Direct Promoter Repression by BCL11A Controls the Fetal to Adult Hemoglobin Switch.

Fetal hemoglobin (HbF, α2γ2) level is genetically controlled and modifies severity of adult hemoglobin (HbA, α2ß2) disorders, sickle cell disease, and ß-thalassemia. Common genetic variation affects expression of BCL11A, a regulator of HbF silencing. To uncover how BCL11A supports the developmental switch from γ- to ß- globin, we use a functional assay and protein binding microarray to establish a requirement for a zinc-finger cluster in BCL11A in repression and identify a preferred DNA recognition sequence. This motif appears in embryonic and fetal-expressed globin promoters and is duplicated in γ-globin promoters. The more distal of the duplicated motifs is mutated in individuals with hereditary persistence of HbF. Using the CUT&RUN approach to map protein binding sites in erythroid cells, we demonstrate BCL11A occupancy preferentially at the distal motif, which can be disrupted by editing the promoter. Our findings reveal that direct γ-globin gene promoter repression by BCL11A underlies hemoglobin switching.

Transcriptional Silencers in Drosophila Serve a Dual Role as Transcriptional Enhancers in Alternate Cellular Contexts.

A major challenge in biology is to understand how complex gene expression patterns are encoded in the genome. While transcriptional enhancers have been studied extensively, few transcriptional silencers have been identified, and they remain poorly understood. Here, we used a novel strategy to screen hundreds of sequences for tissue-specific silencer activity in whole Drosophila embryos. Almost all of the transcriptional silencers that we identified were also active enhancers in other cellular contexts. These elements are bound by more transcription factors than non-silencers. A subset of these silencers forms long-range contacts with promoters. Deletion of a silencer caused derepression of its target gene. Our results challenge the common practice of treating enhancers and silencers as separate classes of regulatory elements and suggest the possibility that thousands or more bifunctional CRMs remain to be discovered in Drosophila and 104-105 in humans.

Bispecific Forkhead Transcription Factor FoxN3 Recognizes Two Distinct Motifs with Different DNA Shapes.

Transcription factors (TFs) control gene expression by binding DNA recognition sites in genomic regulatory regions. Although most forkhead TFs recognize a canonical forkhead (FKH) motif, RYAAAYA, some forkheads recognize a completely different (FHL) motif, GACGC. Bispecific forkhead proteins recognize both motifs, but the molecular basis for bispecific DNA recognition is not understood. We present co-crystal structures of the FoxN3 DNA binding domain bound to the FKH and FHL sites, respectively. FoxN3 adopts a similar conformation to recognize both motifs, making contacts with different DNA bases using the same amino acids. However, the DNA structure is different in the two complexes. These structures reveal how a single TF binds two unrelated DNA sequences and the importance of DNA shape in the mechanism of bispecific recognition.

Risk of Subsequent Respiratory Virus Detection After Primary Virus Detection in a Community Household Study-King County, Washington, 2019-2021.

BACKGROUND: The epidemiology of respiratory viral infections is complex. How infection with one respiratory virus affects risk of subsequent infection with the same or another respiratory virus is not well described. METHODS: From October 2019 to June 2021, enrolled households completed active surveillance for acute respiratory illness (ARI), and participants with ARI self-collected nasal swab specimens; after April 2020, participants with ARI or laboratory-confirmed severe acute respiratory syndrome coronavirus 2 and their household members self-collected nasal swab specimens. Specimens were tested using multiplex reverse-transcription polymerase chain reaction for respiratory viruses. A Cox regression model with a time-dependent covariate examined risk of subsequent detections following a specific primary viral detection. RESULTS: Rhinovirus was the most frequently detected pathogen in study specimens (406 [9.5%]). Among 51 participants with multiple viral detections, rhinovirus to seasonal coronavirus (8 [14.8%]) was the most common viral detection pairing. Relative to no primary detection, there was a 1.03-2.06-fold increase in risk of subsequent virus detection in the 90 days after primary detection; risk varied by primary virus: human parainfluenza virus, rhinovirus, and respiratory syncytial virus were statistically significant. CONCLUSIONS: Primary virus detection was associated with higher risk of subsequent virus detection within the first 90 days after primary detection.

Lineage-specific control of convergent differentiation by a Forkhead repressor.

