A Research On The Clinical Features And Genotype Of Dengue Patients In Zhuhai City During 2007~2013

Objective: By collecting and analyzing the clinical data of dengue fever patients in Zhuhai City during 2007~2013. The dengue virus can be sequenced after genotyping. Homology and phylogenetic analysis of the epidemic strains in different regions will be analyzed, helping to determine the source of infection, which aims at making corresponding prevention measures to the recurrence of the dengue fever epidemic in the infected area.Methods: The clinical features of 164 cases of dengue fever will be analyzed retrospectively. The following methods are used: Specimen collection, RNA will be extracted from the samples, and then the E gene sequencing will be amplified by one step method RT-PCR, whose result will be submitted to BLAST database for Gen Bank searching and typing.To compare with the results of sequencing, the reference sequence which is similar to the sequence of the study will be selected, and then the evolutionary tree will be further analyzed on its reliability.Results: 1. Outbreak area, the peak, age and occupation: With the prevalence of casual onset in Zhuhai city during 2007~2013,the epidemic in Qianshan street Xiangzhou District and Jinan town Doumen District is more concentrated, which peak period is from August to October. Most were located in the group aged from 21 to 50, and male and female ratio is 1. 02 to 1. The career of thepatients mainly distributed in workers and the people of unemployment, respectively, for 38. 4% and 25. 0%. 2. The analysis results of clinical features show that the clinical characteristics mainly focus on fever(164 cases, 100%), headache(133 cases, 81. 10%), rash(118 cases, 71. 95%), muscle pain(96 cases, 58. 54%), dizziness(95 cases, 57. 93%), fatigue(121 cases, 73. 78%) and anorexia(118 cases, 71. 95%), accompanied by nausea(50cases, 31. 49%), chest tightness(23 cases, 14. 02%), skin pruritus(44 cases, 26. 83%),bleeding(23cases, 14. 02%) and so on.(2) Laboratory examination: the examination of a routine blood test manifests that white blood cell(WBC) reduces in 152 cases(93. 25%) and platelet(PLT) reduce in 147 cases(90. 18%). The examination of liver enzymes show that glutamine acid propyl transfer enzyme(ALT) increased in 71 cases(45. 22%), and aspartate aminotransferase(AST) in 117 cases, accounting for 74. 52%; the examination of myocardial enzyme indicates that lactate dehydrogenase(LDH) increase in 113 cases(69. 33%), and creatine kinase(CK) increase in 69 cases(42. 33%); the examination of urine routine shows that 43 cases( 26. 22%), Fecal occult blood test was positive in 20 cases(20.12%).According to electrocardiogram(ECG), 33 patients(20.12) face with the change of ST and T. Ig M antibody test was positive in 136 samples(89.92%). 3. In the specimens of suspected dengue fever in the Center for Disease Control of Zhuhai city during 2007 to 2013, 65 of them are Nucleic acid identification positive specimens,of which 61 were identified as type I dengue virus(local residence), including 41 cases in 2007, 5 cases in 2012 and 15 cases in 2013, 4 were identified as type II dengue virus(non local residence),including 2cases in 2007 and 2 cases in 2012. 17 strains were isolated from the virus, among 24 cases of them, including 2 cases in 2007, 7 cases in 2012 and 15 cases in 2013. 4. Dengue virus type I have done homology and phylogenetic tree analysis during 2007-2013 in Zhuhai: Type I strains have been isolated by Zhuhai Center for Disease Control(CDC) in 2013. 2013XBJ28-2 and other 11 strains, which own the highest homology up to 99. 65% in Thailand isolates(registration number BID-V2277) in 2001, and even in a branch of evolution, the relative credibility is quite high.The isolated virus type I strain 2012JC398 in 2012 and other 3 strains possess the highest homology up to 99. 88% with Vietnam virus strains(registration number V4081), which in a clade.The credibility of the phylogenetic relationship is rather high. Besides, 2007ZH1068 type I strains have the highest homology of 99. 73% with the virus in 2003 from Singapore DENV type 1(registration number SG EHI D1209Y). The homology of DENV-1 is 99.14% between 2007 and 2012, 99.27% between 2007 and 2013,99.14% between 2012 and 2013.Conclusion: 1. The prevalence of local outbreaks in Zhuhai City mainly focus in Qianshan street Xiangzhou District and Jinan town Doumen District, belonging to autumn and winter without obvious gender difference. The majority of people generally suffer from it. 2.From 2007 to 2013, the clinical symptoms of dengue fever in Zhuhai were light, and the declining of white blood cells and platelets is out of sync in the course of the disease, meanwhile,it is very high detection rate of liver enzyme and mycocardial enzyme abnormality, and it shows subclinical syndrome while mycocardial enzyme changes abnormally, which are the typical manifestations of dengue fever. Severe dengue fever has not been found yet, for most of patients recover well after treatment. 3. The prevalence of dengue virus in Zhuhai consists mainly of type I during 2007 and 2013, and it may have been spread for several years by Aedes mosquitoes in Zhuhai. Thus, it is necessary to develop anti-mosquito campaigns and strengthen the monitoring of immigration from Southeast Asian countries.