A fast algorithm for the spread of HIV in a system of prisons

In this paper, we propose a continuous time model for modelling the spread of HIV in a network of prisons. We give some sufficient conditions for the equilibrium points of the system to be stable. We also develop an efficient algorithm based on Newton's method and the Sherman-Morrison-Woodbury formula for computing the equilibrium values of the infectives in each prison. © 2007 Elsevier Ltd. All rights reserved.preprin

Pulmonary tuberculosis in the central prison of Douala, Cameroon

Objective: To determine the prevalence of and factors associated with pulmonary tuberculosis (PTB) in an urban prison in sub-Saharan Africa.Design: A cross-sectional survey. Setting: The Central Prison of Douala, Cameroon. Results: Two thousand four hundred and seventy four (87.4%) out of 2830 inmates underwent screening. Twenty seven (1.1%) of the inmates were under treatment for smear-positive PTB on commencement of the survey while 60 (2.4%) were diagnosed with smear and/or culture-positive PTB during the active case finding, resulting in a point prevalence of PTB of 3.5%. HIV seroprevalence in inmates without clinical signs of PTB was 111/1067 (10.4%) while it amounted to 6/24 (25%) in PTB patients. In multiple stepwise regression analysis, a low BMl, a prison stay of ≤12 months, and a history of previous incarceration were positively associated with PTB. Conclusion: The study results confirm the high prevalence rates of PTB in prison populations and underscore the need for urgent preventive measures. East African Medical Journal Vol. 83(1) 2006: 25-3

Screening for tuberculosis and testing for human immunodeficiency virus in Zambian prisons

Objective: To improve the Zambia Prisons Service's implementation of tuberculosis screening and human immunodeficiency virus (HIV) testing. Methods: For both tuberculosis and HIV, we implemented mass screening of inmates and community-based screening of those residing in encampments adjacent to prisons. We also established routine systems – with inmates as peer educators – for the screening of newly entered or symptomatic inmates. We improved infection control measures, increased diagnostic capacity and promoted awareness of tuberculosis in Zambia's prisons. Findings: In a period of 9 months, we screened 7638 individuals and diagnosed 409 new patients with tuberculosis. We tested 4879 individuals for HIV and diagnosed 564 cases of infection. An additional 625 individuals had previously been found to be HIV-positive. Including those already on tuberculosis treatment at the time of screening, the prevalence of tuberculosis recorded in the prisons and adjacent encampments – 6.4% (6428/100 000) – is 18 times the national prevalence estimate of 0.35%. Overall, 22.9% of the inmates and 13.8% of the encampment residents were HIV-positive. Conclusion: Both tuberculosis and HIV infection are common within Zambian prisons. We enhanced tuberculosis screening and improved the detection of tuberculosis and HIV in this setting. Our observations should be useful in the development of prison-based programmes for tuberculosis and HIV elsewhere

Evaluating strategies for control of tuberculosis in prisons and prevention of spillover into communities: An observational and modeling study from Brazil

Background It has been hypothesized that prisons serve as amplifiers of general tuberculosis (TB) epidemics, but there is a paucity of data on this phenomenon and the potential population-level effects of prison-focused interventions. This study (1) quantifies the TB risk for prisoners as they traverse incarceration and release, (2) mathematically models the impact of prison-based interventions on TB burden in the general population, and (3) generalizes this model to a wide range of epidemiological contexts. Methods and findings We obtained individual-level incarceration data for all inmates (n = 42,925) and all reported TB cases (n = 5,643) in the Brazilian state of Mato Grosso do Sul from 2007 through 2013. We matched individuals between prisoner and TB databases and estimated the incidence of TB from the time of incarceration and the time of prison release using Cox proportional hazards models. We identified 130 new TB cases diagnosed during incarceration and 170 among individuals released from prison. During imprisonment, TB rates increased from 111 cases per 100,000 person-years at entry to a maximum of 1,303 per 100,000 person-years at 5.2 years. At release, TB incidence was 229 per 100,000 person-years, which declined to 42 per 100,000 person-years (the average TB incidence in Brazil) after 7 years. We used these data to populate a compartmental model of TB transmission and incarceration to evaluate the effects of various prison-based interventions on the incidence of TB among prisoners and the general population. Annual mass TB screening within Brazilian prisons would reduce TB incidence in prisons by 47.4% (95% Bayesian credible interval [BCI], 44.4%–52.5%) and in the general population by 19.4% (95% BCI 17.9%–24.2%). A generalized model demonstrates that prison-based interventions would have maximum effectiveness in reducing community incidence in populations with a high concentration of TB in prisons and greater degrees of mixing between ex-prisoners and community members. Study limitations include our focus on a single Brazilian state and our retrospective use of administrative databases. Conclusions Our findings suggest that the prison environment, more so than the prison population itself, drives TB incidence, and targeted interventions within prisons could have a substantial effect on the broader TB epidemic

