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.

Distribution and characteristics of Beilong virus among wild rodents and shrews in China.

Beilong virus (BeiV), a member of the newly recognized genus Jeilongvirus of family Paramyxoviridae, has been reported with limited geographic and host scopes, only in Hongkong, China and from two rat species. Here, by next-generation sequencing (NGS) on dominant wild small animal species in 4 provinces in China, we obtained a complete sequence of BeiV strain from Rattus norvegicus in Guangdong, neighboring HongKong, China. We then made an expanded epidemiological investigation in 11 provinces to obtain the geographic distribution and genetic features of this virus. Altogether 7168 samples from 2005 animals (1903 rodents, 100 shrews, 2 mustelidaes) that belonged to 33 species of Cricetidae, Muridae, Sciuridae and Dipodidae family of Rodentia, 3 species of Soricidae family of Soricomorpha, 2 species of Mustelidae family of Carnivora were examined by RT-PCR and sequencing. A positive rate of 3.7% (266/7168) was obtained that was detected from 22 animal species, including 5 species of Cricetidae family, 12 species of Muridae family, 2 species of Sciuridae family and 3 species of Soricidae family. Phylogenetic analyses based on 154 partial Large gene sequences grouped the current BeiV into two lineages, that were related to their geographic regions and animal hosts. Our study showed the wide distribution of BeiV in common species of wild rodents and shrews in China, highlighting the necessity of epidemiological study in wider regions.

Detection of Severe Acute Respiratory Syndrome Coronavirus 2 RNA on Surfaces in Quarantine Rooms.

We investigated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) environmental contamination in 2 rooms of a quarantine hotel after 2 presymptomatic persons who stayed there were laboratory-confirmed as having coronavirus disease. We detected SARS-CoV-2 RNA on 8 (36%) of 22 surfaces, as well as on the pillow cover, sheet, and duvet cover.

Evaluation of scrub typhus diagnosis in China: analysis of nationwide surveillance data from 2006 to 2016.

BACKGROUND: Scrub typhus is a life-threatening disease caused by Orientia tsutsugamushi, and specific antimicrobial medicine is available. Early and accurate diagnosis is essential for reducing the risk of severe complications and death. In this study, we aimed to evaluate the case diagnosis situation among medical care institutions and geographical regions in China, and the results will benefit both clinical practice and the disease surveillance system. METHODS: We extracted individual scrub typhus case data 2006-2016 from a national disease surveillance system in China. The diagnosis category and interval time from illness onset to diagnosis were compared among three levels of medical care institutions and provinces. The descriptive analysis method was performed in our study. RESULTS: During the 11-year study period, 93 481 scrub typhus cases, including 57 deaths, were recorded in the nationwide surveillance system. The overall proportion of laboratory-confirmed cases was only 4.7%, and this proportion varied greatly among primary medical centres (2.8%), county level hospitals (4.2%), and city level hospitals (6.3%). Notably, the proportion of laboratory-confirmed cases has consistently decreased from 16.3% in 2006 to 2.6% in 2016, and the same decreasing trend was found among all three levels of medical care institutions. The interval from illness onset to case diagnosis (Tdiag) for all cases was 5 days (interquartile range [IQR]: 2-9 days) and decreased from 7 days (IQR: 3-11 days) in 2006 to 5 days (IQR: 2-8 days) in 2016. The risk of death for patients with a Tdiag of > 7 days was 2.2 times higher (OR = 2.21, 95% CI: 1.05-5.21) than that of patients with a Tdiag of < 2 days. CONCLUSIONS: The interval time from illness onset to diagnosis for scrub typhus cases decreased greatly in China; however, the diagnosis rate of cases with laboratory-confirmed results must be increased among all levels of medical care institutions to reduce both the risk of death and the misuse of antibiotics associated with scrub typhus.

The Differential Characteristics Between Severe Fever With Thrombocytopenia Syndrome and Hemorrhagic Fever With Renal Syndrome in the Endemic Regions.

An effective differentiation between severe fever with thrombocytopenia syndrome and hemorrhagic fever with renal syndrome was attained by a model considering patients' age, mouse/tick contact, presence of blush, low back pain, diarrhea, enlarged lymph nodes, and white blood cell count.

Genetic and environmental effects on the bone development of the hand and wrist in Chinese young twins.

We assessed genetic and environmental effects on bone development of the hand and wrist, and on key anthropometric measures in Chinese young twins. In total, 139 monozygotic and 95 dizygotic twin pairs aged from 5 to 18 years were recruited. The twin correlations of total hand and wrist scores for monozygotic (MZ) and dizygotic (DZ) twins were 0.71 and 0.36, respectively. Bivariate model analysis showed moderate genetic correlations only for total skeletal maturity vs. weight and total skeletal maturity vs. waist circumference (r, 0.51 and 0.46, respectively). Our findings demonstrated that genetic factors played important roles in bone development of the hand and wrist in Chinese young twins, and that these genetic effects might be distinct from those influencing anthropometric measures.

Emergency surveillance of influenza during 2009 in the Chinese city of Qingdao.

BACKGROUND: In April, 2009, a new influenza pandemic caused by a swine-origin H1N1 subtype influenza virus was imminent. We thereby carried out an emergency surveillance study in a Chinese city of Qingdao. METHODS: Pharyngeal swab samples were collected from four targeted groups and tested by reverse-transcription polymerase chain reaction. Each laboratory-confirmed pandemic H1N1 case or cluster was investigated, and the hemagglutinin genes of some of the viruses were sequenced and analyzed. RESULTS: A total of 140 pandemic H1N1 cases including 92 from 7 clusters were identified in the four targeted groups. None of them developed into severe infections. Meanwhile, 103 cases of seasonal influenza (98 H3N2 and 5 H1N1) and 10 clusters of seasonal H3N2 influenza were also identified. Among them, 38 pandemic H1N1 and two seasonal H3N2 influenza cases were air travellers, suggesting that air travel facilitates the spread of pandemic and seasonal influenza even in the northern hemisphere summer. In addition, it was found that pandemic H1N1 and seasonal H3N2 influenza viruses co-circulated in two clusters. No significant mutations were found in the hemagglutinin gene sequences of pandemic H1N1 viruses, but the seasonal H3N2 influenza viruses have become genetically distinguishable from those circulating in 2007-2008.