scholarly journals How sex acts scale with the number of sex partners: evidence from Chlamydia trachomatis data and implications for control

2015 ◽  
Author(s):  
Christian L Althaus ◽  
Marc Choisy ◽  
Samuel Alizon ◽  
Keyword(s):  
Sexual Behavior ◽  
Chlamydia Trachomatis ◽  
Population Based ◽  
Transmission Risk ◽  
Sexually Active ◽  
Sex Partners ◽  
Prevalence Data ◽  
Sexually Transmitted ◽  
Improved Model ◽  
The Impact

Mathematical models are frequently used to assess the impact of control interventions for Chlamydia trachomatis and other sexually transmitted infections (STIs). Modeling approaches that stratify the population by the number of sex partners often assume the transmission risk per partner to be constant. However, sexual behavior data suggests that people with many partners share less sex acts per partner than people with fewer partners. This should lower the risk of transmission per partner for highly sexually active individuals and could have important epidemiological consequences for STI transmission. We devise a new epidemiological model that we fit to chlamydia prevalence data from Natsal-2 and CSF, two population-based probability sample surveys of sexual behavior in Britain and France. Compared to a standard model where the transmission risk per partner is constant, a model with realistic numbers of sex acts per partner provides a better fit to the data. Furthermore, the improved model provides evidence for strong assortative mixing among individuals with different numbers of sex partners. Our results suggest that all chlamydia infected individuals with one or more new heterosexual partners per year contribute significantly to ongoing transmission, underlining that control interventions should be aimed towards all sexually active young adults.

scholarly journals How sex acts scale with the number of sex partners: evidence from Chlamydia trachomatis data and implications for control

2015 ◽  
Author(s):  
Christian L Althaus ◽  
Marc Choisy ◽  
Samuel Alizon ◽  
Keyword(s):  
Sexual Behavior ◽  
Chlamydia Trachomatis ◽  
Population Based ◽  
Transmission Risk ◽  
Sexually Active ◽  
Sex Partners ◽  
Prevalence Data ◽  
Sexually Transmitted ◽  
Improved Model ◽  
The Impact

Mathematical models are frequently used to assess the impact of control interventions for Chlamydia trachomatis and other sexually transmitted infections (STIs). Modeling approaches that stratify the population by the number of sex partners often assume the transmission risk per partner to be constant. However, sexual behavior data suggests that people with many partners share less sex acts per partner than people with fewer partners. This should lower the risk of transmission per partner for highly sexually active individuals and could have important epidemiological consequences for STI transmission. We devise a new epidemiological model that we fit to chlamydia prevalence data from Natsal-2 and CSF, two population-based probability sample surveys of sexual behavior in Britain and France. Compared to a standard model where the transmission risk per partner is constant, a model with realistic numbers of sex acts per partner provides a better fit to the data. Furthermore, the improved model provides evidence for strong assortative mixing among individuals with different numbers of sex partners. Our results suggest that all chlamydia infected individuals with one or more new heterosexual partners per year contribute significantly to ongoing transmission, underlining that control interventions should be aimed towards all sexually active young adults.

scholarly journals Number of sex acts matters for heterosexual transmission and control of Chlamydia trachomatis

2015 ◽  
Author(s):  
Christian L Althaus ◽  
Marc Choisy ◽  
Samuel Alizon ◽  
Keyword(s):  
Sexual Behavior ◽  
Chlamydia Trachomatis ◽  
Population Based ◽  
Transmission Risk ◽  
Heterosexual Transmission ◽  
Sexually Active ◽  
Sex Partners ◽  
Sexually Transmitted ◽  
Improved Model ◽  
And Control

