Objective To analyze the standby time of an intelligent rodent surveillance system and its influencing factors in Bayannur in western Inner Mongolia Autonomous Region (Inner Mongolia), China from September 2019 to December 2022, and to determine the correlation between rodent density and standby time. Methods Rodents were monitored using the intelligent internet of things terminal system VIMS 4.0. Statistical analysis was performed using Excel 2016 on the days of normal standby operation, number of rodents videoed, rodent density, standby time, and other indicators of the intelligent terminals, by different aspects (the first rodents of the same species, counties/banners, and different risk levels regions). Results A total of 231 rodents of eight species were detected by 10 effective terminal systems at three effective monitoring sites during the total effective monitoring time of 2 730 d. The top five most common species were Phodopus roborovskii, Meriones meridianus, Spermophilus alaschanicus, Cricetulus barabensis, and Mus musculus. The overall rodent density was 8.46%, and the mean activity frequency was 2.54 rodents/month·terminal system. The dominant species was P. roborovskii, which accounted for 57.58%. The standby time averaged 118.20 d, and ranged from 21 d to 329 d, mostly in 21-98 d, indicating a long standby time. The first rodents crossing the terminals involved four species. For terminals with the same species of the first rodents: in the descending order of rodent density, the top three species of the first rodents were Mu. musculus, S. alaschanicus, and Me. meridianus; in the ascending order of mean standby time, the top three species of the first rodents were Mu. musculus, S. alaschanicus, and Me. meridianus. The mean standby time of the terminals with the same species of the first rodents was moderately correlated with rodent density ( r=-0.634); the standby time was moderately correlated with rodent density in the area without definite risk levels ( r=-0.533). Conclusion This study first demonstrated a significant negative correlation between the mean standby time and rodent density in a certain space range and at a certain time scale.

Objective To investigate and analyze the epidemiological characteristics of animal plague in Siziwang banner, Ulanqab, Inner Mongolia, China from 2009 to 2019, and to provide a basis for scientific prevention and control of plague. Methods Surveillance was performed on the plague in Jiang'an sum and Honggor sum and their surrounding areas according to the Plague Monitoring Scheme of Inner Mongolia from April to November each year from 2009 to 2019. The rodent density was investigated using the trap-on-the-day method with bow-shaped clamps, nocturnal rodents were investigated using the 5-meter clamp method, and the fleas were captured by grooming. According to the diagnostic criteria for plague (WS 279-2008), etiological tests were performed on the testable materials from the rodents and fleas, and serological tests were performed on the blood samples of the rodents using indirect hemagglutination assay. Results During 2009-2019, the mean rodent density was 2.30 mice/hm ² in the plague foci of Siziwang banner, Ulanqab, with the density of Meriones unguiculatus being 1.71 mice/hm ². The capture rate of nocturnal rodents was 1.96%. The flea infestation rate of rodents was 27.37% and the total flea index was 1.55. Seventeen positive rodents and 32 positive fleas were found by the etiological tests. Sixty positive serum samples were found by the serological tests. Conclusion The epidemic of animal plague in Siziwang banner, Ulanqab is active from 2009 to 2019, with a potential new round of epidemic peak in the future. Plague surveillance should be strengthened to prevent prevalence of human plague.

Objective To evaluate the feasibility of DNA barcoding applied to the identification of flies in Fujian province, China, and to set up the nucleic acid sequence database for flies in Fujian. Methods Sixty-four fly specimens belonging to 19 species, 13 genera, and 4 families were collected from Fujian. Genomic DNA was extracted from the flies. Mitochondrial COⅠ gene was amplified by consensus primer PCR and sequenced. Sequence alignment and evolutionary divergence were performed, and a neighbor-joining phylogenetic tree was constructed based on these sequences. Results Intraspecific divergence ranged between 0-3.32%; interspecific divergence ranged between 5.26%-18.30%, except for Lucilia cuprina and Lucilia sericata, which had only 0.69% divergence from each other. The result of phylogenetic tree showed that sequences from the same species gathered closely with each other. The reliability of Bootstrap test was all above 96%. Conclusion DNA barcoding can be effectively used to identify some flies in Fujian province. It can be used as an efficient method supplementary to morphological identification.

