Prevalence Of Latent Infection Research Articles

Prevalence of latent tuberculosis infection and incidence of tuberculin conversion among school contacts older than 5 years in the City of Buenos Aires.

Introduction. Tuberculosis continues to be a common problem in settings of socioeconomic vulnerability. Our primary objective was to establish the prevalence of latent infection and tuberculin conversion among school contacts of tuberculosis cases. Population and methods. In a programmatic area in the south of the City of Buenos Aires, the prevalence of latent infection and tuberculin conversion was assessed in 691 children and adolescents using the tuberculin skin test. The association between loss to follow-up by the health care team and the demographic, school, and baseline care characteristics was studied, and the level of adherence when isoniazid chemoprophylaxis was indicated was described. Results. According to established definitions, the prevalence of latent infection was between 3.4% (95% confidence interval [CI]: 2.3-5.2) and 11.6% (95% CI: 9.3-14.4) in the 610 contacts with at least one skin test. The incidence of tuberculin conversion was between 0.3% and 6.8% in the 294 assessed participants. Age older than 18 years, a higher prevalence of unmet basic needs in the school district, attending the afternoon school shift, negative sputum smear results in the index case, and absence of baseline skin test were associated with contact lost to follow-up. Conclusions. The incidence of tuberculin conversion among school contacts was low. Adherence to isoniazid treatment remains limited. Factors associated with loss of contact tracing were identified, which may guide strategies necessary to improve this process.

Latent infection screening and prevalence in cancer patients born outside of Australia: a universal versus risk-based approach?

Contention surrounds how best to screen patients for latent and undiagnosed infection prior to cancer treatment. Early treatment and prophylaxis against reactivation may improve infection-associated morbidity. This study sought to examine rates of screening and prevalence of latent infection in overseas-born patients receiving cancer therapies. A single-centre retrospective audit of 952 overseas-born patients receiving chemotherapy, targeted agents and immunotherapy between January 1 and December 31 2019 was undertaken at Peter MacCallum Cancer Centre. Pre-treatment screening for hepatitis B (HBV), hepatitis C (HCV), human immunodeficiency virus (HIV), latent tuberculosis (LTBI), toxoplasmosis and strongyloidiasis was audited. Approximately half of our overseas-born patients were screened for HBV (58.9%) and HCV (50.7%). Fewer patients were screened for HIV (30.5%), LTBI (18.3%), strongyloidiasis (8.6%) or toxoplasmosis (8.1%). Although 59.7% of our patients were born in countries with high epidemiological risk for latent infection, according to World Health Organization data, 35% were not screened for any infection prior to commencement of therapy. The prevalence of latent infections amongst overseas-born patients with cancer, and complexities associated with risk-based screening, likely supports universal latent infection screening amongst this higher-risk cohort.

Tuberculin reactivity in schoolchildren, Kassala State, Sudan.

Tuberculin skin test (TST) is widely used for the assessment of Bacillus Calmette-Guérin (BCG) vaccine efficacy and screening of latent TB infection (LTBI). Poor or no data are available on the reactivity of tuberculin in Kassala State. The aim of the present study was to assess the response to the BCG vaccine and to estimate the prevalence of LTBI and the annual rate annual risk of tuberculous infection (ARTI) among vaccinated school children using TST. School-based cross-sectional study was conducted in three localities of Kassala State during 2016-2018. A cluster random sampling method was used for the enrolment. Five tuberculin units of 0.1 mL were injected intradermally in the left forearm of 2568 school children aged 5-15 years. The test was performed after the assessment of child health, nutrition status, and BCG scar status. Tuberculin reaction size was interpreted after 48-72 h. The collected data were analyzed using SPSS (v 20). The classical method was used to estimate ARTI. Overall, there was no reaction in 81.5% of children. Only 0.66% of children had induration 10 mm-28 mm, indicating the prevalence of latent TB with an annual risk of 0.1%. Tuberculin reactivity was statistically significant affected by child age, gender, geographical location, and nutrition status (P < 0.05), whereas BCG scar status had no effect (P > 0.05). The study documented a high proportion of tuberculin nonreactivity irrespective of BCG vaccination status and provides data on the prevalence of latent infection among studied groups. Further studies are needed to address the reasons of low and nonreactivity of tuberculin, and evaluation of the BCG vaccine is recommended.

