Dietary Features Are Associated with Differences in the Urinary Microbiome in Clinically Healthy Adult Dogs.

Nutrition plays an important role in shaping the gut microbiome composition, although the impact of diet on the urinary microbiome (i.e., urobiome) remains unknown. The aim of this pilot study was to discover how nutritional features affect the diversity and composition of the urobiome in dogs. Dietary histories were obtained for 15 clinically healthy adult dogs, including limited nutrient (protein, fat, crude fiber), commercial diet brand, and dietary diversity profiles. The urine samples were collected via cystocentesis, followed by sequencing of the bacterial 16S rRNA gene. The data were analyzed to determine associations between major nutrients and dietary sources with the urobiome's composition. The protein, fat, and crude fiber contents had no statistically significant effect on the alpha or beta diversity. However, the beta diversity values differed (PERMANOVA; p = 0.017, R2 = 0.10) between dogs fed one commercial diet brand compared to dogs consuming any other brand. The beta diversity values also differed (p = 0.019, R2 = 0.10) between dogs consuming more diverse daily diets compared to those consuming less diverse diets (≥3 or <3 unique food sources, respectively). Overall, the results of this pilot study suggest that diet might impact the urobiome and support further exploration of the relationship between diet and the urobiome's composition in dogs.

Approaches to studying emotion using physiological responses to spoken narratives: A scoping review.

Narratives are effective tools for evoking emotions, and physiological measurements provide a means of objectively assessing emotional reactions - making them a potentially powerful pair of tools for studying emotional processes. However, extent research combining emotional narratives and physiological measurement varies widely in design and application, making it challenging to identify previous work, consolidate findings, and design effective experiments. Our scoping review explores the use of auditory emotional narratives and physiological measures in research, examining paradigms, study populations, and represented emotions. Following the PRISMA-ScR Checklist, we searched five databases for peer-reviewed experimental studies that used spoken narratives to induce emotion and reported autonomic physiological measures. Among 3466 titles screened and 653 articles reviewed, 110 studies were included. Our exploration revealed a variety of applications and experimental paradigms; emotional narratives paired with physiological measures have been used to study diverse topics and populations, including neurotypical and clinical groups. Although incomparable designs and sometimes contradictory results precluded general recommendations as regards which physiological measures to use when designing new studies, as a whole, the body of work suggests that these tools can be valuable to study emotions. Our review offers an overview of research employing narratives and physiological measures for emotion study, and highlights weaknesses in reporting practices and gaps in our knowledge concerning the robustness and specificity of physiological measures as indices of emotion. We discuss study design considerations and transparent reporting, to facilitate future using emotional narratives and physiological measures in studying emotions.

Integrated plant conservation through the Global Conservation Consortia.

The 2020 State of the World's Plants and Fungi report revealed that two in five plant species are threatened with extinction. Despite their diverse ecosystem services and myriad human uses, plants receive a fraction of the conservation resources directed at animal taxa. Several existing frameworks-including International Union for Conservation of Nature (IUCN) Specialist Groups, the American Public Gardens Association Plant Collections Network, and the Center for Plant Conservation National Collection of Endangered Plants-have spurred conservation action, but there remains an urgent need to scale up conservation efforts for the world's plants. Here, a new approach to coordinated conservation action for plant taxa is described: the Global Conservation Consortia (GCC). GCC catalyze institutions and experts to collaboratively develop and implement comprehensive strategies to prevent extinction of threatened plant groups. This review focuses on three tree-focused, U.S.-led consortia: cycads, magnolias, and oaks, but the GCC framework is applicable to other taxonomic groups. This review covers consortia design and implementation, provides conservation action case studies, and shares preliminary successes and challenges as this new and exciting approach to conservation is developed.

Overcoming boundaries: Interdisciplinary challenges and opportunities in cognitive neuroscience.

Cognitive neuroscience has considerable untapped potential to translate our understanding of brain function into applications that maintain, restore, or enhance human cognition. Complex, real-world phenomena encountered in daily life, professional contexts, and in the arts, can also be a rich source of information for better understanding cognition, which in turn can lead to advances in knowledge and health outcomes. Interdisciplinary work is needed for these bi-directional benefits to be realized. Our cognitive neuroscience team has been collaborating on several interdisciplinary projects: hardware and software development for brain stimulation, measuring human operator state in safety-critical robotics environments, and exploring emotional regulation in actors who perform traumatic narratives. Our approach is to study research questions of mutual interest in the contexts of domain-specific applications, using (and sometimes improving) the experimental tools and techniques of cognitive neuroscience. These interdisciplinary attempts are described as case studies in the present work to illustrate non-trivial challenges that come from working across traditional disciplinary boundaries. We reflect on how obstacles to interdisciplinary work can be overcome, with the goals of enriching our understanding of human cognition and amplifying the positive effects cognitive neuroscientists have on society and innovation.

