High Rates Of Tuberculosis Research Articles

Prevalence of Human Immune Deficiency Virus in Suspected Tuberculosis Patients Attending Clinics in Benin City NIGERIA

Tuberculosis and HIV have been closely linked since the emergence of acquired immune deficiency syndrome. HIV has contributed to a significant increase in the incidence of tuberculosis worldwide by producing a progressive de- cline in cell immunity. Four hundred and seventy sputum samples were collected from different clinics in and around Be- nin City and tested for tuberculosis and HIV. Of the 470 samples tested, only 147 (32%) were positive while 323 (68%) were negative for tuberculosis. 71 (15%) were positive for HIV alone while 56 (11%) were co-infected with both tubercu- losis and HIV. Of the 103 patients who received BCG at childhood 18.2% tested positive. More males tested positive than their female counterparts, while traders had the highest number of positive case and also had the highest attributable risk. Oredo Local Government Area of Edo State Nigeria had the highest number of positive cases. It could be said that HIV has contributed to the prevalence of tuberculosis in Edo State Nigeria. The high rate of tuberculosis is then associated with increase in HIV infection.

RD Rio Mycobacterium tuberculosis Infection Is Associated with a Higher Frequency of Cavitary Pulmonary Disease

Molecular genotyping has shown Mycobacterium tuberculosis lineages to be geographically restricted and associated with distinct ethnic populations. Whether tuberculosis (TB) caused by some M. tuberculosis lineages can present with a differential clinical spectrum is controversial because of very limited clinical data. We recently reported on the discovery of RD(Rio) M. tuberculosis, a Latin American-Mediterranean sublineage that is the predominant cause of TB in Rio de Janeiro, Brazil. To investigate the clinical attributes of TB caused by RD(Rio) strains, we studied a cohort of TB cases from Belo Horizonte, Brazil, in which clinical information recorded on a standardized questionnaire was collected at the time of microbiological testing. These patients were referred for culture and drug susceptibility testing because of the clinical suspicion of "complicated" TB, as demonstrated by high rates of multidrug resistance (12%) and cavitary TB (80%). We performed spoligotyping and RD(Rio) genotyping on the M. tuberculosis strains and analyzed the clinical data from these patients. RD(Rio) M. tuberculosis accounted for 37% of the total TB burden. Multivariate analysis found a significant association between TB caused by RD(Rio) strains and pulmonary cavitation and residence in Belo Horizonte. Since cavitary TB is associated with higher sputum bacillary load, our findings support the hypothesis that RD(Rio) M. tuberculosis is associated with a more "severe" disease as a strategy to increase transmission. Future studies are needed to confirm these observations and to better define the contribution of RD(Rio) M. tuberculosis to the global TB epidemic.

Persistent risk of tuberculosis in migrants a decade after arrival in Australia

To examine the risk of tuberculosis (TB) in migrants a decade after their arrival in Australia. Retrospective review of laboratory-confirmed cases of TB in migrants diagnosed between 1990 and 2004 by the state TB reference laboratory in Victoria, analysed by a multivariate model comparing migrants diagnosed 10 or more years after arrival with those diagnosed within 10 years of arrival. Time to diagnosis; characteristics of migrants diagnosed with TB, including age, sex, region of birth, site of infection, and drug resistance. A third of migrants (734/1924) were diagnosed with TB 10 or more years after arrival in Australia. This group was more likely to be European-born (adjusted odds ratio [AOR], 3.4; 95% CI, 2.4-5.0) and older than 34 years (35-49 years: AOR, 3.8; 95% CI, 2.0-7.0), reflecting the longer time European migrants have been in Australia. There were two distinct European groups: European Union (EU)/Western and Central/Eastern. The Central/Eastern group were from countries with current high TB rates and, compared with the EU/Western group, were younger (mean age, 50 v 64 years) and more likely to be diagnosed within 10 years of arrival (47% v 14%; P < 0.001). European migrants were more likely to be diagnosed a decade or more after arrival in Australia. Once migrants from the currently high TB incidence areas of Asia and Africa have been in Australia for a similar period of time, their timing of diagnosis may resemble that for migrants from Europe. The current screening policy should be complemented with more sensitive techniques to detect latent TB.