During convergent differentiation, multiple developmental lineages produce a highly similar or identical cell type. However, few molecular players that drive convergent differentiation are known. Here, we show that the C. elegans Forkhead transcription factor UNC-130 is required in only one of three convergent lineages that produce the same glial cell type. UNC-130 acts transiently as a repressor in progenitors and newly-born terminal cells to allow the proper specification of cells related by lineage rather than by cell type or function. Specification defects correlate with UNC-130:DNA binding, and UNC-130 can be functionally replaced by its human homolog, the neural crest lineage determinant FoxD3. We propose that, in contrast to terminal selectors that activate cell type-specific transcriptional programs in terminally differentiating cells, UNC-130 acts early and specifically in one convergent lineage to produce a cell type that also arises from molecularly distinct progenitors in other lineages.

Remembering the Work of Phillip L. Geissler: A Coda to His Scientific Trajectory.

Phillip L. Geissler made important contributions to the statistical mechanics of biological polymers, heterogeneous materials, and chemical dynamics in aqueous environments. He devised analytical and computational methods that revealed the underlying organization of complex systems at the frontiers of biology, chemistry, and materials science. In this retrospective we celebrate his work at these frontiers.

Ceramide-1-phosphate transfer protein enhances lipid transport by disrupting hydrophobic lipid-membrane contacts.

Cellular distributions of the sphingolipid ceramide-1-phosphate (C1P) impact essential biological processes. C1P levels are spatiotemporally regulated by ceramide-1-phosphate transfer protein (CPTP), which efficiently shuttles C1P between organelle membranes. Yet, how CPTP rapidly extracts and inserts C1P into a membrane remains unknown. Here, we devise a multiscale simulation approach to elucidate biophysical details of CPTP-mediated C1P transport. We find that CPTP binds a membrane poised to extract and insert C1P and that membrane binding promotes conformational changes in CPTP that facilitate C1P uptake and release. By significantly disrupting a lipid's local hydrophobic environment in the membrane, CPTP lowers the activation free energy barrier for passive C1P desorption and enhances C1P extraction from the membrane. Upon uptake of C1P, further conformational changes may aid membrane unbinding in a manner reminiscent of the electrostatic switching mechanism used by other lipid transfer proteins. Insertion of C1P into an acceptor membrane, eased by a decrease in membrane order by CPTP, restarts the transfer cycle. Most notably, we provide molecular evidence for CPTP's ability to catalyze C1P extraction by breaking hydrophobic C1P-membrane contacts with compensatory hydrophobic lipid-protein contacts. Our work, thus, provides biophysical insights into how CPTP efficiently traffics C1P between membranes to maintain sphingolipid homeostasis and, additionally, presents a simulation method aptly suited for uncovering the catalytic mechanisms of other lipid transfer proteins.

Abiotic and Biotic Drivers of Soil Fungal Communities in Response to Dairy Manure Amendment.

Modern agriculture often relies on large inputs of synthetic fertilizers to maximize crop yield potential, yet their intensive use has led to nutrient losses and impaired soil health. Alternatively, manure amendments provide plant available nutrients, build organic carbon, and enhance soil health. However, we lack a clear understanding of how consistently manure impacts fungal communities, the mechanisms via which manure impacts soil fungi, and the fate of manure-borne fungi in soils. We assembled soil microcosms using five soils to investigate how manure amendments impact fungal communities over a 60-day incubation. Further, we used autoclaving treatments of soils and manure to determine if observed changes in soil fungal communities were due to abiotic or biotic properties, and if indigenous soil communities constrained colonization of manure-borne fungi. We found that manure amended soil fungal communities diverged from nonamended communities over time, often in concert with a reduction in diversity. Fungal communities responded to live and autoclaved manure in a similar manner, suggesting that abiotic forces are primarily responsible for the observed dynamics. Finally, manure-borne fungi declined quickly in both live and autoclaved soil, indicating that the soil environment is unsuitable for their survival. IMPORTANCE Manure amendments in agricultural systems can impact soil microbial communities via supplying growth substrates for indigenous microbes or by introducing manure-borne taxa. This study explores the consistency of these impacts on soil fungal communities and the relative importance of abiotic and biotic drivers across distinct soils. Different fungal taxa responded to manure among distinct soils, and shifts in soil fungal communities were driven largely by abiotic factors, rather than introduced microbes. This work demonstrates that manure may have inconsistent impacts on indigenous soil fungi, and that abiotic properties of soils render them largely resistant to invasion by manure-borne fungi.

Incidence of SARS-CoV-2 infection and associated risk factors among staff and residents at homeless shelters in King County, Washington: an active surveillance study.

