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Concept: Chlamydia infection


Zika virus infection has been linked to increased risk for Guillain-Barré syndrome and adverse fetal outcomes, including congenital microcephaly. In January 2016, after notification from a local health care provider, an investigation by Dallas County Health and Human Services (DCHHS) identified a case of sexual transmission of Zika virus between a man with recent travel to an area of active Zika virus transmission (patient A) and his nontraveling male partner (patient B). At this time, there had been one prior case report of sexual transmission of Zika virus (1). The present case report indicates Zika virus can be transmitted through anal sex, as well as vaginal sex. Identification and investigation of cases of sexual transmission of Zika virus in nonendemic areas present valuable opportunities to inform recommendations to prevent sexual transmission of Zika virus.

Concepts: Human sexual behavior, Sodomy, Sex, Chlamydia infection, AIDS, Health care, Sexual intercourse, Health care provider


In 2015, we conducted a cross-sectional, Internet-based, U.S. nationally representative probability survey of 2,021 adults (975 men, 1,046 women) focused on a broad range of sexual behaviors. Individuals invited to participate were from the GfK KnowledgePanel®. The survey was titled the 2015 Sexual Exploration in America Study and survey completion took about 12 to 15 minutes. The survey was confidential and the researchers never had access to respondents' identifiers. Respondents reported on demographic items, lifetime and recent sexual behaviors, and the appeal of 50+ sexual behaviors. Most (>80%) reported lifetime masturbation, vaginal sex, and oral sex. Lifetime anal sex was reported by 43% of men (insertive) and 37% of women (receptive). Common lifetime sexual behaviors included wearing sexy lingerie/underwear (75% women, 26% men), sending/receiving digital nude/semi-nude photos (54% women, 65% men), reading erotic stories (57% of participants), public sex (≥43%), role-playing (≥22%), tying/being tied up (≥20%), spanking (≥30%), and watching sexually explicit videos/DVDs (60% women, 82% men). Having engaged in threesomes (10% women, 18% men) and playful whipping (≥13%) were less common. Lifetime group sex, sex parties, taking a sexuality class/workshop, and going to BDSM parties were uncommon (each <8%). More Americans identified behaviors as "appealing" than had engaged in them. Romantic/affectionate behaviors were among those most commonly identified as appealing for both men and women. The appeal of particular behaviors was associated with greater odds that the individual had ever engaged in the behavior. This study contributes to our understanding of more diverse adult sexual behaviors than has previously been captured in U.S. nationally representative probability surveys. Implications for sexuality educators, clinicians, and individuals in the general population are discussed.

Concepts: Appeal, Chlamydia infection, Group sex, United States, Oral sex, Human sexual behavior, Human sexuality, Sexual intercourse


Zika virus has been identified as a cause of congenital microcephaly and other serious brain defects (1). CDC issued interim guidance for the prevention of sexual transmission of Zika virus on February 5, 2016, with an initial update on April 1, 2016 (2). The following recommendations apply to all men and women who have traveled to or reside in areas with active Zika virus transmission* and their sex partners. The recommendations in this report replace those previously issued and are now updated to reduce the risk for sexual transmission of Zika virus from both men and women to their sex partners. This guidance defines potential sexual exposure to Zika virus as having had sex with a person who has traveled to or lives in an area with active Zika virus transmission when the sexual contact did not include a barrier to protect against infection. Such barriers include male or female condoms for vaginal or anal sex and other barriers for oral sex.(†) Sexual exposure includes vaginal sex, anal sex, oral sex, or other activities that might expose a sex partner to genital secretions.(§) This guidance will be updated as more information becomes available.