Mathematical models are instrumental in controlling Chlamydia trachomatis and other sexually transmitted infections (STIs). Modeling approaches that stratify the population by the number of individuals' sex partners often assume the transmission risk per partner to be constant. Sexual behavior data shows, however, that people with many partners share less sex acts per partner than people with fewer partners. This should lower the risk of transmission per partner for highly sexually active individuals and could have important epidemiological consequences for STI transmission and the projected impact of control scenarios. We devise a new epidemiological model that we fit to chlamydia prevalence data from Natsal-2 and CSF, two population-based probability sample surveys of sexual behavior in Britain and France. Compared to a standard model where the transmission risk per partner is constant, a model with realistic numbers of sex acts per partner provides a better fit to the data. Furthermore, the improved model provides evidence for strong assortative mixing among individuals with different numbers of sex partners. Our results suggest that all chlamydia infected individuals with one or more new heterosexual partners per year contribute to ongoing transmission, underlining that control interventions should be aimed towards all sexually active young adults.

scholarly journals Chlamydia trachomatis and urogenital mycoplasms in nonconococcal urethirits in men

2010 ◽  
Vol 63 (1-2) ◽  
pp. 47-50
Author(s):  
Sonja Vesic ◽  
Jelica Vukicevic ◽  
Eleonora Gvozdenovic ◽  
Dusan Skiljevic ◽  
Slobodanka Janosevic ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Ureaplasma Urealyticum ◽  
Mycoplasma Hominis ◽  
Sexually Active ◽  
Transmitted Infection ◽  
Sexually Transmitted ◽  
Nongonococcal Urethritis ◽  
Etiological Agents ◽  
The One

Introduction. Nongonococcal urethritis is the most common sexually transmitted infection in men, with vast majority of the etiological agents such as Chlamydia trachomatis, followed by urogenital mycoplasmas. The aim of this study was to determine the prevalence of Chlamydia trachomatis, Ureaplasma urealyticum and Mycoplasma hominis in nongonococcal urethritis in men, and to examine infections associated with these agents. Material and methods. 299 sexually active, heterosexual men with nongonococcal urethritis were included into the study. Urethral samples were taken with a dacron swab placed into the urethra up to 2-3 cm. The Direct immunojluorescence tehnique was performed for identification of Chlamydia trachomatis. Ureaplasma urealyticum and Mycoplasma hominis were detected with Mycoplasma 1ST assay. Results. Chlamydia trachomatis was detected in 22.75%, Uraeplasma urealyticum in 21.08% and Mycoplasma hominis in 8.02% cases. We found no significant differences in prevalence between Chlamydia trachomatis and Ureaplasma urealyticym (p>0.05). Monoinjections were found in 51.85% with significantly higher rate (p<0.01) than associated infections (11.70%). Among associated infections, coinfection of Chlamydia trahomatis and Ureaplasma urealyticum was predominant. Association of Chlamydia trachomatis with urogenital mycoplasmas was significantly higher (p<0.05) than the one between Ureaplasma urealyticum and Mycoplasma hominis. In 36.45% patients no patogenic microorganisms were detected. Conclusion. These results confirmed the etiological role of Chlamydia trachomatis and urogenital mycoplasmas in nongonococcal urethritis with prevalence of 51.85% in monoinfections and 11.70% in associated infections. In 36.45% of cases the etiology of urethritis was not elucidated. These results suggest that more sensitive diagnostic tool should be applied when searching for the detailed etiology of nongonococcal urethritis.

Sexual behavior and sexual problems among patients with severe chronic psychoses

2003 ◽  
Vol 18 (2) ◽  
pp. 70-76 ◽  
Author(s):  
Michele Raja ◽  
Antonella Azzoni
Keyword(s):  
Sexual Behavior ◽  
High Frequency ◽  
Ad Hoc ◽  
Psychiatric Patients ◽  
Female Gender ◽  
Sexual Performance ◽  
Negative Effects ◽  
Sexually Transmitted ◽  
And Performance ◽  
The Impact