Objective To evaluate the feasibility of DNA barcoding applied to the identification of flies in Fujian province, China, and to set up the nucleic acid sequence database for flies in Fujian. Methods Sixty-four fly specimens belonging to 19 species, 13 genera, and 4 families were collected from Fujian. Genomic DNA was extracted from the flies. Mitochondrial COⅠ gene was amplified by consensus primer PCR and sequenced. Sequence alignment and evolutionary divergence were performed, and a neighbor-joining phylogenetic tree was constructed based on these sequences. Results Intraspecific divergence ranged between 0-3.32%; interspecific divergence ranged between 5.26%-18.30%, except for Lucilia cuprina and Lucilia sericata, which had only 0.69% divergence from each other. The result of phylogenetic tree showed that sequences from the same species gathered closely with each other. The reliability of Bootstrap test was all above 96%. Conclusion DNA barcoding can be effectively used to identify some flies in Fujian province. It can be used as an efficient method supplementary to morphological identification.

Objective To determine the prevalence of hantavirus in rodents based on surveillance data in residential areas of Huludao for the formulation of preventive and control strategies in humans. Methods Rodent cages were used to capture small mammals. Lung samples of the subjects were then taken for detection of Hantavirus antigens using indirect immunofluorescence assay (IFA). Genotyping was conducted using RT-PCR. Results In 2005 and 2006, 254 Rattus norvegicus, 17 Mus musculus and 5 Apodemus agrarius were captured in nine residential areas and two wild fields in Huludao. The virus-carrying rates were 4.72% in R. norvegicus and 5.88% in M. musculus, respectively. Nine strains of Hantavirus were amplified using the RNA derived from the positive lung tissues of R. norvegicus. According to genotyping results, all were identified as Seoul virus (SEOV). A strain of SEOV was also isolated. Hantavirus was not detected from M. musculus and A. agrarius. Conclusion R. norvegicus was the primary host of Hantavirus in residential areas of Huludao and all rodent-carrying Hantavirus strains were identified as SEOV.

Objective To determine the epidemiological characteristics, long-term trend and regional typing of hemorrhagic fever with renal syndrome (HFRS) in Huludao city, which would provide the basis for development of specific control strategies. Methods Epidemiological data on HFRS in the city were retrieved from the National Noticeable Infectious Disease Reporting System for the analysis. Indirect immunofluorescence assay (IFA) was performed to identify the Hanta viral antigen in rodent lung samples for the calculation of virus-carrying rates. The hemagglutination inhibition test was adopted to serotype the serum samples collected from patients at the recovery stage. Results Remaining at a high level since 1998, the HFRS incidence sharply declined from 2006. An onset peak in spring was noticeable, while the number of cases from February to June accounted for 61.37% of the overall patients. The young and middle-age male farmers were at a high risk of contracting the disease. The rat density and virus carrying rates were high, and the SEO serotype was identified from the recovering patients’ sera samples. Conclusion Noticeable decrease of the HFRS incidence in Huludao city was attributable to large-scale vaccination. The SEO serotype was prevalent in this region, while transformation into mixed-type was not yet observed. It is essential to intensify the rodent prevention and control measures and strengthen the observation of the long-term effect of vaccination among inoculated populations. Supplementary immunization may be conducted when necessary.

Objective To assess the course of the first case of human eperythrozoonosis in Huludao city and to determine the current infection situation and influential factors in humans and animals. Methods Blood smears were examined under microscope to determine the infection in humans and animals, blood analyzers employed to detect anemia in humans. Types and density of mosquitoes were analyzed using outdoor light traps. A case-control study followed to identify the influential factors for infection. Results The overall infection rate of eperythrozoon in humans was 30.67% without noticeable significant difference between men and women or among different age groups (χ2＝1.79, P＞0.05; χ2＝1.05, P＞0.05). The infection rate of eperythrozoon in swine was 60.87%. High density of mosquitoes was detected as Aedes vexans and Culex dominated. Anemic symptoms were primarily present in younger children. An excess risk for eperythrozoon infection was noted in swine breeders 2.77 times higher than in others, and the risk in those breeding and delivering swine was 2.97 times higher than pure breeders. Conclusion High prevalence of eperythrozoonosis was found in both humans and animals in the area, children constituting the major victims. Swine were the important reservoir host, breeding swine the risk factor and mosquitoes the transmission medium.