The Prevalence of Latent Mycobacterium Tuberculosis Infection Based on an Interferon-γ Release Assay: A Cross-Sectional Survey Among Urban Adults in Mwanza, Tanzania.

One third of the world's population is estimated to be latently infected with Mycobacterium tuberculosis (LTBI). Surveys of LTBI are rarely performed in resource poor TB high endemic countries like Tanzania although low-income countries harbor the largest burden of the worlds LTBI. The primary objective was to estimate the prevalence of LTBI in household contacts of pulmonary TB cases and a group of apparently healthy neighborhood controls in an urban setting of such a country. Secondly we assessed potential impact of LTBI on inflammation by quantitating circulating levels of an acute phase reactant: alpha-1-acid glycoprotein (AGP) in neighborhood controls. The study was nested within the framework of two nutrition studies among TB patients in Mwanza, Tanzania. Household contacts- and neighborhood controls were invited to participate. The study involved a questionnaire, BMI determination and blood samples to measure AGP, HIV testing and a Quantiferon Gold In tube (QFN-IT) test to detect signs of LTBI. 245 household contacts and 192 neighborhood controls had available QFN-IT data. Among household contacts, the proportion of QFT-IT positive was 59% compared to 41% in the neighborhood controls (p = 0.001). In a linear regression model adjusted for sex, age, CD4 and HIV, a QFT-IT positive test was associated with a 10% higher level of alpha-1-acid glycoprotein(AGP) (10(B) 1.10, 95% CI 1.01; 1.20, p = 0.03), compared to individuals with a QFT-IT negative test. LTBI is highly prevalent among apparently healthy urban Tanzanians even without known exposure to TB in the household. LTBI was found to be associated with elevated levels of AGP. The implications of this observation merit further studies

Force of tuberculosis infection among adolescents in a high HIV and TB prevalence community: a cross-sectional observation study

BACKGROUND: Understanding of the transmission dynamics of tuberculosis (TB) in high TB and HIV prevalent settings is required in order to develop effective intervention strategies for TB control. However, there are little data assessing incidence of TB infection in adolescents in these settings. METHODS: We performed a tuberculin skin test (TST) and HIV survey among secondary school learners in a high HIV and TB prevalence community. TST responses to purified protein derivative RT23 were read after 3 days. HIV-infection was assessed using Orasure(R) collection device and ELISA testing. The results of the HIV-uninfected participants were combined with those from previous surveys among primary school learners in the same community, and force of TB infection was calculated by age. RESULTS: The age of 820 secondary school participants ranged from 13 to 22 years. 159 participants had participated in the primary school surveys. At a 10 mm cut-off, prevalence of TB infection among HIV-uninfected and first time participants, was 54% (n = 334/620). HIV prevalence was 5% (n = 40/816). HIV infection was not significantly associated with TST positivity (p = 0.07). In the combined survey dataset, TB prevalence was 45% (n = 645/1451), and was associated with increasing age and male gender. Force of infection increased with age, from 3% to 7.3% in adolescents [greater than or equal to]20 years of age. CONCLUSIONS: We show a high force of infection among adolescents, positively associated with increasing age. We postulate this is due to increased social contact with infectious TB cases. Control of the TB epidemic in this setting will require reducing the force of infection

The use of Anti-Retroviral drugs in the Prevention of Mother to Child Transmission (PMTCT) of HIV

Mother to child transmission is by far the main mode of transmission of HIV to the child. In an attempt to curb the situation, many interventions have been proposed and targeted at the antenatal, natal and postnatal stages. More recently, the Ministry of Health and Social Welfare developed the National PMTCT guidelines to be used and adopted throughout the country. There are several interventions that have been proposed and implemented, this papers focuses particularly on the use of antiretroviral drugs during each of these phases and outlines some technical challenges faced by the programme before achievement levels can reach those of developed nations.Keywords: ARV‘s, PMTCT, Tanzani

Healthcare workers’ knowledge, attitudes, practices on post exposure prophylaxis for HIV in Dar es Salaam

