scholarly journals The impact of active case finding among high-risk populations on the decline of tuberculosis incidence

2021 ◽  
Author(s):  
Aleksandra Tomczak ◽  
Dominika Warmjak ◽  
Aneta Wiśniewska
Keyword(s):  
High Risk ◽  
Disease Transmission ◽  
Reproduction Number ◽  
Case Finding ◽  
Transmission Risk ◽  
Active Case Finding ◽  
Disease Dynamics ◽  
Active Screening ◽  
Active Case ◽  
The Impact

Introduction: Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis. In 2019 the WHO reported approximately 10 million TB cases and 1.4 million deaths worldwide. TB still remains one of the leading causes of death in humans. Brazil is one of 30 countries with the highest TB burden with 96,000 new cases and 6,700 deaths reported in 2019. From 2015 the TB incidence is increasing by 2%–3% annually. It means that TB control programs need to be improved. Aim: Our aim is to show the impact of active case finding of TB cases among a high-risk subpopulation on decline of the incidence in the general population. Material and methods: We use a SIS-type compartmental mathematical model to describe the disease dynamics. We consider the population as a heterogeneous population which differ in disease transmission risk. Using best-fit techniques we compare the actual data with the model. For the fitted parameters we calculate the basic reproduction number and estimate the TB trends for the next few years applying several preventative protocols. Results and discussion: Using numerical simulations we examine the impact of ACF on the disease dynamics. We show that active screening among high risk subpopulations can help to reduce TB spread. We show how the reproduction number and estimated incidence decline depend on the detection rate. Conclusions: Active screening is one of the most effective ways for reducing the spread of disease. However, due to financial constraints, it can only be used to a limited extent. Properly applied detection can limit the spread of the disease while minimizing costs.

scholarly journals The impact of active case finding on transmission dynamics of tuberculosis: A modelling study

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0257242
Author(s):  
Diepreye Victoria Ayabina ◽  
M. Gabriela M. Gomes ◽  
Nhung Viet Nguyen ◽  
Luan Vo ◽  
Suvesh Shreshta ◽  
...  
Keyword(s):  
Reproduction Number ◽  
Treatment Success ◽  
National Level ◽  
Case Finding ◽  
Transmission Model ◽  
Active Case Finding ◽  
Active Case ◽  
Incidence Data ◽  
Country Level ◽  
The Impact

Background In the last decade, active case finding (ACF) strategies for tuberculosis (TB) have been implemented in many diverse settings, with some showing large increases in case detection and reporting at the sub-national level. There have also been several studies which seek to provide evidence for the benefits of ACF to individuals and communities in the broader context. However, there remains no quantification of the impact of ACF with regards to reducing the burden of transmission. We sought to address this knowledge gap and quantify the potential impact of active case finding on reducing transmission of TB at the national scale and further, to determine the intensification of intervention efforts required to bring the reproduction number (R0) below 1 for TB. Methods We adopt a dynamic transmission model that incorporates heterogeneity in risk to TB to assess the impact of an ACF programme (IMPACT TB) on reducing TB incidence in Vietnam and Nepal. We fit the models to country-level incidence data using a Bayesian Markov Chain Monte Carlo approach. We assess the impact of ACF using a parameter in our model, which we term the treatment success rate. Using programmatic data, we estimate how much this parameter has increased as a result of IMPACT TB in the implementation districts of Vietnam and Nepal and quantify additional efforts needed to eliminate transmission of TB in these countries by 2035. Results Extending the IMPACT TB programme to national coverage would lead to moderate decreases in TB incidence and would not be enough to interrupt transmission by 2035. Decreasing transmission sufficiently to bring the reproduction number (R0) below 1, would require a further intensification of current efforts, even at the sub-national level. Conclusions Active case finding programmes are effective in reducing TB in the short term. However, interruption of transmission in high-burden countries, like Vietnam and Nepal, will require comprehensive incremental efforts. Complementary measures to reduce progression from infection to disease, and reactivation of latent infection, are needed to meet the WHO End TB incidence targets.

scholarly journals A Multi-Faceted Approach to Tuberculosis Active Case Finding among Remote Riverine Communities in Southern Nigeria

2021 ◽  
Vol 18 (18) ◽  
pp. 9424
Author(s):  
Andy Samuel Eyo ◽  
Valerie Okon Obot ◽  
Okezie Onyedinachi ◽  
Nathaly Aguilera Vasquez ◽  
Jacob Bigio ◽  
...  
Keyword(s):  
Community Outreach ◽  
Case Finding ◽  
Control Population ◽  
Active Case Finding ◽  
Access To Health Services ◽  
Historical Trends ◽  
Active Case ◽  
Southern Nigeria ◽  
Community Volunteers ◽  
The Impact

