From Bite to Disease Outbreak: Molecular Epidemiology and Vector Biology of Zoonotic Diseases

Vectors and their associated pathogens thrive under favorable environmental conditions in tropical and subtropical regions. Globally, studying vectors and vector-borne diseases is crucial for understanding outbreaks and high morbidity rates. This chapter reviews how vector bites can lead to individual infections and, under favorable conditions, escalate into local or regional outbreaks. Mechanically, outbreaks occur when vectors bite hosts and transmit pathogens, with ecological and environmental factors contributing to the progression of sporadic cases into outbreaks, underscoring the importance of control and surveillance. Pathogen transmission and the dynamics of disease emergence are significantly influenced by vector biology, which includes species distribution, feeding behavior, and vector competence. Furthermore, by examining genetic variations in pathogens and vectors and tracking the origins of outbreaks, molecular epidemiology offers a potent framework for comprehending these dynamics. Disease severity can usually be limited by enzootic stability in host populations, but disturbances in this equilibrium can result in pathogen spillover into naïve populations, significantly raising the risk of an outbreak. To predict high-risk situations, implement targeted interventions, and apply efficient surveillance techniques to prevent and manage vector-borne disease outbreaks, it is crucial to integrate vector biology with molecular epidemiological insights.