Knowledge, attitude, and practice toward tuberculosis prevention and management among household contacts in Suzhou Hospital, Jiangsu province, China

Background

China is among the 10 high-burden tuberculosis (TB) countries in the world; thus, investigation and management of household contacts is an essential part of TB prevention strategy.

Objective

To explore the knowledge, attitude, and practice (KAP) toward TB prevention and management among household contacts of TB patients.

Methods

This cross-sectional study enrolled household contacts in Suzhou Hospital of Integrated Traditional Chinese and Western Medicine between September 2022 and January 2023; KAP and demographic characteristics were assessed with the self-designed questionnaire and analyzed by multivariate logistic regression.

Results

A total of 503 participants were included; of them, 280 (55.78%) were female, and 303, (60.36%) aged ≥45 years. The KAP scores were 6.24 ± 2.20 (possible range: 0-12), 18.69 ± 2.80 (possible range: 0-36), and 20.37 ± 5.15 (possible range: 0-36), respectively. Suburban (OR = 0.18, 95% CI: 0.04-0.79, p = 0.023) and rural (OR = 0.12, 95% CI: 0.03-0.57, p = 0.008) were independently associated with knowledge. Positive attitude (OR = 7.03, 95% CI: 2.92-16.96, p < 0.001), education (high school or technical secondary school, OR = 4.91, 95% CI: 1.63-14.73, p = 0.005; college and above, OR = 14.94, 95% CI: 3.51-63.58, p < 0.001), and shorter disease duration (3-6 months, OR = 0.40, 95% CI: 0.18-0.90, p = 0.026) were independently associated with better practice scores.

Conclusion

Household contacts of TB patients demonstrated insufficient knowledge, unfavorable attitude, and suboptimal practice toward TB prevention and management. Tailored interventions are needed to ensure information accessibility, especially for individuals living in suburban and rural areas.

Absence of short-term changes in knowledge and attitudes among household contacts of COVID-19 cases during the post-acute phase of the pandemic in Catalonia and Navarre, Spain

Objectives

To evaluate short-term changes in knowledge and attitude towards COVID-19 and preventive measures during the post-acute phase of the pandemic in Spain.

Methods

A survey was performed in Catalonia and Navarre between May-2022 and July-2023 in household contacts of COVID-19 cases. Knowledge and attitude were assessed at baseline and at three months, using a Likert scale. Responses were grouped according to correct or incorrect.

Results

At baseline, 172 subjects were contacted, 118 (69%) of which completed a follow-up interview three months later. Knowledge of correct hand-washing and mask protocols had maintained over time (-1.7%, p = 0.553 and - 2.5%, p = 0.473, respectively). Attitudes toward preventive measures was adequate in the first interview (86%), but attitudes regarding use of face masks decreased significantly (-9.1%, p = 0.048) over time in participants with higher risk of severe COVID-19. However, most short-term changes in knowledge and attitudes were not statistically significant.

Conclusion

Household contacts showed correct knowledge and attitude towards COVID-19 and its preventive measures, without significant changes in the short term despite a relaxation of government-mandated preventive measures. These results provide relevant information in case of a new health emergency due to respiratory viruses.

Gut microbiome dynamics in index patients colonized with extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales after hospital discharge and their household contacts

IMPORTANCE

Colonization with extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) often precedes infections and is therefore considered as a great threat for public health. Here, we studied the gut microbiome dynamics in eight index patients colonized with ESBL-PE after hospital discharge and the impact of exposure to this index patient on the gut microbiome dynamics of their household contacts. We showed that the microbiome composition from index patients is different from their household contacts upon hospital discharge and that, in some of the index patients, their microbiome composition over time shifted toward the composition of their household contacts. In contrast, household contacts showed a stable microbiome composition over time irrespective of low-level extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-Ec) or extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-Kp) gut colonization, suggesting that, in healthy microbiomes, colonization resistance is able to prevent ESBL-PE expansion.

Transmissibility of severe acute respiratory syndrome coronavirus 2 among household contacts of coronavirus disease 2019-positive patients: A community-based study in India

BACKGROUND

This study identified the risk factors for severe acute respiratory syndrome coronavirus 2 infection among household contacts of index patients and determined the incubation period (IP), serial interval, and estimates of secondary infection rate in Kerala, India.

METHODS

We conducted a cohort study in three districts of Kerala among the inhabitants of households of reverse transcriptase polymerase chain reaction-positive coronavirus disease 2019 patients between January and July 2021. About 147 index patients and 362 household contacts were followed up for 28 days to determine reverse transcriptase polymerase chain reaction positivity and the presence of total antibodies against SARS-CoV-2 on days 1, 7, 14, and 28.

RESULTS

The mean IP, serial interval, and generation time were 1.6, 3, and 3.9 days, respectively. The secondary infection rate at 14 days was 43.0%. According to multivariable regression analysis persons who worked outside the home were protected (adjusted odds ratio [aOR], 0.45; 95% confidence interval [CI], 0.24-0.85), whereas those who had kissed the coronavirus disease 2019-positive patients during illness were more than twice at risk of infection (aOR, 2.23; 95% CI, 1.01-5.2) than those who had not kissed the patients. Sharing a toilet with the index patient increased the risk by more than twice (aOR, 2.5; 95% CI, 1.42-4.64) than not sharing a toilet. However, the contacts who reported using masks (aOR, 2.5; 95% CI, 1.4-4.4) were at a higher risk of infection in household settings.

CONCLUSIONS

Household settings have a high secondary infection rate and the changing transmissibility dynamics such as IP, serial interval should be considered in the prevention and control of SARS-CoV-2.

1-Year Incidence of Tuberculosis Infection and Disease Among Household Contacts of Rifampin- and Multidrug-Resistant Tuberculosis

BACKGROUND

Tuberculosis infection (TBI) and TB disease (TBD) incidence remains poorly described following household contact (HHC) rifampin-/multidrug-resistant TB exposure. We sought to characterize TBI and TBD incidence at 1 year in HHCs and to evaluate TB preventive treatment (TPT) use in high-risk groups.

METHODS

We previously conducted a cross-sectional study of HHCs with rifampin-/multidrug-resistant TB in 8 high-burden countries and reassessed TBI (interferon-gamma release assay, HHCs aged ≥5 years) and TBD (HHCs all ages) at 1 year. Incidence was estimated across age and risk groups (<5 years; ≥5 years, diagnosed with human immunodeficiency virus [HIV]; ≥5 years, not diagnosed with HIV/unknown, baseline TBI-positive) by logistic or log-binomial regression fitted using generalized estimating equations.

RESULTS

Of 1016 HHCs, 850 (83.7%) from 247 households were assessed (median, 51.4 weeks). Among 242 HHCs, 52 tested interferon-gamma release assay-positive, yielding a 1-year 21.6% (95% confidence interval [CI], 16.7-27.4) TBI cumulative incidence. Sixteen of 742 HHCs developed confirmed (n = 5), probable (n = 3), or possible (n = 8) TBD, yielding a 2.3% (95% CI, 1.4-3.8) 1-year cumulative incidence (1.1%; 95% CI, .5-2.2 for confirmed/probable TBD). TBD relative risk was 11.5-fold (95% CI, 1.7-78.7), 10.4-fold (95% CI, 2.4-45.6), and 2.9-fold (95% CI, .5-17.8) higher in age <5 years, diagnosed with HIV, and baseline TBI high-risk groups, respectively, vs the not high-risk group (P = .0015). By 1 year, 4% (21 of 553) of high-risk HHCs had received TPT.

CONCLUSIONS

TBI and TBD incidence continued through 1 year in rifampin-/multidrug-resistant TB HHCs. Low TPT coverage emphasizes the need for evidence-based prevention and scale-up, particularly among high-risk groups.

Specialized active leprosy search strategies in an endemic area of the Brazilian Amazon identifies a hypermutated Mycobacterium leprae strain causing primary drug resistance

Introduction

Leprosy, an infectious disease caused by Mycobacterium leprae, remains a public health concern in endemic countries, particularly in Brazil. In this study, we conducted an active surveillance campaign in the hyperendemic city of Castanhal in the northeastern part of the state of Pará using clinical signs and symptoms combined with serological and molecular tools to diagnose new cases and to identify drug resistance of circulating M. leprae strains and their distribution in the community.

Methods

During an active surveillance of one week, we enrolled 318 individuals using three different strategies to enroll subjects for this study: (i) an active survey of previously treated cases from 2006 to 2016 found in the Brazil National Notifiable Disease Information System database (n = 23) and their healthy household contacts (HHC) (n = 57); (ii) an active survey of school children (SC) from two primary public schools in low-income neighborhoods (n = 178), followed by visits to the houses of these newly diagnosed SC (n = 7) to examine their HHC (n = 34) where we diagnosed additional new cases (n = 6); (iii) and those people who spontaneously presented themselves to our team or the local health center with clinical signs and/or symptoms of leprosy (n = 6) with subsequent follow-up of their HHC when the case was confirmed (n = 20) where we diagnosed two additional cases (n = 2). Individuals received a dermato-neurological examination, 5 ml of peripheral blood was collected to assess the anti-PGL-I titer by ELISA and intradermal earlobe skin scrapings were taken from HHC and cases for amplification of the M. leprae RLEP region by qPCR.