Prevalence Of Tuberculosis Symptoms And Latent Tuberculosis Infection Among Prisoners In Northeastern Malaysia

Background: Tuberculosis (TB) is a known public health threat to prison systems due to poor hygiene, crowded living conditions, poor health of inmates, and poor prison healthcare systems. The large population of HIV-infected people living in prisons is especially susceptible to increased TB transmission and higher mortality. In Northeastern Malaysia, there is no screening for active or latent TB infection (LTBI) in the prison system. Aims and Hypothesis: This study serves to measure the prevalence and correlates of LTBI and active TB symptoms in HIV-infected and non-HIV-infected prisoners in Northeastern Malaysia. Given the host of factors that contribute to TB transmission and burden in prisons, it is expected that the burden of LTBI is high. In studying a population of HIV-infected inmates who are not receiving antiretroviral therapy, it is expected that a significant number of inmates will display active TB symptoms. Methods: This is a cross sectional study design that uses Tuberculin Skin Testing (TST) to measure LTBI, and the World Health Organization (WHO) TB symptom survey to measure active TB symptom prevalence. A total of 266 prisoners in Penjara Pengkalan Chepa, Kelantan, Malaysia, were enlisted in the study. After consent, participants underwent two-step TST and were surveyed for active TB symptoms. Standardized cutoffs of ≥5mm and ≥10mm were used to define reactive TST among prisoners with and without HIV, respectively. Clinical and behavioral data were assessed with a questionnaire and HIV-infected prisoners were stratified by CD4 status. Results: LTBI prevalence in Penjara Pengkalan Chepa in July-August 2011 was 87.6%, with significantly lower TST-reactivity among HIV-infected compared to non-HIV-infected prisoners (83.6% vs. 91.5%; p\u3c0.05); however, TB symptoms were similar (16.9% vs. 10.1%; p=0.105). On multivariate analysis, previous incarceration (AOR=4.61: 95%CI=1.76-12.1) was the only significant correlate of LTBI. Increasing age (AOR=1.07: 95%CI=1.01-1.13), lower body mass index (AOR=0.82: 95%CI=0.70-0.96) and having a negative TST (AOR=3.46: 95%CI=1.20-9.97) were correlated with TB symptoms. Conclusion: LTBI is highly prevalent, associated with previous incarceration, and suggests the need for routine TB screening at entry to Malaysian prisons as well as continued surveillance. The prevalence of LTBI symptoms among HIV-infected inmates is alarming and provides further justification for active screening measures. Treating LTBI in prisons is challenging, but new, shorter regimens hold promise for feasible treatment options in prisons

Clinical evaluation of new diagnostic tests and development of testing strategies for tuberculosis diagnosis in Africa