Nigeria accounts for 11% of the worldwide gap between estimated and reported individuals with tuberculosis (TB). Hard-to-reach communities on the Southern Nigeria coast experience many difficulties accessing TB services. We implemented an active case finding (ACF) intervention in Akwa Ibom and Cross River states utilizing three approaches: house-to-house/tent-to-tent screening, community outreach and contact investigation. To evaluate the impact, we compared TB notifications in intervention areas to baseline and control population notifications, as well as to expected notifications based on historical trends. We also gathered field notes from discussions with community volunteers who provided insights on their perspectives of the intervention. A total of 509,768 individuals were screened of which 12,247 (2.4%) had TB symptoms and 11,824 (96.5%) were tested. In total, 1015 (8.6%) of those identified as presumptive had confirmed TB—98.2% initiated treatment. Following implementation, TB notifications in intervention areas increased by 112.9% compared to baseline and increased by 138.3% when compared to expected notifications based on historical trends. In contrast, control population notifications increased by 101% and 49.1%, respectively. Community volunteers indicated a preference for community outreach activities. Multi-faceted, community-based interventions in Nigeria’s coastal areas successfully increase TB detection for communities with poor access to health services.

Active case-finding of tuberculosis in general populations and at-risk groups: a systematic review and meta-analysis

2021 ◽  
pp. 2100090
Author(s):  
Anders Solitander Bohlbro ◽  
Victor Schwartz Hvingelby ◽  
Frauke Rudolf ◽  
Christian Wejse ◽  
Cecilie Blenstrup Patsche
Keyword(s):  
At Risk ◽  
High Risk ◽  
Risk Groups ◽  
Case Finding ◽  
Risk Of Bias ◽  
Sensitivity Analyses ◽  
Active Case Finding ◽  
Active Case ◽  
General Populations ◽  
Prevalence Ratios

The World Health Organization (WHO) recommends active case-finding (ACF) of Tuberculosis (TB) in certain high-risk groups; however, more evidence is needed to elucidate the scope of ACF beyond the current recommendations. In this study we aimed to systematically review yields (the prevalence of active TB) of studies on ACF in general populations and at-risk groups.The review protocol was registered with PROSPERO (registration no.: CRD42020206856). A literature search in PubMed, Embase, and CENTRAL was performed for studies concluded after 31/12/1999 and published before 01/09/2020. Screening yields were estimated and yield/prevalence ratios (ratio between yield of study and WHO estimated prevalence of TB) were calculated to assess which groups might especially benefit from ACF. Finally, risk of bias was assessed, and heterogeneity was investigated using meta-regression and sensitivity analyses.We included 197 studies, with a total of 12 372 530 screened and 53 158 cases found. Yields were high among drug users, close contacts, the poor and marginalised, people living with HIV (PLHIV), and prison inmates across incidence strata and estimated yield/prevalence ratios in screenings of general populations tended to be >1 with an overall ratio of 1.4 and ranging between 1.0 and 1.5. Sensitivity analyses suggested that inclusion of studies at high risk of bias contributed to underestimation of yields.Despite many studies using insensitive screening methods, these results suggest that more at-risk groups should be considered for inclusion in future screening recommendations and that screening of general populations may outperform current case-finding practices, providing evidence for extending ACF beyond the current recommendations.

scholarly journals Assessing the Potential Impact of Immunity Waning on the Dynamics of COVID-19: An Endemic Model of COVID-19

2021 ◽  
Author(s):  
MUSA RABIU ◽  
Sarafa A. Iyaniwura
Keyword(s):  
Disease Transmission ◽  
Reproduction Number ◽  
Transmission Rate ◽  
Backward Bifurcation ◽  
Disease Dynamics ◽  
Potential Impact ◽  
The Impact ◽  
Induced Immunity ◽  
Disease Free ◽  
Pharmaceutical Interventions

Abstract We developed an endemic model of COVID-19 to assess the impact of vaccination and immunity waning on the dynamics of the disease. Our model exhibits the phenomenon of backward bifurcation and bi-stability, where a stable disease-free equilibrium co-exists with a stable endemic equilibrium. The epidemiological implication of this is that the control reproduction number being less than unity is no longer sufficient to guarantee disease eradication. We showed that this phenomenon could be eliminated by either increasing the vaccine efficacy or by reducing the disease transmission rate (adhering to non-pharmaceutical interventions). Furthermore, we numerically investigated the impacts of vaccination and waning of both vaccine-induced immunity and post-recovery immunity on the disease dynamics. Our simulation results show that the waning of vaccine-induced immunity has more effect on the disease dynamics relative to post-recovery immunity waning, and suggests that more emphasis should be on reducing the waning of vaccine-induced immunity to eradicate COVID-19.

