High population burden of Omicron variant (B.1.1.529) is associated with the emergence of severe hepatitis of unknown etiology in children.

OBJECTIVES: To explore a potential country-based ecological link between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant (B.1.1.529) infection and an apparent current global outbreak of severe hepatitis of unknown etiology among children. METHODS: We examined country-level statistical associations between reported detection of one or more unexplained severe hepatitis cases in children and the cumulative number of Omicron (B.1.1.529) cases in 38 Organisation for Economic Co-operation and Development (OECD) member countries plus Romania. RESULTS: At least one focal hepatitis case was detected in 12 of the 39 countries included in our analysis. Numbers of confirmed Omicron cases reported in these 12 countries ranged from 4.4 to 11.9 million. Among the remaining 27 countries, this measure ranged from 0.5 to 5.5 million cases. Countries which reported focal hepatitis cases experienced higher precedent population burdens of Omicron cases relative to those which did not report any such hepatitis cases (p=0.013). CONCLUSION: Prior exposure to Omicron variant (B.1.1.529) may be associated with an increased risk for severe hepatitis among children, indicating a critical need to conduct cofactor studies.

Case Report: Splenic Infarction in Infectious Mononucleosis due to Epstein-Barr Virus Infection.

Epstein-Barr virus (EBV) is the most common cause of infectious mononucleosis (IM) and IM is a clinical syndrome typically characterized by fever, pharyngitis, and cervical lymph node enlargement. We describe the case of a 19-year-old man with IM complicated by splenic infarction. The patient visited our hospital because of upper abdominal pain without a fever and sore throat. Abdominal computed tomography revealed a low-density area in the spleen, which indicated splenic infarction. The next day, he developed a fever. After diminishing abdominal pain and fever, he developed pharyngitis accompanied by fever. Acute EBV infection was confirmed by serological tests. The patient was successfully managed with no specific therapy. Splenic infarction is a rare complication of IM and this case showed that splenic infarction can precede a fever and pharyngitis.

Efficient expression of laccase gene from white-rot fungus Schizophyllum commune in a transgenic tobacco plant.

Ligninolytic enzymes produced by white-rot fungi are effective degraders of recalcitrant aromatic environmental pollutants. However, gene sequences of these enzymes are rich in CpG dinucleotides, which are particularly unfavorable to efficient expression in plants. In order to develop a phytoremediation technique with a ligninolytic enzyme-producing transgenic plant, laccase cDNA (scL) from white-rot fungus Schizophyllum commune was used as a model ligninolytic enzyme, and we attempted to obtain the efficient expression of scL in a transgenic tobacco plant by decreasing the CpG-dinucleotide motif content. We constructed a mutagenized scL sequence, scL12, decreasing the CpG-dinucleotide motif content by 12%, and scL12 was introduced into the tobacco plant. Much higher laccase activity was detected in transgenic scL12 plants than in transgenic scL plants and wild-type plants. Using reverse transcriptase-PCR analysis, scL12 was translated in transgenic scL12 plants whereas mRNA of scL was not detected in the transgenic scL plants, and scL, which is the product of the scL12 gene, was produced in the transgenic scL12 plants using native-polyacrylamide gel electrophoresis analysis. Moreover, transgenic scL12 plants were able to remove trichlorophenol more effectively than transgenic scL plants and wild-type plants. These results suggest that decreasing CpG-dinucleotide motif content in fungal target genes is a useful method for efficient expression of these genes in transgenic plants.