Western Pacific Surveillance and Response最新文献

Objective: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant B.1.1.529 (Omicron) was first detected in Japan in November 2021. In Osaka, public health centres subsequently increased active case finding and encouraged self-isolation. This study investigated the effectiveness of these countermeasures.

Methods: Cases targeted for analysis were persons who had neither recently travelled abroad nor had contact with foreign tourists but tested positive for SARS-CoV-2 between 24 November 2021 and 4 January 2022 and were suspected or confirmed to have the Omicron variant. We performed a descriptive analysis and calculated the reproduction number (R) for each generation using the branching process method. Genomic sequencing data were analysed to plot a haplotype network.

Results: A total of 251 cases were analysed. The median age was 30 years, and 46% (115/251) were in their 20s or younger. The first Omicron case in Osaka was detected on 21 December 2021. Local public health centres conducted health monitoring and contact tracing. We analysed R, using information from six clusters, including 42 pairs with a clear relationship between the case and the infected contact (infector-infectee pairs); the clusters had 19, 21 and 2 cases in each subsequent generation. The basic R (t = 0) was estimated to be 3.2, and subsequent generations (t = 1, 2) of R decreased to 1.1 and 0.1, respectively. The haplotype network showed that these cases constituted a monophyletic group with others detected around Osaka, indicating that these case-related clusters had been contained and were not involved in the nationwide Omicron waves.

Discussion: Active case finding and self-isolation were found to be effective in limiting the spread of an emerging novel variant.

Objective: This cross-sectional, prospective surveillance study sought to determine the prevalence of novel respiratory viruses among domestic ducks in Central Luzon that are known to have frequent contact with wild avian species. Such contact may lead to novel virus spillover events that may harm domestic poultry as well as humans.

Methods: From March 2019 to January 2020, cross-sectional and prospective surveillance for viruses among domestic ducks (Anas luzonica) was conducted by periodically collecting oropharyngeal swabs from ducks on 54 farms across three municipalities within Central Luzon (Region III). A flock of 30 sentinel domestic ducks was also sampled four times after being confined in the Candaba swamp. The resultant 1740 swab samples were pooled (5 samples/pool, 348 pools) by site and screened with molecular assays for respiratory viruses from multiple viral families.

Results: Two farms yielded samples positive for avian influenza virus in Candaba, where adolescent ducks are known to freely mix with wild birds as they graze in rice fields. Overall, the prevalence of avian influenza virus was 2.3% (8/348 pools). Sequencing revealed three pools with highly pathogenic avian influenza H5N6, one with low pathogenicity H5N8, and one with H5 with an unspecified neuraminidase. All the pooled specimens tested were negative for influenza C, adenoviruses, coronaviruses and enteroviruses.

Discussion: Although this study had several limitations, it found supportive evidence that domestic ducks are acquiring avian influenza viruses from wild bird species. These findings underscore recommendations that duck farmers should seek to prevent domestic ducks from mixing with wild avian species.

Objective: On 2 September 2023, the Regional Epidemiology and Surveillance Unit of the Department of Health's Center for Health Development in Calabarzon, Philippines, received a report of foodborne illness due to the ingestion of tuba-tuba (Jatropha curcas) seeds in Talao Talao Village, Lucena City. The objective of this study was to describe the public health event.

Methods: A descriptive study was conducted. Cases were defined as previously well individuals who developed at least one of the following symptoms after eating tuba-tuba seeds: vomiting, abdominal pain, diarrhoea, headache or dizziness. Health records were reviewed, and key informant interviews and environmental surveys were conducted.

Results: Ten cases were identified, ranging in age from 10 to 12 years. The onset of symptoms ranged from 1 to 4 hours after consumption. Six of the cases were taken to the hospital, although two went home before being admitted; all recovered after 3 days. The most common symptom was vomiting (100%); other symptoms included abdominal pain, diarrhoea, dizziness and headache.

Discussion: This investigation confirmed that tuba-tuba seeds were the cause of symptoms among school-aged children in Lucena City. To prevent similar events in the future, we recommend intensifying educational campaigns at both the community and school levels, as tuba-tuba is common in the area.

Problem: Despite the widespread use of designated quarantine hotels to minimize the transmission of COVID-19 from imported cases, there is scant literature on the infrastructure and operational requirements of such facilities.

Context: Travellers to Hong Kong Special Administrative Region (SAR) (China) were required to undergo quarantine in designated hotels for up to 21 days. Prior to operation, all these hotels were modified and hotel staff received structured training in infection control practices.

Action: We conducted retrospective reviews of the procedures and operational protocols that were followed to convert and manage commercial hotels as quarantine hotels during the early part of the pandemic. We also reviewed the training provided and compliance monitoring. Finally, we reviewed intra-hotel outbreak investigations that were conducted between April 2021 and June 2022.

