A technique for re-utilizing catheter insertion sites in children with difficult central venous access.

Maintenance of central venous access in patients with chronic medical conditions such as short bowel syndrome demands forethought and ingenuity. We describe an innovative technique for re-utilizing central venous access sites in patients who have chronic central venous access needs. Records of patients undergoing this technique were reviewed between August 2012 and December 2015. The technique involves "cutting-down" to the sterile fibrous tunnel that naturally forms around tunneled catheters. The fibrous sheath is then isolated and controlled much as would be done for a venous "cut-down." A separate exit site is then created for the new catheter and it is tunneled to the "cut-down" site per routine. The non-functioning catheter is then removed from the surgical field. The proximal fibrous sheath is finally cannulated either directly with the new catheter or with a wire/dilator system. This technique effectively re-uses the same venous access point while allowing for a complete change of the physical line and external site. Twenty attempts at this technique were made in twelve patients; six patients underwent the site re-utilization procedure multiple times. Re-using the fibrous tunnel to re-cycle the internal catheter site was successful in seventeen of twenty attempts. All patients had chronic conditions leading to difficult long-term central venous access [short bowel syndrome (6), hemophilia (2), cystic fibrosis (1), chronic need for central IV access (3)]. Indications for catheter replacement included catheter occlusion/mechanical failure/breakage (9), dislodgement (6), infection (1), and inadequate catheter length due to patient growth (4). Broviac/Hickman catheter sites were most commonly re-used (13; one failure); re-using a portcath site was successful in 5 of 7 attempts. There were no short term infections or mechanical complications. We describe a novel technique for salvaging tunneled central venous catheter access sites. This technique is well suited for patients with difficult and long-term central venous access needs, particularly those with chronic conditions such as intestinal failure. It is specifically useful when tunneled lines are broken, precipitated or clotted and unamenable to wiring.

Estimating the resources required in the roll-out of universal access to antiretroviral treatment in Zimbabwe.

OBJECTIVES: To develop projections of the resources required (person-years of drug supply and healthcare worker time) for universal access to antiretroviral treatment (ART) in Zimbabwe. METHODS: A stochastic mathematical model of disease progression, diagnosis, clinical monitoring and survival in HIV infected individuals. FINDINGS: The number of patients receiving ART is determined by many factors, including the strategy of the ART programme (method of initiation, frequency of patient monitoring, ability to include patients diagnosed before ART became available), other healthcare services (referral rates from antenatal clinics, uptake of HIV testing), demographic and epidemiological conditions (past and future trends in incidence rates and population growth) as well as the medical impact of ART (average survival and the relationship with CD4 count when initiated). The variations in these factors lead to substantial differences in long-term projections; with universal access by 2010 and no further prevention interventions, between 370 000 and almost 2 million patients could be receiving treatment in 2030-a fivefold difference. Under universal access, by 2010 each doctor will initiate ART for up to two patients every day and the case-load for nurses will at least triple as more patients enter care and start treatment. CONCLUSIONS: The resources required by ART programmes are great and depend on the healthcare systems and the demographic/epidemiological context. This leads to considerable uncertainty in long-term projections and large variation in the resources required in different countries and over time. Understanding how current practices relate to future resource requirements can help optimise ART programmes and inform long-term public health planning.

Sexual risk behaviours and sexual health outcomes among heterosexual black Caribbeans: comparing sexually transmitted infection clinic attendees and national probability survey respondents.

We compared sociodemographic characteristics, sexual risk behaviours and sexual health experiences of 266 heterosexual black Caribbeans recruited at a London sexual health clinic between September 2005 and January 2006 with 402 heterosexual black Caribbeans interviewed for a British probability survey between May 1999 and August 2001. Male clinic attendees were more likely than men in the national survey to report: ≥10 sexual partners (lifetime; adjusted odds ratio [AOR]: 3.27, 95% confidence interval [CI]: 1.66-6.42), ≥2 partners (last year; AOR: 5.40, 95% CI: 2.64-11.0), concurrent partnerships (AOR: 3.26, 95% CI: 1.61-6.60), sex with partner(s) from the Caribbean (last 5 years; AOR: 7.97, 95% CI: 2.42-26.2) and previous sexually transmitted infection (STI) diagnosis/diagnoses (last 5 years; AOR: 16.2, 95% CI: 8.04-32.6). Similar patterns were observed for women clinic attendees, who also had increased odds of termination of pregnancy (AOR: 3.25, 95% CI: 1.87-5.66). These results highlight the substantially higher levels of several high-risk sexual behaviours among UK black Caribbeans attending a sexual health clinic compared with those in the general population. High-risk individuals are under-represented in probability samples, and it is therefore important that convenience samples of high-risk individuals are performed in conjunction with nationally representative surveys to fully understand the risk behaviours and sexual health-care needs of ethnic minority communities.