Background : Access to HIV care and treatment has improved over the past several years, but safety standards and precautions have not improved in the same proportions leading to increased risk of exposure to and transmission of HIV through occupational injury, mainly via needle stick injury. This hospital based study of 316 health care workers (HCW) in Dar Es Salaam aimed to investigate the knowledge, attitude and practices on post exposure prophylaxis for HIV exposure. Results: Occupational exposure to HIV was common among HCWs, affecting 169 out of 316 workers surveyed. The affected workers included nurses and doctors. Of the 169 HCWs exposed, 41 had taken post exposure prophylaxis (PEP). Only about one third knew the initial steps to be followed after exposure as recommended in National Guidelines. Hospitals were the major source of information on PEP. Most of the HCWs had satisfactory knowledge on PEP. Approximately fifteen percent of HCWs had used PEP and the mean time to start use of PEP was 13.5 hours. Approximately forty percent failed to use PEP for the full length of time prescribed; the main reason for the shorter duration was adverse affects associated with the antiretroviral drugs. Conclusion: There is a need to intensify education on PEP among HCWs to increase their awareness and knowledge and train HCWs to practice universal safety precautions to decrease risk of HIV transmission. Key words: Post-exposure prophylaxis, HIV, Healthcare workers, resource poor setting

Latent Tuberculosis in Pregnancy: A Systematic Review

BACKGROUND:In countries with low tuberculosis (TB) incidence, immigrants from higher incidence countries represent the major pool of individuals with latent TB infection (LTBI). The antenatal period represents an opportunity for immigrant women to access the medical system, and hence for potential screening and treatment of LTBI. However, such screening and treatment during pregnancy remains controversial. OBJECTIVES:In order to further understand the prevalence, natural history, screening and management of LTBI in pregnancy, we conducted a systematic literature review addressing the screening and treatment of LTBI, in pregnant women without known HIV infection. METHODS:A systematic review of 4 databases (Embase, Embase Classic, Medline, Cochrane Library) covering articles published from January 1st 1980 to April 30th 2014. Articles in English, French or Spanish with relevant information on prevalence, natural history, screening tools, screening strategies and treatment of LTBI during pregnancy were eligible for inclusion. Articles were excluded if (1) Full text was not available (2) they were case series or case studies (3) they focused exclusively on prevalence, diagnosis and treatment of active TB (4) the study population was exclusively HIV-infected. RESULTS:Of 4,193 titles initially identified, 208 abstracts were eligible for review. Of these, 30 articles qualified for full text review and 22 were retained: 3 cohort studies, 2 case-control studies, and 17 cross-sectional studies. In the USA, the estimated prevalence of LTBI ranged from 14 to 48% in women tested, and tuberculin skin test (TST) positivity was associated with ethnicity. One study suggested that incidence of active TB was significantly increased during the 180 days postpartum (Incidence rate ratio, 1.95 (95% CI 1.24-3.07). There was a high level of adherence with both skin testing (between 90-100%) and chest radiography (93-100%.). In three studies from low incidence settings, concordance between TST and an interferon-gamma release assay was 77, 88 and 91% with kappa values ranging from 0.26 to 0.45. In low incidence settings, an IGRA may be more specific and less sensitive than TST, and results do not appear to be altered by pregnancy. The proportion of women who attended follow-up visits after positive tuberculin tests varied from 14 to 69%, while 5 to 42% of those who attended follow-up visits completed a minimum of 6 months of isoniazid treatment. One study raised the possibility of an association of pregnancy/post-partum state with INH hepatitis (risk ratio 2,5, 95% CI 0.8-8.2) and fatal hepatotoxicity (rate ratio 4.0, 95% CI 0.2-258). One study deemed INH safe during breastfeeding based on peak concentrations in plasma and breast milk after INH administration. CONCLUSION:Pregnancy is an opportunity to screen for LTBI. Interferon-gamma release assays are likely comparable to tuberculin skin tests and may be used during pregnancy. Efforts should be made to improve adherence with follow-up and treatment post-partum. Further data are needed with respect to safety and feasibility of antepartum INH therapy, and with respect to alternative treatment regimens