Representation of natural history and transmission of HIV and sexually transmitted diseases in the STDSIM simulation of the Uganda HIV epidemic
| Transmission probability† | Proportion symptomatic | |||||
|---|---|---|---|---|---|---|
| Infection and stage | Mean duration* | M⇒F | F⇒M | Cofactor effect on HIV transmission†‡ | M | F |
| *Individual stage durations were sampled from a Weibull distribution function with shape parameter 2, except for the duration of the early latent stage of HSV-2 and the interval between recurrent HSV-2 ulcers, which used exponential distribution functions; †per contact; equal for recognized and unrecognized episodes; ‡both for susceptibility (in HIV negative partner) and infectivity (in HIV positive partner); §except during recurrent ulcers. | ||||||
| F, female; M, male; na, not applicable. | ||||||
| HIV | ||||||
| Primary | 10 weeks | 0.045 | 0.015 | na | na | na |
| Asymptomatic | 5 years | 0.00225 | 0.00075 | na | na | na |
| Symptomatic pre-AIDS | 2 years | 0.00225 | 0.00075 | na | na | na |
| AIDS | 40 weeks | 0.01125 | 0.00375 | na | na | na |
| Syphilis | ||||||
| Infectious | 6 months | 0.3 | 0.2 | 10× | 80% | 50% |
| Latent | 15 years | 0 | 0 | na | na | na |
| Chancroid | 10 weeks | 0.20 | 0.15 | 25× | 90% | 70% |
| HSV-2 | ||||||
| Primary ulcer | 3 weeks | 0.30 | 0.15 | 25× | 30% | |
| Early latent (with recurrent ulcers) | 15 years | 0.005§ | 0.0025§ | na§ | na§ | na§ |
| Recurrent ulcer | 1 week; Interval between ulcers 6 months | 0.20 | 0.10 | 10× | 15% | 7.5% |
| Late latent | Lifelong | 0 | 0 | na | na | na |
| Gonorrhoea | M 9 weeks; F 13 weeks | 0.22 | 0.15 | 5× | 50% | 20% |
| Chlamydia | M 12 weeks; F 16 weeks | 0.20 | 0.12 | 5× | 30% | 15% |