Editorial: Grazing behavior and welfare of ruminants

The domestication and use of animals for our benefit entails responsibility for their quality of life (1). Animal welfare is a prerequisite for any ethical and sustainable animal production system to be socially defensible and acceptable (2). In nature, animals evolved in a changing environment and developed adaptive mechanisms to increase fitness (3). Cattle evolved in extensive grasslands and rangelands, in herds and families with complex social hierarchy and adapt to challenges posed by their environment through natural selection. Grazing animals face a number of challenges, including tick-borne diseases and lack of access to water and shade. Under human control, it is our responsibility to help animals to cope with such stressors and provide them a good life. This Research Topic aims to identify stressors present in pastoral husbandry systems; assess to the extent they affect health, welfare and production, and propose solutions to mitigate or overcome stressors

Spatial Evaluation and Modeling of Dengue Seroprevalence and Vector Density in Rio de Janeiro, Brazil

Dengue is a major public health problem in many tropical regions of the world, including Brazil, where Aedes aegypti is the main vector. We present a household study that combines data on dengue fever seroprevalence, recent dengue infection, and vector density, in three neighborhoods of Rio de Janeiro, Brazil, during its most devastating dengue epidemic to date. This integrated entomological–serological survey showed evidence of silent transmission even during a severe epidemic. Also, past exposure to dengue virus was highly associated with age and living in areas of high movement of individuals and social/commercial activity. No association was observed between household infestation index and risk of dengue infection in these areas. Our findings are discussed in the light of current theories regarding transmission thresholds and relative role of mosquitoes and humans as vectors of dengue viruses