Diversity Analysis of Tick-Borne Viruses from Hedgehogs and Hares in Qingdao, China.

Tick-borne viruses (TBVs) have attracted increasingly global public health attention. In this study, the viral compositions of five tick species, Haemaphysalis flava, Rhipicephalus sanguineus, Dermacentor sinicus, Haemaphysalis longicornis, and Haemaphysalis campanulata, from hedgehogs and hares in Qingdao, China, were profiled via metagenomic sequencing. Thirty-six strains of 10 RNA viruses belonging to 4 viral families, including 3 viruses of Iflaviridae, 4 viruses of Phenuiviridae, 2 viruses of Nairoviridae, and 1 virus of Chuviridae, were identified in five tick species. Three novel viruses of two families, namely, Qingdao tick iflavirus (QDTIFV) of the family of Iflaviridae and Qingdao tick phlebovirus (QDTPV) and Qingdao tick uukuvirus (QDTUV) of the family of Phenuiviridae, were found in this study. This study shows that ticks from hares and hedgehogs in Qingdao harbored diverse viruses, including some that can cause emerging infectious diseases, such as Dabie bandavirus. Phylogenetic analysis revealed that these tick-borne viruses were genetically related to viral strains isolated previously in Japan. These findings shed new light on the cross-sea transmission of tick-borne viruses between China and Japan. IMPORTANCE Thirty-six strains of 10 RNA viruses belonging to 4 viral families, including 3 viruses of Iflaviridae, 4 viruses of Phenuiviridae, 2 viruses of Nairoviridae, and 1 virus of Chuviridae, were identified from five tick species in Qingdao, China. A diversity of tick-borne viruses from hares and hedgehogs in Qingdao was found in this study. Phylogenetic analysis showed that most of these TBVs were genetically related to Japanese strains. These findings indicate the possibility of the cross-sea transmission of TBVs between China and Japan.

The effect of ambient temperature on hand, foot and mouth disease in Qingdao, China, 2014-2018.

Hand, foot, and mouth disease (HFMD) is a kind of infection gastrointestinal disease. The present study aims to explore the association between ambient temperature and HFMD in Qingdao. A distributed lag nonlinear model with Poisson distribution was adopted to explore the effects of daily mean temperature on HFMD incidence. Our results found that the high temperature had acute and short-term effects and then declined rapidly along the lag days, with the maximum risk occurring 0 day of exposure. Compared with low temperature, higher effects were observed for high-temperature exposure. Overall, we found that the association between temperature and HFMD incidence was non-linear, exhibiting an approximate "J" shape, with peak value occurring at 30.5℃ (RR = 2.208, 95% CI: 1.995-2.444). Our findings suggest that ambient temperature is significantly associated with the incidence of HFMD in Qingdao. Monitoring ambient temperature changes is an appropriate recommendation to prevent HFMD.

SFTSV infection in rodents and their ectoparasitic chiggers.

SFTSV, a tick-borne bunyavirus causing a severe hemorrhagic fever termed as severe fever with thrombocytopenia syndrome (SFTS). To evaluate the potential role of rodents and its ectoparasitic chiggers in the transmission of SFTSV, we collected wild rodents and chiggers on their bodies from a rural area in Qingdao City, Shandong Province, China in September 2020. PCR amplification of the M and L segments of SFTSV showed that 32.3% (10/31) of rodents and 0.2% (1/564) of chiggers (Leptotrombidium deliense) from the rodents were positive to SFTSV. Our results suggested that rodents and chiggers may play an important role in the transmission of SFTSV, although the efficiency of chiggers to transmit SFTSV needs to be further investigated experimentally.

Variability in transmission risk of SARS-CoV-2 in close contact settings: A contact tracing study in Shandong Province, China.