A Novel CARMIL2 Immunodeficiency Identified in a Subset of Cavalier King Charles Spaniels with Pneumocystis and Bordetella Pneumonia.

Pet dogs are a valuable natural animal model for studying relationships between primary immunodeficiencies and susceptibility to Pneumocystis and other opportunistic respiratory pathogens. Certain breeds, such as the Cavalier King Charles Spaniel, are over-represented for Pneumocystis pneumonia (PCP), suggesting the presence of a primary immunodeficiency in the breed. Here, we report the discovery of a CARMIL2 nonsense variant in three Cavalier King Charles Spaniel dogs with either PCP (n = 2) or refractory Bordetella pneumonia (n = 1). CARMIL2 encodes a protein that plays critical roles in T-cell activation and other aspects of immune function. Deleterious CARMIL2 variants have recently been reported in human patients with PCP and other recurrent pneumonias. In addition to opportunistic respiratory infection, the affected dogs also exhibited other clinical manifestations of CARMIL2 deficiencies that have been reported in humans, including early-onset gastrointestinal disease, allergic skin disease, mucocutaneous lesions, abscesses, autoimmune disorders, and gastrointestinal parasitism. This discovery highlights the potential utility of a natural canine model in identifying and studying primary immunodeficiencies in patients affected by PCP.

The neurophysiology of closed-loop auditory stimulation in sleep: A magnetoencephalography study.

Closed-loop auditory stimulation (CLAS) is a brain modulation technique in which sounds are timed to enhance or disrupt endogenous neurophysiological events. CLAS of slow oscillation up-states in sleep is becoming a popular tool to study and enhance sleep's functions, as it increases slow oscillations, evokes sleep spindles and enhances memory consolidation of certain tasks. However, few studies have examined the specific neurophysiological mechanisms involved in CLAS, in part because of practical limitations to available tools. To evaluate evidence for possible models of how sound stimulation during brain up-states alters brain activity, we simultaneously recorded electro- and magnetoencephalography in human participants who received auditory stimulation across sleep stages. We conducted a series of analyses that test different models of pathways through which CLAS of slow oscillations may affect widespread neural activity that have been suggested in literature, using spatial information, timing and phase relationships in the source-localized magnetoencephalography data. The results suggest that auditory information reaches ventral frontal lobe areas via non-lemniscal pathways. From there, a slow oscillation is created and propagated. We demonstrate that while the state of excitability of tissue in auditory cortex and frontal ventral regions shows some synchrony with the electroencephalography (EEG)-recorded up-states that are commonly used for CLAS, it is the state of ventral frontal regions that is most critical for slow oscillation generation. Our findings advance models of how CLAS leads to enhancement of slow oscillations, sleep spindles and associated cognitive benefits and offer insight into how the effectiveness of brain stimulation techniques can be improved.

Horizontal Cleavage Tear Meniscal Repair Using All-Inside Circumferential Compression Sutures.

Horizontal cleavage meniscus tears occur more frequently in older patient populations with degenerative changes within the meniscus. Traditionally, they have been managed with nonsurgical interventions or with partial meniscectomy. As increasing evidence demonstrates the link between partial meniscectomy and progressive osteoarthritis with these types of tears, as well as worse long-term outcomes and reduced cost savings, surgical repair of horizontal cleavage meniscal tears has increased in appropriate patients. This technique article highlights the evaluation, indications, and preferred repair technique for horizontal cleavage tears in appropriately selected patients.

The impact of urine collection method on canine urinary microbiota detection: a cross-sectional study.

