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Background Studies on the association between smoke haze (hereafter ‘haze’) and adverse health effects have increased in recent years due to extreme weather conditions and the increased occurrence of vegetation fires. The possible adverse health effects on under-five children (U5Y) is especially worrying due to their vulnerable condition. Despite continuous repetition of serious haze occurrence in Southeast Asia, epidemiological studies in this region remained scarce. Furthermore, no study had examined the association accounting for three important aspects (time lag, duration and intensity) concurrently. Objective This study aimed to examine the association between haze and U5Y mortality in Malaysia, considering time lag, duration and intensity of exposure. Methods We performed a time-stratified case-crossover study using a generalized additive model to examine the U5Y mortality related to haze in 12 districts in Malaysia, spanning from 2014 to 2016. A ‘haze day’ was characterized by intensity [based on concentrations of particulate matter (PM)] and duration (continuity of haze occurrence, up to 3 days). Results We observed the highest but non-significant odds ratios (ORs) of U5Y mortality at lag 4 of Intensity-3. Lag patterns revealed the possibility of higher acuteness at prolonged and intensified haze. Stratifying the districts by the 95th-percentile of PM distribution, the ‘low’ category demonstrated marginal positive association at Intensity-2 Duration-3 [OR: 1.210 (95% confidence interval: 1.000, 1.464)]. Conclusions We found a null association between haze and U5Y mortality. The different lag patterns of the association observed over different duration and intensity suggest consideration of these aspects in future studies.

Background Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne acute infectious disease caused by the SFTS virus (SFTSV). SFTS has been reported in China, South Korea, and Japan as a novel Bunyavirus. Although several molecular epidemiology and phylogenetic studies have been performed, the information obtained was limited, because the analyses included no or only a small number of SFTSV strains from Japan. Methods The nucleotide sequences of 75 SFTSV samples in Japan were newly determined directly from the patients' serum samples. In addition, the sequences of 7 strains isolated in vitro were determined and compared with those in the patients' serum samples. More than 90 strains that were identified in China, 1 strain in South Korea, and 50 strains in Japan were phylogenetically analyzed. Results The viruses were clustered into 2 clades, which were consistent with the geographic distribution. Three strains identified in Japan were clustered in the Chinese clade, and 4 strains identified in China and 26 in South Korea were clustered in the Japanese clade. Conclusions Two clades of SFTSV may have evolved separately over time. On rare occasions, the viruses were transmitted overseas to the region in which viruses of the other clade were prevalent.

Dimeric T. flavoviridis phospholipase A2 has been studied in terms of the interaction with essential Ca2+ by equilibrium gel filtration, ultraviolet difference spectroscopy, fluorescence measurements, and chemical modifications with p-bromophenacyl bromide. The subunit bound to Ca2+ with a 1:1 molar ratio and no cooperative binding was observed. The hypochromic effect produced upon the binding of Ca2+ is due to perturbation of (a) specific tryptophan residue(s) located in the vicinity of the active site and appears to be characteristic of this enzyme. On the basis of the pH dependence of the dissociation constants, it has been found that the alpha-amino group (pKa 8.7) controls the binding of Ca2+. Deprotonation of the alpha-amino group is possibly accompanied by conformational transition to the active form which is able to bind Ca2+. This is in contrast to the case of bovine pancreatic phospholipase A2 in which Asp-49 (pKa 5.2) is responsible for the metal ion binding (Fleer et al. (1981) Eur. J. Biochem. 113, 283-288). Des-octapeptide(1-8)-phospholipase A2 (L-fragment) was found to be capable of binding Ca2+ under the control of a group with a pKa of 7.6. This pKa value was similar to an apparent pKa of 7.5 determined for the histidine residue in the active site of the native enzyme by way of p-bromophenacyl bromide modification. It appears that the N-terminal (octapeptide) sequence affects the binding mode of Ca2+, possibly because of conformational transition arising from its removal. The reinvestigation showed that the N-terminal octapeptide sequence is Gly-Leu-Trp-Gln-Phe-Glu-Asn-Met.