Results

Anti-PGL-I positivity was highest in the new leprosy case group (52%) followed by the treated group (40.9%), HHC (40%) and lowest in SC (24.6%). RLEP qPCR from SSS was performed on 124 individuals, 22 in treated cases, 24 in newly diagnosed leprosy cases, and 78 in HHC. We detected 29.0% (36/124) positivity overall in this sample set. The positivity in treated cases was 31.8% (7/22), while in newly diagnosed leprosy cases the number of positives were higher, 45.8% (11/23) and lower in HHC at 23.7% (18/76). Whole genome sequencing of M. leprae from biopsies of three infected individuals from one extended family revealed a hypermutated M. leprae strain in an unusual case of primary drug resistance while the other two strains were drug sensitive.

Discussion

This study represents the extent of leprosy in an active surveillance campaign during a single week in the city of Castanhal, a city that we have previously surveyed several times during the past ten years. Our results indicate the continuing high transmission of leprosy that includes fairly high rates of new cases detected in children indicating recent spread by multiple foci of infection in the community. An unusual case of a hypermutated M. leprae strain in a case of primary drug resistance was discovered. It also revealed a high hidden prevalence of overt disease and subclinical infection that remains a challenge for correct clinical diagnosis by signs and symptoms that may be aided using adjunct laboratory tests, such as RLEP qPCR and anti-PGL-I serology.

Polyunsaturated Fatty Acid-Derived Lipid Mediators as Potential Biomarkers for Leprosy Among Individuals with Asymptomatic Mycobacterium leprae Infection

Intra-household contacts (HCs) of leprosy patients are at increased risk of infection by Mycobacterium leprae and about ∼5-10% will develop active disease. A prognostic tool to identify HCs with the greatest risk of progressing to active disease would enhance early leprosy diagnosis and optimize prophylactic intervention. Previous metabolomics studies suggest that host lipid mediators derived from ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) are potential biomarkers for leprosy. In this study, we investigated retrospective sera of leprosy HCs by liquid chromatography-mass spectrometry and enzyme-linked immunoassay to determine whether circulating levels of ω-3 and ω-6 PUFA metabolites were altered in HCs that developed leprosy (HCDL) in comparison to those that did not (HCNDL). Sera were collected from HCs at the time of index case diagnosis and before clinical signs/symptoms of leprosy. Our findings showed that HCDL sera exhibited a distinct metabolic profile in comparison to HCDNL. Specifically, arachidonic acid, leukotriene B4, 11-hydroxyeicosatetraenoic acid, prostaglandin D2, and lipoxin A4 were elevated in HCDL. In contrast, prostaglandin E2 levels were reduced in HCDL. The ω-3 PUFAs, docosahexaenoic acid, eicosapentaenoic acid, and the docosahexaenoic acid-derived resolvin D1 and maresin-1 were also elevated in HCDL individuals compared to HCNDL. Principal component analyses provided further evidence that lipid mediators could serve as an early biomarker for progression to active leprosy. A logistic model identified resolvin D1 and D2, and prostaglandin D2 as having the greatest potential for early detection of HCs that will manifest leprosy.

Gene Expression of Human Beta-Defensin-3 and Cathelicidin in the Skin of Leprosy Patients, Household Contacts, and Healthy Individuals from Indonesia

Background

Leprosy, a chronic infectious peripheral neuropathy, is caused by Mycobacterium leprae. This bacterium produces triacylated lipopeptides that can induce the immune system via the Toll-like receptor 2/1 (TLR 2/1) complex. Activation of TLR 2/1 produces proinflammatory cytokines and antimicrobial peptides (AMPs), including human beta-defensin-3 (HBD-3) and cathelicidin.

Purpose

To analyze differences in gene expression of HBD-3 and cathelicidin in the skin of leprosy patients, household contacts, and healthy individuals.

Patients and Methods

An analytic observational study was conducted at the Outpatient Clinic of Dermatology and Venereology of Dr Mohammad Hoesin General Hospital, Palembang, Indonesia, from January 2021 to June 2022. In each group of 18 subjects, 72 samples were collected, including skin lesion in leprosy patients, normal skin in leprosy patients, household contacts, and healthy individuals. A comparison of HBD-3 and cathelicidin gene expression between the four groups was analyzed using Pearson Chi Square, Kruskal-Wallis, and Mann-Whitney Test.

Results

The median value of HBD-3 gene expression on skin lesion in leprosy patients was 260.61 (0.19-3734.10); normal skin in leprosy patients was 1.91 (0.01-151.17); household contacts skin was 7.93 (0.27-121.10); and healthy individuals' skin was 1.00 (1.00-1.00) is highly significant difference (p < 0.0001). The median value of cathelicidin gene expression on skin lesion in leprosy patients was 38.72 (0.28-1852.17); normal skin in leprosy patients was 0.48 (0.01-15.83); household contacts skin was 9.8 (0.04-128.0); and healthy individual skin was 1.00 (1.00-1.00), also highly significant difference (p < 0.0001).

Conclusion

Gene expression of HBD-3 and cathelicidin increased in skin lesions of leprosy patients and household contacts.

Silent peripheral neuropathy determined by high-resolution ultrasound among contacts of patients with Hansen's disease

Introduction

Hansen's disease (HD) primarily infects peripheral nerves, with patients without HD being free of peripheral nerve damage. Household contacts (HHCs) of patients with HD are at a 5-10 times higher risk of HD than the general population. Neural thickening is one of the three cardinal signs that define a case of HD according to WHO guidelines, exclusively considering palpation examination that is subjective and may not detect the condition in the earliest cases even when performed by well-trained professionals. High-resolution ultrasound (HRUS) can evaluate most peripheral nerves, a validated technique with good reproducibility allowing detailed and accurate examination.

Objective

This study aimed to use the peripheral nerve HRUS test according to the HD protocol as a diagnostic method for neuropathy comparing HHCs with healthy volunteers (HVs) and patients with HD.

Methods

In municipalities from 14 different areas of Brazil we selected at random 83 HHC of MB-patients to be submitted to peripheral nerve ultrasound and compared to 49 HVs and 176 HD-patients.

Results

Household contacts assessed by HRUS showed higher median and mean absolute peripheral nerve cross-sectional area (CSA) values and greater asymmetries (ΔCSA) compared to HVs at the same points. Median and mean absolute peripheral nerve CSA values were higher in patients with HD compared to HCCs at almost all points, while ΔCSA values were equal at all points. Mean ± SD focality (ΔTpT) values for HHCs and patients with HD, respectively, were 2.7 ± 2.2/2.6 ± 2.2 for the median nerve, 2.9 ± 2.7/3.3 ± 2.9 for the common fibular nerve (p > 0.05), and 1.3 ± 1.3/2.2 ± 3.9 for the ulnar nerve (p < 0.0001).

Discussion

Considering HRUS findings for HHCs, asymmetric multiple mononeuropathy signs (thickening or asymmetry) in at least 20% of the nerves evaluated could already indicates evidence of HD neuropathy. Thus, if more nerve points are assessed in HHCs (14 instead of 10), the contacts become more like patients with HD according to nerve thickening determined by HRUS, which should be a cutting-edge tool for an early diagnosis of leprosy cases.

Individual and household risk factors for COVID-19 infection among household members of COVID-19 patients in home-based care in western Uganda, 2020

OBJECTIVE

To investigate factors associated with COVID-19 among household members of patients in home-based care (HBC) in western Uganda.

METHODS

We conducted a case-control and cohort study. Cases were reverse transcriptase-polymerase chain reaction-confirmed SARS-CoV-2 diagnosed 1-30 November 2020 among persons in HBC in Kasese or Kabarole districts. We compared 78 case-households (≥1 secondary case) with 59 control-households (no secondary cases). The cohort included all case-household members. Data were captured by in-person questionnaire. We used bivariate regression to calculate odds and risk ratios.

RESULTS

Case-households were larger than control-households (mean 5.8 vs 4.3 members, P<0.0001). Having ≥1 household member per room (adjusted odds ratio (aOR)=4.5, 95% CI 2.0-9.9), symptom development (aOR=2.3, 95% CI 1.1-5.0), or interaction with primary case-patient (aOR=4.6, 95% CI 1.4-14.7) increased odds of case-household status. Households assessed for suitability for HBC reduced odds of case-household status (aOR=0.4, 95% CI=0.2-0.8). Interacting with a primary case-patient increased the risk of individual infection among household members (adjusted risk ratio=1.7, 95% CI 1.1-2.8).

CONCLUSION

Household and individual factors influence secondary infection risk in HBC. Decisions about HBC should be made with these in mind.