AbstractThe aim of the present study was to investigate sexual behavior in a population of psychiatric patients affected by schizophrenia, schizoaffective disorder or bipolar disorder by means of an ad hoc questionnaire designed to explore the three phases of the sexual response: desire (or interest), arousal, and performance. The study assessed patients’ attitude toward sexuality, several aspects of their sexual behavior, including patients’ awareness of the risk of sexually transmitted diseases (STD), contraceptive strategy preferred by patients, and sexual effects of psychotropic medication. Patients reported a high frequency of sexual dysfunction, in particular, hyposexuality. Schizophrenia diagnosis and female gender were associated with lower levels of sexual performance. The impact of psychotropic drugs on patients’ sexuality was significant, with both positive and negative effects. Although 65.8% of patients reported to be concerned about the risk of contracting infections during sexual intercourse, most of them engaged in sexual behavior at high risk for acquisition and transmission of STD. Patients’ compliance with contraceptive measures was poor.

scholarly journals Population-Based Genetic and Evolutionary Analysis of Chlamydia trachomatis Urogenital Strain Variation in the United States

2004 ◽  
Vol 186 (8) ◽  
pp. 2457-2465 ◽  
Author(s):  
Kim Millman ◽  
Carolyn M. Black ◽  
Robert E. Johnson ◽  
Walter E. Stamm ◽  
Robert B. Jones ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Chlamydia Trachomatis ◽  
Selective Sweep ◽  
Purifying Selection ◽  
The United States ◽  
Population Based ◽  
Evolutionary Strategy ◽  
Evolutionary Analysis ◽  
Sexually Transmitted ◽  
Computational Analyses

ABSTRACT Chlamydia trachomatis is a major cause of ocular and sexually transmitted diseases worldwide. While much of our knowledge about its genetic diversity comes from serotyping or ompA genotyping, no quantitative assessment of genetic diversity within serotypes has been performed. To accomplish this, 507 urogenital samples from a multicenter U.S. study were analyzed by phylogenetic and statistical modeling. No B, Da, or I serotypes were represented. Based on our analyses, all but one previous urogenital B serotype was identified as Ba. This, coupled with the lack of B serotypes in our population, suggests that B has specific tropism for ocular mucosa. We identified a Ba/D recombinant (putative crossover nucleotide 477; P < 0.0001) similar to a B/D mosaic we described previously from an African trachoma patient. Computational analyses of the Ba/D recombinant indicated that upstream changes were less important for tissue tropism than downstream incorporation of the D sequence. Since most serotypes had nonsynonymous/synonymous ratios of <1.0, the major outer membrane protein, encoded by ompA, has many functional constraints and is under purifying selection. Surprisingly, all serotype groups except for J had a unimodal population structure indicating rapid clonal expansion. Of the groups with a unimodal structure, E and Ia and, to a lesser extent, G and K were prevalent, had infrequent incorporation of mutations, and, compared to other groups, had a relatively greater degree of diversifying selection, consistent with a selective sweep of mutations within these groups. Collectively, these data suggest a diverse evolutionary strategy for different serogroups of the organism.

scholarly journals Correlates of HIV Infection Among Sexually Active Adults in Kenya: A National Population-Based Survey

2011 ◽  
Vol 5 (1) ◽  
pp. 125-134 ◽  
Author(s):  
Tom Oluoch ◽  
Ibrahim Mohammed ◽  
Rebecca Bunnell ◽  
Reinhard Kaiser ◽  
Andrea A Kim ◽  
...  
Keyword(s):  
Hiv Infection ◽  
Condom Use ◽  
Population Based ◽  
Consistent Condom ◽  
Sexually Active ◽  
Sex Partners ◽  
Consistent Condom Use ◽  
Nationally Representative ◽  
Active Adults ◽  
Sex Partner