The effect of ultraviolet B‐induced vitamin D levels on host resistance to Mycobacterium tuberculosis: a pilot study in immigrant Asian adults living in the United Kingdom

Asian immigrants to the United Kingdom demonstrate much higher tuberculosis rates than the indigenous population. This is postulated to be because of their low vitamin D levels, consequent upon a combination of diet and their reduced ultraviolet (UV) exposure in the United Kingdom, because vitamin D enhances antimycobacterial activity in in vitro systems. The aim of this study was to examine the relationship between UVB exposure, vitamin D levels and tuberculo-immunity in Asian immigrants in the United Kingdom. Suberythemal UVB treatments were given to eight subjects on 3 consecutive days, using broadband UVB fluorescent lamps. Blood was sampled for 25-hydroxyvitamin D (25-OH D) and whole blood functional assays were performed for antimycobacterial immunity. The mean 25-OH D level increased from a baseline of 11.23 ng/ml (95% CI 6.7-20.39) to 20.39 ng/ml (95% CI 16.6-20) following UVB treatment, P<0.01. However, no significant change in antimycobacterial immunity occurred following UVB exposure. This pilot study in Asian subjects with good baseline tuberculo-immunity has not supported a role for UVB-induced 25-OH D in the immune response to Mycobacterium tuberculosis.

Early Detection of Tuberculosis Outbreaks among the San Francisco Homeless: Trade-Offs Between Spatial Resolution and Temporal Scale

BackgroundSan Francisco has the highest rate of tuberculosis (TB) in the U.S. with recurrent outbreaks among the homeless and marginally housed. It has been shown for syndromic data that when exact geographic coordinates of individual patients are used as the spatial base for outbreak detection, higher detection rates and accuracy are achieved compared to when data are aggregated into administrative regions such as zip codes and census tracts. We examine the effect of varying the spatial resolution in the TB data within the San Francisco homeless population on detection sensitivity, timeliness, and the amount of historical data needed to achieve better performance measures.Methods and FindingsWe apply a variation of space-time permutation scan statistic to the TB data in which a patient's location is either represented by its exact coordinates or by the centroid of its census tract. We show that the detection sensitivity and timeliness of the method generally improve when exact locations are used to identify real TB outbreaks. When outbreaks are simulated, while the detection timeliness is consistently improved when exact coordinates are used, the detection sensitivity varies depending on the size of the spatial scanning window and the number of tracts in which cases are simulated. Finally, we show that when exact locations are used, smaller amount of historical data is required for training the model.ConclusionSystematic characterization of the spatio-temporal distribution of TB cases can widely benefit real time surveillance and guide public health investigations of TB outbreaks as to what level of spatial resolution results in improved detection sensitivity and timeliness. Trading higher spatial resolution for better performance is ultimately a tradeoff between maintaining patient confidentiality and improving public health when sharing data. Understanding such tradeoffs is critical to managing the complex interplay between public policy and public health. This study is a step forward in this direction.

Changes in the incidence of tuberculosis in a cohort of HIV-seroconverters before and after the introduction of HAART