Household secondary attack rate in SARS-CoV-2 infection during the second wave of the COVID-19 pandemic in South India

Background

Coronavirus disease 2019 (COVID-19) has become a major public health problem since its inception disrupting public life and crippling health systems. The mutated variant of the causative virus, Delta, has been notorious in causing rapid upsurge in cases compared to the Alpha variant. The current study tries to find out the household secondary attack rate (HSAR) of COVID-19 and factors associated with it during the second wave of cases in Kerala.

Methodology

A retrospective cohort study was performed among 313 household contacts of 76 COVID-19 patients who had been admitted in Government Medical College, Thrissur, in the southern state of India, Kerala. Data from the participants were collected via phone using a semi-structured interview schedule, and analysis was performed with SPSS software.

Results

The HSAR among household contacts was 59.1% (53.4-64.6%). The risk of acquiring COVID infection among household contacts was higher among contacts of symptomatic index cases with a P value of 0.001 and an odds ratio of 11 (3.7-32.4). index cases were having a home isolation P value of 0.001 and an odds ratio of 3.2 (2-5.1), with delay in COVID-19 testing for index cases with a P value of 0.006. Regarding characteristics of household contacts, higher age groups (p = 0.048), groups living in the same room with an index case P value of 0.021 and an odds ratio of [1.71 (1-2.8)], groups having physical contact with an index case P value of 0.001 and an odds ratio of [3.7 (2.1-7)], groups with touched or cleaned linen/articles with an index case P value of 0.02 and an odds ratio of [1.8 (1-3.1)], and groups having co-morbidities, especially diabetes mellitus (p = 0.0020), were significantly associated with chances of acquiring infection. However, the history of previous COVID positivity in household contacts was a protective factor against the infection P value of 0.009 with an odds ratio of [0.09 (0.01-0.78)].

Conclusion

The study concludes that the second wave of COVID-19 in Kerala was primarily caused by a high SAR, especially among household contacts, and this could have been the reason for the difficulty in control measures during the wave.

Strategies to detect and manage latent tuberculosis infection among household contacts of pulmonary TB patients in high TB burden countries - a systematic review and meta-analysis

OBJECTIVE

To summarise latent tuberculosis infection (LTBI) management strategies among household contacts of bacteriologically confirmed pulmonary tuberculosis (TB) patients in high-TB burden countries.

METHODS

PubMed/MEDLINE (NCBI) and Scopus were searched (January 2006 to December 2021) for studies reporting primary data on LTBI management. Study selection, data management and data synthesis were protocol-driven (PROSPERO-CRD42021208715). Primary outcomes were the proportions of LTBI, initiating and completing tuberculosis preventive treatment (TPT). Reported factors influencing the LTBI care cascade were qualitatively synthesised.

RESULTS

From 3694 unique records retrieved, 58 studies from 23 countries were included. Most identified contacts were screened (median 99%, interquartile range [IQR] 82%-100%; 46 studies). Random-effects meta-analysis yielded pooled proportions for: LTBI 41% (95% confidence interval [CI] 33%-49%; 21,566 tested contacts); TPT initiation 91% (95% CI 79%-97%; 129,573 eligible contacts, 34 studies); TPT completion 65% (95% CI 54%-74%; 108,679 TPT-initiated contacts, 28 studies). Heterogeneity was significant (I²  ≥ 95%-100%) and could not be explained in subgroup analyses. Median proportions (IQR) were: LTBI 44% (28%-59%); TPT initiation 86% (60%-100%); TPT completion 68% (44%-82%). Nine broad themes related to diagnostic testing, health system structure and functions, risk perception, documentation and adherence were considered likely to influence the LTBI care cascade.

CONCLUSION

The proportions of household contacts screened, detected with LTBI and initiated on TPT, though variable was high, but the proportions completing TPT were lower indicating current strategies used for LTBI management in high TB burden countries are not sufficient.

BNT162b2 mRNA Vaccine Effectiveness Given Confirmed Exposure: Analysis of Household Members of Coronavirus Disease 2019 Patients

BACKGROUND

Although BNT162b2 vaccine-efficacy analyses have been published, the effectiveness of the vaccine in preventing coronavirus disease 2019 given confirmed exposure has not been previously demonstrated, even though it has policy implications, such as the need for self-quarantine when exposure has occurred.

METHODS

In a retrospective cohort study, we used data collected between 20 December 2020 and 17 March 2021 from the second largest healthcare provider in Israel to analyze the probability of an additional household infection occurring within 10 days after an index infection. In model 1, vaccine effectiveness was described for Fully Vaccinated individuals (7 or more days from second dose) vs either Unvaccinated individuals or those Recently Vaccinated Once (0-7 days from the first dose, presumably still unprotected). Secondary analyses included correction for differing testing rates. In model 2, we conducted a separate analysis of households comprised of only adults with the same vaccination status.

RESULTS

A total of 173 569 households were included, of which 6351 had an index infection (mean [standard deviation] age, 58.9 [13.5] years); 50% were women. Adjusted vaccine effectiveness of Fully Vaccinated compared with Unvaccinated participants was 80.3% (95% confidence interval [CI], 73.5-85.4) and 82.0% (95% CI, 75.6-86.8) compared with those Recently Vaccinated Once.

CONCLUSIONS

The BNT162b2 vaccine is effective in high-risk real-life exposure scenarios, but the protection afforded in these settings is lower than that previously described. Individuals with a confirmed significant exposure to severe acute respiratory syndrome are still at risk of being infected even if fully vaccinated.

High Prevalence of Tuberculosis Infection and Disease in Child Household Contacts of Adults With Rifampin-resistant Tuberculosis

BACKGROUND

Household contact (HHC) investigation is an important strategy to identify individuals with tuberculosis (TB) exposure, infection and disease, including those who may benefit from tuberculosis preventive therapy (TPT). Data in children exposed to rifampin-resistant TB are limited.

METHODS

In preparation for and to inform the feasibility of an interventional trial, HHC of adults with pulmonary rifampin-resistant TB from high TB-burden countries were evaluated in a cross-sectional study. Using interferon-gamma release assay and study-specific and 2015 international consensus definitions of intrathoracic TB in children, we evaluated the prevalence and predictors of TB infection and disease in child (<15 years) HHCs.

RESULTS

Of 303 child HHCs, median age (range) 7 years (0-14), 57% [95% confidence interval (CI): 50%-64%] had a positive interferon-gamma release assay result (TB infected). TB infection was associated with the index case smoking (P = 0.034), being the parent or sleeping in the same room (P = 0.002) and the child HHC being age ≥5 years and having attended school (P = 0.013). Four had study-defined confirmed TB and 9 had probable TB, a prevalence of 4.3% (95% CI: 2.6%-7.1%). Using the international consensus definitions, 4 had confirmed TB and 49 had unconfirmed TB, a prevalence of 17.2% (95% CI: 12.9%-22.4%). Twenty (7%) children had received TPT.

CONCLUSIONS

The prevalence of TB infection and disease was high in child HHC exposed to rifampin-resistant TB. Few children had routinely received TPT. High-quality evidence is needed to inform strong recommendations for and access to TPT in children exposed to TB resistant to rifampin.

Latent Tuberculosis Infection Diagnosis among Household Contacts in a High Tuberculosis-Burden Area: a Comparison between Transcript Signature and Interferon Gamma Release Assay

Diagnosis of latent tuberculosis infection (LTBI) using biomarkers in order to identify the risk of progressing to active TB and therefore predicting a preventive therapy has been the main bottleneck in eradication of tuberculosis. We compared two assays for the diagnosis of LTBI: transcript signatures and interferon gamma release assay (IGRA), among household contacts (HHCs) in a high tuberculosis-burden population. HHCs of active TB cases were recruited for our study; these were confirmed to be clinically negative for active TB disease. Eighty HHCs were screened by IGRA using QuantiFERON-TB Gold Plus (QFT-Plus) to identify LTBI and uninfected cohorts; further, quantitative levels of transcript for selected six genes (TNFRSF10C, ASUN, NEMF, FCGR1B, GBP1, and GBP5) were determined. Machine learning (ML) was used to construct models of different gene combinations, with a view to identify hidden but significant underlying patterns of their transcript levels. Forty-three HHCs were found to be IGRA positive (LTBI) and thirty-seven were IGRA negative (uninfected). FCGR1B, GBP1, and GBP5 transcripts differentiated LTBI from uninfected among HHCs using Livak method. ML and ROC (Receiver Operator Characteristic) analysis validated this transcript signature to have a specificity of 72.7%. In this study, we compared a quantitative transcript signature with IGRA to assess the diagnostic ability of the two, for detection of LTBI cases among HHCs of a high-TB burden population; we concluded that a three gene (FCGR1B, GBP1, and GBP5) transcript signature can be used as a biomarker for rapid screening.

IMPORTANCE The study compares potential of transcript signature and IGRA to diagnose LTBI. It is first of its kind study to screen household contacts (HHCs) in high TB burden area of India. A transcript signature (FCGR1B, GBP1, & GBP5) is identified as potential biomarker for LTBI. These results can lead to development of point-of-care (POC) like device for LTBI screening in a high TB burdened area.

