Modelling cholera epidemics: the role of waterways, human mobility and sanitation

TLDR

Cholera spreads mainly through hydrologically controlled ecological corridors, and human mobility drives long‑range transmission. The study aims to develop a spatially explicit cholera epidemic model to address social and scientific concerns. The authors use a two‑layer network model combining epidemiology, hydrology, and a gravity‑model host movement, validated against KwaZulu‑Natal 2000–2001 outbreak data. They find that long‑range human movement explains inter‑catchment V.

Abstract

We investigate the role of human mobility as a driver for long-range spreading of cholera infections, which primarily propagate through hydrologically controlled ecological corridors. Our aim is to build a spatially explicit model of a disease epidemic, which is relevant to both social and scientific issues. We present a two-layer network model that accounts for the interplay between epidemiological dynamics, hydrological transport and long-distance dissemination of the pathogen Vibrio cholerae owing to host movement, described here by means of a gravity-model approach. We test our model against epidemiological data recorded during the extensive cholera outbreak occurred in the KwaZulu-Natal province of South Africa during 2000–2001. We show that long-range human movement is fundamental in quantifying otherwise unexplained inter-catchment transport of V. cholerae , thus playing a key role in the formation of regional patterns of cholera epidemics. We also show quantitatively how heterogeneously distributed drinking water supplies and sanitation conditions may affect large-scale cholera transmission, and analyse the effects of different sanitation policies.