Improving strategies for syphilis control in China: selective testing of sexually transmitted disease patients--too little, too late?

Prevalence and associated factors of sexually transmitted infections among methamphetamine users in Eastern China: a cross-sectional study

BACKGROUND

The reported incidence of sexually transmitted infections (STIs) in China has been increasing over the last decades, especially among drug users, which has become one of the main burdens of public health in China. This study was conducted to estimate the prevalence and associated factors of STIs among non-injecting methamphetamine (MA) users in Eastern China.

METHODS

A cross-sectional survey was conducted among 632 MA users in Eastern China in 2017. Demographic characteristics, sexual behaviors, behaviors of MA use and sexual health knowledge were collected through questionnaire. First pass urine specimens were collected and detected for deoxyribonucleic acid (DNA) of Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) with Nucleic Acid Amplification Technology (NAAT), while blood specimens were collected and detected for antibodies of Human immunodeficiency virus (HIV), Herpes simplex virus type-2 (HSV-2), and syphilis with enzyme-linked immune sorbent assay (ELISA).

RESULTS

Among the 632 MA users, 464 (73.42%) were males, 60.92% were < 35 years of age, 546 (86.39%) were Shandong residents. 317 (50.16%, 95% CI 46.26-54.06%) participants were tested positive for at least one kind of STIs, including 242 (38.29%, 95% CI 34.50-42.08%) for HSV-2, 107 (16.93%, 95% CI 14.01-19.85%) for active syphilis, 46 (7.28%, 95% CI 5.25-9.31%) for treated syphilis, 40 (6.33%, 95% CI 4.43-8.23%) for CT, 6 (0.95%, 95% CI 0.19-1.71%) for HIV, and 3 (0.47%, 95% CI 0.06-1.00%) for NG infection. 99 (15.66%, 95% CI 12.83-18.49%) participants were co-infected with two kinds of STIs, including 91 (14.40%, 95% CI 11.66-17.14%) participants were co-infected with HSV-2 and syphilis. 14 (2.22%, 95% CI 1.07-3.37%) participants were co-infected with three kinds of STIs, and 4 HIV positive participants were co-infected with both syphilis and HSV-2. In the multiple logistic regression analysis, the results showed that females (adjusted OR [AOR] = 7.30, 95% CI 4.34-12.30) and individuals ≥ 35 years of age (AOR = 2.97, 95% CI 2.04-4.32) were more likely to test positive for STIs among MA users, whereas participants who acquired sexual health knowledge primarily from the Internet (AOR = 0.57, 95% CI 0.40-0.82) and those whose regular partners did not use drugs (AOR = 0.59, 95% CI 0.37-0.94) were less likely.

CONCLUSIONS

This study found that the prevalence of HSV-2 and syphilis are alarming high among non-injecting MA users in Shandong Province in Eastern China. The prevention and control intervention of STIs among MA users in Shandong were needed, especially on females and MA users ≥ 35 years of age.

Three-dimensional plasmonic nanoclusters

Assembling nanoparticles into well-defined structures is an important way to create and tailor the optical properties of materials. Most advances in metamaterials research to date have been based on structures fabricated in two-dimensional planar geometries. Here, we show an efficient method for assembling noble metal nanoparticles into stable, three-dimensional (3-D) clusters, whose optical properties can be highly sensitive or remarkably independent of cluster orientation, depending on particle number and cluster geometry. Some of the clusters, such as tetrahedra and icosahedra, could serve as the optical kernels for metafluids, imparting metamaterial optical properties into disordered media such as liquids, glasses, or plastics, free from the requirement of nanostructure orientation.