Dengue virus detection in Lao PDR and Colombia: Comparative evaluation of PCR tests.

OBJECTIVES: Dengue virus (DENV) detection by polymerase chain reaction (PCR) facilitates diagnosis of dengue fever, which is the most frequent arboviral disease globally. Two studies were performed in countries with high dengue incidence, to assess the diagnostic performance of different PCR techniques. METHODS/RESULTS: Two hundred and seventy-nine acute phase blood samples from febrile patients were analyzed for DENV by the RealStar Dengue RT-PCR kit (Altona Diagnostics) as gold standard in comparison with the Tropical Fever Core multiplex PCR (Fast Track Diagnostics). In total, 102 samples collected in Savannakhet Province (Lao PDR, Southeast Asia) in 2013 and 35 samples from Valledupar (Colombia, South America) tested positive for DENV by RealStar RT-PCR. In comparison, the Tropical Fever Core multiplex PCR detected 65.0% (65/102) and 68.6% (24/35) of these samples as positive for DENV in Savannakhet and Valledupar, respectively. Diagnostic sensitivity of the multiplex PCR strongly correlated with viral load. A subset of DENV PCR-confirmed samples was additionally tested by BNITM in house Dengue Type RT-PCR in comparison with two commercial test kits (RealStar Dengue Type RT-PCR [Altona Diagnostics], Dengue differentiation PCR [Fast Track Diagnostics]). The leading dengue serotype in Savannakhet was DENV-3 (58% [29/50]), while DENV-1 (53.8% [14/26]) was the predominant serotype found in samples collected in Valledupar by BNITM-type PCR. However, three DENV serotypes were circulating in Valledupar and in Savannakhet. In 2015, additional studies found predominantly DENV-4 (71% [12/17]) in Savannakhet. CONCLUSIONS: Both studies emphasized that routine diagnostics in both regions will benefit from an expanded use of highly sensitive pan-dengue PCRs.

Verification and diagnostic evaluation of the RealStar® Middle East respiratory syndrome coronavirus (N gene) reverse transcription-PCR kit 1.0.

Aim: We report the diagnostic evaluation of a confirmatory reverse transcription-PCR (RT-PCR) kit targeting the Middle East respiratory syndrome coronavirus (MERS-CoV) N gene. Material & methods: 33 patient samples from two collections sites in Riyadh, Saudi Arabia, which were pre-characterized via real-time RT-PCR targeting MERS-CoV orf1a and upE, and were tested using the MERS-CoV N gene, as a confirmatory assay. This diagnostic procedure follows a two-step diagnostics scheme, recommended by the WHO. Results: 18/33 samples tested positive, 11/33 tested negative for MERS-CoV RNA and 2/33 showed uncertain results. Conclusion: The results suggest, that the RealStar® MERS-CoV (N gene) RT-PCR kit 1.0 can be considered a suitable and reliable confirmatory assay in combination with the RealStar MERS-CoV RT-PCR kit 1.0 according to the diagnostic scheme recommended by WHO.