[Temporal relationships between a state of emergency declaration or request and trends in the incidence of unlinked COVID-19 cases in Osaka from October 2020 to May 2021]

Objective　We examined the effectiveness of governmental declarations on the changing temporal trends in the incidence of COVID-19 cases with unknown transmission routes (unlinked cases) before SARS-CoV-2 vaccines became available in Osaka.Methods　Seven-day moving averages of the incidence of unlinked COVID-19 cases were calculated using daily reports posted on the official website of the Osaka Prefectural Government for the third (October 10, 2020-February 28, 2021) and fourth COVID-19 waves and about one week before and after (February 23, 2021-June 27, 2021). Then, we calculated daily percentage changes and identified dates of significant change ("Joinpoint") with a Joinpoint regression analysis. The date of a major change in the behavior of prefectural residents associated with the risk of infection (the date of a sudden change in behavior) was defined as the date counting backward from each Joinpoint date and considering the incubation period and interval between the date of onset and disclosure of the daily report. Subsequently, we examined the temporal relationships between the declaration date and defined date of the sudden change in behavior associated with the risk of infection.Results　Five Joinpoint dates contributing to a significant downward trend were identified: November 23, 2020, and in 2021, January 7, January 18, April 12, and April 30. We defined dates of sudden changes in behavior from each Joinpoint date from the corresponding time lag (8 to 9.9 days): in 2020, November 13 and December 30; in 2021, January 9, April 4, and April 22. Regarding the five estimated dates, the second emergency declaration was issued on January 9, 2021. Further, the first introduction of priority preventive measures was given on April 4, 2021. April 22 fell between the date that the third emergency declaration was requested and the date of its issuance.Conclusion　These descriptive epidemiological findings suggest that the issuance of these declarations could be triggers that reinforced infection avoidance behavior among Osaka prefectural residents, which resulted in the downward trends in unlinked COVID-19 cases.

Detection of Bartonella quintana (Hyphomicrobiales: Bartonellaceae) Among Day Laborers in Osaka, Japan, 2009-2010

Bartonella quintana is a gram-negative bacterium causing trench fever, an illness historically acquired by soldiers during World War I. More recently, outbreaks of trench fever have been reported in those experiencing homelessness in the United States, France, Russia, and Tokyo, as well as in children in Nepal and persons in Ethiopia. Reports of B. quintana infection outside of Tokyo are rare in Japan. The aim of this study was to examine body lice and blood obtained from people staying in shelters in Osaka (2009-2010) for B. quintana via polymerase chain reaction and enzyme-linked immunosorbent assays. Day laborers were defined as homeless individuals and shelter residents in this study. We detected genes of B. quintana in body lice by PCR and antibodies against B. quintana. The positive rate of B. quintana genes was 6/10 (60%) in body lice and the seroprevalence (IgG) of B. quintana was 4/10 (40%). This demonstrates that trench fever was endemic in people staying in shelters in Osaka in 2009-2010.

Results of mass screening for neuroblastoma in 18-month-old infants in Osaka area, Japan

PURPOSE

In 2004, the Japanese government halted nationwide mass screening for neuroblastoma in 6-month-old infants as it led to overdiagnosis of localized tumors with favorable prognoses and failed to reduce neuroblastoma-related mortality. However, a new mass screening program for neuroblastoma in 18-month-old infants (18MS) was conducted in the Osaka prefecture. We assessed the efficacy of the 18MS in screening unfavorable cases.

METHODS

Public health centers in Osaka prefecture, excluding the Osaka city area, provided test kits to the guardians of infants who received a check-up at 18 months of age between 2004 and 2017. For patients whose standardized urinary levels of vanillylmandelic acid or homovanillic acid exceeded the threshold, they were further examined and treated in two specific hospitals Osaka University Hospital and Osaka Women's and Children's Hospital. Screening-positive patients with and without neuroblastoma were retrospectively reviewed.

RESULTS

Among 142,423 children screened during the 18MS, 85 tested positive, and 14 were diagnosed with neuroblastoma. Twelve patients were classified as very low risk, while 2 were classified as high risk, based on the International Neuroblastoma Risk Group risk classification.

CONCLUSION

The 18MS did not screen unfavorable cases with neuroblastoma efficiently, although few participants benefited from it.

Clinical characteristics of COVID-19 in Osaka, Japan: Comparison of the first-third waves with the fourth wave

BACKGROUND

The fourth wave of COVID-19 in Osaka Prefecture, Japan, caused a medical crisis. Here, we aim to identify the risk factors for COVID-19 severity and compare patients between the first-third waves and the fourth wave.

METHODS

We performed an observational retrospective study of COVID-19 cases at the National Hospital Organization Kinki-Chuo Chest Medical Center.

RESULTS

We identified 404 patients (median age: 71.0 years [interquartile range: 56.0-80.0]), of whom 199 (49.1%) had mild disease, 142 (35.2%) had moderate disease, and 63 (15.6%) had severe disease. The overall mortality rate was 5.4% (22/404). Based on multivariate logistic regression analysis, cardiovascular disease, fever, dyspnea, and several inflammatory biomarkers were independent risk factors for moderate to severe disease. For every 1 mg/dL increase in C-reactive protein, 10 IU/L increase in lactate dehydrogenase, and 100 ng/mL increase in ferritin, the risk for moderate to severe disease increased by 18.3%, 12.9%, and 8.9%, respectively. Overall disease severity in the fourth wave was higher than in the first-third waves. However, there was no significant difference in mortality. Because of a shortage of beds, four of the 28 severe patients (14.3%) in the fourth wave could not be transferred to the advanced hospital.

