Ticks are widely distributed in pastoral areas in northwestern China and act as vectors that carry and transmit a variety of pathogens, especially viruses. Our study revealed the diversity of tick viruses in Xinjiang and Inner Mongolia and uncovered the phylogenetic relationships of some RNA viruses, especially the important zoonotic tick-borne severe fever with thrombocytopenia syndrome virus in Inner Mongolia.

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne arbovirus that can cause bleeding and death in humans. The mortality rate in humans is between 5 and 30%. The pathogen is prevalent in more than 30 countries in the world. In China, the CCHFV has been reported in Xinjiang province but not in Inner Mongolia province yet. In this report, we phylogenetically analyzed a new CCHFV strain, HANM-18, identified from Hyalomma asiaticum and Hyalomma dromedarii collected in Alxa Left Banner and Alxa Right Banner of Inner Mongolia, China. Complete sequences of CCHFV were obtained by the nested PCR technique and used for phylogenetic analysis of the identity and evolutionary relationship with other CCHFV strains. Our results showed that the S and L fragments of the HANM-18 strain had a high percentage of identity with strains in Xinjiang, China. The M fragment was significantly homologous to South African isolates. In addition, these data also indicate that the HANM-18 strain may have been prevalent in northwestern Inner Mongolia for many years. This discovery will be helpful in CCHF prevention and control in Inner Mongolia, and it also adds new evidence to the epidemiology of CCHF in China.

The objective of this study was to develop an indirect ELISA utilizing a polyclonal antibody against bovine rotavirus (BRV) VP6 protein. To achieve this, pcDNA3.1-VP6, a recombinant eukaryotic expression plasmid, was constructed based on the sequence of the conserved BRV gene VP6 and was transfected into CHO-K1 cells using the transient transfection method. The VP6 protein was purified as the coating antigen using nickel ion affinity chromatography, and an indirect ELISA was subsequently established. The study found that the optimal concentration of coating for the VP6 protein was 1 μg/mL. The optimal blocking solution was 3% skim milk, and the blocking time was 120 min. The secondary antibody was diluted to 1:4000, and the incubation time for the secondary antibody was 30 min. A positive result was indicated when the serum OD450 was greater than or equal to 0.357. The coefficients of variation were less than 10% both within and between batches, indicating the good reproducibility of the method. The study found that the test result was positive when the serum dilution was 2¹⁷, indicating the high sensitivity of the method. A total of 24 positive sera and 40 negative sera were tested using the well-established ELISA. The study also established an indirect ELISA assay with good specificity and sensitivity for the detection of antibodies to bovine rotavirus. Overall, the results suggest that the indirect ELISA method developed in this study is an effective test for detecting such antibodies.

Crimean-Congo hemorrhagic fever (CCHF) is a highly lethal infectious disease in humans caused by tick-borne Crimean-Congo hemorrhagic fever virus (CCHFV). To determine the potential risk of CCHF in the pastoral area of Northwestern China, the presence of antibody to CCHFV in the sera of two most common tick hosts, sheep and camels, in Inner Mongolia of China was evaluated. The purified recombinant nucleocapsid protein (NP) of CCHFV was prepared from a prokaryotic vector expressing the NP encoding gene, which was employed as the antigen to probe antibody against CCHFV in tick vectors using an immunoblotting assay. In total, 58.3% (35/60) and 54% (12/22) of camels were positive of antibody to CCHFV in sera at Alxa Youqi County and Ulan Hudu Gacha Village of Inner Mongolia Province, respectively. However, only 6.7% (2/30) of sera of sheep were determined positive in antibody to CCHFV in the Wulan Hudug check area in this study. Consequently, these results indicate that 54–58.3% camels were infected by CCHFV after exposure to tick bites in Inner Mongolia, which was significantly higher than 6.7% of infection in the sheep in this area, suggesting there is a certain relationship between the serological reactivity and exposure time to ticks, range of activity, living behaviors, and breeding time. Further intensive surveillance of livestock and exposed population is required to better understand the spread of CCHFV in this area.

To analyze the epidemiological transmission characteristics and spatiotemporal distribution patterns of the elderly HIV-1/AIDS population in NHAR from 2018 to 2023, to provide theoretical support for the targeted formulation and implementation of HIV-1 interventions. A cross-sectional study was conducted in August 2024. Plasma samples were collected from the elderly HIV-1/AIDS patients (> 50 years old) in NHAR, followed by RNA extraction and RT-PCR to amplify the pol gene of HIV-1. The amplicons were sequenced for the partial pol region. Subtyping was performed using online tools from the HIV-1 database and MEGA11. Drug resistance was analyzed using the Stanford University HIVdb algorithm. Molecular transmission networks were constructed using Cytoscape 3.10.0. Logistic regression was performed to identify the potential risk factors. Spatial analysis revealed the geographic patterns of elderly HIV-1/AIDS patients. A total of 208 HIV-1/AIDS patients were included in this study, predominantly male (78.37%), primary school and below (46.63%), heterosexual transmission (80.77%) and farmers (52.40%). Nine genetic subtypes were identified, with CRF07_BC being the most common (54.81%). The overall drug resistance rate was 37.98%. The number of network nodes increased from 18 in 2018 to 107 in 2023, with large propagating clusters in 2023 merging or expanding from smaller clusters in previous years. Logistic regression analysis showed that males had a lower risk of transmission, individuals from Yinchuan, Shizuishan, and Wuzhong had a lower probability of entering the network, and CRF07_BC and CRF01_AE had a higher risk of transmission. From 2020 to 2023, there was a highly significant clustering pattern among elderly HIV/AIDS patients in NHAR, with shifts in hotspots. Yuanzhou District remained a persistent cold spot. This study reveals that the elderly HIV-1/AIDS patients in NHAR were predominantly married, male, and engaged in farming, with low levels of education. An increase in the diversity of viral genetic subtypes was observed, along with a high rate of drug resistance. The molecular network expanded significantly, accompanied by the emergence of large transmission clusters, indicating complex transmission patterns. The spatial distribution of these cases exhibited aggregation, with notable differences observed between districts and counties. To effectively intervene in the transmission of HIV-1 among the elderly population, it is essential to establish a long-term dynamic molecular transmission surveillance network and to improve AIDS screening and drug resistance testing.

Bovine viral diarrhea virus (BVDV) is considered to be the most common agent of severe diarrhea in cattle worldwide, causing fever, diarrhea, ulcers, and abortion. Bovine herpesvirus 1 (BoHV-1) is also a major bovine respiratory disease agent that spreads worldwide and causes extensive damage to the livestock industry. Recombinase polymerase amplification (RPA) is a novel nucleic acid amplification method with the advantages of high efficiency, rapidity and sensitivity, which has been widely used in the diagnosis of infectious diseases. A dual RPA assay was developed for the simultaneous detection of BVDV and BoHV-1. The assay was completed at a constant temperature of 37 °C for 30 min. It was highly sensitive and had no cross-reactivity with other common bovine viruses. The detection rate of BVDV RPA in clinical samples (36.67%) was higher than that of PCR (33.33%), the detection rate of BoHV-1 RPA and PCR were equal. Therefore, the established dual RPA assay for BVDV and BoHV-1 could be a potential candidate for use as an immediate diagnostic.