Objective: To identify factors associated with prevalent HIV in a national HIV survey in Kenya. Methods: The Kenya AIDS Indicator Survey was a nationally representative population-based sero-survey that examined demographic and behavioral factors and serologic testing for HIV, HSV-2 and syphilis in adults aged 15-64 years. We analyzed questionnaire and blood testing data to identify significant correlates of HIV infection among sexually active adults. Results: Of 10,957 eligible women and 8,883 men, we interviewed 10,239 (93%) women and 7,731 (87%) men. We collected blood specimens from 9,049 women and 6,804 men of which 6,447 women and 5,112 men were sexually active during the 12 months prior to the survey. HIV prevalence among sexually active adults was 7.4%. Factors independently associated with HIV among women were region (Nyanza vs Nairobi: adjusted OR [AOR] 1.6, 95%CI 1.1-2.3), number of lifetime sex partners (6-9 vs 0-1 partners: AOR 3.0, 95%CI 1.6-5.9), HSV-2 (AOR 6.5, 95%CI 4.9-8.8), marital status (widowed vs never married: AOR 2.7, 95%CI 1.5-4.8) and consistent condom use with last sex partner (AOR 2.3, 95%CI 1.6-3.4). Among men, correlates of HIV infection were 30-to-39-year-old age group (AOR 5.2, 95%CI 2.6-10.5), number of lifetime sex partners (10+ vs 0-1 partners, AOR 3.5, 95%CI 1.4-9.0), HSV-2 (AOR 4.7, 95%CI 3.2-6.8), syphilis (AOR 2.4, 95%CI 1.4-4.0), consistent condom use with last sex partner (AOR 2.1, 95% CI 1.5-3.1) and lack of circumcision (AOR 4.0, 95%CI 2.8 - 5.5). Conclusion: Kenya’s heterogeneous epidemic will require regional and gender-specific prevention approaches.

Chlamydia Trachomatis Infection in Sexually Active Women with No Known Sexual Contacts with Urethritis

1989 ◽  
Vol 34 (3) ◽  
pp. 464-466 ◽  
Author(s):  
N. Harrison ◽  
I. W. Smith ◽  
H. Young
Keyword(s):  
Chlamydia Trachomatis ◽  
Sexually Active ◽  
Vaginal Symptoms ◽  
Chlamydia Trachomatis Infection ◽  
Sexually Transmitted ◽  
Cervical Infection ◽  
History Of ◽  
Sexual Contacts

During the period from March 1985 to March 1986, 216 consecutive patients with vaginal symptoms were screened for cervical infection with Chlamydia trachomatis and other sexually transmitted organisms. Eleven (5%) yielded C. trachomatis without a history of recent contact with males with urethritis.

scholarly journals Chlamydia trachomatis among HIV infected patients using PCR technique

2013 ◽  
Vol 1 (2) ◽  
pp. 3-10 ◽  
Author(s):  
Y Shah ◽  
A Shrestha ◽  
N Adhikari ◽  
KP Pant ◽  
KS Khadka ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Public Health Problem ◽  
Chlamydia Infection ◽  
Hiv Positive ◽  
Sexually Active ◽  
Medical Sciences ◽  
Important Public Health Problem ◽  
Sexually Transmitted ◽  
Medical College ◽  
Polymerase Chain

Background and Objectives: Chlamydia trachomatis is a sexually transmitted organism and an important public health problem in the sexually active age group. Limited studies are found regarding the prevalence of Chlamydia trachomatis in Nepal. Moreover, no study in Nepal reports the association of Chlamydia and HIV infection. The current study attempts to determine the burden of Chlamydia on HIV positive patients. Material and Methods: A total of 117 HIV positive patients visiting a HIV clinic in Kathmandu, were screened for Chlamydia infection. For this, Urine samples were collected and analyzed using the Multiplex polymerase chain reaction technique (MPCR) and Agarose gel electrophoresis. DNA isolation was performed using QIAamp DNA and Blood mini kit handbook protocol. Results: C. trachomatis was detected in 4.27% of the total 117 HIV patients. Out of positive cases 60% were males and 40% were females. However, Chlamydia is found more prevalent among females (6.89%) than in males (3.4%). Eighty percent of positive cases were asymptomatic. Conclusion: Chlamydia infection was found less commonly among studied patients and most of those cases were asymptomatic. So there is difficulty in timely detection of C. trachomatis and track the clinical sequel, which might be devastating. Hence, routine checkup is recommended for all suspected cases for timely management of the disease Janaki Medical College Journal of Medical Sciences (2013) Vol. 1 (2): 3-10 DOI: http://dx.doi.org/10.3126/jmcjms.v1i2.9261

scholarly journals Serology reflects a decline in the prevalence of trachoma in two regions of The Gambia