CONCLUSIONS

Cardiovascular disease, fever, dyspnea, and several inflammatory biomarkers were risk factors for moderate to severe COVID-19 in our cohort. During the fourth wave, COVID-19 severity worsened, increasing the number of patients who could not be transferred to beds for severe cases, resulting in a medical crisis in Osaka.

Trends in COVID-19 Outbreak in Tokyo and Osaka from January 25 to May 6, 2020: a Joinpoint Regression Analysis of the Outbreak Data

We analyzed the trends of the coronavirus disease 2019 (COVID-19) outbreak in Tokyo and Osaka from January 25 to May 6, 2020. To analyze the trends and identify significant changes in them, we performed a joinpoint regression analysis. From the last week of March, the number of COVID-19 cases soared in Tokyo (β = 103.51) and Osaka (β = 28.07). During the 2nd and 3rd weeks of April, both Tokyo (β = 157.53) and Osaka (β = 60.96) experienced peak growth in COVID-19 cases. Since almost 14 days after the state of emergency declaration, the number of cases showed a containment trend in Osaka, but continued to increase at a concerning rate in Tokyo (β = 90.66).

First surveillance and molecular identification of the Cryptosporidium skunk genotype and Cryptosporidium parvum in wild raccoons (Procyon lotor) in Osaka, Japan

Recent research suggests that raccoons (Procyon lotor) can transmit several important pathogens affecting humans, including protozoans. In Japan, the number of wild raccoons has increased since they were first introduced more than 50 years ago. Here, we report the first survey of Cryptosporidium infection using fecal swabs of raccoons captured in Osaka, Japan. Of 116 raccoons examined by PCR targeting of the Cryptosporidium 18S rRNA gene, 7 (6.03%; 2 adults and 5 young animals) were positive, and the isolates were identified as Cryptosporidium skunk genotype (subtype XVIa) and C. parvum based on sequence and phylogenetic analyses. Both species and the genotype are zoonotic; thus, our results suggest that raccoons could transmit Cryptosporidium infections to humans in Japan.

Characteristics of ammonia gas and fine particulate ammonium from two distinct urban areas: Osaka, Japan, and Ho Chi Minh City, Vietnam

Continuous and simultaneous measurements of ammonia gas (NH₃) and fine particulate ammonium (PM_2.5NH₄⁺) were performed in two distinct urban areas: Osaka, Japan, and Ho Chi Minh City (HCMC), Vietnam. Measurements were performed using a new online instrument. Two measurement periods were conducted during February 11-March 12, 2015 (cold period), and July 1-September 14, 2015 (warm period), at the urban site in Osaka, while 17 days of measurements, from May 21 to June 8, 2015, were conducted at the urban site in HCMC. The average NH₃ concentration at the HCMC site was much higher than that at the Osaka site. The differences in the NH₃ levels between the two cities are a result of their different emission sources. Traffic emission is a significant contributor to the NH₃ levels within the urban area in Osaka. Conversely, the contribution of traffic emission to the NH₃ levels in the HCMC urban area is negligible. With a population of around 8.5 million people living in the urban area of HCMC, the high NH₃ level is due to human sources and poor waste management systems, especially because of the high temperature (30 °C) and dense population of the city (density up to 42,000 inhabitants per km²). In contrast to the NH₃ levels, the highest PM_2.5NH₄⁺ level occurred during the cold period at the Osaka site, and the average level at this site was higher than that at the HCMC site. The availability of atmospheric acids, low temperature, and high humidity facilitates the formation of ammonium. Our results indicate that NH₃ plays a key role in secondary inorganic aerosol formation; therefore, it contributes to a significant amount of PM_2.5 at the Osaka site. In contrast, the high levels of PM_2.5 observed at the HCMC site are likely from road traffic emission, mainly motorcycles, rather than secondary inorganic aerosol formation.

The detection of toxigenic Corynebacterium ulcerans from cats with nasal inflammation in Japan

Corynebacterium ulcerans (toxigenic C. ulcerans) produces the diphtheria toxin, which causes pharyngeal and cutaneous diphtheria-like disease in people, and this bacterium is commonly detected in dogs and cats that are reared at home. It is considered dangerous when a carrier animal becomes the source of infection in people. To investigate the carrier situation of toxigenic C. ulcerans of cats bred in Japan, bacteria were isolated from 37 cats with a primary complaint of rhinitis in 16 veterinary hospitals in Osaka. Toxigenic C. ulcerans was detected in two of the cats. By drug sensitivity testing, the detected bacterium was sensitive to all investigated drugs, except clindamycin. It appears necessary to create awareness regarding toxigenic C. ulcerans infection in pet owners because this bacterium is believed to be the causative organism for rhinitis in cats.

Gastroenteritis outbreaks caused by a DS-1-like G1P[8] rotavirus strain, Japan, 2012-2013

Rotavirus A (RVA) genotype G1P[8], a hallmark of the Wa-like strain, typically contains only genotype 1 genes. However, an unusual RVA G1P[8] with genotype 2 genes was recently detected in Japan. We determined the complete genomic constellation of this RVA. Our findings suggest that mixed RVAs may be more competitive than once thought.