To analyse incidence and determinants of tuberculosis in HIV-seroconverters before and after the introduction of HAART. Data from a multicenter cohort study of 2238 HIV-seroconverters between the 1980s and 2004 were analysed and censored by December 2004. Calendar year at risk intervals were pre-1992, 1992-1996 and 1997-2004. Incident tuberculosis was calculated as cases per 1000 person-years (p-y). Survival analyses using Kaplan-Meier and multivariate Cox regression allowing for late-entry were used. Proportional hazards assumptions were checked with tests based on Schoenfeld residuals. Overall, 173 (7.7%) patients developed tuberculosis over 23 698 p-y at a rate of 7.3 cases per 1000 p-y [95% confidence interval (CI), 6.3-8.5]. Incident tuberculosis was higher in intravenous drug-users (IDUs), 12.3 per 1000 p-y compared with persons infected sexually, 3.8 per 1000 p-y (P < 0.001), and persons with clotting disorders (PCD), 2.7 per 1000 p-y (P < 0.001). A decreasing tuberculosis incidence trend was observed from 1995 in all categories. Highest tuberculosis rates, 44 per 1000 p-y, were observed prior to 1997 in IDUs infected with HIV for 11 years. In multivariable analyses women were less likely to develop tuberculosis [relative hazard (RH), 0.62; 95% CI, 0.41-0.96; P < 0.05) and IDUs were more likely to develop tuberculosis (RH, 3.0; 95% CI, 1.72-5.26, P < 0.001). In the HAART era, the hazard of developing tuberculosis was 70% lower (RH, 0.31; 95% CI, 0.17-0.54; P < 0.001). Before 1997, the risk of tuberculosis increased with time since HIV seroconversion, whereas it remained nearly constant in the HAART era. Since the mid-1990s important decreases in tuberculosis have been observed in HIV-seroconverters that probably reflect the impact of both HAART and tuberculosis control programmes.

Review article: the diagnosis and management of Crohn’s disease in populations with high‐risk rates for tuberculosis

Distinguishing Crohn's disease from intestinal tuberculosis in endemic areas is challenging as both conditions have overlapping clinical, radiological, endoscopic and histological characteristics. Furthermore, high rates of latent tuberculosis confer a considerable risk of reactivation once therapy for established Crohn's disease is started. To review current strategies in differentiating these two conditions, and in managing Crohn's disease, in populations with high rates of tuberculosis. Literature review and clinical experience. While various clinical, radiological, endoscopic and histological parameters may aid in differentiating Crohn's disease from intestinal tuberculosis, these remain imperfect and as treatment options differ misdiagnosis has grave consequences. We propose a diagnostic algorithm, based on currently available evidence and experience, to aid in this dilemma. We also discuss approaches to the management of Crohn's disease, including agents targeting tumour necrosis factor-alpha, in patients at risk of developing tuberculosis. A diagnosis of Crohn's disease in individuals at risk for tuberculosis should only be made after careful interpretation of clinical signs, abdominal imaging and systematic endoscopic and histological assessment. Newer techniques for the diagnosis of latent tuberculosis still need to be validated in this environment, and guidelines on the treatment of latent tuberculosis in this setting require clarification.

Impact of Mobile Radiographic Screening on Tuberculosis among Drug Users and Homeless Persons

In 2002, a mobile radiographic screening program was started in Rotterdam to respond to high rates of tuberculosis (TB) among illicit drug users and homeless persons. We studied trends and characteristics of TB among these risk groups and assessed the impact of the screening program on transmission, using molecular typing. Description of trends, and of demographic and disease-related characteristics of tuberculosis cases among these risk groups between 1993 and 2005. TB was considered to result from recent transmission if the mycobacterial DNA fingerprints of cases were identical to those of other cases in the risk groups in the previous 2 years. During the study period, 206 individuals with TB among illicit drug users and homeless persons were notified, representing 11.4% of the total case load of 1,811 in Rotterdam. The annual number of tuberculosis cases declined from 24 at the start of the screening program to 11 cases in 2005. The screening program identified 28 cases (a prevalence rate of 327 per 100,000 radiographs), of which 12 were smear positive. In 1997-2002, more than 80% of the illicit drug users or homeless persons with TB were infected with one of the Mycobacterium tuberculosis strains prevalent among these risk groups. After nearly 4 years of systematic radiographic screening this proportion declined to 45% in 2005. DNA fingerprinting can be a useful tool to evaluate the impact of a TB screening program. We advocate that screening of illicit drug users and homeless persons should be continued to prevent a resurgence of TB.

