A survey of clinical and laboratory characteristics of dengue fever epidemic from 2014 to 2018 in Guangzhou, China

Abstract

Background: In 2014, a serious dengue outbreak occurred in Guangzhou, South China. In this study, the clinical and laboratory characteristics of dengue fever (DF) group and other febrile illnesses (OFI) group in Guangzhou were described.

Methods: Clinical and laboratory data collected by studying 1,792 patients from Nanfang Hospital, Southern Medical University during 2014 and 2018. Laboratory data was analyzed by SPSS 22.0 statistical software including Full blood counts (SYSMEX XE-5000), Laboratory Biochemical tests (Roche Cobas 8000), Dengue virus RNA (RT-PCR-Fluorescence Probing) and Dengue IgG/IgM Antibody (Colloidal Gold), Dengue Virus NS1 (ELISA).

Results: In the DF group and OFI group, gender ratios were 1.08:1 (male/female, P>0.05) and 1.45:1 (male/female, P<0.05). Adults aged 25-34 years old (29.4%) with the main peak appeared in the DF group, and the same main peak appeared in the OFI group: 25-34 years old (25.13%). Patients were from Medical emergency (41.2% DF group, 29.4% OFI group). The distribution of fever days before treatment was mainly focused within 5 days, with a main peak in the 2 fever days before treatment (24.6%) in the DF group and the main peak in 1 fever day before treatment (46.9%) in OFI group. The major symptoms of the DF group were presented with were fever (100%), myalgia (34.77%), pharyngeal hyperemia (31.33%), headache (25.65%), adenoids (19.62%), and rash (13.25%). In the OFI group, Pharyngeal hyperemia was the most common clinical symptom, accounting for 27.24%, and the next symptom was adenoids (21.26%). The sensitivity and specificity of DV RNA were 61.54%, 100%, respectively, compared to the DF Nonstructural protein 1 (NS1). Dengue virus (DENV) Immunoglobulin M (IgM) IgM in both groups was statistically significant, with DENV-IgM in the DF group were stronger (Z=-7.863, P<0.001), and DENV immunoglobulin G (IgG) were no statistically significant (Z=-1.212, P=0.226). In DF group, 37.14% of serum samples had elevated Alanine transaminase (ALT) levels, 76.85% of them had elevated aspartate aminotransferase (AST) levels, 32.08% of them had elevated creatine kinase (CK) levels, and 2.67% of them had elevated C-reaction protein (CRP) levels, compared with 13.51% of them had elevated ALT levels, 30.65% of them had elevated AST levels, 6.06% of them had elevated CK levels and 69.35% of them had elevated CRP levels of the OFI patients. The prominent manifestations were thrombocytopenia (occurring in 28.07% of the DF group, compared to 5.18% of OFI group) and leucopenia (occurring in 43.27% of DF group and 3.63% of OFI group). The DF incidence of all fever cases was 49.0% within three months in 2014, compared with 1.4% in 2015, 0% in 2016, 0.9% in 2017 and 6.4% in 2018 (P<0.001). DF and OFI can occur in any age and sex. DF occurred in the young and the old, OFI occurred in children and youth. The clinical symptoms of myalgia, headache, rash, weak, Chills, follicular hyperplasia in both groups were statistically significant (P<0.001).

Conclusions: IgM can be easily recognized for early diagnoses, DENV-RNA had lower sensitivity and higher specificity, and DF NS1 enzyme-linked immunosorbent assay (ELISA) has a higher sensitive and specificity. DF is a serious public health problem and an emerging continuous threat in Guangzhou. In high-prevalence areas, effective epidemic monitoring and prevention measures need to be undertaken. After the unprecedented outbreak in 2014, on account of the government and citizen paying more attention to the DF epidemic, the cases of DF were decreased significantly from 2015 to 2018.

Keywords: Dengue fever (DF); Nonstructural protein 1 (NS1); RNA; diagnostics; enzyme-linked immunosorbent assay (ELISA); other febrile illnesses (OFI).