BACKGROUND: The urinary tract harbors unique microbial communities that play important roles in urogenital health and disease. Dogs naturally suffer from several of the same urological disorders as humans (e.g., urinary tract infections, neoplasia, urolithiasis) and represent a valuable translational model for studying the role of urinary microbiota in various disease states. Urine collection technique represents a critical component of urinary microbiota research study design. However, the impact of collection method on the characterization of the canine urinary microbiota remains unknown. Therefore, the objective of this study was to determine whether urine collection technique alters the microbial populations detected in canine urine samples. Urine was collected from asymptomatic dogs by both cystocentesis and midstream voiding. Microbial DNA was isolated from each sample and submitted for amplicon sequencing of the V4 region of the bacterial 16 S rRNA gene, followed by analyses to compare microbial diversity and composition between urine collection techniques. RESULTS: Samples collected via midstream voiding exhibited significantly higher sequence read counts (P = .036) and observed richness (P = .0024) than cystocentesis urine. Bray Curtis and Unweighted UniFrac measures of beta diversity showed distinct differences in microbial composition by collection method (P = .0050, R2 = 0.06 and P = .010, R2 = 0.07, respectively). Seven taxa were identified as differentially abundant between groups. Pasteurellaceae, Haemophilus, Friedmanniella, two variants of Streptococcus, and Fusobacterium were over-represented in voided urine, while a greater abundance of Burkholderia-Caballeronia-Paraburkholderia characterized cystocentesis samples. Analyses were performed at five thresholds for minimum sequence depth and using three data normalization strategies to validate results; patterns of alpha and beta diversity remained consistent regardless of minimum read count requirements or normalization method. CONCLUSION: Microbial composition differs in canine urine samples collected via cystocentesis as compared to those collected via midstream voiding. Future researchers should select a single urine collection method based on the biological question of interest when designing canine urinary microbiota studies. Additionally, the authors suggest caution when interpreting results across studies that did not utilize identical urine collection methods.

Harnessing the power of botanical gardens: Evaluating the costs and resources needed for exceptional plant conservation.

Premise: The effective ex situ conservation of exceptional plants, whether in living collections or cryo-collections, requires more resources than the conservation of other species. Because of their expertise with rare plants, botanical gardens are well positioned to lead this effort, but a well-developed strategy requires a clear understanding of the resources needed. Methods: Grant funding was obtained from the Institute of Museum and Library Services to support a three-year project on cryobanking, and to provide smaller grants to 10 other botanical gardens for one-year projects on either (1) seed behavior studies or (2) the development of protocols for in vitro propagation or cryopreservation. Results: Nine of the partner gardens worked on 19 species (one was unable to continue due to the COVID-19 pandemic), while the larger project focused on 14 species. A point system was developed for tasks accomplished, and the average costs per point of the larger and smaller projects were similar. Labor accounted for half the costs. Projects focused on species in the Asteraceae and Orchidaceae had lower costs per point than other species. Discussion: Both large and small projects can contribute to a strategy for exceptional plant conservation for similar costs. Prioritizing species with lower costs could help advance the field while allowing time for work on more difficult species to develop.

The Portiloop: A deep learning-based open science tool for closed-loop brain stimulation.

Closed-loop brain stimulation refers to capturing neurophysiological measures such as electroencephalography (EEG), quickly identifying neural events of interest, and producing auditory, magnetic or electrical stimulation so as to interact with brain processes precisely. It is a promising new method for fundamental neuroscience and perhaps for clinical applications such as restoring degraded memory function; however, existing tools are expensive, cumbersome, and offer limited experimental flexibility. In this article, we propose the Portiloop, a deep learning-based, portable and low-cost closed-loop stimulation system able to target specific brain oscillations. We first document open-hardware implementations that can be constructed from commercially available components. We also provide a fast, lightweight neural network model and an exploration algorithm that automatically optimizes the model hyperparameters to the desired brain oscillation. Finally, we validate the technology on a challenging test case of real-time sleep spindle detection, with results comparable to off-line expert performance on the Massive Online Data Annotation spindle dataset (MODA; group consensus). Software and plans are available to the community as an open science initiative to encourage further development and advance closed-loop neuroscience research [https://github.com/Portiloop].

Characterization of the urogenital microbiome in Miniature Schnauzers with and without calcium oxalate urolithiasis.