Homeless shelter residents and staff may be at higher risk of SARS-CoV-2 infection. However, SARS-CoV-2 infection estimates in this population have been reliant on cross-sectional or outbreak investigation data. We conducted routine surveillance and outbreak testing in 23 homeless shelters in King County, Washington, to estimate the occurrence of laboratory-confirmed SARS-CoV-2 infection and risk factors during 1 January 2020-31 May 2021. Symptom surveys and nasal swabs were collected for SARS-CoV-2 testing by RT-PCR for residents aged ≥3 months and staff. We collected 12,915 specimens from 2,930 unique participants. We identified 4.74 (95% CI 4.00-5.58) SARS-CoV-2 infections per 100 individuals (residents: 4.96, 95% CI 4.12-5.91; staff: 3.86, 95% CI 2.43-5.79). Most infections were asymptomatic at the time of detection (74%) and detected during routine surveillance (73%). Outbreak testing yielded higher test positivity than routine surveillance (2.7% versus 0.9%). Among those infected, residents were less likely to report symptoms than staff. Participants who were vaccinated against seasonal influenza and were current smokers had lower odds of having an infection detected. Active surveillance that includes SARS-CoV-2 testing of all persons is essential in ascertaining the true burden of SARS-CoV-2 infections among residents and staff of congregate settings.

Burden of long COVID among adults experiencing sheltered homelessness: a longitudinal cohort study in King County, WA between September 2020-April 2022.

BACKGROUND: People experiencing homelessness (PEH) are at increased risk for acquiring SARS-CoV-2, but the burden of long COVID in this population is unknown. METHODS: We conducted a matched prospective cohort study to assess the prevalence, characteristics, and impact of long COVID among sheltered PEH in Seattle, WA between September 2020-April 2022. Adults ≥ 18 years, residing across nine homeless shelters with active respiratory virus surveillance, were eligible to complete in-person baseline surveys and interval follow-up phone surveys. We included a subset of 22 COVID-19-positive cases who tested positive or inconclusive for SARS-CoV-2 and 44 COVID-19-negative controls who tested negative for SARS-CoV-2, frequency matched on age and sex. Among controls, 22 were positive and 22 were negative for one of 27 other respiratory virus pathogens. To assess the impact of COVID-19 on the risk of symptom presence at follow-up (day 30-225 post-enrollment test), we performed log-linear regression with robust standard errors, adjusting for confounding by shelter site and demographic variables determined a priori. RESULTS: Of 53 eligible COVID-19 cases, 22 (42%) completed ≥ 1 follow-up survey. While five (23%) cases reported ≥ 1 symptom at baseline, this increased to 77% (10/13) between day 30-59 and 33% (4/12) day 90 + . The most commonly reported symptoms day 30 + were fatigue (27%) and rhinorrhea (27%), with 8 (36%) reporting symptoms that interfered with or prevented daily activities. Four (33%) symptomatic cases reported receiving medical care outside of a medical provider at an isolation facility. Of 44 controls, 12 (27%) reported any symptoms day 90 + . Risk of any symptoms at follow-up was 5.4 times higher among COVID-19 cases compared to controls (95% CI: 2.7-10.5). CONCLUSIONS: Shelter residents reported a high prevalence of symptoms 30 + days after their SARS-CoV-2 detection, though few accessed medical care for persistent illness. The impact of COVID-19 extends beyond acute illness and may exacerbate existing challenges that marginalized populations face in maintaining their health and wellbeing.

Phylogenomics of Severe Acute Respiratory Syndrome Coronavirus 2 in Emergency Shelters for People Experiencing Homelessness.

BACKGROUND: Residents and staff of emergency shelters for people experiencing homelessness (PEH) are at high risk of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The importance of shelter-related transmission of SARS-CoV-2 in this population remains unclear. It is also unknown whether there is significant spread of shelter-related viruses into surrounding communities. METHODS: We analyzed genome sequence data for 28 SARS-CoV-2-positive specimens collected from 8 shelters in King County, Washington between March and October, 2020. RESULTS: We identified at least 12 separate SARS-CoV-2 introduction events into these 8 shelters and estimated that 57% (16 of 28) of the examined cases of SARS-CoV-2 infection were the result of intrashelter transmission. However, we identified just a few SARS-CoV-2 specimens from Washington that were possible descendants of shelter viruses. CONCLUSIONS: Our data suggest that SARS-CoV-2 spread in shelters is common, but we did not observe evidence of widespread transmission of shelter-related viruses into the general population.