Concepts: Sex, Oral sex, HIV, Human sexuality, AIDS, Human sexual behavior, Chlamydia infection, Sexual intercourse


The last decade has seen a dramatic increase in the availability of sexually explicit media (SEM) on the Internet. Men who have sex with men (MSM) report near universal use of SEM. However, this widespread use of SEM among MSM may contribute to more condomless anal sex. To examine the association of viewing SEM on the Internet and the number of condomless anal sex encounters among MSM, in 2012, an online survey was conducted of 265 MSM from New York, Philadelphia, Baltimore, or Washington D.C. who reported viewing SEM online in the past 3 months. Analyses were performed using negative binomial regression. Nearly all men reported viewing SEM featuring anal sex with (91%) or without (92%) condoms in the past 3 months. Neither viewing more hours of SEM per week or compulsively viewing SEM were associated with more condomless anal sex encounters. Rather, viewing a greater proportion of SEM containing condomless anal sex was associated with engaging in more condomless anal encounters (IRR = 1.25), while viewing a greater proportion of SEM containing anal sex where condoms were used was associated with fewer condomless anal sex encounters (IRR = 0.62). MSM reported that viewing SEM caused changes in their sexual fantasies, desires, and behaviors. These findings provide important insights for health policy and the design of interventions addressing SEM and condomless sex among MSM. The findings suggest that condom use by SEM performers may benefit not only actor health, but also have health implications for SEM viewers.

Concepts: Homosexuality, Sodomy, Human sexual behavior, Sexology, Internet, Chlamydia infection, Condom, Sexual intercourse


Sexually transmitted infections are common causes of morbidity and mortality, including infertility and certain types of cancer. Alcohol tax increases may decrease sexually transmitted infection rates overall and differentially across population subgroups by decreasing alcohol consumption in general and prior to sex, thus decreasing sexual risk taking and sexually transmitted infection acquisition. This study investigated the effects of a Maryland increase in alcohol beverage sales tax on statewide gonorrhea and chlamydia rates overall and within age, gender, and race/ethnicity subpopulations.

Concepts: Human sexuality, Alcoholic beverage, Sexually transmitted diseases and infections, Oral sex, AIDS, Sexually transmitted disease, Human sexual behavior, Chlamydia infection


Recently, the world has experienced a rapidly escalating outbreak of infectious syphilis primarily affecting men who have sex with men (MSM); many are taking highly active antiretroviral therapy (HAART) for HIV-1 infection. The prevailing hypothesis is that HAART availability and effectiveness have led to the perception among both individuals who are HIV-1 infected and those who are uninfected that HIV-1 transmission has become much less likely, and the effects of HIV-1 infection less deadly. This is expected to result in increased sexual risk-taking, especially unprotected anal intercourse, leading to more non-HIV-1 STDs, including gonorrhoea, chlamydia and syphilis. However, syphilis incidence has increased more rapidly than other STDs. We hypothesise that HAART downregulates the innate and acquired immune responses to Treponema pallidum and that this biological explanation plays an important role in the syphilis epidemic.

Concepts: Anal sex, Syphilis, Immune system, Epidemiology, Antiretroviral drug, Chlamydia infection, AIDS, HIV


Clinical and experimental studies have shown that estradiol (E2) confers protection against HIV and other sexually transmitted infections. Here, we investigated the underlying mechanism. Better protection in E2-treated mice, immunized against genital HSV-2, coincided with earlier recruitment and higher proportions of Th1 and Th17 effector cells in the vagina post-challenge, compared to placebo-treated controls. Vaginal APCs isolated from E2-treated mice induced 10-fold higher Th17 and Th1 responses, compared to APCs from progesterone-treated, placebo-treated, and estradiol-receptor knockout mice in APC-T cell co-cultures. CD11c+ DCs in the vagina were the predominant APC population responsible for priming these Th17 responses, and a potent source of IL-6 and IL-1β, important factors for Th17 differentiation. Th17 responses were abrogated in APC-T cell co-cultures containing IL-1β KO, but not IL-6 KO vaginal DCs, showing that IL-1β is a critical factor for Th17 induction in the genital tract. E2 treatment in vivo directly induced high expression of IL-1β in vaginal DCs, and addition of IL-1β restored Th17 induction by IL-1β KO APCs in co-cultures. Finally, we examined the role of IL-17 in anti-HSV-2 memory T cell responses. IL-17 KO mice were more susceptible to intravaginal HSV-2 challenge, compared to WT controls, and vaginal DCs from these mice were defective at priming efficient Th1 responses in vitro, indicating that IL-17 is important for the generation of efficient anti-viral memory responses. We conclude that the genital mucosa has a unique microenvironment whereby E2 enhances CD4+ T cell anti-viral immunity by priming vaginal DCs to induce Th17 responses through an IL-1-dependent pathway.