Colonization of Dogs and Their Owners with Staphylococcus aureus and Staphylococcus pseudintermedius in Households, Veterinary Practices, and Healthcare Facilities

There are uncertainties with respect to the transmission of methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA) and Staphylococcus pseudintermedius between dogs and humans. In this study, we investigated concomitant nasal colonization of dogs and humans in three cohorts. Cohort I, households owning dogs: In 42 of 84 households, 66 humans (36.9%) and 10 dogs (8.9%) carried S. aureus. MRSA, attributed to sequence type (ST) 22 and ST130, were detected in two (1.1%) of the humans but in none of the dogs. Typing by means of spa-typing and whole-genome sequencing (WGS) indicated eight transmissions of S. aureus between humans and dogs in 8 of 42 (19.0%) households with human S. aureus carriers, whereas in 11 of 38 (29.0%) households with ≥two persons and S. aureus colonization of humans, 15 human-to-human transmissions were observed (p = 0.43). S. pseudintermedius was isolated from 42 dogs (37.5%), but from only one human (0.6%). In this case, WGS-based typing indicated strong relatedness of this isolate with a canine isolate from the same household. Cohort II, dogs and their owners visiting a veterinary practice: Among 17 humans and 17 dogs attending a veterinary practice, MSSA was detected in three humans and two dogs, and S. pseudintermedius in only six dogs. Cohort III, dogs used for animal-assisted interventions in human healthcare facilities and their owners: MSSA was obtained in 1 of 59 dogs (1.7%) and in 17 of 60 (28.3%) of the dog owners, while S. pseudintermedius was isolated from seven (12%) dogs and one (1.7%) human owner. We conclude that the risk of exchanging S. aureus/MRSA between humans and dogs is higher than that for S. pseudintermedius.

Transmission of SARS-CoV-2 infection and risk factors in a cohort of close contacts

PURPOSE

Many factors might affect SARS-CoV-2 transmission, but their relevance is not well established. The objectives were to assess the secondary attack rate (SAR) and the risk factors for SARS-CoV-2 transmission from confirmed index cases to their close contacts in household and non-household settings.

METHODS

This cohort study included the close contacts of SARS-CoV-2 infected cases confirmed between May and December 2020 in Navarre, Spain. Epidemiological and clinical variables of the index case and close contacts were collected. The SAR was calculated, and the independent effect of each variable on the transmission risk was evaluated by logistic regression.

RESULTS

A total of 59,900 close contacts of 20,048 index cases were studied, and 53.6% were household contacts. SAR was 34.9% overall, 46.8% in household contacts and 21.1% in non-household contacts. The risk of transmission was higher in household setting (adjusted odds ratio (aOR) 2.96, 95% CI 2.84-3.07), from symptomatic index cases (aOR 1.50, 95% CI 1.43-1.58), immigrants (aOR 1.44, 95% CI 1.36-1.52), and increased with age. A higher susceptibility of close contacts was associated with 5-14 years of age, immigrants (aOR 1.54), very low or low-income level (aOR 1.27, and aOR, 1.17, respectively), healthcare work (aOR 1.21), and diagnosis of diabetes (aOR 1.14, 95%CI 1.03-1.25), chronic kidney disease (aOR 1.18, 95%CI 1.04-1.35), hypertension (aOR 1.11, 95% CI 1.03-1.19), and severe obesity (aOR 1.18, 95% CI 1.00-1.38). Transmission increased progressively from May to September 2020 as the B.1.177 variant became dominant.

CONCLUSION

The risk of SARS-CoV-2 infection was considerable among close contacts of infected persons. The higher risk associated with household contacts, immigrants, older index cases, close contacts with lower income level and comorbidities should be considered to address preventive interventions.

Risk of Secondary Household Transmission of COVID-19 from Health Care Workers in a Hospital in Spain

BACKGROUND

Hospital health care workers are at high risk of developing COVID-19 and transmitting the disease to their family upon returning home; the aim here is to estimate the secondary attack rate of COVID-19 in household contacts of health care workers and their transmission risk factors.

MATERIAL AND METHODS

COVID-19 cases in the health care workers of an academic hospital in Pamplona, Spain, from 2 March to 26 May 2020, were followed up. The secondary attack rate (SAR) was estimated from cases in household contacts of index cases and their risk factors by Poisson regression.

RESULTS

89 index cases were studied from 99 notified cases in health care workers (89.0%), excluding secondary cases or those who lived alone. Forty-six secondary cases confirmed by the laboratory were found among 326 household contacts, a secondary attack rate of 14.11% (95% CI 10.75-18.31), and 33 household contacts with acute infection symptoms without microbiologic confirmation 10.12% (95% CI 7.30-13.87). Considering all the cases, the secondary attack rate was 27.3 (95% CI 22.75-32.38). Risk factors were the gender and profession of the index case, the number of people living in the household, and the number of persons per bedroom. When the index case health worker used a single room, it had a protective effect, with an incidence rate ratio (IRR) of 0.493 (95% CI 0.246-0.985); Conclusions: The secondary attack rate found among household contacts of health care workers is high. The preventive isolation of health care workers in individual rooms in their house may reduce the transmission in their families.

Risks and Preventive Strategies for Clostridioides difficile Transmission to Household or Community Contacts during Transition in Healthcare Settings

The burden of Clostridioides difficile infection (CDI) has greatly increased. We evaluated the risks for CDI transmission to community members after hospitalized patients are discharged. We conducted a systematic literature review in MEDLINE/PubMed, EMBASE, CINAHL plus EBSCO, Web of Science, Cochrane Library, and gray literature during January 2000‒February 2019 and identified 4,798 citations were identified. We eliminated 4,554 citations through title and abstract screening; 217 additional citations did not meet full criteria. We reviewed texts for the 27 remaining articles qualitatively for internal/external validity. A few identified studies describing risks to community members lacked accurate risk measurement or preventative strategies. Primary data are needed to assess efficacy of and inform current expertise-driven CDI prevention practices. Raising awareness among providers and researchers, conducting clinical and health services research, linking up integrated monitoring and evaluation processes at hospitals and outpatient settings, and developing and integrating CDI surveillance systems are warranted.

Human Astrovirus Outbreak in a Daycare Center and Propagation among Household Contacts

We investigated an outbreak of acute gastroenteritis due to human astrovirus in a daycare center, describing the transmission mechanism, the most affected age groups, conditioning factors and the extent of the outbreak among household contacts of the daycare center attenders. Data were collected from persons exposed at the daycare center and their home contacts. Fecal samples from affected and non-affected daycare center attenders were analyzed for viruses causing acute gastroenteritis by RT-PCR. The percentage of households affected and the attack rates (AR) were calculated. The attack rates were compared using the rate ratio (RR) with 95% confidence intervals. Information was obtained from 245 people (76 attenders and 169 contacts) of whom 49 were clinical cases. Five HAstV-4, two HAstV-8 and three non-typable HAstV cases were identified (six from clinical cases and four from asymptomatic infected people). The global AR was 20% (41.2% in children aged < 2 years). Data were obtained from 67 households: 20 households of affected attenders and 47 of non-affected attendees. Household contacts of affected attenders had a higher AR (74.3%) than that of non-affected attendees (2.4%). We found asymptomatic infections amongst daycare attendees. The transmission of HAstV during the outbreak was not limited to the daycare center but extended to household contacts of both affected and non-affected attenders.

Performance of GeneXpert MTB/RIF for Diagnosing Tuberculosis Among Symptomatic Household Contacts of Index Patients in South Africa

BACKGROUND

We describe the performance of GeneXpert MTB/RIF (Xpert) for diagnosing tuberculosis (TB) among symptomatic household contacts (HHCs) of rifampicin-resistant and drug-sensitive index cases.

METHODS

We conducted a cross-sectional study among HHCs of recently diagnosed (<2 weeks) smear-positive and Xpert-positive index cases in the Bojanala District, South Africa. The HHCs were screened for TB symptoms; persons with ≥1 TB symptom provided 1 sputum for smear microscopy, Xpert, and mycobacterial growth indicator tube (MGIT) culture. Diagnostic test performance of Xpert was determined using MGIT as the reference standard.

RESULTS

From August 2013 to July 2015, 619 HHCs from 216 index cases were enrolled: 60.6% were female, median age was 22 years (interquartile range, 9-40), and 126 (20.4%) self-reported/tested human immunodeficiency virus positive. A total of 54.3% (336 of 619) of contacts had ≥1 TB symptom (cough, fever, night sweats, weight loss), 297 of 336 (88.4%) of which provided a sputum; 289 (97.3%) had complete testing and 271 were included in the analysis. In total, 42 (6.8%) of 619 HHCs had microbiologically confirmed TB. The MGIT identified 33 HHCs as positive for Mycobacterium tuberculosis; of these, 7 were positive on Xpert resulting in a sensitivity of 21.2% (95% confidence interval [CI], 9.0-38.9), specificity of 98.3% (95% CI, 95.6-99.5), positive predictive value of 63.6% (95% CI, 30.8-89.1), and negative predictive value of 90.0 (95% CI, 85.7-93.4).