Outcome: Designated quarantine hotels received 842 510 quarantined travellers from December 2020 to October 2022. Ten outbreaks were reported, affecting 28 guests (0.003%) and two staff. Prompt epidemiological investigation and action stopped further transmission.

Discussion: In Hong Kong Special Administrative Region SAR (China), designated quarantine hotels successfully minimized COVID-19 transmission from imported cases to the community and should be considered as part of integrated response plans for future pandemics. Based on our COVID-19 pandemic experience, we recommend specifying requirements for quarantine centres and hotels to ensure adequate ventilation inside guest rooms and corridors, functioning drainage systems and the adoption of stringent infection control practices. We also recommend the installation of closed-circuit television cameras in all common areas to support compliance monitoring and outbreak investigation.

Objective: In 2018, the Shinjuku City Department of Health detected excess cases of hepatitis A virus (HAV) infection. The objectives of this investigation were to characterize the outbreak, identify transmission routes among inpatient cases and make recommendations to control and prevent HAV infection among men who have sex with men.

Methods: Information about cases of HAV infection was collected from the National Epidemiological Surveillance for Infectious Diseases system and inpatient interviews conducted by public health nurses in 2018.

Results: There were 131 HAV cases in 2018. Of these, 98% (129/131) were male, of whom 81% (105/129) were men who have sex with men. Hospitalization was required for 40 cases (31%). The age groups with the highest proportion of cases were 30-39 and 40-49 years (each 34%; 44/131). Two cases (2%) had received the second dose of the HAV vaccine, but only 10 days before symptom onset; all others had received no doses. The sequence type subgroup 13, an RIVM-HAV-16-090-like strain, was seen in 51 cases (39%). Of the 40 hospitalized cases, 21 (53%) participated in an interview conducted using a semistructured questionnaire. Altogether, of 21 cases, 12 (57%) had coinfection with HIV, 13 (62%) had casual sexual contact within the preceding 2 months and 10 (48%) had used social networking services (SNS) to find a sexual partner.

Discussion: In Shinjuku, this outbreak almost exclusively affected the population of men who have sex with men. The detected outbreak strain has previously been reported in outbreaks among men who have sex with men in China, Taiwan (China) and Europe. For HAV prevention, the most important measures are raising awareness of the risk of HAV as a sexually transmitted infection via SNS and promoting immunization at the appropriate time.

Objective: The COVID-19 pandemic disrupted disease surveillance systems globally, leading to reduced notifications of other infectious diseases. This study aims to estimate the impact of the COVID-19 pandemic on the infectious disease surveillance system in Klang district, Selangor state, Malaysia.

Methods: Data on notifiable diseases from 2014 to 2022 were sourced from the Klang District Health Office. The 11 diseases with more than 100 notifications each were included in the study. For these 11 diseases, a negative binomial regression model was used to explore the effect of the pandemic on case notifications and registrations by year, and a quasi-Poisson regression model was used to explore the changes by week.

Results: The results showed a reduction in the number of notifications and registrations for all 11 diseases combined during the pandemic compared with previous years. Changes between expected and observed notifications by week were heterogeneous across the diseases.

Discussion: These findings suggest that restrictive public health and social measures in Klang district may have impacted the transmission of other infectious diseases during the COVID-19 pandemic. The differential impact of the pandemic on disease notifications and reporting highlights the large ancillary effects of restrictive public health and social measures and the importance of building resilience into infectious disease surveillance systems.

Objective: Mortality surveillance was established in the state of Victoria just before the COVID-19 pandemic. Here, we describe the establishment of this surveillance system, justify the modelling approach selected, and provide examples of how the interpretation of changes in mortality rates during the pandemic was influenced by the model chosen.

Methods: Registered deaths occurring in Victoria from 1 January 2015 to 31 December 2020 were sourced from the Victoria Death Index. Observed mortality rates were compared to a raw historical 5-year mean and to predicted means estimated from a seasonal robust regression. Differences between the observed mortality rate and the historical mean (∆MR) and excess mortality rate from the observed and predicted rates were assessed.

Results: There were 20 375 COVID-19 cases notified in Victoria as of 31 December 2020, of whom 748 (3.7%) died. Victorians aged ≥ 85 years experienced the highest case fatality ratio (34%). Mean observed mortality rates in 2020 (MR: 11.6; 95% confidence interval [CI]: 11.4, 11.9) were slightly reduced when compared with the annual rate expected using the historical mean method (mean MR: 12.2; 95% CI: 12.1-12.3; ∆MR: -0.57; 95% CI: -0.77, -0.38), but not from the rate expected using the robust regression (estimated MR: 11.7; 95% prediction interval [PI]: 11.5, 11.9; EMR: -0.05; 95% CI: -0.26, 0.16). The two methods yielded opposing interpretations for some causes, including cardiovascular and cancer mortality.

Discussion: Interpretation of how pandemic restrictions impacted mortality in Victoria in 2020 is influenced by the method of estimation. Time-series approaches are preferential because they account for population trends in mortality over time.