Evaluation of an HIV homecare program for lost-to-follow-up populations: a mixed methods study in Detroit, Michigan

BACKGROUND

Maintaining people living with HIV (PLWHIV) in clinical care is a global priority. In the Metro Detroit area of Michigan, approximately 30% of PLWHIV are out of care. To re-engage lost-to-follow-up patients, Wayne Health Infectious Disease clinic launched an innovative Homecare program in 2017. In addition to home healthcare delivery, the program included links to community resources and quarterly community meetings. We aimed to evaluate Homecare's impact on participants' ability to stay engaged in HIV care and reach viral suppression. We included data from PLWHIV and their healthcare workers.

METHODS

We used a convergent mixed-methods design, including first year program record review, semi-structured interviews, and a validated Likert scale questionnaire rating illness perception before and after Homecare. Interview data were collected from 15 PLWHIV in Metro Detroit and two healthcare workers responsible for program delivery. Semi-structured interviews focused on obstacles to clinic-based care, support networks, and illness perceptions. Interview data were transcribed and analyzed using a thematic approach. A fully coded analysis was used to create a conceptual framework of factors contributing to Homecare's success. Means in eight categories of the Brief Illness Perception (IPQ) were compared using paired T-tests.

RESULTS

In the first year of Homecare, 28 of 34 participants (82%) became virally suppressed at least once. The program offered (1) social support and stigma reduction through strong relationships with healthcare workers, (2) removal of physical and resource barriers such as transportation, and (3) positive changes in illness perceptions. PLWHIV worked towards functional coping strategies, including improvements in emotional regulation, acceptance of their diagnosis, and more positive perspectives of control. Brief-IPQ showed significant changes in six domains before and after Homecare.

CONCLUSION

Homecare offers an innovative system for successfully re-engaging and maintaining lost-to-follow-up PLWHIV in care. These findings have implications for HIV control efforts and could inform the development of future programs for difficult to reach populations.

Aperiodic neural activity is a biomarker for depression severity

A reliable physiological biomarker for Major Depressive Disorder (MDD) is necessary to improve treatment success rates by shoring up variability in outcome measures. In this study, we establish a passive biomarker that tracks with changes in mood on the order of minutes to hours. We record from intracranial electrodes implanted deep in the brain - a surgical setting providing exquisite temporal and spatial sensitivity to detect this relationship in a difficult-to-measure brain area, the ventromedial prefrontal cortex (VMPFC). The aperiodic slope of the power spectral density captures the balance of activity across all frequency bands and is construed as a putative proxy for excitatory/inhibitory balance in the brain. This study demonstrates how shifts in aperiodic slope correlate with depression severity in a clinical trial of deep brain stimulation for treatment-resistant depression (TRD). The correlation between depression severity scores and aperiodic slope is significant in N=5 subjects, indicating that flatter (less negative) slopes correspond to reduced depression severity, especially in the ventromedial prefrontal cortex. This biomarker offers a new way to track patient response to MDD treatment, facilitating individualized therapies in both intracranial and non-invasive monitoring scenarios.

Some Limitations of "Challenges in the Care of Transgender and Gender-Diverse Youth: An Endocrinologist's View"

There is significant disagreement about how to support trans-identified or gender-dysphoric young people. Different experts and expert bodies make strikingly different recommendations based upon the same (limited) evidence. The US-originating "gender-affirmative" model emphasizes social transition and medical intervention, while some other countries, in response to evidence reviews of medical intervention outcomes, have adopted psychological interventions as the first line of treatment. A proposed model of gender-affirming care, comprising only medical intervention for "eligible" youth, is described in Rosenthal (2021). Determining eligibility for these medical interventions is challenging and engenders considerable disagreement among experts, neither of which is mentioned. The review also claims without support that medical interventions have been shown to clearly benefit mental health, and leaves out significant risks and less invasive alternatives. The unreliability of outcome studies and the corresponding uncertainties as to how gender dysphoria develops and responds to treatment are also unreported.

