Identification of Dengue virus serotype during the 2019 dengue outbreak in Ribeirao Preto, Sao Paulo, using a DNA microarray platform.

Brazil is a tropical country where several arthropod born viruses (arboviruses) circulate. Dengue virus (DENV) is the most important arbovirus affection the country; it is responsible for explosive epidemics in cycles of 3 to 5 years. DENV is an enveloped virus and comprise four distinct serotypes (DENV1-4) that belong to the genus Flavivirus, family Flaviviridae. Dengue virus (DENV) infection can be assyntomatic or leads to a wide spectrum of clinical manifestation, ranging from an undifferentiated fever, the self-limiting dengue disease, to the severe dengue, sometimes with fatal outcomes. New epidemics occur when a new DENV serotype is introduced in a region with high prevalence of susceptible individuals. Therefore, surveillance of the circulations of DENV serotypes and other arboviruses is of great interest to prevent or decrease the impact of epidemics caused by these viruses. DNA microarray platform has emerged as a high-throughput method for pathogen surveillance; however, it is a highly cost test that can be used only in specialized laboratories. The objective of this study was to use a DNA microarray platform (SMAvirusChip) previously developed¹, in the surveillance of DENV serotype during the 2019 outbreak and evaluate the possibility of reusing the DNA microarray slides to reduce the cost of the test.
We have analysed 16 serum samples from patients with febrile illness. DENV-2 was detected in 5. The virus serotype was confirmed by a real time RT-PCR, using a specific probe for DENV-2. No other DENV serotype neither other arboviruses was detected in the analysed samples. A single DNA array that was used to analyze a serum sample, which showed no virus detection, was tested successively, after a stripping protocol², with Rocio virus, Chikungunya virus, DENV-1 and DENV-4. All these viruses were specifically detected using the same DNA array, confirming that the slide can be reused, thus reducing the cost of the test.