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 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 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.

scholarly journals Heterosexual Transmission of Human Immunodeficiency Virus Infection – Strategies for Prevention

1991 ◽  
Vol 2 (1) ◽  
pp. 30-36 ◽  
Author(s):  
Brian Conway ◽  
D William Cameron ◽  
Francis A Plummer ◽  
Allan R Ronald
Keyword(s):  
Human Immunodeficiency Virus ◽  
Transmission Rate ◽  
Transmitted Disease ◽  
Immune Deficiency Syndrome ◽  
Educational Interventions ◽  
Sexual Practices ◽  
Heterosexual Transmission ◽  
Sexually Active ◽  
Sexually Transmitted ◽  
Immunodeficiency Virus

In Canada, over 90% of the acquired immune deficiency syndrome cases diagnosed so far have been acquired sexually, with an increasing proportion made up of heterosexual contacts of high risk individuals. In multiple studies, the transmission rate among steady heterosexual partners of infected individuals has been variable. It is likely that complex biological and epidemiological interactions exist between human immunodeficiency virus (HIV) and sexually transmitted diseases with respect to transmission and disease. Other important determinants in transmission of infection may relate to the virus itself. The importance of sexual practices other than vaginal intercourse (such as anal intercourse) in the heterosexual transmission of HIV has not been well studied. The major approach to the control of HIV-associated disease remains the control of primary infection. Sexual practices which are the major epidemiological determinants of HIV transmission can be successfully modified by appropriate educational interventions. The promotion of condom use must form a special part of these interventions. Results of ongoing trials should be available prior to the formulation of recommendations for the use of spermicides. Targeted education programs may allow us to make better use of our resources in a more efficient way. In Canada, groups that could be reached by such programs include: prostitutes and their clients; men and women attending sexually transmitted disease clinics; sexually active women attending family planning clinics; and children and adolescents who are becoming sexually active.

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 Knowledge, attitudes and practices among the youth in Bosnia and Herzegovina relevant for reproductive health

2017 ◽  
Vol 70 (9-10) ◽  
pp. 289-296 ◽  
Author(s):  
Azra Hadzimehmedovic ◽  
Mahira Jahic ◽  
Selma Muratovic
Keyword(s):  
Sexual Behavior ◽  
Reproductive Health ◽  
Sexually Transmitted Infections ◽  
Bosnia And Herzegovina ◽  
Pap Test ◽  
Hormonal Contraceptives ◽  
Sexually Active ◽  
Sexually Transmitted ◽  
Attitudes And Practices ◽  
A Prospective Study

Introduction. The aim of this study was to investigate the sexual behavior, attitudes and knowledge on contraception, sexually transmitted infections and reproductive health among the youth in Bosnia and Herzegovina. Material and Methods. A prospective study included a sample of 6.000 subjects, aged 19-24, of both sexes, investigating the sexual behavior of the youth in Bosnia and Herzegovina in the period 2007 - 2009. Results. Of the interviewed examinees, 61% were sexually active, of which 56.4% had sexual intercourse with one partner (z = 28.51; p < 0.001). The average age of sexarche was significantly lower in males 17.34 ? 1.77 years, than in females 18.20 ? 1.84 years (z = -14.44; p < 0.001). Contraception was used by 67.6% at first intercourse, and by 70.4% at the last intercourse. The most common method of contraception was male condom (74%), coitus interruptus (11.1%), and oral hormonal contraceptives (14.9%). The examined subjects had inadequate knowledge (51.6%) about contraceptive methods, and it was significantly higher in males (64.6%) than in females (42.2%) (z = 10.17; p < 0.001). Some 4.9% of the sexually active females had intentional abortions. Up to 51.7% of females had never had a pelvic examination, and Pap test was done by 37.2%. The examinees obtained information about contraception and sexually transmitted infections from peers 50.7% and parents 9.7%. Only 28% of females had a positive attitude towards oral hormonal contraceptives. Conclusion. The interviewed young people in Bosnia and Herzegovina keep traditional sexual behavior patterns, attitudes and practices. However, more effort should be put into the improvement of knowledge on contraception, sexually transmitted infections, and healthcare protection.

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