Tuberculosis (TB) continues to kill more than 1.5 Mio people every year and causes a significant morbidity burden in the about 9 Mio patients who survived this infectious disease. Rapid and accurate TB diagnosis is considered one cornerstone of the global fight against TB. The “End TB Strategy” of the World Health Organization (WHO) is enforcing the need to develop new TB diagnostic tests, which are addressing the shortcomings of standard diagnostic tests that are currently used in TB epidemic and resource constrained settings like sub-Saharan Africa. In addition, to improved diagnostic tests, innovate testing strategies are needed to detect TB and control TB transmissions within specific risk groups such as prisoners, children and also TB contacts. In the frame of the presented habilitation project, three new diagnostic tests, namely the new Xpert MTB/RIF assay, which was endorsed by WHO in 2010, and two urine- based LAM tests, were evaluated in various clinical diagnostic studies in Tanzania. Further, a cross-sectional TB prevalence study was conducted in 13 Ethiopian prisons to study risk factors for TB in inmates and how successful currently implemented diagnostics algorithms are to detect TB in detention facilities. Finally, the isolated TB strains from these research studies were further analyzed using genotyping techniques in order to analyse mechanisms of TB transmission, spread of drug resistance and pathogenicity of TB strains in different high TB risk populations in Africa. For the Xpert MTB/RIF evaluation, the studies included adult and pediatric cohorts of patients with suspicion of TB. Further, the Xpert MTB/RIF assay was evaluated in a study with household contacts of smear-positive TB patients. Finally, the assay´s capacity to monitor TB treatment was assessed in TB patients who were enrolled in a therapeutic drug trial. The results of these studies contributed relevant information on the diagnostic accuracy of the assay and are also reflected by the current Xpert MTB/RIF policy recommendations from WHO. The most relevant findings were that Xpert MTB/RIF had a significant higher sensitivity compared to smear microscopy and detected up to 60% of smear negative, culture positive adult and paediatric TB cases. Xpert MTB/RIF performs equally well in HIV-positive and HIV-negative TB suspects and only one test in adults is sufficient to reach almost maximal sensitivity. Due to easy handling, rapid availability of test results and good performance in field conditions, the Xpert MTB/RIF test should be considered as the preferred test in contact tracing scenarios in Tanzania. However, due to sustained positive Xpert MTB/RIF results until the end of antimicrobial therapy in up to 27% of smear-positive TB patients, this assay is not useful to monitor microbiological response to TB treatment. The diagnostic capacity of the two LAM-assays was evaluated in a cohort of children with presumed TB. This study showed that LAM-sensitivity was highest, with maximal 70%, in HIV positive TB cases but had poor sensitivity, 28%, in HIV-negative TB suspects. Importantly, those groups of children suffering most from (co-) morbidities and high mortality were more likely to be LAM-positive. Therefore, specifically HIV-positive children with presumed active TB infection and advanced morbidity might benefit most from urine LAM-testing. This is in line with current WHO recommendations on the use of urine-based LAM tests. However, further scientific evidence is needed for a final evaluation of the use of LAM tests for the diagnosis of TB in clinical routine in Africa. The prison studies revealed that TB prevalence with about 450 TB cases among 100.000 convicts was twice as large as in the standard Ethiopian population. About 30% of existing TB cases were not detected by the prison health staff, whereby half on these were smear negative. Risk factors for TB in prisons were related to subject characteristics and behavior (e.g. alcohol drinking and TB contact at home) as well as to prison capacities (e.g. windows in prison cells). Genotypic analyses revealed that TB strains from prisoners were forming joint clusters with TB strains isolated from the Ethiopian standard population. These findings support the concept of interrelated TB epidemics among populations inside and outside prisons. Both sides need to be addressed in TB control programmes, and e.g. systematic and comprehensive TB screenings among new prisoners at entry as well as long-term prisoners might be an important strategy in order to end TB in high risk populations in Africa

Tuberkuloosi iseärasused madala ravikatkestamise, kuid kõrge ravimresistentsusega iseloomustuvates vanglatingimuses