Evaluación infectológica inicial y seguimiento prospectivo de una cohorte de pacientes sometidos a inmunosupresión inducida

El uso de inmunosupresores generó una población creciente de pacientes con defectos en el sistema inmune. Creamos un consultorio especializado en la atención infectológica de dichos pacientes.&#x0D; Objetivos: Describir los antecedentes clínicos y la prevalencia de infecciones latentes, evaluar el estado de vacunación, determinar la necesidad de profilaxis antimicrobiana. Describir la frecuencia de aparición infecciones oportunistas (IO).&#x0D; Materiales y métodos: Estudio descriptivo, prospectivo de pacientes atendidos en un consultorio que estuvieran bajo tratamiento inmunosupresor (noviembre 2015-enero 2017). Se recolectaron datos demográficos, clínicos y factores de riesgo para IO. Se realizó pesquisa de tuberculosis (TB), serologías para HIV, hepatitis A, B y C, sífilis, toxoplasmosis, Chagas, búsqueda de Strongyloides spp. Se indicaron vacunas de acuerdo con las recomendaciones actuales. Se realizó seguimiento para detección de IO.&#x0D; Resultados: n=197, media de edad 50,7 años (DE 14), mujeres 79,7%. Enfermedades de base: artritis reumatoidea 52%, lupus 12%. Drogas inmunosupresoras: metotrexato 45%, corticoides 16%, biológicos anti-TNF 15%, micofenolato 10%, ciclofosfamida 4%. Se diagnosticaron 49 (25%) infecciones: 15 Chagas, 15 anti-HBc positivo aislado, 7 sífilis, 4 VIH, 4 TB latentes, 2 HBV, 1 HCV, 1 estrongiloidiosis. Se indicó profilaxis antimicrobiana en 27 (14%) pacientes. En todos se intervino indicando o completando los esquemas de vacunación. Se detectaron 7 IO. &#x0D; Conclusiones: En el 39% de los pacientes, la evaluación sistematizada arrojó hallazgos que motivaron intervenciones, ya sea terapéuticas o de monitoreo. En el 100% fue necesaria la prescripción de vacunas. Esto pone en evidencia la importancia de evaluar sistemáticamente en consultorios especializados a estos pacientes.

Burden of tuberculosis among household children of adult multi drug resistant patients and their response to first line anti tubercular drugs

ObjectiveThe objective of the study was to find the prevalence and incidence of tuberculosis among household contacts of adult Multi Drug Resistant-tuberculosis (MDR-TB) patients and to evaluate their response to first line anti-tubercular drugs. Materials and methodsThis prospective observational study was conducted from January 2014 to August 2015 at a tertiary care center in India. We included child contacts of ≤14year age of recently diagnosed adult MDR-TB patients. Detailed demographic, socio-economic and treatment history including previous treatment, MDR suspect criterion, and HIV status of the index case was collected. Enrolled children were screened for tuberculosis at initial screening as well as during each follow up visit. Extra-pulmonary or sputum negative pulmonary cases were treated in category I. Sputum positive patients were treated as per sensitivity report. All children were followed up for a period of 1year. ResultsEighty contacts of 21 index cases were enrolled. Disease prevalence at initial screening was 11.3% (n-9) and incidence on follow up was 1.4% (n-1). Prevalence of latent infection was 23.8% with incidence of 15.4% on follow up. Two patients were found to be sputum positive both sensitive to first line drugs. Failure rate of initial treatment was 10% (n-1). This child was initially sputum positive and sensitive to first line drug, but was later found to have MDR-TB. ConclusionMild disease in child contacts of MDR-TB can still show good respond to first line treatment especially in areas with high disease burden.