2017 ◽  
Author(s):  
Stephanie J Migchelsen ◽  
Nuno Sepúlveda ◽  
Diana L Martin ◽  
Gretchen Cooley ◽  
Sarah Gwyn ◽  
...  
Keyword(s):  
Public Health Problem ◽  
Population Based ◽  
Cross Sectional Study ◽  
The Gambia ◽  
Cross Sectional ◽  
Sexually Transmitted ◽  
River Region ◽  
Significant Difference ◽  
Ct Antigens ◽  
The Impact

ABSTRACTTrachoma is caused by Chlamydia trachomatis (Ct). It is targeted for global elimination as a public health problem. In 2014, a population-based cross-sectional study was performed in two previously trachoma-endemic areas of The Gambia. Participants of all ages from Lower River Region (LRR) (N = 1028) and Upper River Region (URR) (N = 840) underwent examination for trachoma and had blood collected for detection of antibodies against the Ct antigen Pgp3, by ELISA. Overall, 30 (1.6%) individuals had active trachoma; the prevalence in children aged 1–9 years was 3.4% (25/742) with no statistically significant difference in prevalence between the regions. There was a significant difference in overall seroprevalence by region: 26.2% in LRR and 17.1% in URR (p<0.0001). In children 1-9 years old, seroprevalence was 4.4% in LRR and 3.9% in URR. Reversible catalytic models using information on age-specific seroprevalence demonstrated a decrease in the transmission of Ct infection in both regions, possibly reflecting the impact of improved access to water, health and sanitation as well as mass drug administration campaigns. Serological testing for antibodies to Ct antigens is potentially useful for trachoma programmes, but consideration should be given to the coendemicity of sexually transmitted Ct infections.

scholarly journals Contact patterns and HPV-genotype interactions yield heterogeneous HPV-vaccine impacts depending on sexual behaviours: an individual-based model

2021 ◽  
Author(s):  
Mélanie Bonneault ◽  
Chiara Poletto ◽  
Maxime Flauder ◽  
Didier Guillemot ◽  
Elisabeth Delarocque-Astagneau ◽  
...  
Keyword(s):  
Sexual Behavior ◽  
Sexual Behaviors ◽  
Vaccine Coverage ◽  
Human Papillomaviruses ◽  
Individual Based Model ◽  
Sexually Transmitted ◽  
Vaccine Introduction ◽  
Contact Patterns ◽  
The Impact ◽  
Genotype Infection

AbstractHuman papillomaviruses are common sexually transmitted infections, caused by a large diversity of genotypes. In the context of vaccination against a subgroup of genotypes, better understanding the role of genotype interactions and human sexual behavior on genotype ecology is essential. Herein, we present an individual-based model that integrates realistic heterosexual partnership behaviors and simulates interactions between vaccine and non-vaccine genotypes. Genotype interactions were considered, assuming a previous vaccine-genotype infection shortened (competition) or extended (synergy) the duration of a secondary non-vaccine-genotype infection. Sexual behavior determined papillomavirus acquisition and transmission: only 19.5% of active individuals with 0–1 partner during the year, but >80% of those with ≥2 partners, were infected before vaccine introduction. Genotype interactions, despite being silent during the pre-vaccination era, markedly impacted genotype ecology after vaccination started, with a significant increase/decrease of non-vaccine prevalence for competitive/synergistic interactions. These changes were more pronounced in individuals with ≤3 partners (up to 30% of prevalence modification assuming 65% vaccine coverage) but barely visible for individuals with >3 partners (at most 0.30%). Results suggest that considering genotype interactions, in conjunction with heterogeneous sexual behaviors, is essential to anticipate the impact of existing and future anti-papillomavirus vaccines targeting a subgroup of genotypes.

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