Dengue diagnosis in Guinea in two returning travelers from Côte d'Ivoire: a case report

Dengue's true burden on the African continent is likely underestimated. The majority of cases originate from West Africa, mostly from Burkina Faso. We report here the detection in Guinea of two imported cases of dengue in travelers returning from Côte d'Ivoire, one fatal (case 1) and one mild (case 2). Case 1 lived in Côte d'Ivoire and was diagnosed during a trip in Conakry, Guinea, on 14 August 2023, 9 days after symptom onset. He died on 21 August of an illness related to severe dengue; dengue virus serotype 3 (DENV-3) was further identified. Case 2 was diagnosed in N'Zérékoré, a forested region of Guinea, with serotype 1 (DENV-1) on 11 July 2024, 2 days after disease onset, while returning from Côte d'Ivoire. He was hospitalized for 9 days until full recovery. In-country phylogenetic analysis of case 2 DENV-1 revealed its linkage with urban dengue viruses known to circulate in West Africa. This timely detection, supported by enhanced diagnostics and genomic surveillance capacity in Guinea's laboratory network, highlights the need to strengthen surveillance systems for early detection of emerging viral infections, and emphasizes the importance of further monitoring dengue circulation dynamics in West Africa.