Characterization of Cytochrome P450s with Key Roles in Determining Herbicide Selectivity in Maize

Safeners such as metcamifen and benoxacor are widely used in maize to enhance the selectivity of herbicides through the induction of key detoxifying enzymes, notably cytochrome P450 monooxygenases (CYPs). Using a combination of transcriptomics, proteomics, and functional assays, the safener-inducible CYPs responsible for herbicide metabolism in this globally important crop have been identified. A total of 18 CYPs belonging to clans 71, 72, 74, and 86 were safener-induced, with the respective enzymes expressed in yeast and screened for activity toward thiadiazine (bentazon), sulfonylurea (nicosulfuron), and triketone (mesotrione and tembotrione) chemistries. Herbicide metabolism was largely restricted to family CYP81A members from clan 71, notably CYP81A9, CYP81A16, and CYP81A2. Quantitative transcriptomics and proteomics showed that CYP81A9/CYP81A16 were dominant enzymes in safener-treated field maize, whereas only CYP81A9 was determined in sweet corn. The relationship between CYP81A sequence and activities were investigated by splicing CYP81A2 and CP81A9 together as a series of recombinant chimeras. CYP81A9 showed wide ranging activities toward the three herbicide chemistries, while CYP81A2 uniquely hydroxylated bentazon in multiple positions. The plasticity in substrate specificity of CYP81A9 toward multiple herbicides resided in the second quartile of its N terminal half. Further phylogenetic analysis of CYP81A9 showed that the maize enzyme was related to other CYP81As linked to agrochemical metabolism in cereals and wild grasses, suggesting this clan 71 CYP has a unique function in determining herbicide selectivity in arable crops.

Rice RS2-9, which is bound by transcription factor OSH1, blocks enhancer-promoter interactions in plants

Insulators characterized in Drosophila and mammals have been shown to play a key role in the restriction of promiscuous enhancer-promoter interactions, as well as reshaping the topological landscape of chromosomes. Yet the role of insulators in plants remains poorly understood, in large part because of a lack of well-characterized insulators and binding factor(s). In this study, we isolated a 1.2-kb RS2-9 insulator from the Oryza sativa (rice) genome that can, when interposed between an enhancer and promoter, efficiently block the activation function of both constitutive and floral organ-specific enhancers in transgenic Arabidopsis and Nicotiana tabacum (tobacco). In the rice genome, the genes flanking RS2-9 exhibit an absence of mutual transcriptional interactions, as well as a lack of histone modification spread. We further determined that O. sativa Homeobox 1 (OSH1) bound two regions of RS2-9, as well as over 50 000 additional sites in the rice genome, the majority of which resided in intergenic regions. Mutation of one of the two OSH1-binding sites in RS2-9 impaired insulation activity by up to 60%, whereas the mutation of both binding sites virtually abolished insulator function. We also demonstrated that OSH1 binding sites were associated with 72% of the boundaries of topologically associated domains (TADs) identified in the rice genome, which is comparable to the 77% of TAD boundaries bound by the insulator CCCTC-binding factor (CTCF) in mammals. Taken together, our findings indicate that OSH1-RS2-9 acts as a true insulator in plants, and highlight a potential role for OSH1 in gene insulation and topological organization in plant genomes.

Major latex protein-like encoding genes contribute to Rhizoctonia solani defense responses in sugar beet

Sugar beets are attacked by several pathogens that cause root damages. Rhizoctonia (Greek for “root killer”) is one of them. Rhizoctonia root rot has become an increasing problem for sugar beet production and to decrease yield losses agronomical measures are adopted. Here, two partially resistant and two susceptible sugar beet genotypes were used for transcriptome analysis to discover new defense genes to this fungal disease, information to be implemented in molecular resistance breeding. Among 217 transcripts with increased expression at 2 days post-infection (dpi), three resistance-like genes were found. These genes were not significantly elevated at 5 dpi, a time point when increased expression of three Bet v I/Major latex protein (MLP) homologous genes BvMLP1, BvMLP2 and BvML3 was observed in the partially resistant genotypes. Quantitative RT-PCR analysis on diseased sugar beet seedlings validated the activity of BvMLP1 and BvMLP3 observed in the transcriptome during challenge by R. solani. The three BvMLP genes were cloned and overexpressed in Arabidopsis thaliana to further dissect their individual contribution. Transgenic plants were also compared to T-DNA mutants of orthologous MLP genes. Plants overexpressing BvMLP1 and BvMLP3 showed significantly less infection whereas additive effects were seen on Atmlp1/Atmlp3 double mutants. The data suggest that BvMLP1 and BvMLP3 may contribute to the reduction of the Rhizoctonia root rot disease in sugar beet. Impact on the defense reaction from other differential expressed genes observed in the study is discussed.

