Ratos, doenças e cidades: caracterização do risco zoonótico e estratégias participativas de prevenção

Abstract

The study of rodent-borne diseases has become increasingly relevant due to the growing impact of these pathogens on global public health, particularly in vulnerable urban contexts. Rising urbanization and the close proximity between human populations and rodent habitats intensify the risk of zoonotic disease transmission, such as Orthohantavirus, in addition to other parasites that may affect both rodents and humans. However, significant gaps remain in the understanding of the spatial and epidemiological dynamics of these pathogens in urban areas, especially in Brazilian cities. This dissertation aims to provide insights into the risk factors that increase rodent and human exposure to various pathogens circulating in urban centers, as well as participatory approaches to mitigate the health impacts of rodents. In Chapter I, we update knowledge on which parasites circulate in rodent populations within vulnerable urban communities, analyzing their spatial distribution and assessing how landscape factors may influence this distribution. We identified 11 species of zoonotic parasites in urban rat populations in Salvador in 2018. Only three nematode species showed spatial aggregation: Angiostrongylus cantonensis, Nippostrongylus brasiliensis, and Capillaria gastrica. Higher individual weight, the presence of wounds, and the dry season influenced the cumulative parasite burden per rat, highlighting the importance of host-level traits and climate in shaping pathogen circulation. In Chapter II, the focus shifts to Seoul orthohantavirus (SEOV), a virus rarely investigated in Brazilian urban environments. This chapter explores SEOV prevalence in Rattus spp., as well as human risk factors for exposure, particularly in high-risk settings such as Salvador’s informal settlements. We found that 32% of rats (37/117) and 14% (91/646) of human residents had been exposed to SEOV. In rodents, higher body weight, proximity to construction debris and accumulated materials, and lack of visits from the zoonosis control center were identified as risk factors. For humans, risk was mainly associated with garbage accumulation in the community, underscoring the importance of basic urban services in tackling rodent-borne diseases. Finally, in Chapter III, we demonstrate that rodent infestations and their associated parasites are facilitated by environmental characteristics and the lack of infrastructure and sanitation in vulnerable urban settlements. We propose a pilot model of systematic rodent surveillance for control in disadvantaged urban areas, with active community participation. The research advocates for multisectoral interventions for rodent control and supports the feasibility of sustainable and participatory strategies aimed at reducing infestation and, consequently, improving public health conditions. This pilot was replicated in a disadvantaged urban settlement in a Bahamian community, demonstrating the potential and replicability of the model.