From superspreaders to disease hotspots: linking transmission across hosts and space

Abstract

Since the identification and imprisonment of “Typhoid Mary,” a woman who infected at least 47 people with typhoid in the early 1900s, epidemiologists have recognized that ‘superspreading’ hosts play a key role in disease epidemics. Such variability in transmission also exists among species within a community (amplification hosts) and among habitat patches across a landscape (disease ‘hotspots’), underscoring the need for an integrative framework for studying transmission heterogeneity. Here, we synthesize literature on human, plant, and animal diseases to evaluate the relative contributions of host, pathogen, and environmental factors in driving transmission heterogeneity across hosts and space. We show that host and spatial heterogeneity are closely linked and that quantitatively assessing the contribution of infectious individuals, species, or environmental patches to overall transmission can aid management strategies. We conclude by posing hypotheses regarding how pathogen natural history influences transmission heterogeneity and highlight emerging frontiers in the study of transmission heterogeneity.

Crossing the scale from within-host infection dynamics to between-host transmission fitness: a discussion of current assumptions and knowledge

“…It is widely acknowledged that there is heterogeneity in the transmission potential of infected hosts [103][104][105]. Understanding how within-host factors of an infected individual contribute to transmission is important in targeting intervention strategies at high transmission hosts [106].…”

Parasite sources and sinks in a patched Ross–Macdonald malaria model with human and mosquito movement: Implications for control

“…and therefore, upon taking the spectral radius of the matrices above, the fact that R(P Q) = 1 (because the product of two row-stochastic matrices is row-stochastic, hence has spectral radius 1), (27) implies (37). To prove (38) and (39) we use a similar argument as in the proof of Theorem 3.…”

“…and hence (30) follows from (27) and the fact that R(P ) = 1 (since P is rowstochastic). To prove that the lower bound is achieved, take P min as the matrix having exactly one column consisting of ones, namely the ith column where i is any index such that R i 0 = (R 0 ) min , and all other columns are zero vectors.…”

“…Host mediated parasite movement on these landscapes drives source-sink parasite dynamics which elimination programs must account for [9], as areas with enough transmission to sustain parasite populations locally will export excess parasites through host movement, known as transmission foci, supporting parasite populations in sink areas, or areas where parasites would not persist otherwise [9]. As transmission foci enable parasite persistence in sinks, they have been proposed as prime targets for control efforts [9,27]. Conceptually, regional malaria elimination can then be achieved by reducing transmission within all transmission foci to below self-sustaining levels [25].…”

Untitled

“…Insights from individual-based multispecies models may thus aid disease control efforts by identifying both individuals and species that require greater control, making the efforts more effective [28]. Furthermore, in systems where individual data has already been collected, such as in many parasite surveys (e.g.…”