Tuberculosis screening of migrants to low-burden nations: insights from evaluation of UK practice.

Tuberculosis (TB) primarily occurs in the foreign-born in European countries, such as the UK, where increasing notifications and the high proportion of foreign-born cases has refocused attention on immigrant (new entrant) screening. We investigated how UK primary care organisations (PCOs) screen new entrants and whether this differs according to TB burden in the PCOs (incidence < 20 or ≥ 20 cases per 100,000 per annum). An anonymous, 20-point questionnaire was sent to all 192 UK PCOs asking which new entrants are screened, who is screened for active TB/latent TB infection (LTBI) and the methods used. Descriptive analyses were undertaken. Categorical responses were compared using the Chi-squared test. 177 (92.2%) out of 192 PCOs responded; all undertook screening action in response to abnormal chest radiographs, but only 107 (60.4%) screened new entrants for LTBI. Few new entrants had active TB diagnosed (median 0.0%, interquartile range (IQR) 0.0-0.5%) but more were identified with LTBI (median 7.85%, IQR 4.30-13.50%). High-burden PCOs were significantly less likely to screen new entrants for LTBI (OR 0.26, 95% CI 0.12-0.54; p<0.0001). Among PCOs screening for LTBI, there was substantial deviation from national guidance in selection of new entrant subgroups and screening method. Considerable heterogeneity and deviation from national guidance exist throughout the UK new entrant screening process, with high-burden regions undertaking the least screening. Forming an accurate picture of current front-line practice will help to inform future development of European new entrant screening policy.

Men who have sex with men and women in Bangalore, South India, and potential impact on the HIV epidemic.

OBJECTIVE: The aim of this study was to quantify differences in patterns of sexual behaviour among men who have sex with men and women (MSMW) compared with men who have sex with men only (MSMO), and to examine the extent to which bisexual behaviour may act as a bridge for introducing HIV infection into the general population. METHODS: A cross-sectional survey in Bangalore city in 2006, which sampled men seeking sex with men in public places and hammams (bath houses where transgender individuals sell sex to men). RESULTS: Among a sample of 357 men reporting same-sex behaviour; 41% also reported sex with a woman in the past year and 14% were currently married to a woman, only two of whom had informed their wives about having sex with men. Condom use was very inconsistent with all male partners, while 98% reported unprotected vaginal sex with their wives. MSMW reported lower rates of risky behaviour with other men than MSMO: fewer reported selling sex (17% vs 58%), or receptive anal sex with known (28% vs 70%) or unknown (30% vs 59%) non-commercial partners. CONCLUSION: Bisexual behaviour was common among men seeking sex with men sampled in this survey. Although MSMW reported lower rates of risky sexual behaviour with male partners than MSMO, inconsistent condom use with both male and female partners indicates a potential means of HIV transmission into the general population. HIV prevention programmes and services should reach bisexual men who potentially expose their male and female partners to HIV.

Measuring trends in age at first sex and age at marriage in Manicaland, Zimbabwe.