Concepts: B cell, Human sexuality, AIDS, Syphilis, Immune system, Chlamydia infection, T cells, Sexual intercourse


Internet-accessed sexually transmitted infection testing (e-STI testing) is increasingly available as an alternative to testing in clinics. Typically this testing modality enables users to order a test kit from a virtual service (via a website or app), collect their own samples, return test samples to a laboratory, and be notified of their results by short message service (SMS) or telephone. e-STI testing is assumed to increase access to testing in comparison with face-to-face services, but the evidence is unclear. We conducted a randomised controlled trial to assess the effectiveness of an e-STI testing and results service (chlamydia, gonorrhoea, HIV, and syphilis) on STI testing uptake and STI cases diagnosed.

Concepts: Oral sex, Epidemiology, Sexually transmitted diseases and infections, Human sexual behavior, Randomized controlled trial, Chlamydia infection, Short Message Service, Sexually transmitted disease


Gonorrhea, the sexually transmitted disease (STD) caused by Neisseria gonorrhoeae, is the second most common notifiable disease in the United States after chlamydia; 468,514 cases were reported to state and local health departments in 2016, an increase of 18.5% from 2015 (1). N. gonorrhoeae has progressively developed resistance to most antimicrobials used to treat the infection (2). As a result, CDC recommends two antimicrobials (250 mg of ceftriaxone [IM] plus 1 g of azithromycin [PO]) for treating uncomplicated gonorrhea to improve treatment efficacy and, potentially, to slow the emergence and spread of antimicrobial resistance. To monitor adherence to the current CDC-recommended regimen for uncomplicated gonorrhea, CDC reviewed enhanced data collected on a random sample of reported cases of gonorrhea in seven jurisdictions participating in the STD Surveillance Network (SSuN) and estimated the proportion of patients who received the CDC-recommended regimen for uncomplicated gonorrhea, by patient characteristics and diagnosing facility type. In 2016, the majority of reported patients with gonorrhea (81%) received the recommended regimen. There were no differences in the proportion of patients receiving the recommended regimen by age or race/ethnicity; however, patients diagnosed with gonorrhea in STD (91%) or family planning/reproductive health (94%) clinics were more likely to receive this regimen than were patients diagnosed in other provider settings (80%). These data document high provider adherence to CDC gonorrhea treatment recommendations in specialty STD clinics, indicating high quality of care provided in those settings. Local and state health departments should monitor adherence with recommendations in their jurisdictions and consider implementing interventions to improve provider and patient compliance with gonorrhea treatment recommendations where indicated.

Concepts: Human sexual behavior, Sexually transmitted diseases and infections, Neisseria, United States, Chlamydia infection, Sexually transmitted disease, Gonorrhea, Neisseria gonorrhoeae


Gonorrhea is the second most commonly reported notifiable disease in the United States; 350,062 gonorrhea cases were reported in 2014. Sexually transmitted infections caused by Neisseria gonorrhoeae are a cause of pelvic inflammatory disease in women, which can lead to serious reproductive complications including tubal infertility, ectopic pregnancy, and chronic pelvic pain. Prevention of sequelae and of transmission to sexual partners relies largely on prompt detection and effective antimicrobial treatment. However, treatment has been compromised by the absence of routine antimicrobial susceptibility testing in clinical care and evolution of antimicrobial resistance to the antibiotics used to treat gonorrhea.

Concepts: Bacteria, Inflammation, Human sexual behavior, Chlamydia infection, Sexually transmitted disease, Gonorrhea, Pelvic inflammatory disease, Neisseria gonorrhoeae