TB in a Low-Incidence Country: Differences Between New Immigrants, Foreign-Born Residents and Native Residents

Background New immigrants and foreign-born residents add to the burden of pulmonary tuberculosis (TB) in low-incidence countries. The highest TB rates have been found among recent immigrants. Active screening programs are likely to change the clinical presentation of TB, but the extent of the difference between immigrant and resident populations has not been studied prospectively. Methods Adult new immigrants were screened upon entry to 1 of 5 immigration centers in Switzerland. Immigrants with abnormal chest radiographs were enrolled and compared in a cohort study to consecutive admitted foreign-born residents from moderate-to-high incidence countries and native residents presenting with suspected TB. Results Of 42,601 new immigrants screened, 112 had chest radiographs suspicious for TB. They were compared with foreign-born residents (n = 118) and native residents (n = 155) with suspected TB (n = 385 patients included). Active TB was confirmed in 40.5% of all patients (immigrants 38.4%, foreign-born residents 50%, native residents 34.8%). Clinical signs and symptoms of TB and laboratory markers of inflammation were significantly less common in immigrants than in the other groups with normal results in >70%. The proportion of positive results on rapid testing to detect M. tuberculosis (MTB) in 3 respiratory specimens was significantly lower in immigrants (34.9% for acid-fast staining; 55.8% for polymerase chain reaction) compared with foreign-born residents (76.2% and 89.1%, respectively) and native residents (83.3% and 90.9%, respectively). Isoniazid resistance and multi-drug resistance were more prevalent in immigrants. Conclusion New immigrants with TB detected in a screening program are often asymptomatic and have a low yield of rapid diagnostic tests but are at higher risk for resistant MTB strains. Postmigration follow-up of pulmonary infiltrates is essential in order to control TB among immigrants, even in the absence of clinical and laboratory signs of infection.

Vitamin D receptor gene polymorphisms and susceptibility M. tuberculosis in Native Paraguayans

Tuberculosis (TB) is a significant health problem for most of the world's populations, and prevalence among indigenous groups is typically higher than among their nonindigenous neighbors. Native South Americans experience high rates of TB, but while research in several other world populations indicates that susceptibility is multifactorial, polygenic, and population-specific, little work has been undertaken to investigate factors involved in Native American susceptibility. We conducted a family-based association study to examine immunologically relevant polymorphisms of a candidate gene, the vitamin D receptor, in conjunction with three measures of TB status in two Native Paraguayan populations, the Aché and the Avá. This is the first large-scale genetic analysis of Native South Americans to examine susceptibility to both infection and disease following exposure to M. tuberculosis. These two types of susceptibility reflect differences in innate and acquired immunity that have proven difficult to elucidate in other populations. Our results indicate that among the Aché, the FokI F allele protects individuals from infection, while the TaqI t allele protects against active disease but not infection. In particular, FF homozygotes are 17 times more likely to test positive for exposure to TB, but no more likely to have ever been diagnosed with active TB. TT individuals are 42 times less likely to mount a delayed-type hypersensitivity response, and the T allele was significantly more likely to have been transmitted to offspring who have been diagnosed with active TB. This ongoing research is of vital importance to indigenous groups of the Americas, because if there is a population-specific component to TB susceptibility, it will likely prove most effective to incorporate this into future treatment and prevention strategies.

