In this research, fifteen carbamate pesticide residues were systematically analyzed by ultra-high performance liquid chromatography–quadrupole-linear ion trap mass spectrometry on a QTRAP 5500 system in both multiple reaction monitoring (MRM) and enhanced product ion (EPI) scan modes. The carbamate pesticide residues were extracted from a variety of samples by QuEChERS method and separated by a popular reverse phase column (Waters BEH C18). Except for the current conformation criteria including selected ion pairs, retention time and relative intensities from MRM scan mode, the presence of carbamate pesticide residues in diverse samples, especially some doubtful cases, could also be confirmed by the matching of carbamate pesticide spectra via EPI scan mode. Moreover, the fragmentation routes of fifteen carbamates were firstly explained based on the mass spectra obtained by a QTRAP system; the characteristic fragment ion from a neutral loss of CH₃NCO (−57 Da) could be observed. The limits of detection and quantification for fifteen carbamates were 0.2–2.0 μg kg⁻¹ and 0.5–5.0 μg kg⁻¹, respectively. For the intra- (n = 3) and inter-day (n = 15) precisions, the recoveries of fifteen carbamates from spiked samples ranged from 88.1% to 118.4%, and the coefficients of variation (CVs) were all below 10%. The method was applied to pesticide residues detection in fruit, vegetable and green tea samples taken from local markets, in which carbamates were extensively detected but all below the standard of maximum residue limit.

A simple, rapid, and efficient liquid chromatography tandem mass spectrometry (LC–MS/MS) method, operated in electrospray ionization and quadrupole linear ion trap modes, has been developed for the identification and structural characterization of aflatoxins in peanuts and its derivative products or bean sauce. Samples (5 g) were extracted with acetonitrile/water/formic acid (79:20:1, v/v). After centrifugation and dilution, the extracts were separated on a C18 analytical column by gradient elution (acetonitrile/0.2% formic acid) and analyzed by UPLC–MS/MS. External calibration was used for qualification. The developed multiple reaction monitoring–information-dependent acquisition–enhanced product ion method enabled quantification and confirmation of the analytes in a single run. Enhanced product ion mode was used for qualitative analysis, while multiple reaction monitoring mode was used for quantitative analysis. An in-house library was constructed for identification. Calibration curves showed good linearity with correlation coefficients (r) higher than 0.994. Limits of detection were determined to be below 0.26 µg kg⁻¹ for most analytes. The recoveries for those substances were in the acceptable range of 80.2%–119.1%. A new LC–MS³ method was established for further confirmation. One pickled pepper peanut was found to contain aflatoxins B1, B2, and G1 with contents of 90.93, 26.64, and 1.92 µg kg⁻¹, respectively.

Mpox, a zoonotic disease caused by the mpox virus (MPXV), has seen a significant shift in its epidemiological status since 2022, evolving from an initial local outbreak to a global epidemic. This recent outbreak of MPXV mainly emerged in several European and American countries and subsequently spread to over 100 countries and regions worldwide. The rapid evolution of MPXV, coupled with increased international interactions, has led to a gradual rise in mpox cases in certain regions of Asia, mostly involving MPXV clade II and its branch strains. In contrast, the more pathogenic and clinically severe MPXV clade Ib has been relatively rare, with no reports in China to date. Here, we analyzed the whole gene sequence of imported MPXV clade Ib variant from the first infection case detected in China. Through whole genome sequencing, we successfully obtained a full-length MPXV genome of 195,405 base pairs (bp). Phylogenetic analysis revealed that the genetic sequence of the MPXV in this case was predominantly clustered with MPXV clade Ib sequences previously reported from multiple African and European countries. Compared with the MPXV clade Ib reference strain DQ011155.1, there are 127 nucleotide alterations and 57 amino acid mutations in the MPXV genome of this case. Given that the MPXV clade Ib has started to appear in China, we must pay more attention to the prevention of and control measures for the spread of mpox.

In 2023, one case of coinfection with type I and type II dengue virus of imported origin was first reported in Jiaxing city. Therefore, we analysed the results of the molecular tracing analysis of this case. We collected serum samples for whole-genome amplification and sequencing and further analysed the whole-genome sequence for homology analysis, evolutionary tree analysis, and protein amino acid mutation site analysis. The results revealed that the JX202301 DENV-1 sequence had the highest homology with the epidemic strains in Guangdong (PP563909, PP563875, PP563840, and PP563879) in 2023, with nucleotide homology ranging from 99.5 to 99.8% and amino acid homology of 100%. The JX202301 DENV-2 sequence had the highest homology with the epidemic strains of 2019 Thailand (MZ636805, MZ636802, MZ636803, MW512454, and MW512419), with nucleotide homology ranging from 98.4 to 99.2% and amino acid homology of 99.7%. By analysing the amino acid mutation sites, we found that, compared with the corresponding reference strains and the epidemic strains in the same branch, there were 52 amino acid difference sites in the viral coding region of the DENV-1 sequence and 51 amino acid difference sites in the viral coding region of the DENV-2 sequence, which were mainly concentrated in the NS1 and NS5 region of the nonstructural proteins. In this study, we described for the first time the genome-wide sequence, genetic variation, and phylogenetic analysis of imported DENV-1 and DENV-2 mixed cases in Jiaxing city. These results provide a scientific basis for dengue fever outbreak surveillance, viral evolution studies, and prevention and control strategy development in Jiaxing city.

The analysis of the molecular epidemiological characteristics of newly diagnosed HIV-infected patients in Jiaxing City is essential for developing effective HIV prevention. Blood samples were collected from newly diagnosed HIV-infected individuals in Jiaxing City from October 2022 to October 2023, and the HIV-1 pol region gene was amplified and sequenced. These sequences were used to construct a molecular transmission network and analyse transmitted drug resistance mutations. We identified 11 subtypes, of which CRF07_BC and CRF01_AE were the most prevalent. The rate of surveillance drug resistance mutation (SDRM) sites in newly diagnosed cases was 9%. A total of 37 molecular transmission clusters were identified, the largest of which was the CRF07_BC-1 cluster (13 nodes). This cluster has five probable high-risk transmitters. Two additional larger clusters in the molecular network were the heterosexual transmission clusters for middle-aged and older males, CRF08_BC-1 (eight nodes) and CRF85_BC-1 (eight nodes). The mean degree of the two clusters was high, and the patients were high-risk transmitters, indicating a higher risk of HIV transmission. The distribution of HIV-1 subtypes in Jiaxing City was widespread, with moderate levels of transmission resistance. Larger molecule clusters carry a high risk of transmission, indicating that we should strengthen monitoring and intervention.