scholarly journals Disaster displacement and zoonotic disease dynamics: The impact of structural and chronic drivers in Sindh, Pakistan

2021 ◽  
Vol 1 (12) ◽  
pp. e0000068
Author(s):  
Dorien H. Braam ◽  
Rafiq Chandio ◽  
Freya L. Jephcott ◽  
Alex Tasker ◽  
James L. N. Wood
Keyword(s):  
Rural Communities ◽  
Disease Transmission ◽  
Disease Risk ◽  
Animal Health ◽  
Forced Migration ◽  
Zoonotic Disease ◽  
Transmission Risk ◽  
Disease Dynamics ◽  
Displaced Populations ◽  
The Impact

Projected increases in human and animal displacement driven by climate change, disasters and related environmental degradation will have significant implications to global health. Pathways for infectious disease transmission including zoonoses, diseases transmitted between animals and humans, are complex and non-linear. While forced migration is considered an important driver for the spread of zoonoses, actual disease dynamics remain under researched. This paper presents the findings of a case study investigating how disaster displacement affected zoonotic disease transmission risk following the 2010 ‘superfloods’ in Sindh province, Pakistan. We interviewed 30 key informants and 17 household members across 6 rural communities between March and November 2019, supported by observational studies and a review of secondary data. Results were analysed using the ecosocial theoretical framework. Buffalo, cattle and goats were often the only moveable asset, therefore livestock was an important consideration in determining displacement modality and destination location, and crowded locations were avoided to protect human and animal health. Meanwhile however, livestock was rarely included in the humanitarian response, resulting in communities and households fragmenting according to the availability of livestock provisions. We found that rather than a driver for disease, displacement acted as a process affecting community, household and individual zoonotic disease risk dynamics, based on available resources and social networks before, during and after displacement, rooted in the historical, political and socio-economic context. We conclude that in rural Sindh, disaster displaced populations’ risk of zoonoses is the result of changes in dynamics rooted in pre-existing structural and chronic inequalities, making people more or less vulnerable to disease through multiple interlinked pathways. Our findings have implications for policy makers and humanitarian responders assisting displaced populations dependent on livestock, with a call to integrate livestock support in humanitarian policies and responses for health, survival and recovery.

scholarly journals Do community-based active case-finding interventions have indirect impacts on wider TB case detection and determinants of subsequent TB testing behaviour? A systematic review

2021 ◽  
Vol 1 (12) ◽  
pp. e0000088
Author(s):  
Helena R. A. Feasey ◽  
Rachael M. Burke ◽  
Marriott Nliwasa ◽  
Lelia H. Chaisson ◽  
Jonathan E. Golub ◽  
...  
Keyword(s):  
Indirect Effect ◽  
Controlled Trial ◽  
Case Finding ◽  
Case Detection ◽  
Active Case Finding ◽  
Community Based ◽  
Active Case ◽  
Attitudes And Practices ◽  
The Impact ◽  
Case Notification

Community-based active case-finding (ACF) may have important impacts on routine TB case-detection and subsequent patient-initiated diagnosis pathways, contributing “indirectly” to infectious diseases prevention and care. We investigated the impact of ACF beyond directly diagnosed patients for TB, using routine case-notification rate (CNR) ratios as a measure of indirect effect. We systematically searched for publications 01-Jan-1980 to 13-Apr-2020 reporting on community-based ACF interventions compared to a comparison group, together with review of linked manuscripts reporting knowledge, attitudes, and practices (KAP) outcomes or qualitative data on TB testing behaviour. We calculated CNR ratios of routine case-notifications (i.e. excluding cases identified directly through ACF) and compared proxy behavioural outcomes for both ACF and comparator communities. Full text manuscripts from 988 of 23,883 abstracts were screened for inclusion; 36 were eligible. Of these, 12 reported routine notification rates separately from ACF intervention-attributed rates, and one reported any proxy behavioural outcomes. Two further studies were identified from screening 1121 abstracts for linked KAP/qualitative manuscripts. 8/12 case-notification studies were considered at critical or serious risk of bias. 8/11 non-randomised studies reported bacteriologically-confirmed CNR ratios between 0.47 (95% CI:0.41–0.53) and 0.96 (95% CI:0.94–0.97), with 7/11 reporting all-form CNR ratios between 0.96 (95% CI:0.88–1.05) and 1.09 (95% CI:1.02–1.16). One high-quality randomised-controlled trial reported a ratio of 1.14 (95% CI 0.91–1.43). KAP/qualitative manuscripts provided insufficient evidence to establish the impact of ACF on subsequent TB testing behaviour. ACF interventions with routine CNR ratios >1 suggest an indirect effect on wider TB case-detection, potentially due to impact on subsequent TB testing behaviour through follow-up after a negative ACF test or increased TB knowledge. However, data on this type of impact are rarely collected. Evaluation of routine case-notification, testing and proxy behavioural outcomes in intervention and comparator communities should be included as standard methodology in future ACF campaign study designs.

