Concurrent infections by two dengue virus serotypes during an outbreak in northwestern Peru, 2008

Objetives. To establish the existence of concurrent infections by different dengue virus (DENV) serotypes in an outbreak in the Northwestern in Peru during 2008. Material and methods. 73 serum samples from patients with dengue were analyzed during an outbreak that occurred in Northwestern in Peru between May and June 2008. Molecular biology techniques were used to serotype the DENV, thus, firstly the viral RNA viral was extracted using Viral QIAamp RNA mini kit (Qiagen, Valencia, California, USA), then the viral cDNA fragments were reverse transcripted and amplified by means of the Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) and the RT-Nested PCR region techniques and finally, genetic sequencing of the viral cDNA fragments were performed using the Big Dye Terminator v.3,1 kit. Results. The 73 dengue cases presented infections by different serotypes: 34 (46.6 per cent) by DENV-3, 29 (39.7 per cent) by DENV-1, 4 (5.5 per cent) by DENV-4, and 6 (8.2 per cent) concurrent infections by DENV-1 and DENV-3. The most frequent clinical manifestations observed among dengue patients were fever and headache (100 per cent), myalgia (94.5 per cent), ocular pain (83.6 per cent), arthralgia (78.1 per cent), shivers(63.0 per cent), nausea/vomiting (38.4 per cent), positive tourniquet test (30.1 per cent), and rash (20.5 per cent). All patients with concurrent infections presented light clinical course of dengue fever (DF) except one patient who had moderate hemorrhagic manifestations. Conclusion. This is the first Peruvian report of patients with concurrent infections of two DENV serotypes without severe clinical manifestations.