Risk of Tuberculosis From Exposure to Tobacco Smoke

There is no consensus whether tobacco smoking increases risk of tuberculosis (TB) infection, disease, or mortality. Whether this is so has substantial implications for tobacco and TB control policies. To quantify the relationship between active tobacco smoking and TB infection, pulmonary disease, and mortality using meta-analytic methods. Eight databases (PubMed, Current Contents, BIOSIS, EMBASE, Web of Science, Centers for Disease Control and Prevention Tobacco Information and Prevention Source [TIPS], Smoking and Health Database [Institute for Science and Health], and National Library of Medicine Gateway) and the Cochrane Tobacco Addiction Group Trials Register were searched for relevant articles published between 1953 and 2005. Included were epidemiologic studies that provided a relative risk (RR) estimate for the association between TB (infection, pulmonary disease, or mortality) and active tobacco smoking stratified by (or adjusted for) at least age and sex and a corresponding 95% confidence interval (CI) (or data for calculation). Excluded were reports of extrapulmonary TB, studies conducted in populations prone to high levels of smoking or high rates of TB, and case-control studies in which controls were not representative of the population that generated the cases, as well as case series, case reports, abstracts, editorials, and literature reviews. Twenty-four studies were included in the meta-analysis. Extracted data included study design, population and diagnostic details, smoking type, and TB outcomes. A random-effects model was used to pool data across studies. Separate analyses were performed for TB infection (6 studies), TB disease (13 studies), and TB mortality (5 studies). For TB infection, the summary RR estimate was 1.73 (95% CI, 1.46-2.04); for TB disease, estimates ranged from 2.33 (95% CI, 1.97-2.75) to 2.66 (95% CI, 2.15-3.28). This suggests an RR of 1.4 to 1.6 for development of disease in an infected population. The TB mortality RRs were mostly below the TB disease RRs, suggesting no additional mortality risk from smoking in those with active TB. The meta-analysis produced evidence that smoking is a risk factor for TB infection and TB disease. However, it is not clear that smoking causes additional mortality risk in persons who already have active TB. Tuberculosis control policies should in the future incorporate tobacco control as a preventive intervention.

The relationship between diabetes and tuberculosis in Saskatchewan: comparison of registered Indians and other Saskatchewan people.

Saskatchewan Aboriginal people are experiencing epidemics of both type 2 diabetes (T2DM) and tuberculosis (TB). The purpose of this study was to determine if a relationship exists between diabetes and TB in Saskatchewan and to establish whether there is a difference in the degree of any association between Aboriginal and non-Aboriginal people. Utilizing Saskatchewan Health databases, TB incidence (cases identified from 1986-2001) was compared between four subpopulations identified from 1991-1995: Registered Indians (RI) with and without diabetes, and other Saskatchewan people (OSKP) with and without diabetes. Diabetic women aged 20-59 years had higher average annual incidence rates of TB than non-diabetic women, but within-population rate ratios of TB in diabetic versus non-diabetic women were only significant in those aged 50-59 (2.7 [CI 1.28, 5.72] in RI and 3.9 [CI 1.58, 9.67] in OSKP). No other within-population diabetic subgroup had significantly higher rates of TB. The only male diabetic group that had a higher rate of TB were RI plus OSKP men aged 50-59 years. Overall, diabetes preceded TB in 87/111 individuals with both diseases (p < 0.0001). Our results suggest that T2DM is a predictor for TB in Saskatchewan women aged 20-59 but particularly in RI and OSKP women aged 50-59 years. This has implications for TB screening and prevention initiatives.

‘ETHNOGRAPHY PLUS’ IN TUBERCULOSIS RESEARCH

We argue that in some contexts we anthropologists need to go beyond ethnography through being involved in multidisciplinary approaches to research problems and through engaging in a more public anthropology in our ethnographic and other writing. This argument is based on our experiences in coming to an understanding of ‘immigrant TB’ in the context of a social sciences research project about tuberculosis in New Zealand. This paper unpacks some of the complexities around relatively high rates of tuberculosis in overseasborn persons in New Zealand, and suggests that the conditions of settlement, including poverty and discrimination, combine with life history to produce the observed epidemiological patterns. A corollary is that while control of tuberculosis at the border is important, support for migrants, ensuring their social participation, access to health care and their rights to freedom from discrimination are also key.