Chemically induced herbicide tolerance in rice by the safener metcamifen is associated with a phased stress response

The closely related sulphonamide safeners, metcamifen and cyprosulfamide, were tested for their ability to protect rice from clodinafop-propargyl, a herbicide normally used in wheat. While demonstrating that both compounds were equally bioavailable in planta, only metcamifen prevented clodinafop from damaging seedlings, and this was associated with the enhanced detoxification of the herbicide. Transcriptome studies in rice cultures demonstrated that whereas cyprosulfamide had a negligible effect on gene expression over a 4 h exposure, metcamifen perturbed the abundance of 590 transcripts. Changes in gene expression with metcamifen could be divided into three phases, corresponding to inductions occurring over 30 min, 1.5 h and 4 h. The first phase of gene induction was dominated by transcription factors and proteins of unknown function, the second by genes involved in herbicide detoxification, while the third was linked to cellular homeostasis. Analysis of the inducible genes suggested that safening elicited similar gene families to those associated with specific biotic and abiotic stresses, notably those elicited by abscisic acid, salicylic acid, and methyl jasmonate. Subsequent experiments with safener biomarker genes induced in phase 1 and 2 in rice cell cultures provided further evidence of similarities in signalling processes elicited by metcamifen and salicylic acid.

1490. Lymphogranuloma Venereum: Correct Diagnosis Makes All the Differences

Background

Lymphogranuloma venereum (LGV) is a sexually transmitted infection that is rare in United States. There is no FDA approved test to differentiate Chlamydia trachomatis (CT) infections caused by LGV serovars making diagnosis challenging. This study characterizes the difficulties of diagnosing LGV during an outbreak in Southeast Michigan.

Methods

We performed a retrospective chart review of patients who met CDC criteria for confirmed and probable LGV at one of the Wayne State University ID Clinics between August 2015 and March 2018. Presenting symptoms, initial diagnoses, diagnostic testing, interval between onset of symptoms and LGV diagnosis, and treatment were reviewed. IRB exemption was obtained.

Results

Of 39 patients with LGV, eight (20%) were probable cases and 31 (80%) were PCR confirmed at CDC. All patients were men having sex with men (MSM) and 38 were HIV infected. In 22 patients (56%), LGV was considered likely at presentation whereas in 17 (44%) patients LGV was not initially considered. 11 (66%) patients with a delayed diagnosis had 14 unnecessary diagnostic tests ordered, including computed tomography (6), colonoscopy (7) and renogram (1); only 3 (14%) with a correct early diagnosis had such tests (P ≤ 0.001). Fifteen (88%) of those with a delayed diagnosis received inappropriate treatment compared with none of those with an initial LGV diagnosis (P ≤ 0.0001). Correct treatment occurred 43 days after presentation in those with a delayed diagnosis, whereas the early diagnosis patients were treated on the day of presentation (P ≤ 0.0001). All 39 patients eventually received 21 days of doxycycline and experienced resolution of symptoms.

Conclusion

LGV is rare in the United States, its clinical presentation in MSM is not well known, and proof requires unlicensed tests. More education is needed so that clinicians consider the diagnosis in MSM with a typical syndrome, start treatment promptly and avoid unnecessary tests.

Disclosures

J. Veltman, Jansen: Speaker’s Bureau, Speaker Bureau payment

Where are the drought tolerant crops? An assessment of more than two decades of plant biotechnology effort in crop improvement

Since the dawn of modern biotechnology public and private enterprise have pursued the development of a new breed of drought tolerant crop products. After more than 20 years of research and investment only a few such products have reached the market. This is due to several technical and market constraints. The technical challenges include the difficulty in defining tractable single-gene trait development strategies, the logistics of moving traits from initial to commercial genetic backgrounds, and the disconnect between conditions in farmer's fields and controlled environments. Market constraints include the significant difficulty, and associated costs, in obtaining access to markets around the world. Advances in the biology of plant water management, including response to water deficit reveal new opportunities to improve crop response to water deficit and new genome-based tools promise to usher in the next era of crop improvement. As biotechnology looks to improve crop productivity under drought conditions, the environmental and food security advantages will influence public perception and shift the debate toward benefits rather than risks.

Verification of a Many-Ion Simulator of the Dicke Model Through Slow Quenches across a Phase Transition

We use a self-assembled two-dimensional Coulomb crystal of ∼70 ions in the presence of an external transverse field to engineer a simulator of the Dicke Hamiltonian, an iconic model in quantum optics which features a quantum phase transition between a superradiant (ferromagnetic) and a normal (paramagnetic) phase. We experimentally implement slow quenches across the quantum critical point and benchmark the dynamics and the performance of the simulator through extensive theory-experiment comparisons which show excellent agreement. The implementation of the Dicke model in fully controllable trapped ion arrays can open a path for the generation of highly entangled states useful for enhanced metrology and the observation of scrambling and quantum chaos in a many-body system.

