Molecular detection of dengue virus RNA in dogs (Canis lupus familiaris) situated in an important tri-border municipality (Brazil x Argentina x Paraguay)

Although the role of humans as the main host that maintains the epidemic cycles of some arboviruses is clarified, there is no consensus that dengue virus (DENV) can be maintained in endemic regions in an enzootic cycle. Therefore, the objective of this study was to investigate the molecular detection of DENV serotypes 1, 2, 3, and 4 RNA in semi-domiciled dogs from urban areas of Foz do Iguaçu, a dengue-endemic municipality located in a tri-border region between Brazil, Paraguay, and Argentina. A total of 100 blood samples were collected from dogs residing in two human dengue hotspots. Samples were analyzed by qRT-PCR using a commercial assay originally developed for human diagnostics. The endogenous 18S rRNA internal control amplified in all samples, confirming RNA integrity and absence of detectable PCR inhibition in the canine matrix under the experimental conditions applied. It was possible to identify the presence of DENV-4 RNA signal in six (6%) of the animals, a value considered epidemiologically high. In a region of Triple Frontier, with fluctuating population, great social inequality and different legislative norms between countries, the inclusion of sentinel animals for dengue in epidemiological surveillance programs is in line with PAHO recommendations. The results found provide molecular evidence of DENV RNA detection in dogs from endemic urban areas and raise important questions regarding the potential epidemiological relevance of dogs in dengue-endemic urban environments.