Monogamous networks and the spread of sexually transmitted diseases

Patterns of sexual mixing and heterogeneity in the number of sexual partners can have a huge effect on the spread of a sexually transmitted disease (STD). The sexual mixing network identifies all partnerships within a population over a given period and is a powerful tool in the study of such infections. Previous models assumed all links within the network to be concurrent active partnerships. We present a novel modelling approach in which we adapt the notion of a sexual contact network to a monogamous population by allowing the nature of the links to change. We use the underlying network to represent potential sexual partnerships, only some of which are active at any one time. Thus serial monogamy can be modelled while maintaining the patterns of mixing displayed by the population.     

Cost benefit analysis of sexually transmitted diseases.

Suggested measures to prevent transmission and sequelae of sexually transmitted diseases are almost universally agreed. But the important question to be answered is whether the interventions are worth the resources spent. To facilitate the decision making on resource allocation, the best possible information should be available concerning the relationships between health intervention programs and changes in the health status. Cost benefit analysis is the main approach used to assess the efficiency of any intervention. If the economic benefits of the program are greater than the costs, the program should be seriously considered. Although information about the costs of management of STDs is scarce in developing countries because of the complicated behavioral, social and economic issues involved, it is widely held that making treatment available for curable sexually transmitted diseases represents one of the most cost-effective ways to improve the health in the world.     

The influence of sexually active non-reproductive groups on persistent sexually transmitted diseases

We describe several population models exposed to a mild life-long sexually transmitted disease, i.e. without significant increased mortality among infected individuals and providing no immunity/recovery. We then modify these models to include non-reproductive groups consisting of those isolated from sexual contact and those who are sexually active but infertile due to choice, medical or other reasons. We analyse the potential effect on the dynamics of the population. We are interested in how the isolated class may curb the growth of the infected group while keeping the healthy population at acceptable levels. We also analyse the difference between being sexually active and abstained within the non-reproductive class and its impact on the epidemic reproductive number and the nature of the bifurcation around the disease-free equilibrium. We provide a comparison with our models introduced in a previous article, which include only the isolated from sexual contact class.     

Association of sexually transmitted infections and human papillomavirus co-infection with abnormal cervical cytology among women in Saudi Arabia

Human papillomavirus (HPV) is a causative agent of cervical and other cancers. Sexually transmitted Infections (STIs) may play a crucial role in HPV persistence, leading to serious complications, including cervical cancer. This study investigated the association of HPV/STI co-infection in cervical samples with cervical dysplasia among women in Saudi Arabia. HPV-positive cervical samples (n = 142) were obtained from previous studies and newly collected samples (n = 209) were obtained from women aged 19–83 years. For HPV detection and genotyping, PCR and Genoflow HPV assay kits were used. STIs were detected using a Genoflow STD array kit. Of 351 samples, 94 (27%) were positive for STIs. Among HPV-positive samples, 36 (25%) were positive for STIs; the most common pathogens were Ureaplasma urealyticum/Ureaplasma parvu (13%) and Mycoplasma hominis (6%). A global significant correlation was detected between HPV and STIs with progression of abnormal cervical cytology (χ² = 176, P < 0.0001). Associations between cervical cytology diagnosis and HPV status, STI types (opportunistic and pathogenic), and the presence of Ureaplasma spp., and Mycoplasma hominis were significant (P < 0.05). Our results suggest that additional study in a larger population is warranted to determine the association between HPV/STI co-infection and cervical neoplasia in Saudi women.     

The influence of sexually active non-reproductive groups on persistent sexually transmitted diseases

We describe several population models exposed to a mild life-long sexually transmitted disease, i.e. without significant increased mortality among infected individuals and providing no immunity/recovery. We then modify these models to include non-reproductive groups consisting of those isolated from sexual contact and those who are sexually active but infertile due to choice, medical or other reasons. We analyse the potential effect on the dynamics of the population. We are interested in how the isolated class may curb the growth of the infected group while keeping the healthy population at acceptable levels. We also analyse the difference between being sexually active and abstained within the non-reproductive class and its impact on the epidemic reproductive number and the nature of the bifurcation around the disease-free equilibrium. We provide a comparison with our models introduced in a previous article, which include only the isolated from sexual contact class.     

女性泌尿生殖系统性病病原体感染情况分析

目的 研究性传播疾病病原体在女性泌尿生殖系统的感染情况。方法 选择2018年广州市皮肤病防治所性病门诊收治的484例女性初诊患者为患者组,选择同期30例健康女性体检者作为对照组,检测两组对象8种性病的患病情况,包括6种法定报告性病（HIV感染、梅毒、生殖器疱疹、沙眼衣原体感染、淋病、尖锐湿疣）和2种非法定报告性病（解脲脲原体及人形支原体感染、假丝酵母菌感染）。结果 484例初诊女性患者中共有292人患性病,占女性初诊患者的60.3%,与对照组相比差异有统计学意义（P<0.05）。292例性病患者合并感染率较高,出现性病合并感染的患者共94人,占32.2%（94/292）。入选患者共有感染类型23型,患者最多可同时患有4种性病。沙眼衣原体感染患者合并感染率最高,达到83.7%（36/43）。结论 应加强女性性病患者性病病原体的全面筛查和相关感染的预防。     

The effect of combat exposure on sexually transmitted diseases

Traumatic exposures can affect beliefs and behaviors related to the spread of sexually transmitted diseases (STDs), a persistent public health problem. I leverage a natural experiment created by variation in US military deployment location assignments to estimate how combat exposure changes a surviving deployed male veteran’s probability of acquiring a sexually transmitted disease. I analyze longitudinal data from 1994 to 2008 on 485 deployed veterans with information theoretic methods to reduce the sensitivity of estimates to small samples, an infrequently observed outcome, and highly correlated covariates. For veterans assigned to a combat zone, I estimate combat exposure results in a 5.4 percentage point increase in the probability of acquiring an STD. Additional estimations provide evidence suggesting risky behaviors involving substance use or multiple sexual partners may serve as pathways from combat exposure to STDs. My results are relevant to discussions regarding STD screening and care needs for trauma exposed individuals.     

The role of sexually transmitted diseases in HIV transmission

More than 42 million people worldwide are now infected with HIV, in spite of sustained prevention activities. Although the spread of HIV has been primarily sexual, epidemiological studies have indicated that the efficiency of the spread of HIV is poor, perhaps as infrequently as 1 in every 1,000 episodes of sexual intercourse. However, sexually transmitted diseases (STDs) that cause ulcers or inflammation greatly increase the efficiency of HIV transmission--by increasing both the infectiousness of, and the susceptibility to HIV infection. STDs might be particularly important in the early stages of a localized HIV epidemic, when people with risky sexual behaviour are most likely to become infected. In China, eastern Europe and Russia, there has been a remarkable increase in the incidence of STDs in recent years, and this is reflected in the rapid increase in the spread of HIV in these areas. Targeted STD detection and treatment should have a central role in HIV prevention in these emerging epidemics.     

Epidemiology of sexually transmitted Chlamydia trachomatis infections in male patients

868 male urethritis patients were studied for the presence of chlamydiae in the 1981-1986 period. 36% of NGU, 31.3% of gonococcal urethritis and 58.8% of PGU urethritis patients presented C. trachomatis infections as detected by cell culture inoculation. Chlamydial infection was recorded more often in the 21-30 years age group (30.8%), in unmarried patients (70.6%), as well as in people with low educational degree (46.6% of cases), 42.3% of the C. trachomatis cases were already confronted with one or more urethritis episodes. 24.7% of patients have been subjected to a previous antichlamydial treatment.