scholarly journals The Impact of Funding on Childhood TB Case Detection in Pakistan

2019 ◽  
Vol 4 (4) ◽  
pp. 146 ◽  
Author(s):  
Amyn A. Malik ◽  
Hamidah Hussain ◽  
Jacob Creswell ◽  
Sara Siddiqui ◽  
Junaid F. Ahmed ◽  
...  
Keyword(s):  
Case Finding ◽  
Active Case Finding ◽  
Average Case ◽  
Active Case ◽  
Implementation Period ◽  
Childhood Tb ◽  
Continuous Stream ◽  
The Cost ◽  
The Impact ◽  
Case Notification

This study is a review of routine programmatically collected data to describe the 5-year trend in childhood case notification in Jamshoro district, Pakistan from January 2013 to June 2018 and review of financial data for the two active case finding projects implemented during this period. The average case notification in the district was 86 per quarter before the start of active case finding project in October 2014. The average case notification rose to 322 per quarter during the implementation period (October 2014 to March 2016) and plateaued at 245 per quarter during the post-implementation period (April 2016 to June 2018). In a specialized chest center located in the district, where active case finding was re-introduced during the post implementation period (October 2016), the average case notification was 218 per quarter in the implementation period and 172 per quarter in the post implementation period. In the rest of the district, the average case notification was 160 per quarter in the implementation period and 78 during the post implementation period. The cost per additional child with TB found ranged from USD 28 to USD 42 during the interventions. A continuous stream of resources is necessary to sustain high notifications of childhood TB.

scholarly journals Role of community-based active case finding in screening tuberculosis in Yunnan province of China

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Jin-Ou Chen ◽  
Yu-Bing Qiu ◽  
Zulma Vanessa Rueda ◽  
Jing-Long Hou ◽  
Kun-Yun Lu ◽  
...  
Keyword(s):  
Public Health ◽  
High Risk ◽  
General Population ◽  
Yunnan Province ◽  
Risk Groups ◽  
Case Finding ◽  
Active Case Finding ◽  
Community Based ◽  
Active Case ◽  
Incidence Proportion

Abstract Background The barriers to access diagnosis and receive treatment, in addition to insufficient case identification and reporting, lead to tuberculosis (TB) spreads in communities, especially among hard-to-reach populations. This study evaluated a community-based active case finding (ACF) strategy for the detection of tuberculosis cases among high-risk groups and general population in China between 2013 and 2015. Methods This retrospective cohort study conducted an ACF in ten communities of Dongchuan County, located in northeast Yunnan Province between 2013 and 2015; and compared to 136 communities that had passive case finding (PCF). The algorithm for ACF was: 1) screen for TB symptoms among community enrolled residents by home visits, 2) those with positive symptoms along with defined high-risk groups underwent chest X-ray (CXR), followed by sputum microscopy confirmation. TB incidence proportion and the number needed to screen (NNS) to detect one case were calculated to evaluate the ACF strategy compared to PCF, chi-square test was applied to compare the incidence proportion of TB cases’ demography and the characteristics for detected cases under different strategies. Thereafter, the incidence rate ratio (IRR) and multiple Fisher’s exact test were applied to compare the incidence proportion between general population and high-risk groups. Patient and diagnostic delays for ACF and PCF were compared by Wilcoxon rank sum test. Results A total of 97 521 enrolled residents were visited with the ACF cumulatively, 12.3% were defined as high-risk groups or had TB symptoms. Sixty-six new TB patients were detected by ACF. There was no significant difference between the cumulative TB incidence proportion for ACF (67.7/100000 population) and the prevalence for PCF (62.6/100000 population) during 2013 to 2015, though the incidence proportion in ACF communities decreased after three rounds active screening, concurrent with the remained stable prevalence in PCF communities. The cumulative NNS were 34, 39 and 29 in HIV/AIDS infected individuals, people with positive TB symptoms and history of previous TB, respectively, compared to 1478 in the general population. The median patient delay under ACF was 1 day (Interquartile range, IQR: 0–27) compared to PCF with 30 days (IQR: 14–61). Conclusions This study confirmed that massive ACF was not effective in general population in a moderate TB prevalence setting. The priority should be the definition and targeting of high-risk groups in the community before the screening process is launched. The shorter time interval of ACF between TB symptoms onset and linkage to healthcare service may decrease the risk of TB community transmission. Furthermore, integrated ACF strategy in the National Project of Basic Public Health Service may have long term public health impact.

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