Outbreak of dengue fever in Ghana: The emergence of DENV-1 serotype

Background Dengue, a mosquito-borne virus continues to be a public health concern in the tropics and subtropical parts of Africa. Due to the increase of urbanization, climate change and trans-Atlantic trade, the transmitting vector, Aedes aegypti, has become prevalent hence the rapid growth of the disease, globally. In Ghana, there have been sporadic laboratory-confirmed cases of dengue reported over the years through surveillance activities. However, despite the detection of these cases, Ghana had never experienced a major outbreak (unlike its neighboring countries) until July 2024. Methods During this outbreak, a total of 1471 suspected dengue fever specimen received from various health facilities in Ghana in NMIMR for molecular diagnostic testing using a RT-qPCR assay for dengue, chikungunya and Zika viruses and selected positives sequenced using Illumina Next Generation Sequencing. Results Dengue fever virus RNA was detected from 206 samples and serotyped as DENV-1 with one DENV-3 coinfection. Thirty-nine genomes were successfully generated after sequencing and phylogenetic analysis of DENV-1 strains revealed two main clusters with AFI isolates in Ghana and isolates from other West African countries (Côte d’Ivoire, Burkina Faso, Benin, and Senegal) circulating between 2017–2019. In 2023, DENV-1 was frequently isolated which could account for it being the predominant serotype transmitted in the recent outbreak. Conclusion The outbreak response and the case management procedures deployed by the health authorities during this outbreak were swift and was enough to prevent a fatal difficult-to-control situation. With the absence of a widely accepted commercialized vaccine and treatment for dengue fever, there is a need to enhance surveillance activities and control the vectors which can transmit DENV in-country to curb the occurrence of outbreaks.