The role of Xpert MTB/RIF using bronchoalveolar lavage fluid in active screening: insights from a tuberculosis outbreak in a junior school in eastern China.

Background: Tuberculosis (TB) outbreaks in schools present a public health challenge. In order to effectively control the spread of transmission, timely screening, accurate diagnosis and comprehensive epidemiological investigations are essential. Methods: In July 2021, a TB outbreak occurred in a junior high school in Y City, Zhejiang Province. Students and faculty were screened for TB by symptom screening, chest radiography, and tuberculin skin test during four rounds of contact screenings. For sputum smear-negative and sputum-scarce patients, bronchoscopy was used to collect BAL samples for Xpert Mycobacterium tuberculosis/rifampin (MTB/RIF). Whole-genome sequencing and bioinformatics analysis were performed on isolates to identify the strains of MTB isolates and predict drug resistance. Results: Between July 2021 and November 2021, a total of 1,257 students and faculty were screened for TB during screenings. A total of 15 students (1.2% of persons screened) aged 15 years were diagnosed with TB. Eighty percent (12/15) of the cases were laboratory-confirmed (10/12 [83%] Xpert MTB/RIF-positive, 2/12 [17%] culture-positive). Most cases (12/15 [80%]) were in students from Class 2. All cases were asymptomatic except for the index case who had symptoms for more than two months. Seven MTB isolates were collected and belonged to lineage 2. Conclusion: Our findings demonstrated the potential of Xpert MTB/RIF using BAL as a screening tool in school TB outbreaks for sputum smear-negative and sputum-sparse suspects, which may not only rapidly improves diagnostic accuracy, but also facilitates epidemiological investigations and homology analysis.

Serological and molecular epidemiology of Japanese Encephalitis in Zhejiang, China, 2015-2018.

BACKGROUND: Shifts have occurred in the epidemiological characteristics of Japanese encephalitis (JE), extending from the molecular level to the population level. The aim of this study was to investigate the seroprevalence of JE neutralizing antibodies in healthy populations from different age groups in Zhejiang Province, and to conduct mosquito monitoring to evaluate the infection rate of Japanese encephalitis virus (JEV) among vectors, as well as the molecular characteristics of the E gene of isolated JEV strains. METHODOLOGY/PRINCIPAL FINDINGS: A total of 1190 sera samples were screened by a microseroneutralization test, including 429 infants (28d-11m) and 761 participants (2y-82y). For those under 1 year old, the geometric mean titers (GMTs) of the JE neutralizing antibody was 9.49 at birth and significantly declined as the age of month increased (r = -0.225, P<0.001). For those above 1-year old, seropositive proportions were higher in subjects aged 1-3 years old as well as ≥25 years old (65%-75%), and relatively lower in subjects aged between 4-25 years old (22%-55%). Four or more years after the 2nd dose of JEV-L (first dose administered at 8 months and the second at 2 years of age), the seropositive proportion decreased to 32.5%, and GMTs decreased to 8.08. A total of 87,201 mosquitoes were collected from livestock sheds in 6 surveillance sites during 2015-2018, from which 139 E gene sequences were successfully amplified. The annual infection rate according to bias-corrected maximum likelihood estimation of JEV in Culex tritaeniorhynchus was 1.56, 2.36, 5.65 and 1.77 per 1000, respectively. JEV strains isolated during 2015-2018 all belonged to Genotype I. The E gene of amplified 139 samples differed from the JEV-L vaccine strain at fourteen amino acid residues, including the eight key residues related to virulence and virus attenuation. No divergence was observed at the sites related to antigenicity. CONCLUSIONS/SIGNIFICANCE: Zhejiang Province was at a high risk of JE exposure due to relatively lower neutralizing antibody levels among the younger-aged population and higher infection rates of JEV in mosquitoes. Continuous, timely and full coverage of JE vaccination are essential, as well as the separation of human living areas and livestock shed areas. In addition, annual mosquito surveillance and periodic antibody level monitoring are important for providing evidence for improvement in JE vaccines and immunization schedules.

Patient with severe fever with thrombocytopenia syndrome virus infection and central nervous system disturbance in Dongyang, Zhejiang Province, China, 2017.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging hemorrhagic fever that was first described in China in 2011. We report a patient who died of Severe fever with thrombocytopenia syndrome virus (SFTSV) infection, with a rapidly progressive central nervous system (CNS) disturbance, in Dongyang, Zhejiang Province, China, in 2017. CASE PRESENTATION: A 64-year-old man was admitted to hospital after 4 days of fever. SFTSV was detected 1 day after the patient was admitted to hospital. The patient presented with CNS disturbance and died 4 days after admission. Detailed clinical and epidemiological investigations and laboratory tests were conducted. Reduced platelet, white blood cell, lymphocyte, and neutrophil counts, elevated lactate dehydrogenase, creatine kinase, aspartate aminotransferaseand alanine aminotransferase concentrations, and an increased activated partial thromboplastin time were observed. In a phylogenetic analysis, the isolate clustered close to a strain derived from South Korea. CONCLUSIONS: This is the first case of SFTSV infection with CNS disturbance in Dongyang, Zhejiang Province, China. The surveillance of suspected cases of SFTS is important in SFTSV endemic regions.

Programmed cell death-involved aluminum toxicity in yeast alleviated by antiapoptotic members with decreased calcium signals.

The molecular mechanisms of aluminum (Al) toxicity and tolerance in plants have been the focus of ongoing research in the area of stress phytophysiology. Recent studies have described Al-induced apoptosis-like cell death in plant and animal cells. In this study, we show that yeast (Saccharomyces cerevisiae) exposed to low effective concentrations of Al for short times undergoes enhanced cell division in a manner that is dose and cell density dependent. At higher concentrations of Al or longer exposure times, Al induces cell death and growth inhibition. Several apoptotic features appear during Al treatment, including cell shrinkage, vacuolation, chromatin marginalization, nuclear fragmentation, DNA degradation, and DNA strand breaks, as well as concomitant cell aggregation. Yeast strains expressing Ced-9, Bcl-2, and PpBI-1 (a plant Bax inhibitor-1 isolated from Phyllostachys praecox), respectively, display more resistance to Al toxicity compared with control cells. Data from flow cytometric studies show these three antiapoptotic members do not affect reactive oxygen species levels, but decrease calcium ion (Ca(2+)) signals in response to Al stress, although both intracellular reactive oxygen species and Ca(2+) levels were increased. The data presented suggest that manipulation of the negative regulation process of programmed cell death may provide a novel mechanism for conferring Al tolerance.