicates the maturity of the gonad and does not necessarily correspond to the age of the individual. In Lovenia elongata, dark growth zones were formed several times per year. Unlike in the other studied species, in Metalia spatagus, the light and dark growth zones appeared to be formed radially, rather than in a ring-like manner. These results may indicate that the frequency and mode of growth zone formation differ across species. As such, it is not appropriate to use the growth zone as a chronometer in spatangoid echinoids. If the growth zone is to be used as an indicator of age, more research is needed about the phase of forming the growth zone in each echinoid species.

Different Life Histories and Life Styles in Spatangoid Echinoids Living in the Shallow Sublittoral Zone in the Oki-Islands, Japan.

The growth rate, reproduction, recruitment and feeding of four spatangoid species in the Okiislands in the Japan Sea were investigated over five years. Nacospatangus alta, which inhabits unstable surface sediments, grows rapidly, reaches sexual maturity early, and has a short life span, indicating that it should be a ruderal, whereas Metalia spatagus and Brissus agassizii, which inhabit relatively stable deep sediment, grow slowly, reach sexual maturity late, and have a long life span, suggesting that they are stress-tolerators. Lovenia elongata, however, inhabits unstable surface sediment but has an exceptional life history; it grows rapidly, but does not reach sexual maturity early and has a long life span, likely because the specific morphology of its spines and tubercles allow it to cope with surface disturbances caused by storms. Lovenia elongata seems to be a competitive ruderal. A trade-off between test formation and gonad development may occur; N. alta constructs a fragile test with very thin plates, allowing the echinoid to allocate energy to increasing test size and developing the gonad to sexual maturity within a year. Lovenia elongata, with thick plates supporting the specific stout spines and tubercles, needs 2 years to reach sexual maturity with a similar rate of test growth to that of N. alta; M. spatagus and B. agassizii construct robust tests with thick plates, presumably necessary for these species, which burrow and live deep in sand under high pressure from surrounding sand. These echinoids do not reach sexual maturity until over 2 years of age. The flexible trade-off related to stress and disturbance associated with burrowing depth in different habitats allows the spatangoids to have different life-history strategies.

Real-time characterization of risks of death associated with the Middle East respiratory syndrome (MERS) in the Republic of Korea, 2015.

BACKGROUND: An outbreak of the Middle East respiratory syndrome (MERS), comprising 185 cases linked to healthcare facilities, occurred in the Republic of Korea from May to July 2015. Owing to the nosocomial nature of the outbreak, it is particularly important to gain a better understanding of the epidemiological determinants characterizing the risk of MERS death in order to predict the heterogeneous risk of death in medical settings. METHODS: We have devised a novel statistical model that identifies the risk of MERS death during the outbreak in real time. While accounting for the time delay from illness onset to death, risk factors for death were identified using a linear predictor tied to a logit model. We employ this approach to (1) quantify the risks of death and (2) characterize the temporal evolution of the case fatality ratio (CFR) as case ascertainment greatly improved during the course of the outbreak. RESULTS: Senior persons aged 60 years or over were found to be 9.3 times (95% confidence interval (CI), 5.3-16.9) more likely to die compared to younger MERS cases. Patients under treatment were at a 7.8-fold (95% CI, 4.0-16.7) significantly higher risk of death compared to other MERS cases. The CFR among patients aged 60 years or older under treatment was estimated at 48.2% (95% CI, 35.2-61.3) as of July 31, 2015, while the CFR among other cases was estimated to lie below 15%. From June 6, 2015, onwards, the CFR declined 0.3-fold (95% CI, 0.1-1.1) compared to the earlier epidemic period, which may perhaps reflect enhanced case ascertainment following major contact tracing efforts. CONCLUSIONS: The risk of MERS death was significantly associated with older age as well as treatment for underlying diseases after explicitly adjusting for the delay between illness onset and death. Because MERS outbreaks are greatly amplified in the healthcare setting, enhanced infection control practices in medical facilities should strive to shield risk groups from MERS exposure.

