The prevalence of bacterial sexually transmitted infections decreased significantly in Botswana in the decade between 1993 and 2002, according to a study published in the November 1st edition of Clinical Infectious Diseases. At the same time, however, the proportion of genital ulcerative disease caused by herpes simplex virus 2 more than doubled, and the investigators found that almost three quarters of patients with genital ulcers were HIV-positive. The investigators suggest that anti-herpes therapy could have the potential to limit HIV transmission.
Adult HIV prevalence in Botswana is 37%, one of the world’s highest. Sexually transmitted infections have been identified as a risk factor for HIV infection and the treatment of sexually transmitted infections is recognised as an important part of HIV prevention strategies. Many countries use the World Health Organization’s syndromic approach to the treatment of sexually transmitted infections. The success of these treatment programmes depend on whether the correct treatment is being provided for the syndrome being observed.
The spread of HIV appears to have been accompanied by a change in the epidemiology of sexually transmitted infections, with more genital ulcerative disease attributable to herpes simplex virus 2.
A study was conducted in 2002 to see if Botswana had the correct treatment approaches for sexually transmitted infections. The results of this survey were compared to those of a similar study conducted in 1993 to see if there had been any significant changes in the spectrum of infections contributing to sexual ill health in the country.
In both 1993 and 2002, the studies included women attending family planning clinics and men and women seeking treatment for sexually transmitted infections. A total of 419 individuals were included in the 1993 study and 954 individuals in the 2002 analysis.
HIV prevalence in 1993 was 17% amongst women attending for family planning, 26% amongst women with vaginal discharge or lower abdominal pain, 27% amongst men with urethral discharge and 37% amongst patients with genital ulcerative disease.
Herpes simplex virus 2 caused 23% of the genital ulcerative disease seen in 1993 and blood tests showed that 52% of patients with genital ulcers were infected with syphilis.
By 2002, the prevalence of HIV infection had increased to 74% amongst those presenting with genital ulcers, 62% amongst men with urethral discharge, 54% amongst women with symptoms of a sexually transmitted infection and 42% amongst women seeking family planning.
Of the patients with genital ulcers, only 2% were infected with syphilis, but the proportion with herpes simplex virus 2 had increased to 58%. This was a highly significant increase on the 1993 results (p < 0.001).
“We found changes in relative prevalence of STDs in Botswana in the past ten years, with decreases in the prevalence of bacterial STDs…and increases in the proportion of ulcers due to herpes simplex virus 2”, write the investigators.
They offer several possible explanations for the changes in the epidemiology of sexually transmitted infections in Botswana during this period. These include HIV-related mortality amongst the core population of individuals with chancroid disease and behaviour change, including later age of sexual debut, fewer sexual partners and increased condom use.
The investigators note that previous World Health Organization guidelines for the treatment of genital ulcerative disease were largely concerned with bacterial causes. Because of the increased prevalence of herpes simplex virus 2 in many countries, the World Health Organization now endorses anti-herpes therapies in settings where there is a herpes prevalence above 30%.
Significant investment will be needed to add aciclovir to the essential drugs list, stress the investigators, and they caution that in “real-life” settings the use benefits of aciclovir for the management of genital ulcers may be limited. They emphasise that the drug needs to be administered within a day of symptoms emerging if the duration and severity of the ulcerative attack is to be limited.
If, however, aciclovir therapy is found to be effective, the investigators conclude “its incorporation into syndromic management could hold great importance for public health, by providing a safe, acceptable, and cost effective method to treat genital ulcerative disease and potentially reduce HIV infectiousness”.
Paz-Bailey G et al. Changes in the etiology of sexually transmitted diseases in Botswana between 1993 and 2002: implications for the clinical management of genital ulcer disease. Clin Infect Dis 41: 1304 – 1312, 2005.