252 research outputs found
HIV and STI Prevalence among Female Sex Workers in CĂ´te d'Ivoire: Why Targeted Prevention Programs Should Be Continued and Strengthened
Objective: To assess condom use and prevalence of STIs and HIV among female sex workers (FSWs), as part of a comprehensive monitoring and evaluation plan of a nationwide sex worker prevention project in Côte d’Ivoire. Design and Methods: Cross sectional surveys were conducted among FSWs attending five project clinics in Abidjan and San Pedro (2007), and in Yamoussoukro and Gagnoa (2009). A standardized questionnaire was administered in a face-toface interview, which included questions on socio-demographic characteristics, sexual behaviour and condom use. After the interview, the participants were asked to provide samples for STI and HIV testing. Results: A total of 1110 FSWs participated in the surveys. There were large differences in socio-demographic and behavioural characteristics between FSW coming for the first time as compared to FSW coming on a routine visit. The prevalence of N. gonorrhoeae or C.trachomatis was 9.1%, 11.8 % among first vs. 6.9 % routine attendees (p = 0.004). The overall HIV prevalence was 26.6%, it was lower among first time attendees (17.5 % as compared to 33.9 % for routine attendees, p,0.001). The HIV prevalence among first attendees was also lower than the proportion of HIV positive tests from routine testing and counselling services in the same clinics. Conclusions: The results show a relatively high STI and HIV prevalence among FSWs in different cities in Côte d’Ivoire. In th
Prevalence of sexually transmitted infections among young people in South Africa: A nested survey in a health and demographic surveillance site
BACKGROUND: Sexually transmitted infections (STIs) and bacterial vaginosis (BV) are associated with increased transmission of HIV, and poor reproductive and sexual health. The burden of STIs/BV among young people is unknown in many high HIV prevalence settings. We conducted an acceptability, feasibility, and prevalence study of home-based sampling for STIs/BV among young men and women aged 15-24 years old in a health and demographic surveillance site (HDSS) in rural KwaZulu-Natal, South Africa. METHODS AND FINDINGS: A total of 1,342 young people, stratified by age (15-19 and 20-24 years) and sex were selected from the HDSS sampling frame; 1,171/1,342 (87%) individuals had ≥1 attempted home visit between 4 October 2016 and 31 January 2017, of whom 790 (67%) were successfully contacted. Among the 645 who were contacted and eligible, 447 (69%) enrolled. Consenting/assenting participants were interviewed, and blood, self-collected urine (men), and vaginal swabs (women) were tested for herpes simplex virus type 2 (HSV-2), chlamydia, gonorrhoea, syphilis, trichomoniasis, and BV. Both men and women reported that sample collection was easy. Participants disagreed that sampling was painful; more than half of the participants disagreed that they felt anxious or embarrassed. The weighted prevalence of STIs/BV among men and women, respectively, was 5.3% and 11.2% for chlamydia, 1.5% and 1.8% for gonorrhoea, 0% and 0.4% for active syphilis, 0.6% and 4.6% for trichomoniasis, 16.8% and 28.7% for HSV-2, and 42.1% for BV (women only). Of the women with ≥1 curable STI, 75% reported no symptoms. Factors associated with STIs/BV included having older age, being female, and not being in school or working. Among those who participated in the 2016 HIV serosurvey, the prevalence of HIV was 5.6% among men and 19% among women. Feasibility was impacted by the short study duration and the difficulty finding men at home. CONCLUSIONS: A high prevalence of STIs/BV was found in this rural setting with high HIV prevalence in South Africa. Most STIs and HIV infections were asymptomatic and would not have been identified or treated under national syndromic management guidelines. A nested STI/BV survey within a HDSS proved acceptable and feasible. This is a proof of concept for population-based STI surveillance in low- and middle-income countries that could be utilised in the evaluation of STI/HIV prevention and control programmes
Network Harness: Metropolis Public Transport
We analyze the public transport networks (PTNs) of a number of major cities
of the world. While the primary network topology is defined by a set of routes
each servicing an ordered series of given stations, a number of different
neighborhood relations may be defined both for the routes and the stations. The
networks defined in this way display distinguishing properties, the most
striking being that often several routes proceed in parallel for a sequence of
stations. Other networks with real-world links like cables or neurons embedded
in two or three dimensions often show the same feature - we use the car
engineering term "harness" for such networks. Geographical data for the routes
reveal surprising self-avoiding walk (SAW) properties. We propose and simulate
an evolutionary model of PTNs based on effectively interacting SAWs that
reproduces the key features.Comment: 5 pages, 4 figure
Non-Sexual Transmission of Trichomonas vaginalis in Adolescent Girls Attending School in Ndola, Zambia