Two Cases of Thrombocytopenia, Anasarca, Fever, Reticulin Fibrosis/Renal Failure, and Organomegaly (TAFRO) Syndrome with High Serum Procalcitonin Levels, Including the First Case Complicated with Adrenal Hemorrhaging.

Thrombocytopenia, Anasarca, Fever, Reticulin fibrosis/Renal failure, and Organomegaly (TAFRO) syndrome is a recently described systemic inflammatory disorder characterized by thrombocytopenia, anasarca, fever, reticulin fibrosis/renal failure, and organomegaly. It has an acute or subacute onset of unknown etiology, although some pathological features resemble those of multicentric Castleman disease. We here report two cases of TAFRO syndrome. The symptoms and pathological findings in these cases met the 2015 diagnostic criteria. Our cases showed high serum procalcitonin levels, suggesting bacterial infection as an onset trigger. In addition, Case 1 is the first case complicated with adrenal hemorrhaging. Case 2 is the second case of tocilizumab-resistant TAFRO syndrome successfully treated with rituximab.

Identifying determinants of heterogeneous transmission dynamics of the Middle East respiratory syndrome (MERS) outbreak in the Republic of Korea, 2015: a retrospective epidemiological analysis.

OBJECTIVES: To investigate the heterogeneous transmission patterns of Middle East respiratory syndrome (MERS) in the Republic of Korea, with a particular focus on epidemiological characteristics of superspreaders. DESIGN: Retrospective epidemiological analysis. SETTING: Multiple healthcare facilities of secondary and tertiary care centres in an urban setting. PARTICIPANTS: A total of 185 laboratory-confirmed cases with partially known dates of illness onset and most likely sources of infection. PRIMARY AND SECONDARY OUTCOME MEASURES: Superspreaders were identified using the transmission tree. The reproduction number, that is, the average number of secondary cases produced by a single primary case, was estimated as a function of time and according to different types of hosts. RESULTS: A total of five superspreaders were identified. The reproduction number throughout the course of the outbreak was estimated at 1.0 due to reconstruction of the transmission tree, while the variance of secondary cases generated by a primary case was 52.1. All of the superspreaders involved in this outbreak appeared to have generated a substantial number of contacts in multiple healthcare facilities (association: p<0.01), generating on average 4.0 (0.0-8.6) and 28.6 (0.0-63.9) secondary cases among patients who visited multiple healthcare facilities and others. The time-dependent reproduction numbers declined substantially below the value of 1 on and after 13 June 2015. CONCLUSIONS: Superspreaders who visited multiple facilities drove the epidemic by generating a disproportionate number of secondary cases. Our findings underscore the need to limit the contacts in healthcare settings. Contact tracing efforts could assist early laboratory testing and diagnosis of suspected cases.

Estimating the risk of Middle East respiratory syndrome (MERS) death during the course of the outbreak in the Republic of Korea, 2015.

OBJECTIVES: A large cluster of the Middle East respiratory syndrome (MERS) linked to healthcare setting occurred from May to July 2015 in the Republic of Korea. The present study aimed to estimate the case fatality ratio (CFR) by appropriately taking into account the time delay from illness onset to death. We then compare our estimate against previously published values of the CFR for MERS, i.e., 20% and 40%. METHODS: Dates of illness onset and death of the MERS outbreak in the Republic of Korea were extracted from secondary data sources. Using the known distribution of time from illness onset to death and an integral equation model, we estimated the delay-adjusted risk of MERS death for the South Korean cluster. RESULTS: Our most up-to-date estimate of CFR for the MERS outbreak in South Korea was estimated at 20.0% (95% confidence intervals (CI): 14.6, 26.2). During the course of the outbreak, estimate of the CFR in real time appeared to have decreased and become significantly lower than 40%. CONCLUSIONS: The risk of MERS death in Korea was consistent with published CFR. The estimate decreased with time perhaps due to time-dependent increase in case ascertainment. Crude ratio of cumulative deaths to cases underestimates the actual risk of MERS death because of time delay from illness onset to death.