A clarification of transmission terms in host-microparasite models: numbers, densities and areas

• DOI: 10.1017/s0950268802007148
• Publication Date: 2002-09-19T08:23:41Z
• Authors: M. BEGON; M. BENNETT; R. G. BOWERS; N. P. FRENCH; S. M. HAZEL; J. TURNER
• Keywords: Confusion; Density dependence; Transmission rate; Susceptible individual

Transmission is the driving force in dynamics of any infectious disease. A crucial element understanding disease dynamics, therefore, 'transmission term' describing rate at which susceptible hosts are 'converted' into infected by their contact with material. Recently, conventional form this term has been increasingly questioned, and new terminologies conventions have proposed. Here, we review derivation transmission terms, explain basis confusion, provide clarification. The root problem a failure to include explicit consideration area occupied host population, alongside both number density within population. We argue that terms 'density-dependent transmission' 'frequency-dependent remain valid useful (though 'fuller' for former identified), but 'mass action', 'true mass action' 'pseudo all unhelpful should be dropped. Also, contrary what often assumed, distinction between homogeneous heterogeneous mixing population orthogonal density- frequency-dependent modes.