OBJECTIVES: To identify risk factors for trichomoniasis among young women in Ndola, Zambia. METHOD: The study was a cross-sectional study among adolescent girls aged 13-16 years in Ndola, Zambia. Study participants were recruited from schools in selected administrative areas that represented the different socio-economic strata in town. Consenting participants were interviewed about their socio-demographic characteristics; sexual behaviour; and hygiene practices. Self-administered vaginal swabs were tested for Trichomonas vaginalis. HSV-2 antibodies were determined on serum to validate the self-reported sexual activity. RESULTS: A total of 460 girls participated in the study. The overall prevalence of trichomoniasis was 27.1%, 33.9% among girls who reported that they had ever had sex and 24.7% among virgins. In multivariate analysis the only statistically significant risk factor for trichomoniasis was inconsistent use of soap. For the virgins, none of the risk factors was significantly associated with trichomoniasis, but the association with use of soap (not always versus always) and type of toilet used (pit latrine/bush versus flush toilet) was of borderline significance. CONCLUSION: We found a high prevalence of trichomoniasis in girls in Ndola who reported that they had never had sex. We postulate that the high prevalence of trichomoniasis in virgins in Ndola is due to non-sexual transmission of trichomoniasis via shared bathing water and inconsistent use of soap
Elementary processes governing the evolution of road networks
Urbanisation is a fundamental phenomenon whose quantitative characterisation
is still inadequate. We report here the empirical analysis of a unique data set
regarding almost 200 years of evolution of the road network in a large area
located north of Milan (Italy). We find that urbanisation is characterised by
the homogenisation of cell shapes, and by the stability throughout time of
high-centrality roads which constitute the backbone of the urban structure,
confirming the importance of historical paths. We show quantitatively that the
growth of the network is governed by two elementary processes: (i)
`densification', corresponding to an increase in the local density of roads
around existing urban centres and (ii) `exploration', whereby new roads trigger
the spatial evolution of the urbanisation front. The empirical identification
of such simple elementary mechanisms suggests the existence of general, simple
properties of urbanisation and opens new directions for its modelling and
quantitative description.Comment: 10 pages, 6 figure
A longitudinal analysis of the vaginal microbiota and vaginal immune mediators in women from sub-Saharan Africa
In cross-sectional studies increased vaginal bacterial diversity has been associated with vaginal inflammation which can be detrimental for health. We describe longitudinal changes at 5 visits over 8 weeks in vaginal microbiota and immune mediators in African women. Women (N = 40) with a normal Nugent score at all visits had a stable lactobacilli dominated microbiota with prevailing Lactobacillus iners. Presence of prostate-specific antigen (proxy for recent sex) and being amenorrhoeic (due to progestin-injectable use), but not recent vaginal cleansing, were significantly associated with microbiota diversity and inflammation (controlled for menstrual cycle and other confounders). Women (N = 40) with incident bacterial vaginosis (Nugent 7-10) had significantly lower concentrations of lactobacilli and higher concentrations of Gardnerella vaginalis, Atopobium vaginae, and Prevotella bivia, at the incident visit and when concentrations of proinflammatory cytokines (IL-1β, IL-12p70) were increased and IP-10 and elafin were decreased. A higher 'composite-qPCR vaginal-health-score' was directly associated with decreased concentrations of proinflammatory cytokines (IL-1α, IL-8, IL-12(p70)) and increased IP-10. This longitudinal study confirms the inflammatory nature of vaginal dysbiosis and its association with recent vaginal sex and progestin-injectable use. A potential role for proinflammatory mediators and IP-10 in combination with the vaginal-health-score as predictive biomarkers for vaginal dysbiosis merits further investigation
Quality Control and Performance of HIV Rapid Tests in a Microbicide Clinical Trial in Rural KwaZulu-Natal
Background
Quality control (QC) and evaluation of HIV rapid test procedures are an important aspect of HIV prevention trials. We describe QC and performance of two rapid tests, Determine™ and Uni-Gold™ used in a microbicide clinical trial in rural KwaZulu-Natal, South Africa.
Methods/Results
Internal QC of both HIV rapid tests was conducted at the trial site using a Uni-Gold control kit (Uni-Gold™Recombigen® HIV). Both assays produced the expected results for a total of 4637 QC tests. Study participants were tested for HIV at screening and, if enrolled, at regular time points throughout the study. Positive or discordant results were confirmed by a double HIV immunoassay testing strategy at a local laboratory. Overall, 15292 HIV rapid test were performed. Sensitivity and specificity of Determine was 98.95% (95% CI: 97.72–99.61) and 99.83% (95% CI: 99.70–99.91) respectively [positive predictive value (PPV) 97.91% (95% CI: 96.38–98.92)], for Uni-Gold it was 99.30% (95% CI: 98.21–99.81) and 99.96% (95% CI: 99.88–99.99) respectively [PPV 99.47% (95% CI: 98.46–99.89)].
Conclusions
The results suggest that a Uni-Gold control kit can be used for internal QC of both Uni-Gold and the HIV-1 component of the Determine rapid tests. Both rapid tests performed proficiently in the trial population
Role of IgM testing in the diagnosis and post-treatment follow-up of syphilis: a prospective cohort study
Objectives The diagnosis of repeat syphilis and its followup remains challenging. We aimed to investigate if IgM
testing may assist in the diagnosis of syphilis reinfection/
relapse and its treatment follow-up.
