Abstract:To ascertain the rule of specific antibody production in dengue virus infection so as to making the early diagnosis of dengue fever cases in the outbreak of dengue fever by means of laboratory methods,serum samples from 441 patients or the close contacts in a dengue fever outbreak of Fujian province and 22 convalescent serum samples were collected to detect the production of specific IgM and IgG antibodies by using the captures ELISA assay.Combined with the data from field case survey,the results were analyzed.According to the case definition set in this study,228 cases were confirmed.Among these cases,226 cases were proved to be IgM-positive,while 119 cases to be IgG-positive.Of the IgM-positive cases,118 cases were showed to be IgG-positive simultaneously.In 119 IgG-positive samples,only one sample was showed to be IgM-negative.For the samples which were both negative for IgM and IgG,RT-PCR assay was used to detect the specific nucleic acid of which one sample was found to be positive in this assay.Twenty two convalescent serum samples were all positive to these two types of antibodies.Most cases of patients aged from 10 to 70.Among the confirmed cases,their occupations were diverse and the gender ratio was 1:1.53.After dengue virus infection the viral IgM antibody was detectable from onset of disease to at least one and half month later.The IgG antibody prevalence was low at early stage of disease,but it escalated late on and its detection rate raise up to 95% after 50 days later.Only few individuals developed IgM antibodies to the detectable level at early stage of disease.It is evident that the rule of antibody production in dengue virus infection is consistent to the previous reports and can be used to instruct the antibody test-based laboratory diagnosis of dengue fever in the disease outbreak.