OBJECTIVE: To identify reporting biases and to determine the influence of inconsistent reporting on observed trends in the timing of age at first sex and age at marriage. METHODS: Longitudinal data from three rounds of a population-based cohort in eastern Zimbabwe were analysed. Reports of age at first sex and age at marriage from 6837 individuals attending multiple rounds were classified according to consistency. Survival analysis was used to identify trends in the timing of first sex and marriage. RESULTS: In this population, women initiate sex and enter marriage at younger ages than men but spend much less time between first sex and marriage. Among those surveyed between 1998 and 2005, median ages at first sex and first marriage were 18.5 years and 21.4 years for men and 18.2 years and 18.5 years, respectively, for women aged 15-54 years. High levels of reports of both age at first sex and age at marriage among those attending multiple surveys were found to be unreliable. Excluding reports identified as unreliable from these analyses did not alter the observed trends in either age at first sex or age at marriage. Tracing birth cohorts as they aged revealed reporting biases, particularly among the youngest cohorts. Comparisons by birth cohorts, which span a period of >40 years, indicate that median age at first sex has remained constant over time for women but has declined gradually for men. CONCLUSIONS: Although many reports of age at first sex and age at marriage were found to be unreliable, inclusion of such reports did not result in artificial generation or suppression of trends.

The role of testing and counselling for HIV prevention and care in the era of scaling-up antiretroviral therapy.

OBJECTIVE: HIV Testing and Counselling (TC) programmes are being scaled-up as part of efforts to provide universal access to antiretroviral treatment (ART). METHODS AND FINDINGS: Mathematical modelling of TC in Zimbabwe shows that if universal access is to be sustained, TC must include prevention counselling that enables behaviour change among infected and uninfected individuals. The predicted impact TC is modest, but improved programmes could generate substantial reductions in incidence, reducing need for ART in the long-term. CONCLUSIONS: TC programmes that focus only on identifying those in need of treatment will not be sufficient to bring the epidemic under control.

Fewer partners or more condoms? Modelling the effectiveness of STI prevention interventions.

BACKGROUND: Some advocates of HIV prevention have counterposed programmes aimed at reducing numbers of sex partners to programmes aimed at increasing condom use. In this polarised debate, arguments about their relative effectiveness have been based on limited evidence. OBJECTIVES: To explore the theoretical impact of changing partner acquisition rates and condom use on the population level incidence of sexually transmitted infections different in different populations. METHODS: A standard deterministic compartmental model of the transmission dynamics of a sexually transmitted disease is solved numerically. The change in behaviour required to prevent a single case of infection is calculated for a range of scenarios. RESULTS: When the transmission probability per sex act is low across partnerships, the incidence of infection responds similarly to changes in partner numbers and numbers of unprotected sex acts. High transmission probabilities alter the relationships, with the effectiveness of increasing condom use improving as the background number of unprotected sex acts decreases. The divergence in patterns of impact is marked when there is heterogeneity in the transmission probability per act across partnerships. CONCLUSIONS: Both reducing numbers of sex partners and increasing condom use can lower the incidence of sexually transmitted infections. Unfortunately, there is no simple and general rule that will allow the efficiency of interventions to be calculated. Heterogeneity in transmission probability across infections, which may occur for both bacterial and viral infections, can reduce the effectiveness of condom use as an intervention if that use is inconsistent.

Interpreting declines in HIV prevalence: impact of spatial aggregation and migration on expected declines in prevalence.

BACKGROUND: Declines in the prevalence of HIV might occur due to natural epidemic dynamics rather than changes in risk behaviour. Determining the cause of an observed decline is important in understanding the epidemiology of HIV. OBJECTIVE: To explore how patterns of recruitment and interactions between subpopulations in different areas influence the predicted decline in the prevalence of HIV in the absence of reductions in risk behaviour. METHODS: A deterministic mathematical model of the heterosexual transmission of HIV in high prevalence endemic settings incorporating various patterns of recruitment to high-risk behaviour groups, population growth and migration was solved numerically. The possibility that apparent trends are generated or obscured through aggregating data from across areas experiencing different epidemics is also considered. RESULTS: Declines in the prevalence of HIV can occur even if individuals do not change behaviour, raising the possibility that epidemic downturns could be wrongly attributed to interventions. This effect is greatest when individuals do not enter higher risk groups to compensate for reductions in size caused by deaths from AIDS and when migration is non-random with respect to risk or infectious status and migration patterns change as the epidemic matures. In contrast, aggregating prevalence data from subregions with different epidemic profiles tends to mask declines in prevalence. CONCLUSIONS: Interpreting surveillance data is important in understanding widespread responses to HIV epidemics. The results show that understanding patterns of adoption of risk behaviours and patterns of migration is important in interpreting declines in the prevalence of HIV.

