Ectoparasitic hematophagous dipters: potential reservoirs of dengue virus?

Recently, the presence of antibodies and dengue virus (DV) RNA in neotropical wild mammals, including Desmodus rotundus, was reported. In a previous study, DV was also found in a high percentage (39.6%) of ectoparasitic hematophagous dipters specifics of these hematophagous bats. In order to verify the susceptibility of these ectoparasites to DV, in this work experimental infections with VD2 of organs explants of Strebla wiedemanni and of Melophagus ovinus were performed using C6/36 cells as control. Viral titers (UFP/mL) were determined at 0, 48 and 96 hrs pi. Infected organs were observed by electron microscopy and under the confocal microscopy indirect immunofluorescence (IIF) using specific conjugates against DV. The infected organs of both species of ectoparasites replicated DV at titers similar to those obtained with the C6/36 cell line (≥10⁶ UFP/mL). Electron microscopy and IIF showed DV replication in the digestive tract, tracheoles, reproductive organs of males but not in females, and milk glands (MG) of both species. In the fatty bodies of the MG of M. ovinus, zones with a high affinity for the DV were observed. In this work the susceptibility of S. wiedemanni and M. ovinus to DV was demonstrated and consequently the probable role of this ectoparasites as wild reservoirs of DV.