Surveillance of Wastewater to Monitor the Prevalence of Gastroenteritis Viruses in Chiba Prefecture (2014-2019).

BACKGROUND: In Japan, sentinel surveillance is used to monitor the trend of infectious gastroenteritis. Another method of pathogen surveillance, wastewater-based epidemiology, has been used recently because it can help to monitor infectious disease without relying on patient data. Here, we aimed to determine the viral trends reflected in the number of reported patients and number of gastroenteritis virus-positive samples. We focused on gastroenteritis viruses present in wastewater and investigated the usefulness of wastewater surveillance for the surveillance of infectious gastroenteritis. METHODS: Real-time polymerase chain reaction was used for viral gene detection in wastewater. The number of reported patients per pediatric sentinel site and number of viral genome copies were compared for correlation potential. The number of gastroenteritis virus-positive samples reported by National Epidemiological Surveillance of Infectious Disease (NESID) and the status of gastroenteritis viruses detected in wastewater were also evaluated. RESULTS: Genes of norovirus genotype I, norovirus genotype II, sapovirus, astrovirus, rotavirus group A, and rotavirus group C were detected in wastewater samples. Viruses were detected in wastewater during periods when no gastroenteritis virus-positive samples were reported to NESID. CONCLUSION: Norovirus genotype II and other gastroenteritis viruses were detected in wastewater even during periods when no gastroenteritis virus-positive samples were found. Therefore, surveillance using wastewater can complement sentinel surveillance and is an effective tool for the surveillance of infectious gastroenteritis.

The First Case of Zika Virus Isolated from a Japanese Patient Who Returned to Japan from Fiji in 2016.

Outbreaks of Zika virus (ZIKV) infection in tropical and subtropical regions are a cause of worldwide concern and represent a public health emergency. ZIKV was isolated from a 17-year-old patient with fever and maculopapular rash. The patient returned to Japan from the Republic of Fiji in late April 2016. The complete genome sequence of the ZIKV isolate (ZIKV/Hu/S36/Chiba/2016), which might be the first strain to be isolated in Japan, was identified and reported.