Seroepidemiology as basis for design of a human papillomavirus vaccination program.

We have performed a serological survey of HPV type 16-antibody prevalence by age and sex in Sweden and used it as a basis for modelling the optimal vaccination strategies in this population. Samples of 3,317 subjects were tested for HPV16-specific antibodies. The observed age-specific seroprevalences along with sexual behaviour data were used to infer parameter values for a mathematical model representing Sweden and the preventive effect of possible strategies estimated. By the year 2055, vaccination of females starting at age 12 in 2008 was most efficient, estimated to prevent 5.8 million cumulative HPV16 infections. Catch-up programs had a strong additional preventive effect. Vaccination also targeting males increased protective effect by about 4%, but had lower preventive effect per vaccination given. Addition of an HPV serosurvey to existing models and data has enabled us to estimate effect of different vaccination strategies, optimized to the HPV epidemiology in our population.

Discrepancies between UN models and DHS survey estimates of maternal orphan prevalence: insights from analyses of survey data from Zimbabwe.

OBJECTIVES: Model-based estimates of maternal (but not paternal) orphanhood are higher than those based on data from demographic and health surveys (DHS). We investigate the consistency of reporting of parental survival status in data from Manicaland, Zimbabwe. METHODS: We compared estimates of paternal and maternal orphan prevalence in three rounds of a prospective household census in Manicaland (1998-2005) with estimates from DHS surveys and UNAIDS model projections. We investigated the consistency of reporting of parental survival status across the three rounds and compared estimates of adult mortality from the orphan data with direct estimates from concurrent follow-up of a general population cohort. Qualitative data were collected on possible reasons for misreporting. RESULTS: Paternal and maternal orphan prevalence is increasing in Zimbabwe. Mothers reported as deceased in round 1 of the Manicaland survey were more likely than fathers to be reported as alive in rounds 2 or 3 (33.3% vs 13.4%). This pattern was most apparent among younger children. The qualitative findings suggest that foster parents sometimes claim adopted children as their natural children. CONCLUSIONS: These results are consistent with misreporting of foster parents as natural parents. This appears to be particularly common among foster mothers and could partly explain the discrepancy between mathematical model and DHS estimates of maternal orphanhood.

Measuring effectiveness in community randomized trials of HIV prevention.

BACKGROUND: Complicated HIV transmission dynamics make it unclear how to design and interpret results from community-randomized controlled trials (CRCT) of interventions to prevent infection. METHODS: Mathematical modelling was used to investigate the effectiveness of interventions to prevent HIV transmission aimed at high-risk groups and factors related to the chance of recording a statistically significant result. RESULTS: Behaviour change by high-risk groups can substantially reduce HIV incidence in the whole population, although its effect is sensitive to the structure of the sexual network and the phase of the epidemic. There is a delay between the behaviour change happening and its full effect being realized in the low-risk group and this can pull the measured incidence rate ratio towards one and reduce the chance of recording a statistically significant result in a CRCT. Our simulations suggest that only with unrealistically favourable study conditions would a statistically significant result be likely with 5 years follow-up or less. Small differences in the epidemiological parameters between communities can lead to misleading incidence rate ratios. Behaviour change independent of the intervention can increase the epidemiological impact of the intervention and the chance of recording a statistically significant result. CONCLUSIONS: HIV prevention interventions, especially those targeted at high-risk groups may take longer to work at the population level and need more follow-up time in a CRCT to generate statistically significant results. Mathematical modelling can be used in the design and analysis of CRCTs to understand how the impact of the intervention could develop and the implications this has for statistical power.

Sexual identity and its contribution to MSM risk behavior in Bangaluru (Bangalore), India: the results of a two-stage cluster sampling survey.