The Clinical and Genomic Epidemiology of Rhinovirus in Homeless Shelters-King County, Washington.

BACKGROUND: Rhinovirus (RV) is a common cause of respiratory illness in all people, including those experiencing homelessness. RV epidemiology in homeless shelters is unknown. METHODS: We analyzed data from a cross-sectional homeless shelter study in King County, Washington, October 2019-May 2021. Shelter residents or guardians aged ≥3 months reporting acute respiratory illness completed questionnaires and submitted nasal swabs. After 1 April 2020, enrollment expanded to residents and staff regardless of symptoms. Samples were tested by multiplex RT-PCR for respiratory viruses. A subset of RV-positive samples was sequenced. RESULTS: There were 1066 RV-positive samples with RV present every month of the study period. RV was the most common virus before and during the coronavirus disease 2019 (COVID-19) pandemic (43% and 77% of virus-positive samples, respectively). Participants from family shelters had the highest prevalence of RV. Among 131 sequenced samples, 33 RV serotypes were identified with each serotype detected for ≤4 months. CONCLUSIONS: RV infections persisted through community mitigation measures and were most prevalent in shelters housing families. Sequencing showed a diversity of circulating RV serotypes, each detected over short periods of time. Community-based surveillance in congregate settings is important to characterize respiratory viral infections during and after the COVID-19 pandemic. CLINICAL TRIALS REGISTRATION: NCT04141917.

Human Parainfluenza Virus in Homeless Shelters before and during the COVID-19 Pandemic, Washington, USA.

To determine the epidemiology of human parainfluenza virus in homeless shelters during the COVID-19 pandemic, we analyzed data and sequences from respiratory specimens collected in 23 shelters in Washington, USA, during 2019-2021. Two clusters in children were genetically similar by shelter of origin. Shelter-specific interventions are needed to reduce these infections.

Characteristics of COVID-19 in Homeless Shelters : A Community-Based Surveillance Study.

BACKGROUND: Homeless shelters are a high-risk setting for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission because of crowding and shared hygiene facilities. OBJECTIVE: To investigate SARS-CoV-2 case counts across several adult and family homeless shelters in a major metropolitan area. DESIGN: Cross-sectional, community-based surveillance study. (ClinicalTrials.gov: NCT04141917). SETTING: 14 homeless shelters in King County, Washington. PARTICIPANTS: A total of 1434 study encounters were done in shelter residents and staff, regardless of symptoms. INTERVENTION: 2 strategies were used for SARS-CoV-2 testing: routine surveillance and contact tracing ("surge testing") events. MEASUREMENTS: The primary outcome measure was test positivity rate of SARS-CoV-2 infection at shelters, determined by dividing the number of positive cases by the total number of participant encounters, regardless of symptoms. Sociodemographic, clinical, and virologic variables were assessed as correlates of viral positivity. RESULTS: Among 1434 encounters, 29 (2% [95% CI, 1.4% to 2.9%]) cases of SARS-CoV-2 infection were detected across 5 shelters. Most (n = 21 [72.4%]) were detected during surge testing events rather than routine surveillance, and most (n = 21 [72.4% {CI, 52.8% to 87.3%}]) were asymptomatic at the time of sample collection. Persons who were positive for SARS-CoV-2 were more frequently aged 60 years or older than those without SARS-CoV-2 (44.8% vs. 15.9%). Eighty-six percent of persons with positive test results slept in a communal space rather than in a private or shared room. LIMITATION: Selection bias due to voluntary participation and a relatively small case count. CONCLUSION: Active surveillance and surge testing were used to detect multiple cases of asymptomatic and symptomatic SARS-CoV-2 infection in homeless shelters. The findings suggest an unmet need for routine viral testing outside of clinical settings for homeless populations. PRIMARY FUNDING SOURCE: Gates Ventures.

Membrane hydrophobicity determines the activation free energy of passive lipid transport.