Tratamiento de la tuberculosis pulmonar

The treatment of tuberculosis is important both to preserve the health of the patient and to prevent the spread of the disease amongst the population. Its bacteriological bases are found in the high number of bacillae existing in the majority of human TB lesions and the capacity to mutate of Mycobacterium tuberculosis when it achieves a high number of divisions; this makes it essential to associate drugs that avoid the selection of resistant mutants. In our setting the pharmacological therapy that has shown greatest efficacy consists in the association during two months of isoniacide, rifampicine and pyrazinamide followed by four additional months with the first two drugs. In general the first choice tuberculostatic drugs are well tolerated, but they can produce potentially serious secondary effects that it is necessary to understand and know how to manage. This article also describes how to act from the therapeutic point of view facing certain special situations and when the initial treatments have been abandoned or have failed. In the last five years in Navarre, there has been a significant increase in the presence of immigrants proceeding from developing countries with high rates of tuberculosis and primary resistances. Because of its specific socio-economic conditions and its cultural idiosyncrasy, this group frequently generates difficulties with respect to complying with the treatment, as well in follow-up and control. The treatment of tuberculosis must always be carried out by expert doctors.

Risk factors for active tuberculosis among adults on highly active antiretroviral therapy in Africa: a reply

We thank Seyler and colleagues for their insightful thoughts concerning risk factors for the development of tuberculosis during HAART. Three studies addressing this question have been published and have differing findings [1–3]. The persistence of high rates of tuberculosis during HAART is an important issue, and an accurate identification of risk factors is key to the development of appropriate strategies to reduce this burden of disease. Studies from Cape Town, South Africa [1] and Europe/north America [3] found that more advanced pretreatment immunodeficiency and lack of response to HAART were the principal factors associated with the risk of tuberculosis during HAART. In contrast, Seyler and colleagues [2] found in a west African cohort in Abidjan that the only risk factor was a previous history of tuberculosis. We have previously suggested that the lack of an association between the risk of tuberculosis and pretreatment immunodeficiency in the Abidjan study may relate to the restricted composition of the cohort [4,5]. The inclusion of few patients with stage 1 or 2 disease or CD4 cell counts greater than 200 cells/μl will have diminished the power to assess CD4 cell count and clinical stage as risk factors. Explaining the discrepancy in findings concerning a history of previous tuberculosis as a risk factor is probably more complex. HIV-associated immunodeficiency is an important risk factor for the recurrence of tuberculosis, whether caused by relapse (resulting from incomplete sterilization of tuberculous lesions) or exogenous re-infection [6]. Evidence suggests that the restoration of Mycobacterium tuberculosis-specific immunity is incomplete during at least the first year of HAART [7], and it is therefore certainly plausible that a previous history of tuberculosis would persist as a significant risk factor for incident tuberculosis after the initiation of HAART. However, whether such an association is demonstrable in a given cohort is likely to be determined by the proportion of patients who have a past history of tuberculosis, the relative strength of association of other variables such as baseline CD4 cell count and their risk of re-exposure to tuberculosis. Whereas the underrecording of a previous history of tuberculosis may be a significant problem in community-based tuberculosis clinics [8], which are frequently overburdened in much of sub-Saharan Africa, we doubt that this is likely to be a significant factor among carefully documented patients in a study cohort, many of whom were in long-term medical care before antiretroviral therapy. Although the proportion of patients in the Cape Town cohort who had a previous history of tuberculosis was comparatively low (14%), this probably reflects the sociodemographic composition and immune profile of the cohort rather than reflecting underreporting. In marked contrast, approximately 50% of patients accessing a community-based antiretroviral treatment programme based within in a poor urban township in Cape Town (previously described in Lawn et al. [9]) have a history of previous tuberculosis. It may prove that study populations with markedly differing baseline characteristics and levels of community exposure to tuberculosis may have different risk factors associated with incident tuberculosis during HAART. The relative contribution of relapse versus re-infection as a cause of recurrent tuberculosis is also likely to differ between settings. Inadequate antituberculosis treatment increases the risk of tuberculosis relapse; in contrast, a higher incidence of tuberculosis in a community is associated with an increased likelihood of exogenous re-infection [6,10]. As patients with tuberculosis in Cape Town receive a 6-month rifampicin-containing regimen and the tuberculosis incidence rates in some communities are among the highest in the world [11], we suspect that a large proportion of recurrent tuberculosis is caused by exogenous re-infection. In this context, one would expect that antituberculosis treatment would be followed by a time-dependent reduction in tuberculosis incidence, and that the rate would gradually increase with time after the completion of antituberculosis treatment as the opportunity for re-exposure increases. Seyler and colleagues rightly point out that among patients with a history of previous tuberculosis, a greater proportion of those in the Cape Town cohort compared with the Abidjan cohort completed antituberculosis treatment in the year before the initiation of HAART. This may have conferred a time-dependent protective effect against tuberculosis during the first 1–2 years of HAART in the Cape Town cohort when the majority of cases of incident tuberculosis occurred. This may be an important factor contributing to the differing findings between the Abidjan and Cape Town studies. The potential benefit from the co-administration of isoniazid prophylaxis concurrently when initiating HAART may thus be diminished if a high proportion of enrolling patients have recently completed antituberculosis treatment. In conclusion, risk factors for tuberculosis during HAART may differ between study populations of differing composition and in different settings. Data from many different sites are needed to clarify the overall picture. Sponsorship: S.D.L. is funded by the Wellcome Trust, London, UK.

