Seroprevalence and molecular surveillance for dengue virus infections among febrile patients and mosquito vectors in Ogbomoso, Nigeria

Background: Dengue fever is a leading cause of illness and death in tropical and subtropical regions. The World Health Organization estimates that there are 390 million dengue infections each year, of which 96 million manifest apparently. Objectives: This study aimed to determine the seroprevalence and molecular surveillance of dengue viral infections among febrile patients and mosquito vectors in Ogbomoso, Nigeria. Materials and Methods: A cross sectional study was conducted between February and July 2024 in Ogbomoso, Oyo State, Nigeria. Four hundred serum samples from febrile patients of all ages and mosquito vectors were collected. Serum samples were analyzed using DENV RDT kit for IgM and IgG and RT-PCR, while the mosquito samples were subjected to only RT-PCR. Malaria co-infection was detected using an RDT kit confirmed microscopically. Chi-square tool was used to determine the association between socio-demographics, clinical features and risk factors among the febrile patients. Result: Of the 400 participants, 126(31.5%) were males and 274(68.5%) were females. Dengue IgG was detected in 223/400(55.8%), while DENV IgM was found in 12/400(3.0%), and 165/400(41.3%) had neither IgG nor IgM. Co-infections with malaria were found in 70/400(31.4%) for IgG and 4/400(33.3%) for IgM. All serum samples and mosquitoes were negative for DENV RNA by RT-PCR. The highest infection rates for IgM were in the 11-20 and 21-30 age groups. Environmental and behavioral factors, such as improper water storage and proximity to bushes were not significantly associated with dengue seropositivity. Conclusion: This study provides evidence that dengue virus is circulating in Ogbomoso, Oyo State, Nigeria. The high rate of coinfection between DENV IgM and malaria, advocates for routine serological screening of febrile patients for both infections, improved diagnostic capacity, and targeted public health interventions to control and prevent dengue outbreaks. Therefore, dengue virus tests should be included in the routine test for aetiology of fever to avoid misdiagnosis