CONCLUSIONS

Among symptomatic HHCs investigated for TB, Xpert performed suboptimally compared with MGIT culture. The poor performance of Xpert for diagnosing TB suggests that a more sensitive test, such a Xpert Ultra or culture, may be needed to improve yield of contact investigation, where feasible.

Peripheral Blood Mucosal-Associated Invariant T Cells in Tuberculosis Patients and Healthy Mycobacterium tuberculosis-Exposed Controls

BACKGROUND

In human blood, mucosal-associated invariant T (MAIT) cells are abundant T cells that recognize antigens presented on non-polymorphic major histocompatibility complex-related 1 (MR1) molecules. The MAIT cells are activated by mycobacteria, and prior human studies indicate that blood frequencies of MAIT cells, defined by cell surface markers, decline during tuberculosis (TB) disease, consistent with redistribution to the lungs.

METHODS

We tested whether frequencies of blood MAIT cells were altered in patients with TB disease relative to healthy Mycobacterium tuberculosis-exposed controls from Peru and South Africa. We quantified their frequencies using MR1 tetramers loaded with 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil.

RESULTS

Unlike findings from prior studies, frequencies of blood MAIT cells were similar among patients with TB disease and latent and uninfected controls. In both cohorts, frequencies of MAIT cells defined by MR1-tetramer staining and coexpression of CD161 and the T-cell receptor alpha variable gene TRAV1-2 were strongly correlated. Disease severity captured by body mass index or TB disease transcriptional signatures did not correlate with MAIT cell frequencies in patients with TB.

CONCLUSIONS

Major histocompatibility complex (MHC)-related 1-restrictied MAIT cells are detected at similar levels with tetramers or surface markers. Unlike MHC-restricted T cells, blood frequencies of MAIT cells are poor correlates of TB disease but may play a role in pathophysiology.

Tuberculosis Preventive Therapy for Individuals Exposed to Drug-resistant Tuberculosis: Feasibility and Safety of a Community-based Delivery of Fluoroquinolone-containing Preventive Regimen

BACKGROUND

Observational studies have demonstrated the effectiveness of a fluoroquinolone-based regimen to treat individuals presumed to be infected with drug-resistant tuberculosis (DR-TB). We sought to assess the feasibility of this approach in an urban setting in South Asia.

METHODS

From February 2016 until March 2017, all household contacts of DR-TB patients enrolled at the Indus Hospital were screened for TB symptoms at home. Children aged 0-17 years, symptomatic adults, and those with an immunocompromising condition (human immunodeficiency virus, diabetes, or malnutrition) were evaluated for TB disease. Contacts diagnosed with TB disease were started on treatment. Contacts without TB disease aged <5 years, contacts aged between 5 and 17 years with either a positive tuberculin skin test or an immunocompromising condition, or contacts aged ≥18 years with an immunocompromising condition were offered 6 months of treatment with a fluoroquinolone.

RESULTS

One hundred households with 800 contacts were enrolled: 353 (44.1%) individuals aged ≤17 years with a median age of 19 years (interquartile range, 10-32); 423 (52.9%) were males. In total, 737 (92.1%) individuals were screened, of which 8 were already on treatment for TB (1.1%); another 3 (0.4%) contacts were diagnosed with TB disease and started on treatment. Of 215 eligible for infection treatment, 172 (80.0%) contacts initiated and 121 (70.3%) completed treatment. No TB disease or significant adverse events were observed during 12 months of follow-up.

CONCLUSIONS

Fluoroquinolone-based treatment for contacts with presumed DR-TB infection is feasible and well tolerated in a high TB burden setting.

"I got tested at home, the help came to me": acceptability and feasibility of home-based TB testing of household contacts using portable molecular diagnostics in South Africa

OBJECTIVE

The effectiveness of household contact investigations is limited by low referral uptake for clinic-based TB testing by symptomatic household contacts. We qualitatively investigated the acceptability and perceived benefits of home-based TB testing using a portable GeneXpert-I instrument (GX-I) in an urban South African township.

METHODS

In-depth interviews were conducted with household contacts tested and those that observed testing. Semi-structured interviews explored household contact's understanding of TB, perceptions of the GX-I device and testing procedures, confidentiality, willingness to refer others, and views on home- vs. clinic-based testing. Focus group discussions with home-based TB testing implementing staff assessed operational considerations for scale-up. Data were analysed using a constant comparison approach to qualitatively evaluate the acceptability and feasibility of home-based TB testing.

RESULTS

Thirty in-depth interviews and two focus group discussions were conducted. Observing one's own sputum being tested resulted in an emergent trust in home-based TB testing, the GX-I device and one's test results. Home-based TB testing was considered convenient, helped to overcome apathy towards testing and mitigated barriers to clinic-based testing. Perceptions that home-based TB testing contributes to improved household and community health resulted in an emergent theme of alleviation of health insecurities. Operational concerns regarding inadvertent disclosure of one's diagnosis to household members and time spent in people's homes were identified.

CONCLUSIONS

Home-based TB testing was acceptable and feasible. Individuals expressed belief in the machine by being able to witness the testing process. Though most themes mirrored qualitative studies of home-based HIV testing, the alleviation of health insecurities theme is unique to home-based TB testing. Future research must evaluate the impact of home-based TB testing on case finding yield, time-to-treatment initiation and household outcomes.

Secondary attack rate of COVID-19 in household contacts: a systematic review

Coronavirus disease 2019 (COVID-19) is a novel virus with continuously evolving transmission trends. Contact tracing and quarantining of positive cases are chief strategies of disease control that has been accepted globally, though scientific knowledge regarding household transmission of the COVID-19 through contact of positive case is sparse. Current systematic review was planned to assess global statistics and characteristics of household secondary attack rate (SAR) of COVID-19. Eligible articles were retrieved through search of-MEDLINE, SCOPUS and EMBASE for the period December 2019 to 15 June 2020. Search terms were developed to identify articles reporting household SARs in various countries. After initial screening of 326 articles, 13 eligible studies were included in the final evidence synthesis. We found that SAR varies widely across countries with lowest reported rate as 4.6% and highest as 49.56%. The rates were unaffected by confounders such as population of the country, lockdown status and geographic location. Review suggested greater vulnerability of spouse and elderly population for secondary transmission than other household members. It was also observed that quarantining and isolation are most effective strategies for prevention of the secondary transmission of the disease. Symptomatic status of the index case emerged to be a critical factor, with very low transmission probability during asymptomatic phase. Present review findings recommend that adequate measures should be provided to protect the vulnerable population as only case tracing and quarantining might be insufficient. It should be combined with advisory for limiting household contacts and active surveillance for symptom onset.

Azithromycin to Prevent Pertussis in Household Contacts, Catalonia and Navarre, Spain, 2012-2013

We retrospectively assessed the effectiveness of azithromycin in preventing transmission of pertussis to a patient's household contacts. We also considered the duration between symptom onset in the primary patient and azithromycin administration. We categorized contacts into 4 groups: those treated within <7 days, 8-14 days, 15-21 days, and >21 days after illness onset in the primary patient. We studied 476 primary index patients and their 1,975 household contacts, of whom 4.5% were later identified as having pertussis. When contacts started chemoprophylaxis within <21 days after the primary patient's symptom onset, the treatment was 43.9% effective. Chemoprophylaxis started >14 days after primary patient's symptom onset was less effective. We recommend that contacts of persons with pertussis begin chemoprophylaxis within <14 days after primary patient's symptom onset.

Risk factors associated with occurrence of COVID-19 among household persons exposed to patients with confirmed COVID-19 in Qingdao Municipal, China

Tracing and isolation of close contacts is used to control outbreaks of coronavirus disease 2019 (COVID-19) in China. However, risk factors associated with the occurrence of COVID-19 among close contacts have not been well described. A total of 106 household contacts were included in this study, of whom 19 developed into COVID-19 cases, and the secondary attack rate was 17.9%. Multivariable analysis showed that increasing risk of occurrence of COVID-19 among household contacts was associated with female index patients (adjusted hazard ratio [aHR] = 3.84, 95% CI = 1.07-13.78), critical disease index patients (aHR = 7.58, 95% CI = 1.66-34.66), effective contact duration with index patients > 2 days (aHR = 4.21, 95% CI = 1.29-13.73), and effective contact duration > 11 days (aHR = 17.88, 95% CI = 3.26-98.01). The sex and disease severity of index patients with COVID-19 and longer effective contact duration with patients with confirmed COVID-19 could help epidemiologists to identify potential COVID-19 cases among household contacts at an early stage.