Strategies and tools to improve crop productivity by targeting photosynthesis

Crop productivity needs to substantially increase to meet global food and feed demand for a rapidly growing world population. Agricultural technology developers are pursuing a variety of approaches based on both traditional technologies such as genetic improvement, pest control and mechanization as well as new technologies such as genomics, gene manipulation and environmental modelling to develop crops that are capable of meeting growing demand. Photosynthesis is a key biochemical process that, many suggest, is not yet optimized for industrial agriculture or the modern global environment. We are interested in identifying control points in maize photoassimilation that are amenable to gene manipulation to improve overall productivity. Our approach encompasses: developing and using novel gene discovery techniques, translating our discoveries into traits and evaluating each trait in a stepwise manner that reflects a modern production environment. Our aim is to provide step change advancement in overall crop productivity and deliver this new technology into the hands of growers.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'.

Trehalose 6-Phosphate Regulates Photosynthesis and Assimilate Partitioning in Reproductive Tissue

Transgenic maize (Zea mays) that expresses rice (Oryza sativa) TREHALOSE PHOSPHATE PHOSPHATASE1 (TPP1) from the rice MADS6 promoter, which is active over the flowering period, produces higher yields than wild type. This yield increase occurs with or without drought conditions during flowering. To understand the mechanistic basis of the increased yield, we characterized gene expression and metabolite profiles in leaves and developing female reproductive tissue, comprising florets, node, pith, and shank, over the flowering period with and without drought. The MADS6 promoter was most active in the vasculature, particularly phloem companion cells in florets and pith, consistent with the largest decreases in trehalose 6-phosphate (T6P) levels (2- to 3-fold) being found in pith and florets. Low T6P led to decreased gene expression for primary metabolism and increased gene expression for secondary metabolism, particularly lipid-related pathways. Despite similar changes in gene expression, the pith and floret displayed opposing assimilate profiles: sugars, sugar phosphates, amino acids, and lipids increased in florets, but decreased in pith. Possibly explaining this assimilate distribution, seven SWEET genes were found to be up-regulated in the transgenic plants. SnRK1 activity and the expression of the gene for the SnRK1 beta subunit, expression of SnRK1 marker genes, and endogenous trehalose pathway genes were also altered. Furthermore, leaves of the transgenic maize maintained a higher photosynthetic rate for a longer period compared to wild type. In conclusion, we found that decreasing T6P in reproductive tissues down-regulates primary metabolism and up-regulates secondary metabolism, resulting in different metabolite profiles in component tissues. Our data implicate T6P/ SnRK1 as a major regulator of whole-plant resource allocation for crop yield improvement.

HIV Pre-Exposure Prophylaxis (PrEP) Uptake, Initiation, and Persistence in the Detroit Public Health STD Clinic

Background

HIV pre-exposure prophylaxis (PrEP) is an effective HIV prevention tool; however, little is known about PrEP uptake, initiation, and persistence among patients prescribed PrEP in STD clinics.

Methods

Between July 2016 and March 2017, STD clinic staff compiled reports detailing the eligibility and initiation of PrEP in the Detroit STD Clinic. Staff called all patients prescribed PrEP to determine whether they had started PrEP, were still on PrEP, and their reasons for never initiating or discontinuing PrEP. We used chi-square tests to evaluate differences in PrEP initiation and discontinuation by age and race, calculated the population’s mean duration on PrEP (persistence), and used proportional hazards regression to assess differences in persistence by age and race.

Results

A total of 161 STD clinic patients were eligible for PrEP, of whom 71 (44%) were prescribed PrEP. Of the 71 patients prescribed PrEP, staff successfully interviewed 45 (63%) a median of 113 days following their receipt of prescription. Thirty-four (76%) interviewed patients had initiated PrEP, of whom 17 (50%) had subsequently discontinued their medication a mean of 92 days (95% confidence interval [CI]: ± 23.8) following receipt of a prescription. Figure 1 illustrates the PrEP care continuum for our clinic. There was no significant difference in PrEP initiation or discontinuation by age or race. There was no significant difference in persistence by race. Ages 18–24 had the shortest mean persistence (62 days, 95% CI: ±37.5), while those ages 35–44 had the longest mean persistence (146 days, 95% CI: ± 47.3) though this was not a significant difference (hazard ratio 0.39, P = 0.28). The most common reason for not initiating or discontinuing PrEP was concern about side effects (29%).

