Detection of Dengue Fever Virus Serotype – 4 by using One-Step Real-Time RT-PCR in Hodeidah, Yemen

Background: Dengue and other fever like illnesses including chikungunya and malaria are common in Hodeidah, Yemen. Several outbreaks confirmed the presence of dengue serotypes 1-3.

Aim: Confirm dengue fever infection and identify the circulating dengue virus serotypes in Hodeidah, using real time one step Reverse Transcription–Polymerase Chain Reaction (RT-PCR).

Methods: Suspected dengue cases presented to health facilities between September 2012 and June 2013. Cases were informed about the study and asked to participate; 179 patients consented and were interviewed and blood samples were collected. The samples were tested at the National Centre of Public Health Laboratories (NCPHL) in Sana’a. Samples were initially tested by Enzyme Linkage Immunosorbent Assay (ELISA). Viral RNA was then extracted and prepared for serotypes detections using real time RT–PCR in one step pathway. Furthermore, agarose gel electrophoresis documentation system was used to confirm dengue serotypes.

Results: Dengue virus was confirmed by RT-PCR in 69 of 179 specimens. The four dengue fever serotypes were identified. DENV-4 was the predominant serotype at 31.88%, followed by DENV-2 at 23.18%, DENV-3 at 20.28%, and DENV-1 at 10.14%. Concurrent infection with more than one serotype was detected in 14.49% of the specimens.

Conclusion: We confirmed dengue virus infection using real time RT-PCR and identified DENV-4 serotype for the first time in Yemen. We also detected concurrent infections with more than on serotype. All serotypes are now present in Yemen increasing the risk of severe dengue and dengue hemorrhagic fever in future infections.