| OBJECTIVE:To understand the composition,density,seasonal fluctuation of rodents,its ectoparasites and the infections of rodent-borne pathogens at Shenwan Port area of Zhongshan.To clarify the genetic type,genetic characteristics and variation relationship of pathogens carried by rodents,which may provide important data support for prevention and control of the transmission of rodent-borne diseases.To identify species of rodents and their ectoparasites and obtain their DNA barcode information by using DNA-barcode.METHODS:Rodents were captured by cage-trap in Shenwan freight and passenger port area during May 2017 to June 2018.Ectoparasites of rodents were collected by combing the body.Morphological identification and DNA barcoding were used to identify the species of rodents and its ectoparasites.The lung,liver,spleen and kidney of rodents were obtained by dissection in laboratory.RNA was extracted from lung tissues and DNA was extracted from liver,spleen and kidney tissues.7 kinds of pathogens in rodents were checked with nucleic acid detection method,Negative PCR products were sequenced and then phylogenetic analysis of sequences.RESULTS:1.Monitoring results of rodents in Shenwan Port: A total of 69 rodents were captured,which belong to 3 species of 3 genera,2 families and 2 orders.There were 58 Suncus murinus,accounting for 84.05%,which were dominant species.The average density of rodent was 3.89%,and the seasonal fluctuation was obvious(0.70%-7.14%),with two peaks appeared in July-August and March-April.2.Contamination of ectoparasites among rodents: Individuals of 12 sucking lice,2 Nosopsyllus nicanu,95 lxodes granulatus,3 Laelaps echidninus and 148 Leptotrombidium deliense were collected from rodents.The rates of rodents contaminated louse,flea,tick and mite were 2.90(2/69),1.45%(1/69),20.29%(14/69)and 4.35%(3/69)separately.3.Detection of pathogens in rodents: 2 rodents were positive Hantavirus and the infection rate was 2.90%(2/69),the genotype was Seoul virus.3 rodents were positive Leptospira and the infection rate was 4.35%(3/69),phylogenetic analysis showed that there were two genotypes of L.interrogans and L.borgpetersenii.8 rodents were positive Bartonella and the infection rate was 11.59%(8/69),phylogenetic analysis showed that there were two genotypes of B.tribocorum and B.sp..1 rodent was detected to be infected with Hantavirus,Bartonella and Leptospira,and the positive rate was 1.45%(1/69).The nucleic acid detection of other four pathogens including Francisella tularensis,Yersinia pestis,Orientia tsutsugamushi and Borrelia burgdorferi were negative.4.Identification of DNA barcode: The 69 COI gene sequence of rodents were successfully amplified by DNA barcode,and the rodents species were successfully identified.The NJ tree was constructed,four rodent species were divided into single branch seperately,so different species of genera and species were distinguished.DNA barcode technology successfully amplified the COI fragment of ectoparasites the and obtained the corresponding DNA barcode sequence.CONCLUSION:1.Density of rodents is high at Shenwan port area,rodent density fluctuations throughout the year,eradication of rats should be strengthened.2.Fleas,ticks and mites exist among rodents,in which and contamination of tick is common in rodents,and prevention and control of related infectious diseases should be strengthened.3.There are Hantavirus,pathogenic Leptospira,and Bartonella infection in the rodents of Shenwan Port.The genotype is pathogenic to humans and there exist risk of infection in the population.Its prevalence needs to be further investigated.4.Sequence alignment,genetic distance analysis and sequence cluster analysis of COI gene sequence of rodents can accurately and quickly identify species.DNA barcode technology also can correct errors in morphological identification.This method can also be applied to the identification of ectoparasites. |
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