Conclusion

Clinicians in the Detroit STD clinic prescribed PrEP for less than half of PrEP-eligible patients, only 76% of those prescribed PrEP ever filled their first prescription, and the mean duration of use among those who filled a first prescription was under 6 months. Our findings highlight the need for further evaluation of why eligible patients are not prescribed PrEP, intensified support services to encourage PrEP persistence, and improved patient counseling about potential side effects.

Disclosures

All authors: No reported disclosures.

How does decision complexity affect shared decision making? An analysis of patient-provider antiretroviral initiation dialogue

OBJECTIVES

This study analyzed patient-provider dialogue regarding anti-retroviral therapy (ART) initiation, assessing the degree to which shared decision making (SDM) occurred.

METHODS

We analyzed 24 audio-recorded dialogues between 14 HIV providers and their patients regarding ART initiation. We coded transcribed dialogues for seven SDM elements. We stratified dialogues into three levels of decision complexity (basic, intermediate, complex) based on patient CD4 counts and evaluated SDM criteria fulfillment at each level of decision complexity.

RESULTS

There were five basic, twelve intermediate, and seven complex decisions in our sample. While only two met the defined criteria for SDM, the mean number of SDM elements present increased with each level of decision complexity. Discussion of the clinical issue requiring the decision occurred most frequently (88%), while discussion of pros/cons (13%), patient's understanding (21%), and decision alternatives (29%) occurred least frequently.

CONCLUSION/PRACTICE IMPLICATIONS

While few dialogues met the defined SDM criteria, providers are having conversations that respond to decision complexity. Clinicians should be aware that discussion of pros/cons, alternatives, and uncertainties are frequently skipped, even when these elements are clearly relevant, as in complex decisions. In addition, rhetorical questions to assess patient preferences and understanding are insufficient to fully engage patients in SDM.

Notes from the Field: Cluster of Lymphogranuloma Venereum Cases Among Men Who Have Sex with Men - Michigan, August 2015-April 2016

Lymphogranuloma venereum (LGV) is a sexually transmitted disease (STD) caused by infection with invasive Chlamydia trachomatis serovars L1-L3 (1). LGV is characterized by inguinal and/or femoral lymphadenopathy, typically following a transient, self-limited genital ulcer or papule that might go unnoticed. Rectal infection can result in proctocolitis that can present with mucoid and/or hemorrhagic rectal discharge, anal pain, constipation, fever, and tenesmus, and signs of granulomas and/or ulcerations on anoscopy (1,2). LGV can be an invasive, systemic infection, and if it is not treated early, LGV proctocolitis can lead to chronic colorectal fistulas and strictures (2). In Europe, outbreaks of LGV have been reported among men who have sex with men (MSM), often in association with human immunodeficiency virus (HIV) coinfection (3-5). The prevalence of LGV in the United States is unknown (1), because diagnostic tests to differentiate LGV from non-LGV Chlamydia trachomatis are not widely available (6), and providers might not know that they should report cases that are presumptively treated.

Putative calcium-binding domains of the Caenorhabditis elegans BK channel are dispensable for intoxication and ethanol activation

Alcohol modulates the highly conserved, voltage- and calcium-activated potassium (BK) channel, which contributes to alcohol-mediated behaviors in species from worms to humans. Previous studies have shown that the calcium-sensitive domains, RCK1 and the Ca(2+) bowl, are required for ethanol activation of the mammalian BK channel in vitro. In the nematode Caenorhabditis elegans, ethanol activates the BK channel in vivo, and deletion of the worm BK channel, SLO-1, confers strong resistance to intoxication. To determine if the conserved RCK1 and calcium bowl domains were also critical for intoxication and basal BK channel-dependent behaviors in C. elegans, we generated transgenic worms that express mutated SLO-1 channels predicted to have the RCK1, Ca(2+) bowl or both domains rendered insensitive to calcium. As expected, mutating these domains inhibited basal function of SLO-1 in vivo as neck and body curvature of these mutants mimicked that of the BK null mutant. Unexpectedly, however, mutating these domains singly or together in SLO-1 had no effect on intoxication in C. elegans. Consistent with these behavioral results, we found that ethanol activated the SLO-1 channel in vitro with or without these domains. By contrast, in agreement with previous in vitro findings, C. elegans harboring a human BK channel with mutated calcium-sensing domains displayed resistance to intoxication. Thus, for the worm SLO-1 channel, the putative calcium-sensitive domains are critical for basal in vivo function but unnecessary for in vivo ethanol action.