BACKGROUND: Understanding the relative transmissibility of SARS-CoV-2 virus across different contact settings and the possibility of superspreading events is important for prioritizing disease control. Such assessment requires proper consideration of individual level exposure history, which is made possible by contact tracing. METHODS: The case-ascertained study in Shandong, China including 97 laboratory-confirmed index cases and 3158 close contacts. All close contacts were quarantined after their last exposure of index cases. Contacts were tested for COVID-19 regularly by PCR to identify both symptomatic and asymptomatic infections. We developed a Bayesian transmission model to the contact tracing data to account for different duration of exposure among individuals to transmission risk in different settings, and the heterogeneity of infectivity of cases. RESULTS: We estimate secondary attack rates (SAR) to be 39% (95% credible interval (CrI): 20-64%) in households, 30% (95% CrI: 11-67%) in healthcare facilities, 23% (95% CrI: 7-51%) at workplaces, and 4% (95% CrI: 1-17%) during air travel. Models allowing heterogeneity of infectivity of cases provided a better goodness-of-fit. We estimated that 64% (95% CrI: 55-72%) of cases did not generate secondary transmissions, and 20% (95% CrI: 15-26%) cases explained 80% of secondary transmissions. CONCLUSIONS: Household, healthcare facilities and workplaces are efficient setting for transmission. Timely identification of potential superspreaders in most transmissible settings remains crucial for containing the pandemic.

Genotype and mutation patterns of macrolide resistance genes of Mycoplasma pneumoniae from children with pneumonia in Qingdao, China, in 2019.

OBJECTIVES: This study assessed the incidence and resistance of Mycoplasma pneumoniae (MP) in children in Qingdao, China, in 2019. METHODS: We detected MP infection in 78 pharyngeal swabs from children with pneumonia by qPCR. The RepMP4 element in the P1 adhesin gene, domain V of the 23S rRNA gene, and the L4/L22 ribosomal proteins were amplified by nested PCR. Evolutionary analysis was conducted based on the P1 gene sequence. Resistance mutations in domain V of the 23S rRNA gene and L4/L22 ribosomal proteins were analysed. RESULTS: The incidence of MP infection in children with pneumonia was 59.0% (46/78). The mean duration of MP infection was longer than that of non-MP infection. According to P1 gene sequencing of 21 samples, 12 (57.1%) were type 1 and 9 (42.9%) were type 2. Drug resistance mutations A2063G in domain V of 23S rRNA gene and T508C in L22 were identified from all sequenced MP. However, mutations at positions 2064 and 2617 were not found in this study. C162A mutation appeared in most type 2 samples. A430G mutation appeared in one type 1 sample and in several type 2 samples. T279C mutation in L22 was mostly found in type 2 samples. CONCLUSION: The incidence of MP infection was 59.0% in children with pneumonia in Qingdao in 2019. Type 1 MP infection was slightly more common than type 2, indicating that the genotype of MP is gradually shifting from type 1 to type 2. Macrolide resistance mutation A2063G could be detected in all sequenced MP.

Long Distance Transmission of SARS-CoV-2 from Contaminated Cold Chain Products to Humans - Qingdao City, Shandong Province, China, September 2020.

What is already known about this topic? Though coronavirus disease 2019 (COVID-19) has largely been controlled in China, several outbreaks of COVID-19 have occurred from importation of cases or of suspected virus-contaminated products. Though several outbreaks have been traced to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) isolated on the outer packaging of cold chain products, live virus has not been obtained. What is added by this report? In September 2020, two dock workers were detected as having asymptomatic SARS-CoV-2 infection using throat swabs during routine screening in Qingdao, China. Epidemiological information showed that the two dock workers were infected after contact with contaminated outer packaging, which was confirmed by genomic sequencing. Compared to the Wuhan reference strain, the sequences from the dock workers and the package materials differed by 12-14 nucleotides. Furthermore, infectious virus from the cold chain products was isolated by cell culture, and typical SARS-CoV-2 particles were observed under electron microscopy. What are the implications for public health practice? The international community should pay close attention to SARS-CoV-2 transmission mode through cold chain, build international cooperative efforts in response, share relevant data, and call on all countries to take effective prevention and control measures to prevent virus contamination in cold-chain food production, marine fishing and processing, transportation, and other operations.

The association between ambient air pollution and scarlet fever in Qingdao, China, 2014-2018: a quantitative analysis.