Epidemiology of Tuberculosis in the Southeastern Iran

In order to study the epidemiology of tuberculosis (TB) in Zabol, situated in the Southeast of Iran, this study was performed. Two thousand seven hundred and twenty-nine cases of tuberculosis disease were identified during 1998-2002. The notification rate was 135/100,000 population in 2002, which was higher than this rate in previous years. The notification rate of TB in Afghan population was significantly higher than Iranian population (202 cases/100,000 in Afghan and 122 cases/100,000 in Iranian population. The case notifications in 1998-2001 were 134, 131, 130, and 130 in 100,000 populations, respectively. The prevalence of smear-positive cases was 76/100,000 population in 2002 and the ratio of smear-positive cases to smear-negative and extrapulmonary cases was 1.46. This region remains high TB rates. It is necessary to pay attention to the detection of TB, by making their register in order to enhance the effectiveness and to reduce the cost of existing methods.

Tuberculosis, HIV seroprevalence and intravenous drug abuse in prisoners

High rates of tuberculosis (TB) and HIV are believed to exist in Russian prisons. Prisoners with TB were studied in order to identify the following: 1) prevalence of HIV, and risk factors for HIV and other blood-borne virus infections; and 2) clinical and social factors that might compromise TB treatment effectiveness and/or patient adherence and, hence, encourage treatment failure. A 1-yr cross-sectional prevalence study of 1,345 prisoners with TB was conducted at an in-patient TB facility in Samara, Russian Federation. HIV and hepatitis B and/or C co-infection occurred in 12.2% and 24.1% of prisoners, respectively, and rates were significantly higher than in civilians. Overall, 48.6% of prisoners used drugs, of which 88.3% were intravenous users. Prisoners were more likely to be intravenous drug users and HIV positive compared with civilians with TB, and 40.2% of prisoners shared needles. Two-thirds of prisoners (68.6%) had received previous TB drug therapy (frequently multiple, interrupted courses) and were significantly more likely than civilians to have had previous therapy consistent with the high drug-resistance rates seen. Prisons are major drivers of the tuberculosis and HIV epidemics. Novel strategies are needed to reduce the spread of blood borne diseases, particularly in intravenous drug users.

Does immune reconstitution syndrome promote active tuberculosis in patients receiving highly active antiretroviral therapy?

