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Emerging vector-borne pathogens (VBPs) pose a continuous background threat to the global health. Knowledge of the occurrence, distributions and epidemiological characteristics of VBP are lacking in many countries. Outbreaks of novel VBP are of increasing global interest including those arising in China.A systematic review of published literature was undertaken to characterize the spectrum of VBPs causing human illness in China. We searched five databases for VBP-related articles in English and Chinese published between January 1980 and June 2021, that excluded those listed in the National Notifiable Diseases Surveillance System of China. The study is registered with PROSPERO, CRD42021259540.A total of 906 articles meeting the selection criteria were included in this study. A total of 44,809 human infections with 82 species of VBPs including 40 viruses, 33 bacteria (20 Rickettsiales bacteria, eight Spirochaetales bacteria, and five other bacteria) and nine parasites, were identified in China. Rickettsiales bacteria were the most common and widely distributed pathogens with 18,042 cases reported in 33 provinces by 347 reviewed articles, followed by Spirochaetales bacteria with 15,745 cases in 32 provinces (299 articles), viruses with 8455 cases in 30 provinces (139 articles), other bacteria with 2053 cases in 19 provinces (65 articles), parasites with 514 cases in 17 provinces (44 articles), and multiple pathogens with 3626 cases in 14 provinces (23 articles).This review helps improve the understanding of VBPs in China, demonstrating the need to consider a wider surveillance of VBPs in many different settings, thus helping to inform future research and surveillance efforts.Natural Science Foundation of China.

An in vivo animal model of bone adaptation was used to examine a possible role for matrix metalloproteinase-1 in the local mediation of bone remodeling: to corrode the coupling of osteocytes to the matrix in an attempt to autoregulate the cell's perception of its mechanical environment. Twelve young (12-16 months old) skeletally mature turkeys were separated into groups to be studied for stimulus periods of either 3 or 30 days. In each animal, the left ulna was functionally isolated and subjected to either disuse or 3,000 microstrain at 1 Hz for 10 minutes per day. The right ulna remained intact and served as an intra-animal control. No significant differences in bone area were detected at 3 days; however, ulnae subjected to disuse lost 8 +/- 4% (+/-SD) of bone area by 30 days. Over the same period, ulnae subjected to the mechanical stimulus gained 21 +/- 9% of bone area. With use of in situ reverse transcription-polymerase chain reaction, less than 2% of the osteocytes examined from the intact control ulnae stained positively for matrix metalloproteinase-1 mRNA. An antibody raised against matrix metalloproteinase-1 revealed no positively labeled osteocytes in the intact ulnae. This low percentage of osteocytes expressing matrix metalloproteinase-1 mRNA was similar to that seen in ulnae subjected to the osteogenic mechanical stimuli. In contrast, ulnae subjected to either 3 or 30 days of disuse showed evidence of matrix metalloproteinase-1 mRNA activity in a high percentage of osteocytes (89 +/- 5 and 66 +/- 8%, respectively; each time point significantly different from intact ulnae, as well as from each other, p < 0.05). The percentage of osteocytes labeled with the anti-matrix metalloproteinase-1 antibody was also highly elevated following 3 days of disuse (74 +/- 17%). These data demonstrate that an early response of bone to disuse is the upregulation of matrix metalloproteinase-1 activity in osteocytes. It is proposed that this upregulation of collagenase activity is indicative of the cell's degradation of coupling to the matrix, and it thus reflects the osteocyte's regulation of its own mechanical environment. We believe that such autoregulation of the osteocyte's physical environment will accommodate subtle changes in the bone's functional environment without the need to add or resorb bone tissue.

Reverse transcript polymerase chain reaction (RT-PCR) was developed for use in situ to measure mechanically mediated changes in gene expression activity in osteocytes within dense cortical bone. Using the functionally isolated turkey ulna model of bone adaptation, the left ulna of 6 old adult (36-40 months) male turkeys were subject to 4 weeks of a mechanical regimen consisting either of (1) 3000 microstrain at 1 Hz for 5 minutes/day or (2) 500 microstrain at 30 Hz for 10 minutes/day. The right ulna of each bird remained intact and served as control. Only a small percentage of osteocytes in the intact control bones and the 3000 microstrain ulnae showed any evidence of mRNA for collagen (each 1.2% +/- 0.3%). However, mRNA for collagen type I was strongly evident in 92.4% (+/-2%) of the osteocytes within the ulnae subject to the high frequency, low magnitude load. Sense primer control sections from both experimental and intact animals were used to verify that only osteocytes of the loaded bone had elevated the level of collagen mRNA. This high frequency, low magnitude mechanical stimulus was also sufficient to stimulate substantial new bone formation (14% +/- 5% over intact controls), whereas the low frequency, high magnitude stimulus failed to elicit any bone formation (-3% +/- 7%). These experiments show that specific mechanical regimens can activate the osteocyte's expression of a message responsible for the synthesis of proteins remote from the site where the formation of bone is ultimately to occur, even under systemic distress such as aging. Further, these data suggest that osteocytes perceive the strain environment and that they play a role in orchestrating the modeling/remodeling response. By developing a technique as flexible and powerful as RT-PCR for use in dense cortical bone, determining the relative contribution of specific proteins to the transduction of regulatory signals to formative or resorptive responses is facilitated.