O-64 Innovations in dengue surveillance: serotype distribution, transmission dynamics, and implications for outbreak preparedness in Guyana, South America

Methods: A national, retrospective, cross-sectional study analyzed 1,289 PCR confirmed dengue positive samples collected through the National Public Health Reference Laboratory and the Vector Control Services, 189 of which were serotyped and analyzed Data were extracted and organized in Excel files by variable category and imported into SPSS for analysis using descriptive statistics: frequencies, percentages and central tendencies.

Results: Among n=7,458 febrile illness samples, n=1,289 (17.3%) were dengue positive; females accounted for 56%. N=224 samples submitted for serotyping, n=189 (84.3%) were processed, with DENV-2 (n=128) predominating and widely distributed across the coastal regions (Region 5 (n=63), 4 (n=26), 6 (n=26), 2 (n=8), 10 (n=4) and single case in hinterland region 8. DENV-3 (n=58) also showed coastal pattern with cases concentrated in regions 2 (n=17), 4 (n=13), 5 (n=20), 6 (n=7) and single case in hinterland region 7. Sporadic DENV-4 (n=2) and DENV2/3 (n=1) were observed exclusively in the coastal region 4 where the capital Georgetown can be found; representing a key transmission hotspot with the greatest serotype diversity.

Conclusion: The study demonstrates multi-serotype circulation in Guyana, with DENV-2 predominance and co-circulation of DENV-3 in coastal regions, increasing the risk of severe dengue through secondary infection. The exclusive detection of DENV-4 in Region 4 highlights geographical clustering of less common serotypes. Despite being limited by routine surveillance data, which may be affected by underreporting and partial serotype testing coverage, these findings underscore the importance of strengthened surveillance, targeted vector control in coastal hotspots, and expanded routine serotyping to inform future vaccination considerations and enhance national outbreak preparedness.