To assess whether highly active anti-retroviral therapy (HAART) contributes to the presentation of active tuberculosis (TB). Retrospective single-centre cohort study. A total of 111 HIV-infected individuals with active TB were identified at an urban teaching hospital between February 1997 and April 2004. Those receiving HAART at the time of TB diagnosis were assessed. Nineteen of 111 (17%) were receiving HAART when TB developed. Within this group there appeared to be two distinct populations. Thirteen of 19, 12 from ethnic or social groups with high background rates of TB, developed disease a median of 41 days (range, 7-109) after starting HAART ('early TB' group). In six of 19 ('late TB' group), TB occurred a median of 358 days after HAART initiation (range, 258-598). The 'early TB' group had lower CD4 cell counts when starting HAART in comparison with the 'late TB' group (median; 87 versus 218 x 10 cells/l; P = 0.04); however no difference was observed in the rate of change of CD4 cell count (P = 0.5) or HIV load. Paradoxical reaction rate in the 'early TB' group was significantly greater than in the 'late-TB' group (62 versus 0%, P = 0.02) and greater than in a similar control population who started HAART while taking anti-TB therapy (62 versus 30%, P = 0.05). These data suggest anti-HIV treatment may amplify the presentation of active TB. This has implications for antiretroviral programmes in countries with high TB rates and warrants prospective investigation of a larger cohort.

Rate of Reinfection Tuberculosis after Successful Treatment Is Higher than Rate of New Tuberculosis

In a high-tuberculosis (TB) incidence area of Cape Town, South Africa, there is a very high rate of unexplained recurrent TB. The incidence of new bacteriologically confirmed disease in the area is 313 per 100,000 individuals. To estimate the rate of recurrent TB attributable to reinfection after successful treatment. All patients with reported TB in the area between 1993 and 1998 were followed up to 2001 for disease needing retreatment (recurrences). Patients who were multi-drug-resistant or who had treatment failure, were transferred, or died during treatment were excluded. Analysis was restricted to patients for whom DNA fingerprinting of their Mycobacterium tuberculosis isolates was obtained. Reinfection TB was defined as a recurrent TB episode in which the strains of the separate episodes differed by more than four bands. 612 of 897 (68%) patients had a DNA fingerprint available at enrollment. Median duration of follow-up was 5.2 years. Recurrent TB occurred in 108 of 612 (18%) patients, of whom 61 of 447 (14%) experienced recurrence after successful treatment, and 47 of 165 (28%) experience recurrence after default. Of the 108 patients with recurrent TB, 68 (63%) had a DNA fingerprint in the second episode. Among these patients, 24 of 31 (77%) recurrences after successful treatment and 4 of 37 (11%) recurrences after default were attributable to reinfection. The reinfection disease rate after successful treatment was estimated at 2.2 per 100 person-years. The age-adjusted incidence rate of TB attributable to reinfection after successful treatment was four times that of new TB. People who had TB once are at a strongly increased risk of developing TB when reinfected.

Perceptions of tuberculosis: attributions of cause, suggested means of risk reduction, and preferred treatment in the Limpopo province, South Africa.

Despite the availability of effective treatment regimens, exceptionally high rates of tuberculosis persist in South Africa. A better understanding of public perceptions of tuberculosis is important for the improvement of the existing tuberculosis-control programmes. This study was aimed at investigating public perceptions about causes, suggested means of risk reduction, and preferred treatment of tuberculosis. The cross-sectional study included a sample of 80 community members from four different age groups chosen by quota sampling in a semi-urban community. Results indicated that 13.75% of the community members reported biomedical causes of tuberculosis, 35% suggested biomedical methods as a means for risk reduction, and 91.25% preferred medical treatment. Significant gender but not age difference was found. Women reported more often than men a biomedical cause of tuberculosis. A number of misconceptions about the cause and risk reduction of tuberculosis were also mentioned. The results suggest that people in a semi-urban area of the Limpopo province have limited knowledge and understanding of tuberculosis. It is suggested that healthcare workers provide services for increasing basic knowledge about causes and risk reduction of tuberculosis of the population in every age group.