| Objective:The purpose of this study was to investigate the species distribution,dominance,common species and diversity patterns of small animals in the border areas of the natural plague foci in Yunnan province at different latitudes,altitude gradients,indoor and outdoor,and at different latitudes.In order to find out the existence and distribution of Francisella tularesis in Yunnan,the infection status of Francisella tularesis was investigated by molecular epidemiological test.Methods:A total of 36 sampling sites in 9 districts were selected to conduct small-scale animal sampling in the border area of the natural plague foci of house rat in Yunnan province and in Moxi Town,Bamo City,Kachin State,the Republic of Myanmar.According to latitude,terrain,altitude,and other environmental conditions,it is divided into high and low latitude areas,indoor and outdoor areas,domestic and abroad areas,and four elevation zones,using community ecological indicators to analyze their community structure,diversity,and other indicators.DNA extraction was performed on the collected small animal viscera specimens in the P2+ biosafety laboratory under strict sterile experimental conditions.First,nested PCR technology was used to amplify the Fop A gene of Francisella tularensis.Then,the positive material was verified again using the TUL-4 gene and the 16 S r RNA gene.Finally,the positive PCR product will be sent to the biotech company for sequencing,and then use the results to build an evolutionary tree and analyze it.Results:1.In the 37 sampling sites in 5 prefectures(cities),8 counties(cities)and 16townships(towns)in the natural plague foci of house rat in Yunnan province and 9overseas sampling sites in Moxi Town,Bamo City,Kachin state,republic of Myanmar,16,753 tools were laid,and 1,139 small animal specimens were captured,belonging to 3orders,4 families,11 genera and 20 species(subspecies),with a total capture rate of5.99%.The Rattus flacipectus is the dominant species in this area,and its composition proportion is as high as 77.44%,which is in an absolute dominant position.2.A total of 9,672 rat cages were placed indoors,and 332 small animal specimens were captured,belonging to 3 orders,3 families,7 genera and 8 species(subspecies),with a total capture rate of 4.76%.A total of 9781 rat traps were placed outdoors,and807 small animal specimens were captured,belonging to 20 species(subspecies)of 3orders,4 families,11 genera,with a total capture rate of 6.87%.Among them,the capture rate of Rattus flacipectus was the highest,reaching 4.11%,accounting for65.80%.In comparison with the community ecological indexes,all of them were higher in the outdoor area,indicating that the species richness,diversity,balance and ecological dominance of the outdoor area were greater than that of the indoor area.The main reason is closely related to the influence of human activities.The outdoor natural environment is changeable,and the factors such as climate,vegetation,and a food source are abundant,so there is a more abundant species distribution.3.A total of 12,393 cages were placed at high latitudes,and 899 small animal specimens were captured,belonging to 3 orders,4 families,11 genera and 18 species(subspecies),with a total capture rate of 6.16%.A total of 4,360 cages were placed in low latitudes,and 240 specimens of small animals were captured,belonging to 2 orders,2 families,8 genera,13 species(subspecies),and a total capture rate of 5.50%.Among them,the capture rate of Rattus flacipectus was the highest,reaching 3.28%,accounting for 59.58%.In terms of community ecological indexes,species richness in the high latitude region is greater than that in the low latitude region,but in terms of diversity,balance and ecological dominance,species richness in the low latitude region is higher than that in the high latitude region.4.According to the different elevations in the high latitudes,from the four elevations I,II,III and IV,1 family 2 genera 2 species(subspecies),2 orders 2 families4 genera 5 species(subspecies),4 orders 4 families 10 genera 16 species(subspecies)and 4 orders 4 families 8 genera 9 species(subspecies)were captured,respectively;The Rattus flacipectus were in an absolutely dominant position in the four elevations,and the capture rates were 1.75%,2.93%,5.88%,and 4.87%,respectively.The composition ratios were 61.90%,74.78%,73.86% and 74.22%.Respectively.According to the different elevations in the low latitudes,the four elevations from lowto high zones I,II,III and IV,and only one species of mouse was captured in the first three elevations;More than 1300 meters above sea level,2 orders,2 families,8 genera and 13 species(subspecies)were captured.The Rattus flacipectus occupied an absolutely dominant position,with the comprehensive capture rate of 5.98% and the proportion of 36.6%.Species richness varies significantly in different elevation zones in high latitudes.With the elevation increases,the "Z" character is basically reduced after a slight decrease in the regeneration height,and the highest richness is from 1000 to 1300 meters above sea level.There was a significant negative correlation between species richness and ecological dominance(r=-0.8947,p=0.0403),while there was a significant positive correlation between diversity index and ecological dominance(r=1,p<0.01).From the perspective of species richness,the elevation belt IV in the low latitudes is higher than that in the high latitudes and lower than that in the high latitudes and lower than that in the high latitudes and lower than that in the high latitudes and lower than that in the high latitudes.5.The tools were placed in the territory for 370 times,and 19 small animal specimens were captured,belonging to 2 orders,2 families,3 genera and 3 species(subspecies),with a total capture rate of 5.14%.Among them,the capture rate of Rattus flacipectus was the highest,which was 4.32%,accounting for 72.92%.Tools were distributed abroad for 370 times,and 19 small animal specimens were captured,belonging to 2 orders,2 families,3 genera and 4 species(subspecies).The capture rate is 3.75%.Among them,the capture rate of Rattus flacipectus was the highest,which was 2.72%,accounting for 84.21%.Ecological index comparison,different district was relatively close,overseas slightly higher than domestic,shows that overall,the two species were abundant difference was not big,latitude,altitude,vegetation types,and natural environment factors have a huge difference,the performance of a few differences,maybe the main and the level of economic development of both human activities,the foreign economy is relatively backward,the natural environment affected by human activities is small,so as to retain the more species diversity.6.In this study,997 organ specimens of small animals(There were 968 spleens and29 liver)were collected from 8 counties(cities)near the border of our province and one overseas area(Moxi Town,Bamo City,Kachin State,Myanmar).Three different gene fragments of Francisella(Fop A gene,Tul-4 gene,and 16 S r RNA gene)were screened by the PCR method,and finally,no positive samples were detected.Conclusion:1.In this area,whether indoor or outdoor,high or low latitude,high or low altitude,domestic or foreign,Rattus flacipectus all shows the absolute dominant position in the whole region,which indicate that Rattus flacipectus were still the dominant species in this area.2.The distribution of secondary dominant mouse species and common mouse species has certain differences between indoor and outdoor,high and low latitude,high and low altitude,and domestic and foreign,especially obvious differences in latitude and altitude.3.Under the influence of ecological geography,landscape and human activities,the richness,and diversity of small animal species in the survey area were generally higher outdoors than indoors,slightly higher abroad than within China,and the highest in 1000-1300 m elevation zones in high latitudes and higher than 1300 m elevation zones in low latitudes.4.Through the investigation and study,temporary not found in the investigation area Francisella tularensis clues,the main reason may be the area itself does not exist Francisella tularensis,and could also exist but failed to find,it needs to be further expanding the scope of the investigation and survey specimen species(such as increased ticks,fleas,medical arthropods insects),through the systematic research to further clarify the bacteria existence and its distribution in Yunnan.5.Through this study,the bacteriological separation,culture,identification and molecular biological inspection and detection techniques of Francisella tularensis were established in Yunnan,which provided an effective technical reserve for further research,investigation and even detection and treatment of public health emergencies in the future. |
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