Prevalência das infecções latentes por BoHV-1 e BoHV-5 em bovinos de corte no Estado do Paraná

RESUMOO objetivo deste trabalho foi determinar a prevalência das infecções latentes por BoHV-1 e por BoHV-5 em bovinos de corte criados no Estado do Paraná. Os gânglios do nervo trigêmeo foram coletados de 400 bovinos hígidos, entre 18 e 36 meses de idade, provenientes de 90 propriedades rurais localizadas em diferentes mesorregiões geográficas do Estado e abatidos em frigorífico com Serviço de Inspeção Federal. A reação em cadeia da polimerase com amplificação do gene que codifica a glicoproteína C foi empregada para a detecção do DNA viral. Cento e nove bovinos eram herpéticos (27,25%), sendo 14,25% (57/400) infectados com BoHV-1, 9,75% (39/400) infectados com BoHV-5 e 3,25% (13/400) portadores de infecção mista. A distribuição geográfica foi heterogênea e as infecções foram mais prevalentes nas mesorregiões localizadas ao norte do Estado. A vigilância para a encefalite por BoHV-5 deve ser intensificada na mesorregião Noroeste.

Simulation of risk of tuberculosis infection in healthcare workers in hospitals of an intermediate incidence country.

We simulated the frequency of tuberculosis infection in healthcare workers in order to classify the risk of TB transmission for nine hospitals in Medellín, Colombia. We used a risk assessment approach to estimate the average number of infections in three risk groups of a cohort of 1082 workers exposed to potentially infectious patients over 10- and 20-day periods. The risk level of the hospitals was classified according to TB prevalence: two of the hospitals were ranked as being of very high priority, six as high priority and one as low priority. Consistent results were obtained when the simulation was validated in two hospitals by studying 408 healthcare workers using interferon gamma release assays and tuberculin skin testing. The latent infection prevalence using laboratory tests was 41% [95% confidence interval (CI) 34·3-47·7] and 44% (95% CI 36·4-51·0) in those hospitals, and in the simulation, it was 40·7% (95% CI 32·3-49·0) and 36% (95% CI 27·9-44·0), respectively. Simulation of risk may be useful as a tool to classify local and regional hospitals according to their risk of nosocomial TB transmission, and to facilitate the design of hospital infection control plans.

Cutaneous leishmaniasis in a patient receiving infliximab

Leishmaniasis is endemic in the Mediterranean region, and the prevalence of latent infection in this area is high. Treatment with tumour necrosis factor (TNF) antagonists represents a major breakthrough in the treatment of several inflammatory diseases, including psoriasis. Reports describing opportunistic leishmaniasis in European patients treated with TNF-α antagonist drugs are rapidly accumulating. We describe a case of cutaneous leishmaniasis in a patient treated with infliximab and corticosteroids.

Contact investigation for tuberculosis: a systematic review and meta-analysis

Investigation of contacts of patients with tuberculosis (TB) is a priority for TB control in high-income countries, and is increasingly being considered in resource-limited settings. This review was commissioned for a World Health Organization Expert Panel to develop global contact investigation guidelines.We performed a systematic review and meta-analysis of all studies reporting the prevalence of TB and latent TB infection, and the annual incidence of TB among contacts of patients with TB.After screening 9,555 titles, we included 203 published studies. In 95 studies from low- and middle-income settings, the prevalence of active TB in all contacts was 3.1% (95% CI 2.2–4.4%, I2=99.4%), microbiologically proven TB was 1.2% (95% CI 0.9–1.8%, I2=95.9%), and latent TB infection was 51.5% (95% CI 47.1–55.8%, I2=98.9%). The prevalence of TB among household contacts was 3.1% (95% CI 2.1–4.5%, I2=98.8%) and among contacts of patients with multidrug-resistant or extensively drug-resistant TB was 3.4% (95% CI 0.8–12.6%, I2=95.7%). Incidence was greatest in the first year after exposure. In 108 studies from high-income settings, the prevalence of TB among contacts was 1.4% (95% CI 1.1–1.8%, I2=98.7%), and the prevalence of latent infection was 28.1% (95% CI 24.2–32.4%, I2=99.5%). There was substantial heterogeneity among published studies.Contacts of TB patients are a high-risk group for developing TB, particularly within the first year. Children <5 yrs of age and people living with HIV are particularly at risk. Policy recommendations must consider evidence of the cost-effectiveness of various contact tracing strategies, and also incorporate complementary strategies to enhance case finding.