Clinician empathy is associated with differences in patient-clinician communication behaviors and higher medication self-efficacy in HIV care

OBJECTIVE

We examined associations of clinicians' empathy with patient-clinician communication behaviors, patients' rating of care, and medication self-efficacy.

METHODS

We analyzed 435 adult patients and 45 clinicians at four outpatient HIV care sites in the United States. Negative binomial regressions investigated associations between clinician empathy and patient-clinician communication, assessed using the Roter Interaction Analysis System (RIAS). Logistic regressions investigated associations between clinician empathy and patient ratings of clinician communication, overall satisfaction, and medication self-efficacy.

RESULTS

Clinicians in the highest vs. lowest empathy tertile engaged in less explicitly emotional talk (IRR 0.79, p<0.05), while clinicians in the middle vs. lowest engaged in more positive talk (IRR 1.31, p<0.05), more questions (IRR 1.42, p<0.05), and more patient activating talk (IRR 1.43, p<0.05). Patients of higher empathy clinicians disclosed more psychosocial and biomedical information. Patients of clinicians in both the middle and highest (vs. lowest) empathy tertiles had greater odds of reporting highest medication self-efficacy (OR 1.80, 95% CI 1.16-2.80; OR 2.13, 95% CI 1.37-3.32).

CONCLUSIONS

Clinician empathy may be expressed through addressing patient engagement in care, by fostering cognitive, rather than primarily emotional, processing.

PRACTICE IMPLICATIONS

Clinicians should consider enhancing their own empathic capacity, which may encourage patients' self-efficacy in medication adherence.

Respecting patients is associated with more patient-centered communication behaviors in clinical encounters

OBJECTIVE

Attitudes towards patients may influence how clinicians interact. We investigated whether respect for patients was associated with communication behaviors during HIV care encounters.

METHODS

We analyzed audio-recordings of visits between 413 adult HIV-infected patients and 45 primary HIV care providers. The independent variable was clinician-reported respect for the patient and outcomes were clinician and patient communication behaviors assessed by the Roter Interaction Analysis System (RIAS). We performed negative binomial regressions for counts outcomes and linear regressions for global outcomes.

RESULTS

When clinicians had higher respect for a patient, they engaged in more rapport-building, social chitchat, and positive talk. Patients of clinicians with higher respect for them engaged in more rapport-building, social chitchat, positive talk, and gave more psychosocial information. Encounters between patients and clinicians with higher respect for them had more positive clinician emotional tone [regression coefficient 2.97 (1.92-4.59)], more positive patient emotional tone [2.71 (1.75-4.21)], less clinician verbal dominance [0.81 (0.68-0.96)] and more patient-centeredness [1.28 (1.09-1.51)].

CONCLUSIONS

Respect is associated with positive and patient-centered communication behaviors during encounters.

PRACTICE IMPLICATIONS

Clinicians should be mindful of their respectful attitudes and work to foster positive regard for patients. Educators should consider methods to enhance trainees' respect in communication skills training.

The burrowing behavior of the nematode Caenorhabditis elegans: a new assay for the study of neuromuscular disorders

The nematode Caenorhabditis elegans has been a powerful model system for the study of key muscle genes relevant to human neuromuscular function and disorders. The behavioral robustness of C. elegans, however, has hindered its use in the study of certain neuromuscular disorders because many worm models of human disease show only subtle phenotypes while crawling. By contrast, in their natural habitat, C. elegans likely spends much of the time burrowing through the soil matrix. We developed a burrowing assay to challenge motor output by placing worms in agar-filled pipettes of increasing densities. We find that burrowing involves distinct kinematics and turning strategies from crawling that vary with the properties of the substrate. We show that mutants mimicking Duchenne muscular dystrophy by lacking a functional ortholog of the dystrophin protein, DYS-1, crawl normally but are severely impaired in burrowing. Muscular degeneration in the dys-1 mutant is hastened and exacerbated by burrowing, while wild type shows no such damage. To test whether neuromuscular integrity might be compensated genetically in the dys-1 mutant, we performed a genetic screen and isolated several suppressor mutants with proficient burrowing in a dys-1 mutant background. Further study of burrowing in C. elegans will enhance the study of diseases affecting neuromuscular integrity, and will provide insights into the natural behavior of this and other nematodes.