The collective behavior of lipids with diverse chemical and physical features determines a membrane's thermodynamic properties. Yet, the influence of lipid physicochemical properties on lipid dynamics, in particular interbilayer transport, remains underexplored. Here, we systematically investigate how the activation free energy of passive lipid transport depends on lipid chemistry and membrane phase. Through all-atom molecular dynamics simulations of 11 chemically distinct glycerophospholipids, we determine how lipid acyl chain length, unsaturation, and headgroup influence the free energy barriers for two elementary steps of lipid transport: lipid desorption, which is rate limiting, and lipid insertion into a membrane. Consistent with previous experimental measurements, we find that lipids with longer, saturated acyl chains have increased activation free energies compared to lipids with shorter, unsaturated chains. Lipids with different headgroups exhibit a range of activation free energies; however, no clear trend based solely on chemical structure can be identified, mirroring difficulties in the interpretation of previous experimental results. Compared to liquid-crystalline phase membranes, gel phase membranes exhibit substantially increased free energy barriers. Overall, we find that the activation free energy depends on a lipid's local hydrophobic environment in a membrane and that the free energy barrier for lipid insertion depends on a membrane's interfacial hydrophobicity. Both of these properties can be altered through changes in lipid acyl chain length, lipid headgroup, and membrane phase. Thus, the rate of lipid transport can be tuned through subtle changes in local membrane composition and order, suggesting an unappreciated role for nanoscale membrane domains in regulating cellular lipid dynamics.

Targeted Degradation of the Oncogenic Phosphatase SHP2.

SHP2 is a protein tyrosine phosphatase that plays a critical role in the full activation of the Ras-MAPK pathway upon stimulation of receptor tyrosine kinases, which are frequently amplified or mutationally activated in human cancer. In addition, activating mutations in SHP2 result in developmental disorders and hematologic malignancies. Several allosteric inhibitors have been developed for SHP2 and are currently in clinical trials. Here, we report the development and evaluation of a SHP2 PROTAC created by conjugating RMC-4550 with pomalidomide using a PEG linker. This molecule is highly selective for SHP2, induces degradation of SHP2 in leukemic cells at submicromolar concentrations, inhibits MAPK signaling, and suppresses cancer cell growth. SHP2 PROTACs serve as an alternative strategy for targeting ERK-dependent cancers and are useful tools alongside allosteric inhibitors for dissecting the mechanisms by which SHP2 exerts its oncogenic activity.

COVID-19 Outbreak Among Three Affiliated Homeless Service Sites - King County, Washington, 2020.

On March 30, 2020, Public Health - Seattle and King County (PHSKC) was notified of a confirmed case of coronavirus disease 2019 (COVID-19) in a resident of a homeless shelter and day center (shelter A). Residents from two other homeless shelters (B and C) used shelter A's day center services. Testing for SARS-CoV-2, the virus that causes COVID-19, was offered to available residents and staff members at the three shelters during March 30-April 1, 2020. Among the 181 persons tested, 19 (10.5%) had positive test results (15 residents and four staff members). On April 1, PHSKC and CDC collaborated to conduct site assessments and symptom screening, isolate ill residents and staff members, reinforce infection prevention and control practices, provide face masks, and advise on sheltering-in-place. Repeat testing was offered April 7-8 to all residents and staff members who were not tested initially or who had negative test results. Among the 118 persons tested in the second round of testing, 18 (15.3%) had positive test results (16 residents and two staff members). In addition to the 31 residents and six staff members identified through testing at the shelters, two additional cases in residents were identified during separate symptom screening events, and four were identified after two residents and two staff members independently sought health care. In total, COVID-19 was diagnosed in 35 of 195 (18%) residents and eight of 38 (21%) staff members who received testing at the shelter or were evaluated elsewhere. COVID-19 can spread quickly in homeless shelters; rapid interventions including testing and isolation to identify cases and minimize transmission are necessary. CDC recommends that homeless service providers implement appropriate infection control practices, apply physical distancing measures including ensuring resident's heads are at least 6 feet (2 meters) apart while sleeping, and promote use of cloth face coverings among all residents (1).

Acute Effects of Gastrocnemius/Soleus Self-Myofascial Release Versus Dynamic Stretching on Closed-Chain Dorsiflexion.

