Evaluation of arbovirus vertical transmission in Aedes aegypti and Aedes albopictus (Diptera: Culicidae) under natural conditions

Natural vertical transmission (TVN) is considered the least studied form of dengue virus (DENV) transmission worldwide, and may represent an important mechanism of maintenance of this pathogen in the environment. Bearing in mind that the dynamics of DENV infection may vary according to wild vector populations and origin of the isolated virus, vertical transmission rates may also vary according to the region. However, although the city of São Paulo is the most populous in Latin America and has suffered from major dengue epidemics, TVN has never been detected in this area. The present work aims to carry out an experimental, empirical and meta-analytical approach to vertical transmission of arboviruses in Ae. aegypti and Ae. albopictus species in natural conditions through a bibliographic survey of the literature, investigation of vertical transmission in the city of São Paulo and comparison of the Minimum Infection Rates (IMT) obtained in Brazil and worldwide. In this work we obtained 62 studies on DENV\'s TVN, 5 on ZIKV and 4 on CHIKV. We analyzed 2,730 males (940 of Ae. aegypti and 1,790 of Ae. albopictus), collected in an urban park located in the city of São Paulo, to verify the presence of vertical transmission and to compare the Minimum Infection Rates obtained. As a result, South America and Asia were the largest producers of knowledge on the subject and this may be related to the high number of endemic countries on both continents. The low quantity of studies carried out in North and Central America indicates the need for a better understanding of the dynamics of this phenomenon in these areas. In addition, we describe, for the first time, the confirmation of natural vertical transmission of the DENV-3 serotype in the city of São Paulo in two pools of males of Ae. albopictus in periods that did not register autochthonous human cases of this serotype, indicating that green areas may be acting as a refuge areas for serotypes of silent circulation, with TVN being one of its possible maintenance mechanisms in this environment. Finally, the comparison of the TMI\'s did not corroborate the hypothesis of the existence of a general trend of favoring the natural vertical transmission of a certain serotype over the other, as well as between vector species. (AU)