Väitekirja elektrooniline versioon ei sisalda publikatsiooneTuberkuloosi (TB), selhulgas ravimresistentse TB-i, esinemissagedus vanglas viibivate inimeste seas on 28 korda kõrgem kui tavaelanikkonna hulgas. Hilinenud diagnostika ja ravi suurendab TB-I levikut vanglates ja ühsikonnas tervikuna ning tõstab ebasoodsa ravitulemuse tõenäosust. TB-i ja eriti multiresistentset TB-i põdevate patsientide ravi edukuse määr on kogu maailmas madal, kusjuures viibimist kinnipidamisasutuses peetakse üheks ebasoodsa ravitulemuse riskiteguriks. Elmira Gurbanova uuring viidi läbi Aserbaidžaani Vabariigi kinnipidamisasutustes. Aserbaidžaan kuulub 30 kõrge RR-TB-i haigestumisega riigi hulka maailmas. Uuringu eesmärk oli hinnata Maailma Terviseorganisatsioon (MTO) poolt soovitatava sõeluuringu, diagnostika ja ravi mõju TB-i ja ravimresistentse TB-i esinemissagedusele vanglas, mida iseloomustab kõrge ravimresistentse TB-i esinemissagedus ja madal ravikatkestamise tase. Selleks, et hinnata tuberkuloosi sõeluuringu mõju TB-i haigestumisele ja ravitulemustele enne ja pärast kiirtestide, nagu Xpert MTB / RIF ja vedelkultuuri, kasutuselevõttu, kaasati uuringusse 2315 TB-i põdevat patsienti 19-st vanglast. Tuvastati, et kiirtestide kasutuselevõtt TB-i diagnostikaalgoritmides alandas suhteliselt lühikese aja jooksul vastavalt 3-, 10- ja 5-kordselt kogu TB-i haigestumist, mikroskoopial positiivsete uute juhtude esinemissagedust ja RIF-resistentsete juhtude esinemissagedust. Lisaks, peale kiirtestide kasutuselvõttu olid ravitulemused paremad patsientidel, keda raviti esimese rea TB-I ravimitega. Selleks, et tuvastada, kas selliste juhtude, kus erinevate määramismeetoditega, nagu Xpert MTB/RIF ja MGIT-vedelkultuur, saadud rifampitsin (RIF)-tundlikkuse määramistulemused lahknevad, testiti 532 patsiendilt võetud proove mõlema meetodiga. Analüüsiti, kas RIF-tundlikkuse esinemissagedus sõltub sellest, kas kasutatakse ühte ja sama rögaproovi või järjestikuseid, eri aegadel kogutud rögaproove. Vastuolulisi RIF-tundlikkuse tulemusi esines 6,2% proovidest. Leiti, et lahknevate RIF-tundlikkuse tulemuste määr ei sõltu sellest, kas kasutatakse üht ja sama proovi või erinevaid järjestikuseid proove. Kõige sagedamini täheldatud lahknevate tulemuste muster oli selline, kus RIF-resistentsus Xpert MTB/ RIF-l kombineerus RIF-tundlikkusega MGIT-kultuuris ning kus RIF-resistentsus oli peamiselt tingitud L511P mutatsioonist. RIF-resistentsuse kliiniline tähendus on aga sellistel juhtudel tõenäoliselt vähene, kuna raitulemused oluliselt ei erinenud. Kasutades Aserbaidžaani kinnipidamisasutuste eelist, mis seisneb madalas ravikatkestajate hulgas, analüüsiti RIF-resistentse TB-ga patsientide ebasoodsa ravitulemusega seotud riksifaktorid. Uuringusse kaasati 444 kinnipidamisasutustes viibivat RIF-resistentse TB-ga patsienti. Efektiivne ravitulemus saavutati 78,4%-l haigetest. Suurema arvu efektiivsete bakteritsiidsete ravimite kasutamine pärast RIF-resistentse TB-i ravikuuri kuuendat kuud oli peamiseks efektiivse raviga seotud teguriks. Olukord, kus kopsudes ei olnud nähtavaid patoloogiale viitavaid radioloogilisi muutusi ja kehamassiindeks oli vähemalt 18,5 kg/m2, suurendab samuti oluliselt efektiivse ravi tõenäosust. Vangustusega seotud teguritel, nagu karistuse liik või varasemate vangistuste arv, ei olnud ravitulemustele olulist mõju.Compared with the general population, prevalence of TB including its drug-resistant forms among prisoners is up to 28 times higher. Delayed diagnosis and treatment increase TB transmission and prevalence in prisons, which spills over the community. Treatment success rates among patients with TB and multidrug-resistant TB are globally low and historically, imprisonment is considered a risk factor for poor treatment outcome. Elmira Gurbanova’s study was performed in prisons of Azerbaijan, which is among the 30 high rifampicin resistant (RR) TB-burden countries in the world. The study aimed to evaluate the impact of the WHO-recommended screening, diagnostics, and treatment to the burden of TB and multi/extremely drug-resistant TB (M/XDR-TB) in the high-burden, but low-default prison settings. To evaluate the impact of TB screening on the notification and treatment outcomes in prisons before and after introduction of Xpert MTB/RIF and Mycobacteria growth indicator tube (MGIT) culture into the screening algorithms, a total of 2,315 TB patients were identified in 19 prisons and analyzed at this study. The 3-, 10-, and 5-fold significant decrease in the annual rates of the notified, smear-positive, and RR-TB cases, respectively, with significant linear trends towards decrease was identified. The treatment success with first-line drugs also increased significantly. To identify the rate of discordant rifampicin (RIF) susceptibility results by Xpert MTB/RIF and MGIT when the same sputum sample or sequential ones are used for the tests, samples from 532 patients were prospectively tested with both methods. Out of the tested samples, 6.2% had discordant RIF-susceptibility results. No significant association of the discordant RIF-susceptibility results with application of both tests on one sample versus sequential ones was found. L511P mutation accounted significantly on the discrepancy among those RIF-resistant on Xpert MTB/RIF, but sensitive on MGIT, while no significant association was identified between the outcomes of treatment with the first- or second-line drugs and the presence of any mutation. To identify the pure factors associated with the cure among RR-TB patients, taking the advantage of very low loss-to-follow-up rate among patients with TB in Azerbaijan prisons, 444 RR-TB patients identified and enrolled into the treatment, of them 78.4% were cured. Higher number of effective bactericidal drugs in the regimen after the 6th month of treatment, chest x-ray without visible pathology, and BMI ≥18.5 at the treatment start significantly increased the chances for cure. The prison-related factors, such as the type of sentence or number of previous imprisonments, had no significant impact on the treatment outcomes.https://www.ester.ee/record=b522842