History of household member with tuberculosis or related death in newly diagnosed patients in India

Among new smear-positive pulmonary tuberculosis (TB) patients aged ⩾15 years from marginalised populations in India, one in four had a history of a household member with TB and one in 10 had a TB-related death in the household. This contribution of household transmission to overall TB transmission provides evidence for a potential population-level benefit of TB preventive treatment for all household contacts (without active TB). Females with TB had a significantly higher household TB exposure than males. Targeted TB preventive treatment (if implemented in a phased manner) among female household contacts may be explored after considering other factors.

Asymptomatic SARS-CoV-2 Infection in Household Contacts of a Healthcare Provider, Wuhan, China

We found that all 5 asymptomatic household contacts of a Wuhan, China, physician with coronavirus disease had severe acute respiratory syndrome coronavirus 2 detected by PCR. The index patient and 2 contacts also had abnormal chest computed tomography scans. Asymptomatic infected household contacts of healthcare workers with coronavirus disease might be underrecognized.

A foodborne norovirus outbreak in a nursing home and spread to staff and their household contacts

On 16 March 2018, a nursing home notified a possible acute gastroenteritis outbreak that affected 11 people. Descriptive and case-control studies and analysis of clinical and environmental samples were carried out to determine the characteristics of the outbreak, its aetiology, the transmission mechanism and the causal food. The extent of the outbreak in and outside the nursing home was determined and the staff factors influencing propagation were studied by multivariate analysis. A turkey dinner on March 14 was associated with the outbreak (OR 4.22, 95% CI 1.11-16.01). Norovirus genogroups I and II were identified in stool samples. The attack rates in residents, staff and household contacts of staff were 23.49%, 46.22% and 22.87%, respectively. Care assistants and cleaning staff were the staff most frequently affected. Cohabitation with an affected care assistant was the most important factor in the occurrence of cases in the home (adjusted OR 6.37, 95% CI 1.13-36.02). Our results show that staff in close contact with residents and their household contacts had a higher risk of infection during the norovirus outbreak.

Feasibility of Identifying Household Contacts of Rifampin-and Multidrug-resistant Tuberculosis Cases at High Risk of Progression to Tuberculosis Disease

BACKGROUND

We assessed multidrug-resistant tuberculosis (MDR-TB) cases and their household contacts (HHCs) to inform the development of an interventional clinical trial.

METHODS

We conducted a cross-sectional study of adult MDR-TB cases and their HHCs in 8 countries with high TB burdens. HHCs underwent symptom screenings, chest radiographies, sputum TB bacteriologies, TB infection (TBI) testing (tuberculin skin test [TST] and interferon gamma release assay [IGRA]), and human immunodeficiency virus (HIV) testing.

RESULTS

From October 2015 to April 2016, 1016 HHCs from 284 MDR-TB cases were enrolled. At diagnosis, 69% of MDR-TB cases were positive for acid-fast bacilli sputum smears and 43% had cavitary disease; at study entry, 35% remained smear positive after a median MDR-TB treatment duration of 8.8 weeks. There were 9 HHCs that were diagnosed with TB prior to entry and excluded. Of the remaining 1007 HHCs, 41% were male and the median age was 25 years. There were 121 (12%) HHCs that had new cases of TB identified: 17 (2%) were confirmed, 33 (3%) probable, and 71 (7%) possible TB cases. The TBI prevalence (defined as either TST or IGRA positivity) was 72% and varied by age, test used, and country. Of 1007 HHCs, 775 (77%) were considered high-risk per these mutually exclusive groups: 102 (10%) were aged <5 years; 63 (6%) were aged ≥5 and were infected with HIV; and 610 (61%) were aged ≥5 years, were negative for HIV or had an unknown HIV status, and were TBI positive. Only 21 (2%) HHCs were on preventive therapy.

CONCLUSIONS

The majority of HHCs in these high-burden countries were at high risk of TB disease and infection, yet few were receiving routine preventive therapy. Trials of novel, preventive therapies are urgently needed to inform treatment policy and practice.

Treatment for latent tuberculosis infection in low- and middle-income countries: progress and challenges with implementation and scale-up

Introduction: Treatment of latent tuberculosis infection (LTBI) is a crucial but neglected component of global tuberculosis control. The 2018 United Nations High-Level Meeting committed world leaders to provide LTBI treatment to at least 30 million people, including 4 million children<5 years, 20 million other household contacts and 6 million HIV-infected people by 2022.Areas covered: This review searched MEDLINE between 1990 and 2019 and discussed: i) high-risk groups to be prioritized for diagnosis and treatment of LTBI; ii) challenges with diagnosing LTBI in programmatic settings; iii) LTBI treatment options including isoniazid monotherapy, shorter regimens (rifampicin-monotherapy, rifampicin-isoniazid and rifapentine-isoniazid) and treatments for contacts of drug-resistant patients; iv) issues with programmatic scale-up of treatment including policy considerations, ruling out active TB, time to start treatment, safety, uninterrupted drug supplies and treatment adherence; and v) recording and reporting.Expert opinion: In 2017, <1.5 million persons were reported to be treated for LTBI. This must rapidly increase to 6 million persons annually. If HIV programs focus on HIV-infected people already accessing or about to start antiretroviral therapy and TB programs focus on household contacts, these targets could be achieved. Isoniazid remains the current treatment of choice although shorter courses of rifapentine-isoniazid are possible alternatives.

What Proportion of New Tuberculosis Patients Has a History of Household Tuberculosis Exposure? A Cross-Sectional Study from Udupi District, South India

While tuberculosis (TB) preventive therapy among household contacts is effective at an individual level, its population-level impact on reducing TB incidence has been unclear. In this study, we aimed to assess, among the new tuberculosis patients started on treatment between 1 October, 2018 and 30 June, 2019 in the public health facilities of Udupi district (South India): i) the proportion with a ‘history of household TB exposure’ and ii) sociodemographic and clinical factors associated with it. We conducted a cross-sectional study involving record review and patient interviews. Of 565 TB patients, 273(48%) were interviewed. Of them, 71(26%, 95% CI: 21%–32%) patients had a ‘history of household TB exposure (ever)’ with about half exposed in the past five years of diagnosis. Considering a new TB case as a proxy for incident TB, and ‘history of household TB exposure’ a proxy for household transmission, and assuming 100% effectiveness of preventive therapy, we may infer that a maximum of 26% of the incident cases can be prevented by giving preventive therapy to all household contacts of TB patients. In multivariable analysis, females and tobacco users had a significantly higher prevalence of household TB exposure. If there are resource constraints, these subgroups may be prioritized.

Influenza Transmission Dynamics in Urban Households, Managua, Nicaragua, 2012-2014

In this low-income country setting, ≈16% of household contacts acquired infections from index patients, despite high oseltamivir use.

During August 2012–November 2014, we conducted a case ascertainment study to investigate household transmission of influenza virus in Managua, Nicaragua. We collected up to 5 respiratory swab samples from each of 536 household contacts of 133 influenza virus–infected persons and assessed for evidence of influenza virus transmission. The overall risk for influenza virus infection of household contacts was 15.7% (95% CI 12.7%–19.0%). Oseltamivir treatment of index patients did not appear to reduce household transmission. The mean serial interval for within-household transmission was 3.1 (95% CI 1.6–8.4) days. We found the transmissibility of influenza B virus to be higher than that of influenza A virus among children. Compared with households with <4 household contacts, those with >4 household contacts appeared to have a reduced risk for infection. Further research is needed to model household influenza virus transmission and design interventions for these settings.

Nutritional status evaluation and nutrient intake in adult patients with pulmonary tuberculosis and their contacts

INTRODUCTION

Malnutrition is a common status in patients with tuberculosis (TB). Because TB is disseminated through the sputum of infected persons, individuals who maintain relations with a TB patient are at high risk of infection; this risk is greater when contacts present an inadequate nutritional status. The aim of this work was to analyse and compare the nutritional status and macro and micronutrient intake of TB patients and their household contacts.

METHODOLOGY

A cross-sectional study was carried out in TB patients from Nuevo Leon, México, and their household contacts. Thirty-nine patients diagnosed with TB and 62 contacts were evaluated. Anthropometric evaluation was performed considering weight, height, body mass index (BMI) and waist-hip ratio (WHR); nutrient intake was evaluated by applying 24-hour dietary recalls.

RESULTS

According to anthropometric assessment, the study population showed a greater trend towards being overweight and obese; 62% of TB patients and contacts had this type of malnutrition, while only 8% of individuals were undernourished. A greater tendency towards malnutrition was observed in the TB patient group.

CONCLUSIONS

TB patients and their contacts presented as overweight and obese. Both groups showed similar patterns in macro and micronutrient intake. Implications of deficiencies in the intake of these nutrients are discussed on the basis of their effects on individual health.