BACKGROUND: Calcium oxalate (CaOx) uroliths are common in dogs. Humans with CaOx urolithiasis exhibit alterations of the urinary and urogenital microbiomes that might mediate urolith formation. Detection of urogenital microbes associated with CaOx in dogs could inform disease pathophysiology. OBJECTIVE: To identify compositional differences in the urogenital microbiome of Miniature Schnauzers with and without CaOx uroliths. ANIMALS: Nineteen midstream, voided urine samples from Miniature Schnauzers with (n = 9) and without (n = 10) a history of CaOx urolithiasis. METHODS: Analytical cross-sectional study. Microbial DNA was extracted from previously frozen urine samples and sequenced for the bacterial 16S rRNA V3-V4 hypervariable regions. Diversity and composition of microbial populations were compared between urolith formers and controls. RESULTS: Alpha and beta diversity measures were similar between groups. Five individual bacterial taxa differed in abundance (indicator values >0.5 and P < .05): Acinetobacter, 2 Geobacillus variants, and Hydrogenophaga were overrepresented in the urine of urolith formers, and Sphingopyxis was overrepresented in controls. Two distinct subtypes of urine microbial composition were observed based on beta diversity measures, independent of urolith status, and other clinical variables. CONCLUSIONS AND CLINICAL IMPORTANCE: Although we did not detect a difference in the overall urogenital microbial composition between groups, observed differences in individual bacterial taxa might be clinically relevant. For example, Acinetobacter was overrepresented in urolith formers and is associated with CaOx urolithiasis in humans. Two unique clusters of the microbiome were identified, independent of urolith status, which may represent distinct urotypes present in Miniature Schnauzers.

Specificity of Affective Responses in Misophonia Depends on Trigger Identification.

Individuals with misophonia, a disorder involving extreme sound sensitivity, report significant anger, disgust, and anxiety in response to select but usually common sounds. While estimates of prevalence within certain populations such as college students have approached 20%, it is currently unknown what percentage of people experience misophonic responses to such "trigger" sounds. Furthermore, there is little understanding of the fundamental processes involved. In this study, we aimed to characterize the distribution of misophonic symptoms in a general population, as well as clarify whether the aversive emotional responses to trigger sounds are partly caused by acoustic salience of the sound itself, or by recognition of the sound. Using multi-talker babble as masking noise to decrease participants' ability to identify sounds, we assessed how identification of common trigger sounds related to subjective emotional responses in 300 adults who participated in an online study. Participants were asked to listen to and identify neutral, unpleasant and trigger sounds embedded in different levels of the masking noise (signal-to-noise ratios: -30, -20, -10, 0, +10 dB), and then to evaluate their subjective judgment of the sounds (pleasantness) and emotional reactions to them (anxiety, anger, and disgust). Using participants' scores on a scale quantifying misophonia sensitivity, we selected the top and bottom 20% scorers from the distribution to form a Most-Misophonic subgroup (N = 66) and Least-Misophonic subgroup (N = 68). Both groups were better at identifying triggers than unpleasant sounds, which themselves were identified better than neutral sounds. Both groups also recognized the aversiveness of the unpleasant and trigger sounds, yet for the Most-Misophonic group, there was a greater increase in subjective ratings of negative emotions once the sounds became identifiable, especially for trigger sounds. These results highlight the heightened salience of trigger sounds, but furthermore suggest that learning and higher-order evaluation of sounds play an important role in misophonia.

Sleep affects higher-level categorization of speech sounds, but not frequency encoding.

Sleep can increase consolidation of new knowledge and skills. It is less clear whether sleep plays a role in other aspects of experience-dependent neuroplasticity, which underlie important human capabilities such as spoken language processing. Theories of sensory learning differ in their predictions; some imply rapid learning at early sensory levels, while other propose a slow, progressive timecourse such that higher-level categorical representations guide immediate, novice learning, while lower-level sensory changes do not emerge until later stages. In this study, we investigated the role of sleep across both behavioural and physiological indices of auditory neuroplasticity. Forty healthy young human adults (23 female) who did not speak a tonal language participated in the study. They learned to categorize non-native Mandarin lexical tones using a sound-to-category training paradigm, and were then randomly assigned to a Nap or Wake condition. Polysomnographic data were recorded to quantify sleep during a 3 h afternoon nap opportunity, or equivalent period of quiet wakeful activity. Measures of behavioural performance accuracy revealed a significant improvement in learning the sound-to-category training paradigm between Nap and Wake groups. Conversely, a neural index of fine sound encoding fidelity of speech sounds known as the frequency-following response (FFR) suggested no change due to sleep, and a null model was supported, using Bayesian statistics. Together, these results support theories that propose a slow, progressive and hierarchical timecourse for sensory learning. Sleep's effect may play the biggest role in the higher-level learning, although contributions to more protracted processes of plasticity that exceed the study duration cannot be ruled out.

Sigma oscillations protect or reinstate motor memory depending on their temporal coordination with slow waves.

