BackgroundDengue virus (DENV) is a major public health threat, withAedes albopictusbeing the confirmed vector responsible for dengue epidemics in Guangzhou, China. Mosquito densoviruses (MDVs) are pathogenic mosquito-specific viruses, and a novel MDV was previously isolated fromAe. albopictusin Guangzhou. This study aims to determine the prevalence of MDVs in wildAe. albopictuspopulations and investigate their potential interactions with DENV and impact on vector susceptibility for DENV.MethodsThe prevalence of MDV in wild mosquitoes in China was investigated using open access sequencing data and PCR detection inAe. albopictusin Guangzhou. The viral infection rate and titers in MDV-persistent C6/36 cells were evaluated at 12, 24, 48, 72, 96, and 120 h post infection (hpi) by indirect immunofluorescence assay (IFA) and real time quantitative PCR (RT-qPCR). The midgut infection rate (MIR), dissemination rate (DR), and salivary gland infection rate (SGIR) in various tissues of MDV-infected mosquitoes were detected and quantified at 0, 5, 10, and 15 days post infection (dpi) by RT-PCR and RT-qPCR. The chi-square test evaluated dengue virus serotype 2 (DENV-2) andAedes aegyptidensovirus (AaeDV) infection rates and related indices in mosquitoes, while Tukey's LSD andt-tests compared viral titers in C6/36 cells and tissues over time.ResultsThe results revealed a relatively wide distribution of MDVs inAedes,Culex, andAnophelesmosquitoes in China and an over 68% positive rate. In vitro,significant reductions in DENV-2 titers in supernatant at 120 hpi, and an apparent decrease in DENV-2-positive cells at 96 and 120 hpi were observed. In vivo, DENV-2 in the ovaries and salivary glands was first detected at 10 dpi in both monoinfected and superinfectedAe. albopictusfemales, while MDV superinfection with DENV-2 suppressed the salivary gland infection rate at 15 dpi. DENV-2 titer in the ovary and salivary glands ofAe. albopictuswas reduced in superinfected mosquitoes at 15 dpi.ConclusionsMDVs is widespread in natural mosquito populations, and replication of DENV-2 is suppressed in MDV-infectedAe. albopictus, thus reducing vector susceptibility to DENV-2. Our study supports the hypothesis that MDVs may contribute to reducing transmission of DENV and provides an alternative strategy for mosquito-transmitted disease control.Graphical abstractSupplementary InformationThe online version contains supplementary material available at 10.1186/s40249-023-01099-8.