Increased Risk for Invasive Group A Streptococcus Disease for Household Contacts of Scarlet Fever Cases, England, 2011-2016

The incidence of scarlet fever in England and Wales is at its highest in 50 years. We estimated secondary household risk for invasive group A Streptococcus (iGAS) disease within 60 days after onset of scarlet fever. Reports of scarlet fever in England during 2011–2016 were matched by residential address to persons with laboratory-confirmed iGAS infections. We identified 11 iGAS cases in ≈189,684 household contacts and a 60-day incidence rate of 35.3 cases/100,000 person-years, which was 12.2-fold higher than the background rate (2.89). Infants and contacts >75 years of age were at highest risk. Three cases were fatal; sepsis and cellulitis were the most common manifestations. Typing for 6 iGAS cases identified emm 1.0 (n = 4), emm 4.0 (n = 1), and emm 12.0 (n = 1). Although absolute risk in household contacts was low, clinicians assessing household contacts should be aware of the risk to expedite diagnosis and initiate life-saving treatment.

Low prevalence of anti-xenobiotic antibodies among the occupationally exposed individuals is associated with a high risk of cancer

Cancer is one of the major health problem globally, responsible for high morbidity and mortality. Exposure of humans to xenobiotics is associated with the development of cancer. Further, these xenobiotics may combine with the body proteins and can act as a hapten and elicit an antibody response. In this study, we examined whether the regular exposer to xenobiotics evokes anti-xenobiotic antibodies and the presence of these antibodies have any correlation with the prevention of cancer. Interestingly, we noticed that the healthy household contacts showed significantly greater titers of anti-xenobiotic antibodies, as compared to cancer patients. Consequently, suggesting that the higher level of anti-xenobiotic antibodies may be responsible for neutralizing the effect of xenobiotics in the healthy subjects. Thereby, preventing the individuals from disease. In contrast, the presence of a significantly lower level of anti-xenobiotic antibodies in the cancer patients may be a causative factor for disease infliction. In conclusion, immunotherapy employing anti-xenobiotic antibodies may provide a prudent remedial measure to clear xenobiotics from the body of the individuals and thereby protecting from cancer.

Vibrio cholerae Transmits Through Water Among the Household Contacts of Cholera Patients in Cholera Endemic Coastal Villages of Bangladesh, 2015-2016 (CHoBI7 Trial)

Recurrent cholera causes significant morbidity and mortality in cholera endemic estuarine areas of Bangladesh. There have been limited studies to investigate the transmission patterns of V. cholerae associated with cholera in Bangladesh. In this study, we characterized V. cholerae serogroup O1 isolated from 30 cholera patients, 76 household contacts, 119 stored drinking water samples, and 119 water source samples in Bakerganj and Mathbaria, two cholera endemic coastal regions in Bangladesh. Results of phenotypic and molecular characterization of V. cholerae isolates (n = 56) confirmed them to be toxigenic belonging to serogroup O1 biotype El Tor (ET), and possessing cholera toxin of the classical biotype (altered ET). Molecular fingerprinting of the V. cholerae O1 of clinical and water origins determined by PFGE of Not-I- digested genomic DNA showed them to be closely related, as the PFGE banding patterns were highly homogenous. Phylogenetic analysis using dendrogram of cholera patients, household contacts, and household groundwater sources showed isolates within households to be clonally linked, suggesting water as an important vehicle of transmission of cholera in the coastal villages of Bangladesh. Transmission of toxigenic V. cholerae O1 through drinking water in cholera endemic rural settings underscores the urgent need for evidence based water, sanitation, and hygiene interventions promoting safe drinking water to prevent morbidity and mortality related to cholera and other enteric infections in Bangladesh.

Anti-Lipoarabinomannan-Specific Salivary IgA as Prognostic Marker for Leprosy Reactions in Patients and Cellular Immunity in Contacts

Leprosy causes the most common peripheral neuropathy of infectious etiology, posing an important public health problem worldwide. Understanding the molecular and immunological mechanisms of nerve damage induced by M. leprae is mandatory to develop tools for early diagnosis and preventive measures. The phenolic glycolipid 1 (PGL-1) and lipoarabinomannan (LAM) antigens are major components of the bacterial surface and are implicated on leprosy immunopathogenesis and neural damage. Although the anti-PGL-1 serum IgM is highly used for operational classification of patients, the anti-LAM salivary IgA (sIgA) has not been investigated as diagnostic or prognostic marker in leprosy. Our aim was to assess the presence of anti-LAM sIgA in leprosy patients and their contacts in order to demonstrate whether such expression was associated with leprosy reactions. Distinct patterns of anti-LAM slgA were observed among groups, which were stratified into treatment-naïve patients (116), patients who completed multidrug therapy—MDT (39), household contacts (111), and endemic controls (11). Both anti-LAM sIgA and anti-PGL-I serum IgM presented similar prognostic odds toward leprosy reactions [(odds ratio) OR = 2.33 and 2.78, respectively]. Furthermore, the anti-LAM sIgA was highly correlated with multibacillary (MB) forms (OR = 4.15). Contrarily, among contacts the positive anti-LAM sIgA was highly correlated with those with positive Mitsuda test, suggesting that the presence of anti-LAM slgA may act as an indicator of cellular immunity conferred to contacts. Our data suggest that anti-LAM slgA may be used as a tool to monitor patients undergoing treatment to predict reactional episodes and may also be used in contacts to evaluate their cellular immunity without the need of Mitsuda tests.

BCG and Adverse Events in the Context of Leprosy

Background

Notwithstanding its beneficial immunoprophylactic outcomes regarding leprosy and childhood TB, BCG vaccination may cause adverse events, particularly of the skin. However, this local hyper-immune reactivity cannot be predicted before vaccination, nor is its association with protection against leprosy known. In this study we investigated the occurrence of adverse events after BCG (re)vaccination in contacts of leprosy patients and analyzed whether the concomitant systemic anti-mycobacterial immunity was associated with these skin manifestations.

Methods

Within a randomized controlled BCG vaccination trial in Bangladesh, 14,828 contacts of newly diagnosed leprosy patients received BCG vaccination between 2012 and 2017 and were examined for adverse events 8 to 12 weeks post-vaccination. From a selection of vaccinated contacts, venous blood was obtained at follow-up examination and stimulated with Mycobacterium leprae (M. leprae) antigens in overnight whole-blood assays (WBA). M. leprae phenolic glycolipid-I-specific antibodies and 32 cytokines were determined in WBAs of 13 individuals with and 13 individuals without adverse events after vaccination.

Results

Out of the 14,828 contacts who received BCG vaccination, 50 (0.34%) presented with adverse events, mainly (80%) consisting of skin ulcers. Based on the presence of BCG scars, 30 of these contacts (60%) had received BCG in this study as a booster vaccination. Similar to the pathological T-cell immunity observed for tuberculoid leprosy patients, contacts with adverse events at the site of BCG vaccination showed elevated IFN-γ levels in response to M. leprae-specific proteins in WBA. However, decreased levels of sCD40L in serum and GRO (CXCL1) in response to M. leprae simultaneously indicated less T-cell regulation in these individuals, potentially causing uncontrolled T-cell immunity damaging the skin.

Conclusion

Skin complications after BCG vaccination present surrogate markers for protective immunity against leprosy, but also indicate a higher risk of developing tuberculoid leprosy.

Clinical Trial Registration

Netherlands Trial Register: NTR3087.

Intensity of exposure to pulmonary tuberculosis determines risk of tuberculosis infection and disease

Household contacts of pulmonary tuberculosis (TB) patients are at increased risk of TB infection and disease. However, their risk in relation to the intensity of exposure remains unknown.We studied smear-positive TB cases and their household contacts in Vitória, Brazil. We collected clinical, demographic and radiographic information from TB cases, and obtained tuberculin skin test (TST) and QuantiFERON-TB Gold (QFT) results from household contacts. We measured intensity of exposure using a proximity score and sleep location in relation to the TB index case and defined infection by TST ≥10 mm or QFT ≥0.35 UI·mL-1 We ascertained secondary TB cases by reviewing local and nationwide case registries.We included 160 TB index cases and 894 household contacts. 464 (65%) had TB infection and 23 (2.6%) developed TB disease. Risk of TB infection and disease increased with more intense exposures. In an adjusted analysis, the proximity score was associated with TB disease (OR 1.61, 95% CI 1.25-2.08; p<0.000); however, its diagnostic performance was only moderate.Intensity of exposure increased risk of TB infection and disease among household contacts; however, its diagnostic performance was still suboptimal. A biomarker to target preventive therapy is urgently needed in this at-risk population.

Infectiousness of HIV-Seropositive Patients with Tuberculosis in a High-Burden African Setting

RATIONALE

Policy recommendations on contact investigation of HIV-seropositive patients with tuberculosis have changed several times. Current epidemiologic evidence informing these recommendations is considered low quality, and few large studies investigating the infectiousness of HIV-seropositive and -seronegative index cases have been performed in sub-Saharan Africa.

OBJECTIVES

We assessed the infectiousness of HIV-seropositive and -seronegative patients with tuberculosis to their household contacts and examined potential modifiers of this relationship.

