| Dengue fever is caused by dengue virus(DENV)transmitted by Aedes mosquitoes and the main manifestations of dengue fever patients are high fever,headache,rash,muscle pain and so on.Severe patients suffer from hemorrhage or shock,or even death.In recent years,dengue fever epidemic has become a serious public health problem due to its severe situation,widening transmission range and increasing incidence.DENV,zika virus(ZIKV)and chikungumya virus(CHIKV)are mainly transmitted by Aedes mosquitoes,their epidemic areas overlap and clinical manifestations are similar,easily to be missed in diagnosis.The problem of co-infection with the three viruses take a new challenge to the prevention and treatment of dengue fever.At present,there are no effective vaccines and antiviral drugs for dengue fever,and the key to prevention and control is mosquito conrtrol.Effective means are needed to monitor the status of mosquito vectors.Reverse transcription-polymerase chain reaction(RT-PCR),which is commonly used at present,has high sensitivity,but it requires high operation and equipment.Because of its low detection flux,it is not convenient for large-scale insect vector screening in epidemic period.Our laboratory has established a method to detect DENV non-structural protein 1(NS1)antigen:in serum by enzyme linked immunosorbent assay(ELISA)and is simple and sensitiveThe contents of this study include the following two aspects:First,Clinical characteristics of co-infection of 406 cases dengue fever:in Guangzhou during 2015 to 2018Objective:By analyzing the detection of ZIKV and CHIKV and screening the co-infection of DENY in Guangzhou during 2015 to 2018 to find out the co-infection of the three viruses.Methods:406 dengue fever patients admitted to our hospital during 2015 to 2018 were selected as the research objects.ZIKV,CHIKV and the serotypes of DENV were detected by RT-PCR.The clinical features of dengue fever were summarized and analyzed.Results:ZIKV and CHIKV nucleic acids were detected in 380 dengue fever patients and the results were both negative.Co-infection case of the three viruses was not found.DENV serotypes were detected in 96 dengue fever patients and 69 cases were positive.Among them,58 cases(84.1%)were DENV-1,10 cases(14.5%)were DENV-2,1 case(1.5%)was DENV-3,DENV-4 was not detected and co-infection of different serotypes of dengue virus was not found.Of all the 406 patients,371(91.4%)were diagnosed as dengue fever and 35(8.6%)were severe cases.The most common manifestations included fever(96.6%),fatigue(34.00%)and skin rash(31.0%).Significantly higher incidence(P<0.05)of hemorrhage,cough,sputum,vomiting and abdominal pain were found in severe dengue fever.The most common laboratory findings were leucopenia(69.0%)and thrombocytopenia(50.7%).Significant increase(P<0.05)of total bilirubin,aspartate aminotransferase,serum creatinine,high-sensitivity C-reactive protein and procalcitonin were observed in severe dengue fever.Conclusions:In 406 patients of dengue fever during 2015 to 2018,co-infection case with ZIKV or CHIKV was not found and co-infection of different serotypes of DENV was not found,too.Most cases of dengue fever were mild and DENV-1 was the dominant serotype.Second,evaluation of enzyme linked immunosorbent assay(ELISA)for the detection of dengue virus-infected mosquitoesObjective:The DENV NS1 antigen of Aedes albopictus was detected by ELISA and compared with the nucleic acid detection result by RT-PCR.The feasibility,sensitivity and specificity of this method for DENV detection in mosquitoes were evaluated.Methods:Twenty-five Balb/c suckling mice of 1～3 days were divided into four experimental groups and one control group,five mice in each group.The suckling mice in the experimental group were intracranially injected with DENV-1,DENV-2,DENV-3 and DENV-4 virus solution.The suckling mice in the control group were intracranially injected with the same volume of PBS solution.After symptoms occurred,the suckling mice in the infected group and the control group were put into mosquito cages respectively.Female mosquitoes with full blood were separated after they were bitten and sucked for 2 hours.The twenty mosquitoes were collected for DENV detection at 3,6,9,12,15 and 18 days after the bite.The DENV NS1 antigen in mosquitoes was detected by ELISA and the feasibility and performance of this method was evaluated by using RT-PCR as a reference method.Results:The results showed that after mosquito bit mice infected DENV 1-4,the virus could be detected as early as 3 days after biting and as late as 18 days after biting,and the minimum number of mosquitoes is 1.The total positive rates of DENV 1-4 RNA in mosquitoes were 17.5%,34.17%,62%and 10%,respectively.The total positive rates of DENV 1-4 NS1 antigen in mosquitoes 3.33%,9.17%,15%and 0%,respectively.Using RT-PCR as a reference method,ELISA showed a sensitivity of 0.22(0.16-0.30)and a specificity of 1(0.99-1)for detecting NS1 antigen.The sensitivity was general and the specificity was good.Conclusions:ELISA can be used for detecting DENV in mosquito.Although the operation is simple and high throughput,the sensitivity of ELISA is lower than that of RT-PCR. |
