First detection of multiple cases related to CV-A16 strain of B1c clade in Beijing in 2022.

Coxsackievirus A16 (CV-A16) is a significant etiologic agent of hand, foot, and mouth disease (HFMD) and herpangina (HA), with the capacity to progress to severe complications, including encephalitis, aseptic meningitis, acute flaccid paralysis, myocarditis, and other critical conditions. Beijing's epidemiological surveillance system, established in 2008, encompasses 29 hospitals and 16 district disease control centers. From 2019 to 2021, the circulation of CV-A16 was characterized by the co-circulation of B1a and B1b clades. Multiple cases of HFMD linked to clade B1c has not been reported in Beijing until 2022. This study enrolled 400 HFMD and 493 HA cases. Employing real-time RT-PCR, 368 enterovirus-positive cases were identified, with 180 selected for sequencing. CV-A16 was detected in 18.89% (34/180) of the cases, second only to CV-A6, identified in 63.33% (114/180). Full-length VP1 gene sequences were successfully amplified and sequenced in 22 cases, revealing the presence of clades B1a, B1b, and B1c in 14, 3, and 5 cases, respectively. A cluster of five B1c clade cases occurred between June 29 and July 17, 2022, within a 7-km diameter region in Shunyi District. Phylogenetic analysis of five complete VP1 gene sequences and two full-genome sequences revealed close clustering with the 2018 Indian strain (GenBank accession: MH780757.1) within the B1c India branch, with NCBI BLAST results showing over 98% similarity. Comparative sequence analysis identified three unique amino acid variations (P3S, V25A, and I235V). The 2022 Shunyi District HFMD cases represent the first instances of spatiotemporally correlated CV-A16 B1c clade infections in Beijing, underscoring the necessity for heightened surveillance of B1c clade CV-A16 in HFMD and HA in this region.

The first reported cases of severe fever with thrombocytopenia syndrome virus from domestic sick camel to humans in China.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne disease with an increasing annual incidence rate. In this case report, we presented two patients infected with the SFTS virus, suggesting a potential direct transmission route from camels to humans through blood contact. Both patients developed symptoms after engaging in the slaughtering of one sick camel, while their family members living in the same environment or co-diners remained unaffected. Subsequent detection revealed a high viral load of SFTS virus, reaching 1010 viral RNA copies/ml, in the sample obtained from the sick camel. Metagenomic sequencing did not identify any other pathogens. The SFTS virus was successfully isolated from both patient and camel samples. The complete nucleotide sequences obtained from the infected patients demonstrated a remarkable 100% similarity to those found in the camel, and genetic evolution analysis classified the virus as genotype A. Additionally, partial sequences of the SFTS virus were identified in ticks captured from the camel rearing environment, however, these sequences showed only 95.9% similarity to those found in camel and humans. Furthermore, immunoglobulin M and immunoglobulin G antibodies were detected in serum samples collected from the patient. Our findings provide evidence that camel may serve as a competent reservoir for transmitting the SFTS virus to humans. Further in vitro investigations into SFTS virus infections in large animals are warranted to understand their role in viral maintenance and transmission.

Clinical, epidemiological, and virological features of Mpox in Beijing, China - May 31-June 21, 2023.

The first locally acquired case in the Chinese mainland was reported on May 31, 2023, lagging behind other countries. In this study, we aimed to examine the early clinical and epidemiological characteristics of the earliest cases of Mpox in Beijing, China. Additionally, we investigated the sequence and transmission patterns of the Mpox virus (MPXV). We analyzed 37 reported cases of Mpox in Beijing from May 31, 2023 to June 21, 2023. The age range of the subjects was 24-51 years. Thirty-six cases (97.3%) were identified in men who have sex with men (MSM), and 19 cases (51.4%) tested positive for the human immunodeficiency virus. Thirty-three cases were symptomatic, while four were asymptomatic. Skin lesions were observed in 32 cases (97.0%), fever in 26 (78.8%), and swollen lymph nodes in 17 (51.5%). Rash typically appeared in the genital or perianal area 1-3 days before fever onset, with a minimum incubation period of 2 days. For individuals with skin rashes, the skin lesion samples showed 100% positivity and low Ct values. There were high oropharyngeal swab (75.8%) and blood (84.6%) positivity rates. All MPXV strains belonged to the B.1.3 branch of the West African lineage. These strains carried 76-86 nucleotide substitutions compared with the reference human MPXV genome, and genetic diversity was observed. Our findings provide the first insights into the landscape of early transmission of Mpox in Beijing and help inform policy formulation in the Chinese mainland.