Methods This substudy was conducted in the context
of a syphilis biomarker discovery study (ClinicalTrials.
gov Nr: NCT02059525). Sera were collected from 120
individuals with a new diagnosis of syphilis (72 with repeat
infections) and 30 syphilis negative controls during a
cohort study investigating syphilis biomarkers conducted
at a sexually transmitted infection/HIV clinic in Antwerp,
Belgium. Syphilis was diagnosed based on a simultaneous
positive treponemal and non-treponemal assay result and/
or positive serum PCR targeting polA. Specimens collected
at visit of diagnosis, and 3 and 6 months post-treatment
were tested by two enzyme immunoassays (EIAs),
recomWell (Mikrogen; MI) and Euroimmun (EU), to detect
anti-treponemal IgM. Baseline specimens were also tested
for anti-treponemal IgM using a line immunoassay (LIA)
recomLine (MI). Quantitative kinetic decay curves were
constructed from the longitudinal quantitative EIA results.
Results An overall sensitivity for the diagnosis of syphilis
of 59.8% (95% CI: 50.3%–68.7%), 75.0% (95% CI:
66.1%–82.3%) and 63.3% (95% CI: 54.8%–72.6%) was
obtained for the EU, MI EIAs and MI LIA, respectively. When
only considering repeat syphilis, the diagnostic sensitivity
decreased to 45.7% (95% CI: 33.9%–58.0%), 63.9% (95%
CI: 51.7%–74.6%) and 47.2% (95% CI: 35.5%–59.3%),
respectively. IgM seroreverted in most cases 6 months
after treatment. Post-treatment IgM concentrations
decreased almost 30% faster for initial syphilis compared
with repeat infection. The IgM EIAs and IgM LIA agreed
from fairly to moderately (Cohen’s kappa (κ): 0.36 (EU EIA);
Îş: 0.53 (MI EIA); Îş: 0.40 (MI LIA)) with the diagnosis of
syphilis.
Conclusions IgM detection was not a sensitive method to
diagnose syphilis and was even poorer in the diagnosis of
syphilis repeat infections
Prevalence of sexually transmitted infections among young people in South Africa: A nested survey in a health and demographic surveillance site.
BACKGROUND: Sexually transmitted infections (STIs) and bacterial vaginosis (BV) are associated with increased transmission of HIV, and poor reproductive and sexual health. The burden of STIs/BV among young people is unknown in many high HIV prevalence settings. We conducted an acceptability, feasibility, and prevalence study of home-based sampling for STIs/BV among young men and women aged 15-24 years old in a health and demographic surveillance site (HDSS) in rural KwaZulu-Natal, South Africa. METHODS AND FINDINGS: A total of 1,342 young people, stratified by age (15-19 and 20-24 years) and sex were selected from the HDSS sampling frame; 1,171/1,342 (87%) individuals had ≥1 attempted home visit between 4 October 2016 and 31 January 2017, of whom 790 (67%) were successfully contacted. Among the 645 who were contacted and eligible, 447 (69%) enrolled. Consenting/assenting participants were interviewed, and blood, self-collected urine (men), and vaginal swabs (women) were tested for herpes simplex virus type 2 (HSV-2), chlamydia, gonorrhoea, syphilis, trichomoniasis, and BV. Both men and women reported that sample collection was easy. Participants disagreed that sampling was painful; more than half of the participants disagreed that they felt anxious or embarrassed. The weighted prevalence of STIs/BV among men and women, respectively, was 5.3% and 11.2% for chlamydia, 1.5% and 1.8% for gonorrhoea, 0% and 0.4% for active syphilis, 0.6% and 4.6% for trichomoniasis, 16.8% and 28.7% for HSV-2, and 42.1% for BV (women only). Of the women with ≥1 curable STI, 75% reported no symptoms. Factors associated with STIs/BV included having older age, being female, and not being in school or working. Among those who participated in the 2016 HIV serosurvey, the prevalence of HIV was 5.6% among men and 19% among women. Feasibility was impacted by the short study duration and the difficulty finding men at home. CONCLUSIONS: A high prevalence of STIs/BV was found in this rural setting with high HIV prevalence in South Africa. Most STIs and HIV infections were asymptomatic and would not have been identified or treated under national syndromic management guidelines. A nested STI/BV survey within a HDSS proved acceptable and feasible. This is a proof of concept for population-based STI surveillance in low- and middle-income countries that could be utilised in the evaluation of STI/HIV prevention and control programmes
Integrating fluctuations into distribution of resources in transportation networks
We propose a resource distribution strategy to reduce the average travel time
in a transportation network given a fixed generation rate. Suppose that there
are essential resources to avoid congestion in the network as well as some
extra resources. The strategy distributes the essential resources by the
average loads on the vertices and integrates the fluctuations of the
instantaneous loads into the distribution of the extra resources. The
fluctuations are calculated with the assumption of unlimited resources, where
the calculation is incorporated into the calculation of the average loads
without adding to the time complexity. Simulation results show that the
fluctuation-integrated strategy provides shorter average travel time than a
previous distribution strategy while keeping similar robustness. The strategy
is especially beneficial when the extra resources are scarce and the network is
heterogeneous and lowly loaded.Comment: 14 pages, 4 figure
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