Co-infection between Zika and different Dengue serotypes during DENV outbreak in Brazil

Abstract Background The recent introduction of new arboviruses in the Americas, as Zika virus (ZIKV) and Chikungunya virus (CHIKV), increased the risk of outbreaks and arboviral co-infections. Herein, we report twelve cases of co-infection of ZIKV and different DENV serotypes in a city located in the northwest region of Sao Paulo State, Brazil, which is hyper-endemic to Dengue. Methods Between January and November 2016, 1254 suspected cases of arboviral infection were available by our surveillance program in Sao Jose do Rio Preto. All suspected patients were examined and, when they were arboviral disease-suspectd, had sera separated and viral RNA analyzed by PCR/qPCR assays to determine the diagnosis of DENV 1-4, ZIKV, or CHIKV in the same samples. After the molecular results, twelve patients with ZIKV-DENV coinfection were identified and their clinical and laboratory characteristics were described. Results The mean between symptoms onset and collected sample of 3 days. DENV-1 was identified in seven co-infected patients and DEN2 in other five. Two patients presented alarm signs of Dengue and no one was hospitalized. Conclusions The constant presence of co-circulating arboviruses increases the chance of co-infection and demonstrates the importance of the differential diagnosis, especially during periods of arboviral outbreaks. The impact of this co-infection is known individual and collectively.