Continuous evolution and emerging lineage of seasonal human coronaviruses: A multicenter surveillance study.

The seasonal human coronaviruses (HCoVs) have zoonotic origins, repeated infections, and global transmission. The objectives of this study are to elaborate the epidemiological and evolutionary characteristics of HCoVs from patients with acute respiratory illness. We conducted a multicenter surveillance at 36 sentinel hospitals of Beijing Metropolis, China, during 2016-2019. Patients with influenza-like illness (ILI) and severe acute respiratory infection (SARI) were included, and submitted respiratory samples for screening HCoVs by multiplex real-time reverse transcription-polymerase chain reaction assays. All the positive samples were used for metatranscriptomic sequencing to get whole genomes of HCoVs for genetical and evolutionary analyses. Totally, 321 of 15 677 patients with ILI or SARI were found to be positive for HCoVs, with an infection rate of 2.0% (95% confidence interval, 1.8%-2.3%). HCoV-229E, HCoV-NL63, HCoV-OC43, and HCoV-HKU1 infections accounted for 18.7%, 38.3%, 40.5%, and 2.5%, respectively. In comparison to ILI cases, SARI cases were significantly older, more likely caused by HCoV-229E and HCoV-OC43, and more often co-infected with other respiratory pathogens. A total of 179 full genome sequences of HCoVs were obtained from 321 positive patients. The phylogenetical analyses revealed that HCoV-229E, HCoV-NL63 and HCoV-OC43 continuously yielded novel lineages, respectively. The nonsynonymous to synonymous ratio of all key genes in each HCoV was less than one, indicating that all four HCoVs were under negative selection pressure. Multiple substitution modes were observed in spike glycoprotein among the four HCoVs. Our findings highlight the importance of enhancing surveillance on HCoVs, and imply that more variants might occur in the future.

Study on age-dependent pre-existing 2009 pandemic influenza virus T and B cell responses from Chinese population.

BACKGROUND: The outbreak of the 2009 H1N1 influenza pandemic (H1N1pdm) affected thousands of people in Mexico and the United States, and spread rapidly throughout the world from April 2009 to July 2010. To explore the age-specific prevalence of seroprotection against H1N1pdm infection, we estimated pre-existing humoral and cellular immunities of residents in Northern China against H1N1pdm and seasonal H1N1 virus in an age-dependent manner. METHODS: Anonymous serum samples were collected from 1425 to 1434 adult healthy individuals before and after the pandemic outbreak, and then grouped by birth year 1913-1990. The antibody titers of H1N1pdm and seasonal H1N1 were determined using microneutralization (MN) assays, and the proportion of seropositive was estimated based on the year of birth. Separately, another 63 blood samples were collected in 2006 and prepared for analysis of virus specific memory B and IFN-γ+ T cells using the ELISpot assays. RESULTS: The prevalence of pre-existing H1N1pdm-specific sero-antibodies in the elderly population (>60 years old) was 7.8%. The younger group, aged 19 to 60 years, exhibited a significant increase in seropositivity for H1N1pdm after the pandemic (4.9% before pandemic and 18.9% after pandemic, p < 0.05). The prevalence of H1N1pdm specific MBCs before the pandemic in the elderly (>60 years) and younger populations (<60 years) was 38% (8/21) and 48% (20/42), respectively (p = 0.6). The IFN-γ+ T cell responses to the pandemic and seasonal viruses were significantly lower in the elder group than those in the younger group (<60 years) (p < 0.05). CONCLUSIONS: Pre-existing serum antibodies and memory B cells against H1N1pdm were low in all age group, whereas diminished memory T cell responses to this virus were observed in the elderly population both before and after the pandemic.

