A conventional PCR-based method to detect the E2 gene of the rubella virus for epidemiological analysis.

To eliminate the rubella virus (RV), genetic characterization is vital for its detection, identification of endemic transmission, and diagnosis of imported cases. The 739-nucleotide region in the E1 gene has primarily been used for genotyping for epidemiological analysis. However, in the 2018-2019 RV outbreak, identical sequences were observed in patients who were not epidemiologically linked. Additionally, the 739 nt sequences from the outbreak in Tokyo in 2018-2019 were identical to RV identified in China in 2019. This suggests that this region may be insufficient to identify the detected RV strains as endemic or imported. In 62.4% of the specimens, the E1 gene sequences of the 1E RV genotype were identical. Additionally, the observed discordance of sequences from the mainly detected identical sequence in the 739-nt sequence of the E1 gene were one (31.0%), two (3.5%), three (2.6%), and four (0.23%). Moreover, a comparison of the complete structural protein-coding region suggests that the E2 gene is more diverse than the E1 and the capsid gene. Thus, conventional polymerase chain reaction (PCR) primers were developed to detect the E2 gene and improve epidemiological analysis. A comparison of the sequences identified during the RV outbreak in Tokyo revealed genetic differences in the sequences (15 of the 18 specimens). These results suggest that additional information could be obtained by simultaneously analyzing the E2 and the E1 region. The identified sequences can potentially aid in evaluating the RV strains detected during epidemiological analysis.

Genetic Characteristics of the Virus Detected in the First Mpox Imported Case in Tokyo, Japan.

Mpox, caused by the mpox virus (MPXV), produces symptoms similar to those of smallpox when transmitted to humans. Since 1970, this disease has been endemic, particularly in Africa. However, since May 2022, the number of patients without a history of travel to endemic areas has increased rapidly globally. Under these circumstances, in July 2022, two different real-time PCR methods were used on specimens brought to the Tokyo Metropolitan Institute of Public Health. MPXV was detected in the skin samples, and it was inferred that the virus was a West African strain. Furthermore, a more detailed analysis of the genetic characteristics of the detected MPXV using next-generation sequencing revealed that the MPXV detected in Tokyo was strain B.1, which corresponds to the same strain that is prevalent in Europe and the USA. This suggests that mpox reported for the first time in Japan was imported and related to outbreaks in Europe and the USA. Therefore, it is necessary to continue monitoring outbreaks in Japan in conjunction with global epidemics.

Treatment with tecovirimat of the first two cases of monkeypox in Japan.

Outbreaks of monkeypox in Europe and North America have been reported since May 2022. At the end of July, we encountered the first two cases of monkeypox diagnosed in Japan. Case 1 was a white man who traveled to Spain where he had sexual intercourse with men. He presented to our hospital with fever, rash, and tiredness, and was diagnosed with monkeypox based on positive PCR test results from the skin lesions. He was admitted to our hospital, received tecovirimat 600 mg twice daily, and was discharged on day 15. Case 2 involved a Japanese man who visited us because of fatigue, muscle pain, headache, and oral ulcers. He was living in New York and traveled to Japan one day before presentation. He had experienced sexual intercourse with men four times during the previous month. The patient was diagnosed with monkeypox based on positive PCR results from the blood. He was admitted to our hospital, received tecovirimat 600 mg twice daily, and was discharged on day 14. These were the first two cases of monkeypox diagnosed in Japan. Based on their history and epidemiology, the viruses seem to have been imported from Europe and North America, respectively. After initiation of tecovirimat, both patients showed mild symptoms and immediate disappearance of viral DNA. The second case was notable for being diagnosed without skin rash. Our report suggests that tecovirimat could decrease the viral load rapidly, and that our prompt diagnosis contributed to the prevention of a monkeypox outbreak in Japan.

Molecular and Epidemiological Analysis of Respiratory Syncytial Virus Detected in Tokyo, Japan in 2021 Season.

During the COVID-19 pandemic in 2021, Japan experienced an outbreak of respiratory syncytial virus (RSV) infection. A total of 51 RSV cases were detected in infant specimens, including 38 rhinorrhea and 13 nasopharyngeal swabs, collected at the Tokyo Metropolitan Institute of Public Health. Of the 51 cases, 12 were RSV-A and 39 were RSV-B. The G protein gene sequence of RSV-A belonged to the ON1 genotype, whereas RSV-B belonged to the BA9 genotype; thus, different types of RSV were detected during the same period, suggesting that the unusual 2021 RSV season was not due to a single strain or genotype. Of all RSV-positive cases, the proportion of patients aged ≥2 years was 56.8% in 2021, higher than the 31.2% reported in the past 5 years. This indicates that infants aged <1 year who were originally susceptible to RSV infection were less likely to be infected with RSV because of the COVID-19 control measures. The 2021 epidemic peaked in the 28th week, 9 weeks earlier than the average from 2016 to 2020. Therefore, it seems necessary to accumulate and analyze further data, such as factors that led to the outbreak and the characteristics of the detected viruses in 2021.

Characterization of Bovine papillomavirus 28 (BPV28) and a novel genotype BPV29 associated with vulval papillomas in cattle.

Papillomavirus (PV) infections are associated with the development of cutaneous and mucosal tumors in humans and various animal species. In humans, infection of high-risk human PVs (HPVs) causes anogenital cancers, while in animals, anogenital-associated PVs are not well understood. Among animal PVs, Bos taurus PVs (BPVs) have the most diverse genotypes, up to 28 of them. The present study will report two unique BPVs identified in vulval papilloma lesions from two Holstein Friesian cattle by conventional PCR and sequencing. In the first case, BPV28 harboring two L1 open reading frames (ORFs) due to a five-nucleotide deletion was identified. In the second case, histologically diagnosed as papilloma, an unclassified BPV genotype was detected. However, in both cases, the immunohistochemistry against PV antigen was negative. The full genome of the unclassified BPV was amplified by inverse PCR and analyzed by genome-walking sequencing. The L1 nucleotide sequence was most identical to BPV genotype 6 (BPV6), showing 78 % identity, indicating that this novel BPV should be classified as species Xipapillomavirus 1, genotype BPV29. The mRNA expression of three early genes (E1, E2, E10), but not L1, was confirmed in both BPV28- and BPV29-detected papilloma lesions. The present study suggests the involvement of novel types of BPV in vulval papilloma. The alteration of BPV28 pathogenicity due to the frameshift mutation of L1 needs to be elucidated in the future.

Genomic characterization of a novel bovine papillomavirus type 28.

Infection of bovine papillomavirus (BPV) has been associated with mucosal and/or cutaneous tumor development in bovids. To date, up to 27 genotypes of BPVs have been identified and classified based on the nucleotide sequence identity of L1 open reading frame. In the present study, the complete sequence of a novel BPV concurrently identified with BPV1 and BPV2 in the facial cutaneous papilloma lesion of a domestic cattle was characterized. The whole genome of the unclassified BPV was 7263 base pairs in full length with GC ratio of 42.9%. In comparison with published BPV sequences, L1 nucleotide sequence of the novel BPV shared 75% identity with BPV15, and was suggested to be classified in the genus, Xipapillomavirus. According to the criteria established by the International Committee on the Taxonomy of Viruses, the novel BPV was designated as BPV type 28.