BACKGROUND: We conducted a distributed lag non-linear time series analysis to quantify the association between air pollution and scarlet fever in Qingdao city during 2014-2018. METHODS: A distributed lag non-linear model (DLNM) combined with a generalized additive mixed model (GAMM) was applied to quantify the distributed lag effects of air pollutions on scarlet fever, with daily incidence of scarlet fever as the dependent variable and air pollutions as the independent variable adjusted for potential confounders. RESULTS: A total of 6316 cases of scarlet fever were notified, and there were 376 days occurring air pollution during the study period. Scarlet fever was significantly associated with air pollutions at a lag of 7 days with different relative risk (RR) of air pollution degrees [1.172, 95% confidence interval (CI): 1.038-1.323 in mild air pollution; 1.374, 95% CI 1.078-1.749 in moderate air pollution; 1.610, 95% CI 1.163-2.314 in severe air pollution; 1.887, 95% CI 1.163-3.061 in most severe air pollution]. CONCLUSIONS: Our findings show that air pollution is positively associated with scarlet fever in Qingdao, and the risk of scarlet fever could be increased along with the degrees of air pollution. It contributes to developing strategies to prevent and reduce health impact from scarlet fever and other non-vaccine-preventable respiratory infectious diseases in air polluted areas.

Eosinophil: A Nonnegligible Predictor in COVID-19 Re-Positive Patients.

Although vaccine resources are being distributed worldwide, insufficient vaccine production remains a major obstacle to herd immunity. In such an environment, the cases of re-positive occurred frequently, and there is a big controversy regarding the cause of re-positive episodes and the infectivity of re-positive cases. In this case-control study, we tracked 39 patients diagnosed with COVID-19 from the Jiaodong Peninsula area of China, of which 7 patients tested re-positive. We compared the sex distribution, age, comorbidities, and clinical laboratory results between normal patients and re-positive patients, and analysed the correlation between the significantly different indicators and the re-positive. Re-positive patients displayed a lower level of serum creatinine (63.38 ± 4.94 U/L vs. 86.82 ± 16.98 U/L; P =0.014) and lower albumin (34.70 ± 5.46 g/L vs. 41.24 ± 5.44 g/L, P =0.039) at the time of initial diagnosis. In addition, two positive phases and the middle negative phase in re-positive patients with significantly different eosinophil counts (0.005 ± 0.005 × 109/L; 0.103 ± 0.033 × 109/L; 0.007 ± 0.115 × 109/L; Normal range: 0.02-0.52 × 109/L). The level of eosinophils in peripheral blood can be used as a marker to predict re-positive in patients who once had COVID-19.

Epidemiological Characteristics of Hand, Foot, and Mouth Disease Outbreaks in Qingdao, 2009-2018.

BACKGROUND: In China, hand, foot, and mouth disease (HFMD) outbreaks have become an important issue recent years. We analyzed the epidemiological characteristics of HFMD outbreaks in Qingdao during 2009-2018, and provided evidences for prevention and control of the disease. METHODS: Data were analyzed by descriptive analysis and correlation analysis, and throat swabs were detected for enterovirus RNA using RT-PCR. RESULTS: Overall, 116 HFMD outbreaks were reported in Qingdao during 2009-2018, with the epidemic of the outbreaks exhibiting a decreasing tendency. The characteristics of outbreaks presented two patterns, including two-peak pattern and rural area to urban-rural fringe area to urban areas pattern. Male patients were predominant in these outbreaks. The location of the outbreaks changed from nursery to community. Non-EV71/CA16 enteroviruses were gradually becoming predominant enteroviruses serotypes. The durations of outbreaks were positively correlated with response times and the number of cases. CONCLUSION: The epidemiological characteristics analysis of HFMD outbreaks could provide a scientific basis for the prevention and control the disease. Reporting and handling promptly are the keys to control epidemic outbreaks of HFMD.

Association between floods and the risk of dysentery in China: a meta-analysis.

The association between floods and the risk of dysentery remain controversial. Therefore, we performed a meta-analysis to clarify this relationship. A literature search was performed in PubMed, Web of science, and Embase for relevant articles published up to November 2019. Random-effects model was used to pool relative risks with 95% confidence intervals. The sensitivity analysis was carried out to evaluate the stability of the results. Publication bias was estimated using Egger's test. Eleven studies from 10 articles evaluated the association between floods and the risk of dysentery in China. The pooled RR (95% CI) of dysentery for the flooded time versus non-flooded period was 1.48 (95% CI: 1.14-1.91). Significant association was found in subgroup analysis stratified by dysentery styles [dysentery: 1.61 (95% CI: 1.34-1.93) and bacillary dysentery: 1.46 (95% CI: 1.06-2.01)]. The pooled RR (95%CI) of sensitivity analysis for dysentery was 1.26 (95% CI: 1.05-1.52). No significant publication bias was found in our meta-analysis. This meta-analysis confirms that floods have significantly increased the risk of dysentery in China. Our findings will provide more evidence to reduce negative health outcomes of floods in China.