METHODS

Adults suffering from their first episode of pulmonary tuberculosis were identified in Kampala, Uganda. Field workers visited index households and enrolled consenting household contacts. Latent tuberculosis infection was measured through tuberculin skin testing, and relative risks were calculated using modified Poisson regression models. Standard assessments of interaction between latent tuberculosis infection, the HIV serostatus of index cases, and other variables were performed.

MEASUREMENTS AND MAIN RESULTS

Latent tuberculosis infection was found in 577 of 878 (65.7%) and 717 of 974 (73.6%) household contacts of HIV-seropositive and -seronegative tuberculosis cases (relative risk, 0.89; 95% confidence interval, 0.82-0.97). On further stratification, cavitary lung disease (P < 0.0001 for interaction) and smear status (P = 0.02 for interaction) of tuberculosis cases modified the infectiousness of HIV-seropositive indexes. Cough duration of index cases did not display interaction (P = 0.499 for interaction).

CONCLUSIONS

This study suggests that HIV-seropositive tuberculosis cases may be less infectious than HIV-seronegative patients only when they are smear-negative or lack cavitary lung disease. These results may explain heterogeneity between prior studies and provide evidence suggesting that tuberculosis contact investigation should include HIV-seropositive index cases in high disease burden settings.

Immunologic Markers of Protection in Leishmania (Viannia) braziliensis Infection: A 5-Year Cohort Study

BACKGROUND

The control of Leishmania braziliensis by individuals with subclinical infection (SC) are unknown.

METHODS

A cohort of 308 household contacts (HCs) of patients with cutaneous leishmaniasis (CL) was established in 2010 in an endemic area and followed up for 5 years. Whole-blood cultures stimulated with soluble Leishmania antigen and a Leishmania skin test (LST) were performed in years 0, 2, and 4. The identification of the lymphocyte subsets secreting interferon (IFN) γ and the ability of monocytes to control Leishmania were determined.

RESULTS

During follow-up, 118 subjects (38.3%) had evidence of L. braziliensis infection. Of the HCs, CL was documented in 45 (14.6%), 101 (32.8%) had SC infection, and 162 (52.6%) did not have evidence of exposure to L. braziliensis The ratio of infection to disease was 3.2:1. IFN-γ production, mainly by natural killer cells, was associated with protection, and a positive LST result did not prevent development of disease. Moreover, monocytes from subjects with SC infection were less permissive to parasite penetration and had a greater ability to control L. braziliensis than cells from patients with CL.

CONCLUSIONS

Protection against CL was associated with IFN-γ production, negative LST results, impaired ability of Leishmania to penetrate monocytes, and increased ability to control Leishmania growth.

Pertussis in infants less than 6 months of age and household contacts, Italy, April 2014

We report pertussis cases in 4 infants less than 6 months admitted with symptoms compatible with pertussis to the intensive care unit of the Università Cattolica del Sacro Cuore in Rome, April 2014. Realtime PCR confirmed pertussis diagnosis for the 4 infants, 2 of them were cousins, and for the household contacts of 1 of them. Analysis of pertussis toxin, its promoter and pertactin was also performed. First of all, this report emphasizes the need to investigate household contact of infants with pertussis; secondly, to evaluate the selective vaccination of household members of newborns as an effective program to reduce pertussis in infants.

Randomized Controlled Trial of Hospital-Based Hygiene and Water Treatment Intervention (CHoBI7) to Reduce Cholera

The risk for cholera infection is >100 times higher for household contacts of cholera patients during the week after the index patient seeks hospital care than it is for the general population. To initiate a standard of care for this high-risk population, we developed Cholera-Hospital-Based-Intervention-for-7-Days (CHoBI7), which promotes hand washing with soap and treatment of water. To test CHoBI7, we conducted a randomized controlled trial among 219 intervention household contacts of 82 cholera patients and 220 control contacts of 83 cholera patients in Dhaka, Bangladesh, during 2013-2014. Intervention contacts had significantly fewer symptomatic Vibrio cholerae infections than did control contacts and 47% fewer overall V. cholerae infections. Intervention households had no stored drinking water with V. cholerae and 14 times higher odds of hand washing with soap at key events during structured observation on surveillance days 5, 6, or 7. CHoBI7 presents a promising approach for controlling cholera among highly susceptible household contacts of cholera patients.

Screening for asymptomatic scalp carriage in household contacts of patients with tinea capitis during 1997-2011: a retrospective hospital-based study

For anthropophilic tinea capitis (TC), household spread and asymptomatic scalp carriage (ASC) is considered an important route of transmission and incomplete clearance. To investigate ASC in household contacts of patients diagnosed with TC in a tertiary hospital in Athens, Greece, we retrospectively reviewed the medical files of household contacts that were screened for ASC from 1997 to 2011. Only 34 household contacts of 15 index cases agreed to come for screening. Thirty-three (97%) household contacts were asymptomatic scalp carriers. The most commonly isolated species was Trichophyton violaceum (59%). There was a statistically significant association of ASC with the isolated dermatophyte species (T. violaceum, P-value: 0.029), and with the age of younger than 16 years old (P-value: 0.005), while there was no association with gender (P-value: 0.672). A small number of household contacts accepted to proceed for screening. ASC was found in nearly all screened household contacts and was associated with T. violaceum and younger age. The low number of household contacts that accepted screening may reflect the ignorance of the general population about the possibility of ASC among household contacts in case of a patient with TC.

Differential expression of alpha II spectrin in monocytes of tuberculosis patients

Monocytes play a crucial role in immune response to tuberculosis. The present study focuses on identifying differences in the monocyte proteome profile of tuberculosis patients, household contacts and healthy controls. Differential protein expression was studied by two-dimensional (2D) gel electrophoresis. One of the spots consistently showed either lower intensity or was absent in patients and was identified as alpha II-spectrin. The decreased expression of αII-spectrin was further validated by quantitative PCR (qPCR) and western blot analysis. This study suggests the possible role of decreased levels of αII-spectrin in the pathology of tuberculosis.

Community-randomized trial of enhanced DOTS for tuberculosis control in Rio de Janeiro, Brazil

SETTING

Central Rio de Janeiro, Brazil.

OBJECTIVE

To compare the impact of routine DOTS vs. enhanced DOTS (DOTS-Ampliado or DOTS-A) on tuberculosis (TB) incidence.

DESIGN

Cluster-randomized trial in eight urban neighborhoods pair-matched by TB incidence and randomly assigned to receive either the DOTS-A or DOTS strategy. DOTS-A added intensive screening of household contacts of active TB cases and provision of treatment to secondary cases and preventive therapy to contacts with latent TB infection (LTBI) to the standard DOTS strategy. The primary endpoint was the TB incidence rates in communities after 5 years of intervention.

RESULTS

From November 2000 to December 2004, respectively 339 and 311 pulmonary TB cases were enrolled and 1003 and 960 household were identified in DOTS and DOTS-A communities. Among contacts from DOTS-A communities, 26 (4%) had active TB diagnosed and treated, 429 (61.3%) had LTBI detected and 258 (60.1%) started preventive therapy. TB incidence increased by 5% in DOTS communities and decreased by 10% in DOTS-A communities, for a difference of 15% after 5 years (P = 0.04).

CONCLUSION

DOTS-A was associated with a modest reduction in TB incidence and may be an important strategy for reducing the burden of TB.

Comparison of an in-house and a commercial RD1-based ELISPOT-IFN-gamma assay for the diagnosis of Mycobacterium tuberculosis infection

OBJECTIVE

To compare a RD1-based in-house ELISPOT-interferon-gamma (IFN-gamma) assay with a commercial (T-SPOT.TB) assay for the diagnosis of Mycobacterium tuberculosis (TB) infection and the efficacy of the tuberculin skin test (TST) and ELISPOT assay in detecting latent TB infection (LTBI).

DESIGN

Eighty-six subjects (65 household contacts of contagious TB-infected patients, 13 subjects with active or previous TB infection, and 8 with suspected TB infection) were consecutively recruited in the context of a surveillance program.

METHODS

Enrolled subjects underwent the Mantoux TST and two different ELISPOT-IFN-gamma assays: an in-house assay using a pool of selected M. tuberculosis peptides (MTP) and the commercial T-SPOT.TB assay.

RESULTS

The in-house and commercial ELISPOT-IFN-gamma assays showed almost complete concordance (99%) in diagnosing acute or LTBI. When comparing the efficacy of the TST with the in-house ELISPOT assay in detecting TB infection, a small agreement was observed (k=0.344, P<0.0001): 36% of the subjects with a positive TST were ELISPOT-MTP negative and 12% with a negative TST were ELISPOT-MTP positive. Furthermore, 78% of the ELISPOT-MTP negative individuals were ELISPOT- Bacillus Calmette-Guérin (BCG) positive, most of whom had received BCG vaccination.

CONCLUSION

Our in-house ELISPOT assay based on a restricted pool of highly selected peptides is equivalent to the commercial T-SPOT.TB assay, is cheaper and is probably not confounded, unlike the TST, by BCG vaccination in our setting.