[Studies on prevalence and control of several common chronic diseases among Beijing adults in 2005].

OBJECTIVE: To understand the prevalence and control of several common chronic disease in Beijing adults. METHODS: 16,658 adult residents were randomly selected with stratified multi-stage cluster sampling method. Each participant was invited to receive a set of standardized questionnaire, physical examinations and laboratory tests. RESULTS: Data showed that the prevalence, awareness, treatment and the rate of control on hypertension among the adults in Beijing were 29.1%, 49.3%, 42.3% and 10.6% respectively. The counterparts of diabetes mellitus were 8.8%, 56.7%, 50.0% and 15.0%. The four corresponding figures for dyslipidemia were 33.2%, 31.1%, 13.0% and 4.3%, respectively. 22.9% of the Beijing adults had metabolic syndrome including 8.1 per thousand suffering from myocardial infarction and 18.4 per thousand from stroke. Except for diabetes, all the chronic diseases had higher prevalence rate in rural area than in urban area, according to the findings under our study. Postmenopausal women were more susceptible to chronic disease than men. CONCLUSION: The prevalence rate of chronic disease in Beijing was still high. The prevalence rate in rural area had exceeded the level in urban area. Adjustment and attention should be made according to the prevalence features and weakness existed in present chronic disease control strategy.

[Nutrition and health status of the Beijing residents].

OBJECTIVE: To investigate the constitution and health status of the Beijing residents, and the primary influencing factors on nutrition and health, as to finding out the epidemiological characters and the changing trend of chronic diseases and to establish scientific basis for the establishment of public health and disease prevention policies of Beijing. METHODS: A stratified multi-stage cluster randomly sampling method was used. In total, 18 districts were surveyed, and among them, 9 were conducted dietary survey. The investigation was based on household, and all family members were surveyed at their home. After having got the compliance from the family members, question asking, medical examination, laboratory test and dietary investigation were carried out in these people. RESULTS: The incidence rate of hypertension was 25.0% for the resident > or = 15 year-old, and over 50% for middle-aged and elderly people (> or = 45 years old). The incidence of diabetes for those not younger than 15 years old was 7.7%. The over-weight rate and the obesity rate for adults were 35.1% and 20.6%, respectively. CONCLUSION: The following risk factors of chronic disease, such as unreasonable diet pattern, deficient intake of some micronutrients, over-weight and obesity, lack of physical examination, smoking and over-drinking, should be the important factors influencing the health of Beijing residents severely.

[Re-survey on epidemiological history of 1 091 probable cases with severe acute respiratory syndrome in Beijing].

OBJECTIVE: To know their real epidemiological histories in 1,091 probale cases of severe acute respiratory syndrome (SARS) without definite history of contact with SARS patients in the first survey. METHODS: All the probable SARS cases until June 9, 2003 without definite history of contact with SARS patients in the first epidemiological survey were included in a re-survey with questionnaire. The second survey was carried out during June 9 to 30, 2003. RESULTS: The results showed that history of contact with other SARS patients was obtained in 15.9% of 1 091 probale SRAS cases in the second survey, transmission of SARS to others was found in 10.5% of them, and source of infection in hospital was found in 46.5%. Comprehensive judgement based on epidemiological history showed that probale history of contact with SARS patients could be found in 72.9% of 1,091 probale cases of SARS in the second survey. CONCLUSION: Source of infection could be found through additional survey in part of probale cases of SARS without it in initial epidemiological survey.