Point-of-Care Testing to Guide Treatment and Estimate Risk Factors for Sexually Transmitted Infections in Adolescents and Young People With Human Immunodeficiency Virus in Eswatini

Background

The World Health Organization (WHO) estimates 127 million new cases of Chlamydia trachomatis (CT), 87 million new cases of Neisseria gonorrhea (NG), and 156 million new cases of Trichomonas vaginalis (TV) each year, which corresponds to 355 (219-606), 303 (216-468), and 243 (97.6-425) thousand disability-adjusted life-years. In low-resource settings, however, sexually transmitted infections (STIs) are treated syndromically and many individuals with asymptomatic infection may be missed, especially adolescents and young adults with human immunodeficiency virus (HIV).

Methods

We enrolled patients aged 15-24 with HIV (N = 300) attending a family-centered HIV clinic in Mbabane, Eswatini. Participants completed a sexual history questionnaire and provided urine as well as oropharyngeal and/or vaginal swabs, if sexually active, for testing with Xpert CT/NG and TV tests. Analysis included bivariate and multivariate odds ratios and test sensitivity and specificity.

Results

Sexually transmitted infection rates were highest (25.0%; 95% confidence interval [CI], 15.2-37.3) in females ages 20-24 who were ever sexually active. In patients with confirmed STIs, NG (15 of 32, 47%) was more common than CT (9 of 32, 28%) and TV (8 of 32, 25%). Syndromic screening alone had a sensitivity of 32.0% (95% CI, 14.9-53.3) and specificity of 86.0% (95% CI, 79.0-91.4) but varied by gender. The presence of an STI was associated with reporting new sexual partner(s) (OR = 2.6; 95% CI, 1.1-6.4), sometimes to never using condoms (OR = 4.2; 95% CI, 1.7-10.2), most recent sexual partner >25 years old (OR = 3.2; 95% CI, 1.3-7.9), and HIV diagnosis at age ≥15 years (OR = 3.4; 95% CI, 1.4-8.2).

Conclusions

Syndromic screening alone performed poorly. Routine diagnostic testing significantly increases STI detection and should be considered in high-risk populations, such as adolescents and young adults with HIV.

Colour-generating interactions across the corpus callosum

Human vision has the remarkable property that, over a wide range, changes in the wavelength composition of the source light illuminating a scene result in very little change in the colour of any of the objects. This colour constancy can be explained by the retinex theory, which predicts the colour of a point on any object from a computed relationship between the radiation from that point and the radiation from all the other points in the field of view (Fig. 1). Thus the computations for colour perception occur across large distances in the visual field. It has not been clear, however, whether these long-range interactions take place in the retina or the cortex. Reports that long-range colour interactions can be reproduced binocularly when one band of wavelengths enters one eye and a different band enters the other might seem to establish the cortex as the site of the computation. Many observers, however, see very unsatisfactory colour or no colour at all in this binocular situation, suggesting that the cortex may not be the only site at which the computation is carried out, or even the most important site. We have now tested the role of the cortex in a human subject in whom the nerve fibres connecting cortical areas subserving two separate parts of the visual field had been severed, and find that the cortex is necessary for long-range colour computations.