The distribution of SARS-CoV-2 contamination on the environmental surfaces during incubation period of COVID-19 patients.

Roles of environmental factors in transmission of COVID-19 have been highlighted. In this study, we sampled the high-touch environmental surfaces in the quarantine room, aiming to detect the distribution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on the environmental surfaces during the incubation period of coronavirus disease 2019 (COVID-19) patients. Fifteen sites were sampled from the quarantine room, distributing in the functional areas such as bedroom, bathroom and living room. All environmental surface samples were collected with sterile polyester-tipped applicator pre-moistened in viral transport medium and tested for SARS-CoV-2. Overall, 34.1% of samples were detected positively for SARS-CoV-2. The positive rates of Patient A, B and C, were 46.2%, 0% and 61.5%, respectively. SARS-CoV-2 was detected positively in bedroom and bathroom, with the positive rate of 50.0% and 46.7%, respectively. In contrast, living room had no positive sample detected. Environmental contamination of SARS-CoV-2 distributes widely during the incubation period of COVID-19, and the positive rates of SARS-CoV-2 on environmental surfaces are relatively high in bathroom and bedroom.

Risk factors associated with occurrence of COVID-19 among household persons exposed to patients with confirmed COVID-19 in Qingdao Municipal, China.

Tracing and isolation of close contacts is used to control outbreaks of coronavirus disease 2019 (COVID-19) in China. However, risk factors associated with the occurrence of COVID-19 among close contacts have not been well described. A total of 106 household contacts were included in this study, of whom 19 developed into COVID-19 cases, and the secondary attack rate was 17.9%. Multivariable analysis showed that increasing risk of occurrence of COVID-19 among household contacts was associated with female index patients (adjusted hazard ratio [aHR] = 3.84, 95% CI = 1.07-13.78), critical disease index patients (aHR = 7.58, 95% CI = 1.66-34.66), effective contact duration with index patients > 2 days (aHR = 4.21, 95% CI = 1.29-13.73), and effective contact duration > 11 days (aHR = 17.88, 95% CI = 3.26-98.01). The sex and disease severity of index patients with COVID-19 and longer effective contact duration with patients with confirmed COVID-19 could help epidemiologists to identify potential COVID-19 cases among household contacts at an early stage.

Cold-chain transportation in the frozen food industry may have caused a recurrence of COVID-19 cases in destination: Successful isolation of SARS-CoV-2 virus from the imported frozen cod package surface.

Coronavirus disease 2019 (COVID-19) pandemic has spread in 220 countries/regions to wreak havoc to human beings around the world. At present, the second wave of COVID-19 has begun in many European countries. The complete control of COVID-19 is very urgent. Although China quickly brought the virus under control, there have been eight sporadic outbreaks in China since then. Both in Xinfadi of Beijing and Dalian outbreak of COVID-19, environmental swab samples related to imported cold chain food were tested nucleic acid positive for SARS-CoV-2. In this outbreak in Qingdao, we directly isolated SARS-CoV-2 from the cod outer package's surface swab samples. This is the first time worldwide, SARS-CoV-2 were isolated from the imported frozen cod outer package's surface, which showed that imported frozen food industry could import SARS-CoV-2 virus.

Environmental contamination by SARS-CoV-2 of an imported case during incubation period.

We collected environmental surface samples prior to and after disinfection of a quarantine room to evaluate the stability of SARS-CoV-2 during the incubation period of an imported case traveling to Qingdao, China. Overall, 11 of 23 (47.8%) of the first batch of environmental surface samples (within 4 h after case confirmation) were tested positive for SARS-CoV-2. Whereas only 2 of 23 (8.7%) of the second batch of environmental samples (after first disinfection) were tested positive for SARS-CoV-2. The majority of samples from the bedroom (70%) were positive for SARS-CoV-2, followed by 50% of samples from the bathroom and that of 33% from the corridor. The inner walls of toilet bowl and sewer inlet were the most contaminated sites with the highest viral loads. SARS-CoV-2 was widely distributed on object surfaces in a quarantine room of a later diagnosed COVID-19 case during the incubation period. Proper disinfection is crucial to minimize community transmission of this highly contagious virus.