🏗️ Conceptual Overview In the epidemiology of sexually transmitted infections (STIs), population heterogeneity plays a dominant role. Transmission is often sustained by a relatively small subset of individuals with high rates of partner change. The Core-Group STI Model formalizes this observation by explicitly partitioning the population into activity-defined subgroups and examining how a highly active … Read more
🏗️ Conceptual Overview Transmission dynamics within hospitals differ fundamentally from those in the community. High patient turnover, intensive contact with healthcare workers, and the presence of asymptomatic carriers create conditions in which pathogens can persist and spread silently. The Colonization–Infection Hospital Model is a specialized compartmental framework designed to capture these features by explicitly distinguishing … Read more
🏗️ Conceptual Overview Within mathematical epidemiology, the Closed Population SIR Model is the canonical framework for analyzing acute, short-term epidemic outbreaks. The defining assumption is that the epidemic unfolds on a time scale that is short relative to host demographic processes. As a result, births, natural deaths, and migration are neglected, and the total population … Read more
🏗️ Conceptual Overview During the early phase of an epidemic, the classical assumption of purely exponential growth frequently fails to describe observed transmission patterns. Social distancing, spatial clustering, contact heterogeneity, and early behavioral responses can all slow epidemic expansion well before susceptible depletion becomes relevant. The Chowell Generalized Growth Model (GGM) is a phenomenological epidemic … Read more
🧫 Conceptual Overview Classical epidemiological models often assume that transmission occurs exclusively through direct contact between individuals. For many pathogens, however, the environment plays an active and dynamic role in disease transmission. Examples include enteric viruses such as Norovirus and environmental bacteria such as Vibrio cholerae, where pathogens persist, accumulate, and decay outside the host. … Read more
🏗️ Conceptual Overview In mathematical epidemiology, direct observation of transmission intensity over long time horizons is often impossible. The Catalytic Model provides a principled method to infer the force of infection (λ)—the per capita rate at which susceptible individuals acquire infection—using cross-sectional serological data stratified by age. Rather than tracking infections forward in calendar time, … Read more
🏢 Conceptual Overview Classical epidemic models commonly assume bilinear (mass-action) transmission, where the incidence rate grows proportionally with the product of susceptible and infectious individuals. The Capasso–Serio model relaxes this assumption by introducing a saturated (nonlinear) incidence function, capturing situations in which transmission does not increase indefinitely as the number of infectious individuals grows. Such … Read more
🏗️ Conceptual Overview In mathematical epidemiology, the Bilinear Incidence SIR Model, commonly known as the Mass-Action SIR model, represents the foundational deterministic framework for modeling infectious disease transmission. It assumes a homogeneous, well-mixed population in which the rate of new infections is proportional to the product of the number of susceptible individuals and the number … Read more
📈 Conceptual Overview Vector-borne infectious diseases such as Dengue, Zika, and Malaria require the simultaneous modeling of two biologically distinct populations: a vertebrate host and an arthropod vector. The Bailey–Dietz model extends the classical Ross–Macdonald framework by providing a clear system of ordinary differential equations that explicitly capture the bidirectional transmission cycle between humans and … Read more
📈 Conceptual Overview In contrast to microparasite models, which track whether hosts are infected or not, the Anderson–May macroparasite model focuses on infections where disease severity and transmission depend on the parasite burden within individual hosts. This framework is essential for helminth infections such as hookworm, schistosomiasis, and lymphatic filariasis, where morbidity increases nonlinearly with … Read more