In India, there are categories of MSM (hijras, kothis, double-deckers, panthis and bisexuals), which are generally associated with different HIV-risk behaviors. Our objective was to quantify differences across MSM identities (n = 357) and assess the extent they conform to typecasts that prevail in policy-orientated discourse. More feminine kothis (26%) and hijras (13%) mostly reported receptive sex, and masculine panthis (15%) and bisexuals (23%) insertive anal sex. However, behavior did not always conform to expectation, with 25% and 16% of the sample reporting both insertive and receptive anal intercourse with known and unknown noncommercial partners, respectively (p < 0.000). Although behavior often complied with stereotyped role and identity, male-with-male sexual practices were fluid. Reification of these categories in an intervention context may hinder our understanding of the differential HIV risk among MSM.

Human papillomavirus and HPV vaccines: a review.

Cervical cancer, the most common cancer affecting women in developing countries, is caused by persistent infection with "high-risk" genotypes of human papillomaviruses (HPV). The most common oncogenic HPV genotypes are 16 and 18, causing approximately 70% of all cervical cancers. Types 6 and 11 do not contribute to the incidence of high-grade dysplasias (precancerous lesions) or cervical cancer, but do cause laryngeal papillomas and most genital warts. HPV is highly transmissible, with peak incidence soon after the onset of sexual activity. A quadrivalent (types 6, 11, 16 and 18) HPV vaccine has recently been licensed in several countries following the determination that it has an acceptable benefit/risk profile. In large phase III trials, the vaccine prevented 100% of moderate and severe precancerous cervical lesions associated with types 16 or 18 among women with no previous infection with these types. A bivalent (types 16 and 18) vaccine has also undergone extensive evaluation and been licensed in at least one country. Both vaccines are prepared from non-infectious, DNA-free virus-like particles produced by recombinant technology and combined with an adjuvant. With three doses administered, they induce high levels of serum antibodies in virtually all vaccinated individuals. In women who have no evidence of past or current infection with the HPV genotypes in the vaccine, both vaccines show > 90% protection against persistent HPV infection for up to 5 years after vaccination, which is the longest reported follow-up so far. Vaccinating at an age before females are exposed to HPV would have the greatest impact. Since HPV vaccines do not eliminate the risk of cervical cancer, cervical screening will still be required to minimize cancer incidence. Tiered pricing for HPV vaccines, innovative financing mechanisms and multidisciplinary partnerships will be essential in order for the vaccines to reach populations in greatest need.

Behaviour change in generalised HIV epidemics: impact of reducing cross-generational sex and delaying age at sexual debut.

BACKGROUND: Sexual behavioural change is essential to prevent HIV infections in Africa and statistical analysis of risk factors at the individual-level may be used to design interventions. The importance of reducing cross-generational sex (young women having sex with older men) and delaying age at first sex on the spread of HIV at the population-level has been presumed but not scientifically investigated and quantified. METHODS: A mathematical model of heterosexual spread of HIV was developed to predict the population-level impact of reducing cross-generational sex and delaying sexual debut. RESULTS: The impact of behaviour change on the spread of HIV is sensitive to the structure and reaction of the sexual network. Reducing cross-generational sex could have little impact on the risk of infection unless it is accompanied by a reduction in the number of risky sexual contacts. Even peer-to-peer sexual mixing can support high endemic levels of HIV. The benefit of delaying sexual debut is comparatively small and is reduced if males continue to prefer young partners or if young women spend more time unmarried. In Manicaland, Zimbabwe, if older men were to use condoms as frequently as young men, the reduction in risk of infection could exceed that generated by a two-year delay in first sex. CONCLUSIONS: At the individual-level avoiding sex with older partners and delaying sexual debut can decrease the risk of infection but at the population-level these interventions may do little to limit the spread of HIV without wider-ranging behavioural changes throughout the sexual network.

Strategies for the introduction of human papillomavirus vaccination: modelling the optimum age- and sex-specific pattern of vaccination in Finland.

