Figure 1.

(a) Representation of a MP model for sexually active heterosexual men and women. The heterosexual population comprises subpopulations with an equal number of men and women. The proportion of high-activity individuals is allowed to vary between subpopulations (light grey squares, low-activity men; dark grey squares, high-activity men; light grey circles, low-activity women; dark grey circles, high-activity women; solid two-head arrows, partnerships within subpopulations; dashed two-head arrows, partnerships between subpopulations). (b) Schematic of infection states for gonorrhoea. Individuals have three infection states: uninfected and susceptible, symptomatic and care-seeking, and non-care-seeking. Arrows represent transitions between infection states (solid arrows, λ: rate of infection from contact with infectious members of opposite gender; dashed arrows, σ: recovery rate in symptomatic care-seeking patients; dotted arrows, κ: recovery rate in non-care-seeking patients).