Rubella outbreak among workers in three small- and medium-size business establishments associated with imported genotype 1E rubella virus-Shizuoka, Japan, 2015.

On 12 February 2015, a local health department (LHD) in Shizuoka prefecture identified two reported rubella cases in its jurisdiction as employees of the same company. As other employees at the company resided both inside and outside of the health department's jurisdiction, it began collaborating with two additional LHDs and the National Institute of Infectious Diseases to investigate and respond to the outbreak, which subsequently identified cases in two additional companies. We obtained epidemiological, clinical, and outbreak response information from the national epidemiological surveillance of infectious disease system's database, the local health departments, and the associated companies. One specimen for genetic sequencing was collected from each of the three companies. The outbreak included a total of twenty-five cases, with seventeen confirmed and eight probable cases from three companies. Among them, 24 (96%) were male, 22 (88%) were employees of one company (Company X), and none had rubella vaccination history. The median age was 45 years (interquartile range: 40-51). Epidemiological information did not reveal the source of infection nor transmission route. All rubella viruses sequenced from the three specimens were classified into genotype 1E. The nucleotide sequences in the 739 bp-window region were completely identical in two specimens, with only one nucleotide difference in the third specimen. According to phylogenetic analysis, these strains were closely related to the Southeast and East Asian lineage. This rubella outbreak at three companies, ranging in size from small- to medium-size, in Japan occurred among unvaccinated employees aged at least 30 years, most of whom were male. Virologic analyses suggest all cases were infected with the same viral strain imported from Southeast Asia. Similar to these companies, most employees at small- and medium-size businesses in Japan are males with no vaccination history for rubella, which poses a serious risk for associated cases of congenital rubella syndrome (CRS).

[A food poisoning outbreak caused by purple Washington clam contaminated with norovirus (Norwalk-like virus) and hepatitis A virus].

A party of 57 people dined together in a restaurant in Hamamatsu City on December 11, 2001. The next day, 22 of them developed symptoms of acute gastroenteritis, such as diarrhea, vomiting, and fever. Examination of 4 fecal specimens from these patients by ELISA for Norovirus (Norwalk-like virus, NV) detected both genogroup I (GI) and genogroup II (GII) NV in all the 4 specimens. In addition, RT-PCR and real-time PCR methods for NV detected the NV gene. Approximately one month after the outbreak of the food poisoning (acute gastroenteritis) by NV, 4 individuals in the same party developed type A hepatitis. Both RT-PCR and real-time PCR methods for hepatitis A virus (HAV) detected the HAV gene in their fecal specimens. The party of these patients ate purple Washington clam (Saxidomus purpuratus, imported from China) steamed with red pepper. Since this food appeared to have caused the viral infections, the one with the same lot number was subjected to viral examinations, which successfully detected the NV GI, NV GII, and HAV genes. These results led to the conclusion that the clam contaminated with NV and HAV had caused the food poisoning. The DNA sequences of the NV detected in the patients and the clam had 74 to 99% homology, indicating strains of various genotypes. All the strains of HAV that were derived from the patients and the clam were genotype 1A, and these sequences had over 95% homology, but were not completely identical. This outbreak led to the demonstration of imported fishery products as a cause of type A hepatitis, and indicated the need for guiding and enlightening people on the importance of adequate cooking of bivalves.