Phase III trials have demonstrated the efficacy of human papillomavirus (HPV) vaccines in preventing transient and persistent high-risk (hr) HPV infection and precancerous lesions. A mathematical model of HPV type 16 infection and progression to cervical cancer, parameterised to represent the infection in Finland, was used to explore the optimal age at vaccination and pattern of vaccine introduction. In the long term, the annual proportion of cervical cancer cases prevented is much higher when early adolescents are targeted. Vaccinating against hr HPV generates greater long-term benefits if vaccine is delivered before the age at first sexual intercourse. However, vaccinating 12 year olds delays the predicted decrease in cervical cancer, compared to vaccinating older adolescents or young adults. Vaccinating males as well as females has more impact on the proportion of cases prevented when vaccinating at younger ages. Implementing catch-up vaccination at the start of a vaccination programme would increase the speed with which a decrease in HPV and cervical cancer incidence is observed.

First Report of Arceuthobium aureum subsp. aureum in Mexico.

The golden dwarf mistletoe (Arceuthobium aureum Hawksw. & Wiens subsp. aureum, Viscaceae) parasitizes several pines (Pinus spp., Pinaceae) in central Guatemala (1). In September 2006, we observed golden dwarf mistletoe parasitizing Pinus maximinoi H.E. Moore in southern Chiapas, Mexico; 1 km west of El Rosario along Mexico Route 211 (15°19'23″N, 92°17'45″W, elevation 1,720m). Golden dwarf mistletoe can be distinguished from the closely related Peterson's dwarf mistletoe (A. aureum Hawksw. & Wiens subsp. petersonii Hawksw. & Wiens) by its smaller shoots, occurrence below 2,200 m in elevation, and flowering period (1). The shoots of the dwarf mistletoe at the El Rosario location were less than 20 cm high and male plants were not flowering. Male plants of Peterson's dwarf mistletoe observed at the type locality and other locations in Chiapas during September were in full flower. Although only 29 trees were infected at this location, infection was severe on 11 trees, but no mortality associated with dwarf mistletoe infection was observed. Mistletoe infection did not induce the formation of witches'-brooms near El Rosario, but infection by golden dwarf mistletoe on P. maximinoi does induce witches'-brooms on older trees in Guatemala (2). The golden dwarf mistletoe population near El Rosario is approximately 150 km west of the nearest known population of this species in Guatemala (1). To our knowledge, this is the first report of golden dwarf mistletoe in Mexico. Specimens of golden dwarf mistletoe from Chiapas, Mexico were deposited at the Deaver Herbarium, Northern Arizona University, Flagstaff (Accession No. 83122). References: (1) F. Hawksworth and D. Wiens. Dwarf Mistletoes: Biology, Systematics, and Pathology. USDA For. Serv. Agric. Handb. 709, 1996. 2) R. Mathiasen et al. Madrono 23:122, 2004.

Utility of the Determine Syphilis TP rapid test in commercial sex venues in Peru.

OBJECTIVES: This study sought to evaluate the utility of the Determine Syphilis TP test performed in Peruvian commercial sex venues for the detection of active syphilis; and determine the feasibility of integrating rapid syphilis testing for female sex workers (FSW) into existing health outreach services. METHODS: We tested 3586 female sex workers for syphilis by Determine in the field using whole blood fingerstick, and by rapid plasma reagin (RPR) and Treponema pallidum haemagglutination assay (TPHA) in a central laboratory in Lima using sera. RESULTS: 97.4% of the FSW offered rapid syphilis testing participated; and among those who tested positive, 87% visited the local health centre for treatment. More than twice as many specimens were RPR reactive using serum in Lima (5.7%) than tested positive by whole blood Determine in the field (2.8%), and although most were confirmed by TPHA, only a small proportion (0.7%) were RPR reactive at >or=1:8 dilutions, and likely indicating active syphilis. Sensitivity, specificity and positive predictive value of the Determine Syphilis TP test in whole blood when compared to serum RPR reactivity at any dilution confirmed by TPHA as the gold standard were 39.3%, 99.2% and 71.4%, respectively. Sensitivity improved to 64.0% when using serum RPR >or=1:8 confirmed by TPHA. Invalid tests were rare (0.3%). CONCLUSIONS: Rapid syphilis testing in sex work venues proved feasible, but Determine using whole blood obtained by fingerstick was substantially less sensitive than reported in previous laboratory-based studies using serum. Although easy to perform in outreach venues, the utility of this rapid syphilis test was relatively low in settings where a large proportion of the targeted population has been previously tested and treated.