Targeted memory reactivation (TMR) during post-learning sleep is known to enhance motor memory consolidation but the underlying neurophysiological processes remain unclear. Here, we confirm the beneficial effect of auditory TMR on motor performance. At the neural level, TMR enhanced slow wave (SW) characteristics. Additionally, greater TMR-related phase-amplitude coupling between slow (0.5-2 Hz) and sigma (12-16 Hz) oscillations after the SW peak was related to higher TMR effect on performance. Importantly, sounds that were not associated to learning strengthened SW-sigma coupling at the SW trough. Moreover, the increase in sigma power nested in the trough of the potential evoked by the unassociated sounds was related to the TMR benefit. Altogether, our data suggest that, depending on their precise temporal coordination during post learning sleep, slow and sigma oscillations play a crucial role in either memory reinstatement or protection against irrelevant information; two processes that critically contribute to motor memory consolidation.

A scoping review of autoantibodies as biomarkers for canine autoimmune disease.

BACKGROUND: Autoantibody biomarkers are valuable tools used to diagnose and manage autoimmune diseases in dogs. However, prior publications have raised concerns over a lack of standardization and sufficient validation for the use of biomarkers in veterinary medicine. OBJECTIVES: Systematically compile primary research on autoantibody biomarkers for autoimmune disease in dogs, summarize their methodological features, and evaluate their quality; synthesize data supporting their use into a resource for veterinarians and researchers. ANIMALS: Not used. METHODS: Five indices were searched to identify studies for evaluation: PubMed, CAB Abstracts, Web of Science, Agricola, and SCOPUS. Two independent reviewers (AET and ELC) screened titles and abstracts for exclusion criteria followed by full-text review of remaining articles. Relevant studies were classified based on study objectives (biomarker, epitope, technique). Data on study characteristics and outcomes were synthesized in independent data tables for each classification. RESULTS: Ninety-two studies qualified for final analysis (n = 49 biomarker, n = 9 epitope, and n = 34 technique studies). A high degree of heterogeneity in study characteristics and outcomes reporting was observed. Opportunities to strengthen future studies could include: (1) routine use of negative controls, (2) power analyses to inform sample sizes, (3) statistical analyses when appropriate, and (4) multiple detection techniques to confirm results. CONCLUSIONS: These findings provide a resource that will allow veterinary clinicians to efficiently evaluate the evidence supporting the use of autoantibody biomarkers, along with the varied methodological approaches used in their development.

Target sequence capture in orchids: Developing a kit to sequence hundreds of single-copy loci.

PREMISE: Understanding relationships among orchid species and populations is of critical importance for orchid conservation. Target sequence capture has become a standard method for extracting hundreds of orthologous loci for phylogenomics. Up-front cost and time associated with design of bait sets makes this method prohibitively expensive for many researchers. Therefore, we designed a target capture kit to reliably sequence hundreds of orthologous loci across orchid lineages. METHODS: We designed an Orchidaceae target capture bait set for 963 single-copy genes identified in published orchid genome sequences. The bait set was tested on 28 orchid species, with representatives of the subfamilies Cypripedioideae, Orchidoideae, and Epidendroideae. RESULTS: Between 1,518,041 and 87,946,590 paired-end 150-base reads were generated for target-enriched genomic libraries. We assembled an average of 812 genes per library for Epidendroideae species and a mean of 501 genes for species in the subfamilies Orchidoideae and Cypripedioideae. Furthermore, libraries had on average 107 of the 254 genes that are included in the Angiosperms353 bait set, allowing for direct comparison of studies using either bait set. DISCUSSION: The Orchidaceae963 kit will enable greater accessibility and utility of next-generation sequencing for orchid systematics, population genetics, and identification in the illegal orchid trade.

Knowledge, attitudes, and practices regarding cervical cancer screening among women in metropolitan Lima, Peru: a cross-sectional study.

