51 Sexually Transmitted Infections

David Mabey 26/09/18

What have we learned from STI research in sub saharan africa. Mabey 2010

Total new infections per year in 2012 estimated to be 350 million of various STIs

Incidence in Kampala is about 100x higher than that seen in england and wales

In Africa there are number of countries where more than 5% of women attending antenatal clinics are positive for syphilis.

In SSA, about 8% of women have syphilis in 2004. Resulting in 2 million pregnancies with syphilis. Resulting in 500,000 deaths of foetal/infants from congenital syphilis

Most countries in SSA have a >50% prevalence of HSV-2

51.1 Why do you have rates of STIS higher in SSA than Europe

  • Stigmatisation
  • Lack of access to treatment
  • Lack of access to contraception
  • Social Demographics (more young people = more STIs!)

51.2 Case Report - HIV plus STI’s

25 yrs man with fever, sore throat, rash, generalised lymphadenopathy. Unprotected sex 3 weeks previously

Painless chancre on penis. No discharge.

Investigations:

  • VDRL (negative)
  • HIV Antibody Test (negative)
  • Dark Field Microscopy (treponema pallidum)

Reason for negative antibody was acute phase.

Higher risk for HIV seroconversion in men who had genital ulcers, and also in those who were uncircumsised.

HIV increases severity and duration of some STI’s, and also the chance of transmission

Genital ulcerations increase risk of HIV transmission.

STI’s causing genital discharge would increase the risk of viral shedding in fluids.

NOT CERTAIN IF TRUE: STI control studies in the 1990’s and early 2000’s in Tanzania. Intervention would reduce the incidence of HIV by about 40%. This isn’t due to changes in sexual behaviour. Probably due to reduced duration of STIs. But it didnt reduce incidence of STIs

But what about Herpes? Suppressive treatment of herpes to prevent HIV acquisition in women in tanzania didn’t change HIV incidence. But when you look at only those who took their tablets, you could see a reduction in risk. Similar thing seen in another study in Africa and Peru.