Table 2b.
Disease states in typhoid models.
| Abbeviation | Disease state | Comment |
|---|---|---|
| N | Newborn | Susceptible in Cvjetanović’s model, refractory in Saul's |
| S | Susceptible; | |
| S1 S2 | Fully and partially susceptible | |
| E; | ‘Exposed’; | Infected but not (yet) infectious |
| Es; Ea | Symptomatic or asymptomatic | |
| I; | Infectious; | |
| Is Ia | Symptomatic or asymptomatic | Primary infection of a fully susceptible individual or asymptomatic/subclinical infection of a previously partially susceptible individual |
| I1 I2 | Primary or subclinical infection | |
| C; | Carrier; | |
| Ct; Cl | Temporary; long-term | |
| R; | Removed/resistant/refractory/recovered; | Not able to be infected, immune. |
| Rt; Rl; | Temporary immunity; long-term immunity; | Clinical immunity is against disease but allows infection and onward transmission. |
| Rc; Rs | Natural immunity to clinical disease; natural sterile immunity) | Sterile immunity is against any infection. |
| V | Vaccinated | |
| Vc; Vs | Vaccine-induced immunity to clinical disease; Vaccine-induced sterile immunity | |
| W | ‘Water’ | Long-cycle transmission from water or environmental contamination, contributed to by all infectious or carrier classes. |