CONTEXT: Limited ankle dorsiflexion (DF) range of motion has been correlated with decreased flexibility of the gastrocnemius/soleus complex. Decreased ankle DF range of motion can lead to an increase in lower-extremity injuries, for example, acute ankle sprains, Achilles tendinopathy. OBJECTIVE: The purpose of this study was to determine whether a single application of the intervention to the gastrocnemius/soleus complex via multidirectional self-myofascial release using a foam roller, multiplanar dynamic stretch performed in downward dog, or a combination of both techniques acutely improved ankle DF. DESIGN: Subjects were assigned to groups via random card selection. Investigators provided verbal cues as needed to yield correct performance of interventions. Both interventions were performed twice for 1 minute using a dynamic walking rest of 30.48 m at a self-selected pace between interventions. Statistical analyses were completed using a 1-way analysis of variance, at α level ≤ .05. SETTING: A convenience sample study. PARTICIPANTS: A total of 42 asymptomatic physical therapy students (18 females and 24 males) with mean age of 26.12 (4.03) years volunteered to participate. INTERVENTIONS: Multidirectional self-myofascial release using a foam roller, multiplanar dynamic stretch performed in downward dog, or a combination of both techniques. MAIN OUTCOME MEASURES: Weight-bearing right ankle DF measurements were recorded in centimeters using a forward lunge technique (intraclass correlation coefficient = .98, .97, and .96). RESULTS: Data analysis revealed no significant difference between the 3 groups in all pre-post measurements (P = .82). Mean (SD) measurements from pretest to posttest for myofascial release, dynamic stretching, and combination interventions were 0.479 (0.7) cm, 0.700 (0.7) cm, and 0.907 (1.4) cm, respectively. CONCLUSION: Until further studies are conducted, the selection of technique to increase ankle DF range of motion should be based on each individual patient's ability, preference, and response to treatment.

Exploiting Chromophore-Protein Interactions through Linker Engineering To Tune Photoinduced Dynamics in a Biomimetic Light-Harvesting Platform.

Creating artificial systems that mimic and surpass those found in nature is one of the great challenges of modern science. In the context of photosynthetic light harvesting, the difficulty lies in attaining utmost control over the energetics, positions and relative orientations of chromophores in densely packed arrays to transfer electronic excitation energy to desired locations with high efficiency. Toward achieving this goal, we use a highly versatile biomimetic protein scaffold from the tobacco mosaic virus coat protein on which chromophores can be attached at precise locations via linkers of differing lengths and rigidities. We show that minor linker modifications, including switching chiral configurations and alkyl chain shortening, lead to significant lengthening of the ultrafast excited state dynamics of the system as the linkers are shortened and rigidified. Molecular dynamics simulations provide molecular-level detail over how the chromophore attachment orientations, positions, and distances from the protein surface lead to the observed trends in system dynamics. In particular, we find that short and rigid linkers are able to sandwich water molecules between chromophore and protein, leading to chromophore-water-protein supracomplexes with intricately coupled dynamics that are highly dependent on their local protein environment. In addition, cyclohexyl-based linkers are identified as ideal candidates to retain rotational correlations over several nanoseconds and thus lock relative chromophore orientations throughout the lifetime of an exciton. Combining linker engineering with judicious placement of chromophores on the hydrated protein scaffold to exploit different chromophore-bath couplings provides a clear and effective path to producing highly controllable artificial light-harvesting systems that can increasingly mimic their natural counterparts, thus aiding to elucidate natural photosynthetic mechanisms.

Treatment outcomes of TB-infected individuals attending public sector primary care clinics in rural Liberia from 2015 to 2017: a retrospective cohort study.

OBJECTIVES: In June 2015, Partners in Health (PIH) and the Liberian Ministry of Health began a community health worker (CHW) programme containing food support, reimbursement of transport and social assistance to address gaps in tuberculosis (TB) treatment exacerbated by the 2014-2015 Ebola virus disease (EVD) epidemic. The purpose of this article was to analyse the performance of routine clinical TB care and the effects of this CHW programme. METHODS: Retrospective cohort study utilising data from TB patient registers at a census of all health facilities treating TB in the south-east region of Liberia from January 2015 - April 2017. Competing risks Cox regression analyses were used to generate subhazard ratios (sHR) analysing factors associated with rates of TB cure (smear negative), treatment completion (no smear), lost to follow-up (LTFU) and death. RESULTS: LTFU rates decreased 76% pre- vs. post-CHW intervention, from 14.6% in pre-intervention to 3.4% post-intervention (P < 0.001). Although the post-intervention had better cure rates (sHR 1.07, CI 0.58-1.9), treatment completion (sHR 1.53, CI 1.00 2.39) and lower death rates (sHR 0.64, CI 0.34-1.2), statistical significance was not reached. Younger patients had significantly lower death and cure rates, while older patients had higher LTFU and cure rates. Overall, 31% of patients were cured, 44% completed treatment without a confirmatory smear, 5% were LTFU, 9% died, 0.5% failed treatment, and 10% transferred out. CONCLUSIONS: In challenging environments, LTFU can be reduced by CHW accompaniment and socio-economic assistance to patients with TB. Approaches are needed to improve cure verification in young patients and reduce mortality.