BACKGROUND: Cervical cancer is a leading cause of cancer deaths among women of reproductive age in Peru. Screening and early identification of pre-cancerous lesions are a cornerstone of the cervical cancer prevention strategy. Yet, there is limited literature on barriers to screening among Peruvian women. In this cross-sectional study, we aimed to examine Peruvian women's knowledge, attitudes, and practices regarding cervical cancer screening and identify possible reasons for the gap between knowledge and screening. METHODS: The study was conducted in metropolitan Lima from June-August 2019. We purposefully recruited 12 women who had previously been screened, and 12 who had never been screened for cervical cancer. The women completed a 40-question knowledge and attitude survey and an in-depth interview about barriers to screening. Descriptive analysis was used to calculate a knowledge and attitude score and qualitative analysis was guided by the Health Belief Model constructs. RESULTS: Previously screened participants had greater knowledge of cervical cancer symptoms, risk factors, and prevention (mean score = 28.08, S.D. = 4.18) compared to participants who had never been screened (mean score = 21.25, S.D. = 6.35). Both groups described lack of priority and embarrassment as barriers to cervical cancer screening. For participants who had never been screened before, major barriers included the fear of a cancer diagnosis and lack of information about screening services. Pregnancy, unusual gynecological symptoms and encouragement from friends and family were cues to action for participants seeking screening. Most participants in both groups recognized the benefits of getting screened for cervical cancer. Being previously screened increased participants' self-efficacy for engaging in screening behaviors again. Misconceptions regarding screening procedures and cervical cancer were also noted as barriers for participants accessing screening services. CONCLUSIONS: Improving knowledge and awareness about cervical cancer and screening programs may improve screening behaviors among women. Targeting women who have never been screened before and addressing their fears and concerns around embarrassment may be other areas for intervention. Misconceptions that deter women from screening services are an important issue that should be addressed in order to increase the number of women who get timely screenings.

Oscillatory Entrainment of the Frequency-following Response in Auditory Cortical and Subcortical Structures.

There is much debate about the existence and function of neural oscillatory mechanisms in the auditory system. The frequency-following response (FFR) is an index of neural periodicity encoding that can provide a vehicle to study entrainment in frequency ranges relevant to speech and music processing. Criteria for entrainment include the presence of poststimulus oscillations and phase alignment between stimulus and endogenous activity. To test the hypothesis of entrainment, in experiment 1 we collected FFR data for a repeated syllable using magnetoencephalography (MEG) and electroencephalography in 20 male and female human adults. We observed significant oscillatory activity after stimulus offset in auditory cortex and subcortical auditory nuclei, consistent with entrainment. In these structures, the FFR fundamental frequency converged from a lower value over 100 ms to the stimulus frequency, consistent with phase alignment, and diverged to a lower value after offset, consistent with relaxation to a preferred frequency. In experiment 2, we tested how transitions between stimulus frequencies affected the MEG FFR to a train of tone pairs in 30 people. We found that the FFR was affected by the frequency of the preceding tone for up to 40 ms at subcortical levels, and even longer durations at cortical levels. Our results suggest that oscillatory entrainment may be an integral part of periodic sound representation throughout the auditory neuraxis. The functional role of this mechanism is unknown, but it could serve as a fine-scale temporal predictor for frequency information, enhancing stability and reducing susceptibility to degradation that could be useful in real-life noisy environments.SIGNIFICANCE STATEMENT Neural oscillations are proposed to be a ubiquitous aspect of neural function, but their contribution to auditory encoding is not clear, particularly at higher frequencies associated with pitch encoding. In a magnetoencephalography experiment, we found converging evidence that the frequency-following response has an oscillatory component according to established criteria: poststimulus resonance, progressive entrainment of the neural frequency to the stimulus frequency, and relaxation toward the original state on stimulus offset. In a second experiment, we found that the frequency and amplitude of the frequency-following response to tones are affected by preceding stimuli. These findings support the contribution of intrinsic oscillations to the encoding of sound, and raise new questions about their functional roles, possibly including stabilization and low-level predictive coding.

X-linked CD40 ligand deficiency in a 1-year-old male Shih Tzu with secondary Pneumocystis pneumonia.

An approximately 1-year-old male intact Shih Tzu dog was referred to a tertiary facility with a history of progressive tachypnea, increased respiratory effort, and weight loss over a 3-month period that failed to improve with empirical antimicrobial treatment. Upon completion of a comprehensive respiratory evaluation, the dog was diagnosed with severe Pneumocystis pneumonia and secondary pulmonary hypertension. Clinical signs resolved and disease resolution was confirmed after completion of an 8-week course of trimethoprim-sulfonamide, 4-week tapering dose of prednisone to decrease an inflammatory response secondary to acute die-off of organisms, a 2-week course of clopidogrel to prevent clot formation, and a 2-week course of a phosphodiesterase-5 inhibitor to treat pulmonary hypertension. Immunodiagnostic testing and genetic sequencing were performed to evaluate for potential immunodeficiency as an underlying cause for the development Pneumocystis pneumonia, and identified an X-linked CD40 ligand deficiency.