Prevalence of Latent Infection with Mycobacterium Tuberculosis in Mazowieckie Province Using Interferon Gamma Release Assay after Stimulation with Specific Antigens ESAT-6 and CFP-10

Introduction: Over 8000 cases of tuberculosis (TB) are diagnosed annually in Poland. People infected with Mycobacterium tuberculosis (MTB) have a risk of active disease of around 10% during their whole life, and the risk is highest in the first two years after infection. Recognizing infection before TB disease development enables prophylaxis against its activation and ceases transmission of infection. Knowledge about the proportion of infected people in the population is crucial to predict the number of new cases of active disease. Materials and methods: The prevalence of latent TB infection (LTBI) was tested in 700 healthy adult inhabitants of the Mazowieckie province in different age groups, using both tuberculin skin test (TST) and interferon gamma release assay (IGRA). Commercial test QuantiFERON®-TB-Gold In Tube (QFT) was used. All participants were mandatorily BCG vaccinated according to the Polish vaccination schedule. Results: Twenty-three per cent of participants tested positively for QFT, which was significantly less than for TST (50.3%). The prevalence of positive QFT results increased with age, as well as the incidence of TB in Poland. Positive QFT was most frequent in the oldest age group (48.8%) and rarest in the youngest (7.1%). Conversely, positive TST occurred more often in younger participants (45%), who rarely suffer from TB. Among people over 60, with the highest TB incidence rate, only 33.8% tested positively with TST. Concordance between both tests was low, with a kappa value of 0.198. The prevalence of LTBI defined as positive QFT among health care workers (HCW) was significantly higher than among other participants (32.2% v. 20.4%, p &lt; 0.01). Conclusions: LTBI was diagnosed in 23.3% of the tested population of the Mazowieckie province. QFT is a better tool for diagnosing LTBI as it shows a positive correlation with age (as the incidence of TB disease does). Concordance between both tests is low. The prevalence of LTBI in HCW is higher than in other participants.

Tumor necrosis factor alpha antagonist drugs and leishmaniasis in Europe

Leishmaniasis is endemic in Europe and the prevalence of latent infection in the Mediterranean region is high. Reports describing opportunistic leishmaniasis in European patients treated with tumor necrosis factor (TNF) alpha antagonist drugs are rapidly accumulating. For other granulomatous infections, risk of opportunistic disease varies by mode of TNF-alpha antagonism. This study explores whether this may also be the case for leishmaniasis. We ascertained the relative frequency of exposure to different TNF antagonist drugs among published cases of opportunistic leishmaniasis in Europe and compared this with the prescription of these drugs in Europe. We found that risk of opportunistic leishmaniasis is higher in patients receiving anti-TNF monoclonal antibodies (infliximab or adalimumab) compared with patients treated with the TNF-receptor construct etanercept. Clinicians may want to consider these observations, which suggest that etanercept should be favoured over anti-TNF monoclonal antibodies in individuals living in or visiting areas endemic for leishmaniasis until evidence from prospective research is available. A European adverse event reporting system is required to identify rare opportunistic infections associated with immunosuppressive and immunomodulatory biotherapies.

Drug combinations and the bioavailability of rifampicin

Lipid nanoparticle formulations (LNFs) are on the frontier of the rapidly expanding arena of nanotechnology-based therapeutics. The prospect of improved antitubercular therapy (ATT) using LNFs as drug carriers shows great potential. Numerous hurdles recurrently associated with the use of antitubercular drugs (ATDs) like organ toxicity, variable bioavailability, poor gastrointestinal (GI) absorption, solubility, chemical instability, prevalence of latent infection, and emergence of drug-resistant M. tuberculosis strains may be overcome or mitigated by the use of LNFs for tuberculosis (TB) therapy. The emergence of two newer subtypes of LNFs, namely, solid-lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs), further expand the role of these versatile drug carriers in TB treatment. As such, it is anticipated that LNFs will emerge as one of the more promising carrier systems in the near future for the efficient delivery of ATDs to effectively address current issues with their clinical use. This review focuses on the current role of lipid-based nanoparticle formulations in ATT with a special emphasis on two key variants of LNF technology: SLNs and NLCs that are formulated using nanoencapsulation. We also present the rationale and approaches for future translation and successful commercialization of LNFs.