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Data are limited on the incidence of coronavirus disease 2019 (COVID-19) reinfection in children. This population-based cohort study in Niigata, Japan from January to November 2022 demonstrated the incidence of reinfection was 1337/48 099 (2.8%), and the hazard ratio for reinfection in vaccinated children was 0.29 (95% confidence interval, 0.20–0.40). [ABSTRACT FROM AUTHOR]

The taxonomy of the genus Pennella Oken, 1815 , a large parasitic copepod, is in a deplorable state. We performed morphological and genetic analyses on 52 Pennella individuals collected from 12 species of definitive hosts. Based on the morphological characteristics and their hosts, 29 individuals were determined or suggested to be large-size species (P. balaenoptera , P. filosa , P. instructa , and P. benz i), whereas 20 were considered intermediate- or small-size species. The remaining three small individuals, presumed to be newly attached, exhibited insufficient morphological characteristics for species identification or grouping. Mitochondrial DNA cytochrome c oxidase subunit 1 (COI) sequence analysis detected 154 haplotypes from 52 individuals classified into Groups I–IV. Sequences of Group IV were determined to be pseudogenes. Levels of divergence between all groups were significant (F ST = 0.488–0.830, P < 0.001). All haplotypes of Group I were detected in intermediate- and small-size groups possessing large and well-branched antennary processes on the cephalothorax. Although Groups I and II exhibited the smallest difference in nucleotide sequence divergence (F ST = 0.488 and K2P = 1.485 ± 0.355%), the morphological characteristics of Group I appeared to be distinct from those of the other groups. The substantial sequence divergence (F ST = 0.830 and K2P = 4.123 ± 0.719%) between Groups II and III also supported their species status, but no characteristic morphological difference was observed between individuals in these groups. Results suggest that Pennella may contain only two or three species. and that some morphological characteristics and definitive host species previously used for species identification are not valid. [ABSTRACT FROM AUTHOR]

The majority of human group A rotaviruses possess the P[8] VP4 genotype. Recently, a genetically distinct subtype of the P[8] genotype, also known as OP354-like P[8] or lineage P[8]-4, emerged in several countries. However, it is unclear for how long the OP354-like P[8] gene has been circulating in humans and how it has spread. In a global collaborative effort 98 (near-)complete OP354-like P[8] VP4 sequences were obtained and used for phylogeographic analysis to determine the viral migration patterns. During the sampling period, 1988–2012, we found that South and East Asia acted as a source from which strains with the OP354-like P[8] gene were seeded to Africa, Europe, and North America. The time to the most recent common ancestor (TMRCA) of all OP354-like P[8] genes was estimated at 1987. However, most OP354-like P[8] strains were found in threemain clusters with TMRCAs estimated between 1996 and 2001. The VP7 gene segment of OP354-like P[8] strains showed evidence of frequent reassortment, even in localized epidemics, suggesting that OP354-like P[8] genes behave in a similar manner on the evolutionary level as other P[8] subtypes. The results of this study suggest that OP354-like P[8] strains have been able to disperse globally in a relatively short time period. This, in combination with a relatively large genetic distance to other P[8] subtypes, might result in a lower vaccine effectiveness, underscoring the need for a continued surveillance of OP354-like P[8] strains, especially in countries where rotavirus vaccination programs are in place. [ABSTRACT FROM AUTHOR]

The forestomach contents of 498 minke whales Balaenoptera acutorostrata sampled in the Northwestern Pacific from May to September through the 1994–1999 JARPN surveys, were analysed. Sixteen prey species consisting of 1 copepod, 4 euphausiids, 1 squid, and 10 fishes were identified. The minke whale in the Northwestern Pacific is a swallowing, feeding-type species. It feeds on swarming zooplankton and schooling fishes, suggesting that minke whales pursue single prey-species aggregations. The results showed geographical and seasonal changes of prey species. On the Pacific side of Japan, Japanese anchovy was the most important prey species in May and June, while Pacific saury was most important in July and August. Walleye pollock was also an important prey species during June and September in coastal waters, over the continental shelf. In the southern Okhotsk Sea krill was the most important prey species in July and August. These changes probably reflect changes in the availability of the prey species in these areas. It would seem that there might be direct competition between minke whales and the fishery for Pacific saury. Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved. [Copyright &y& Elsevier]