Frédérique Retornaz

Dogs can detect volatile organic compounds (VOCs) associated with infectious diseases, but their ability to distinguish between symptomatic and asymptomatic SARS-CoV-2 infections has not been fully established. In this exploratory proof-of-concept study with a limited number of dogs, eight non-working dogs (without experience in scent detection) began training with either symptomatic or asymptomatic Delta samples; seven reached the testing phase and were then evaluated on the alternate group to assess cross-generalization. Training initially used a yes/no protocol but was adapted to a line-up design after poor performance. When presented with novel Delta samples from the other category, dogs significantly discriminated them from controls, achieving a mean sensitivity of 71% and a specificity of 51%, with no difference between training groups. In contrast, performance dropped when dogs were tested with a small number of asymptomatic Omicron-positive samples from vaccinated individuals, with a mean sensitivity of 35% and a specificity of 55%. Dogs can thus generalize across symptomatic and asymptomatic COVID-19 cases for the Delta variant; performance decreased for Omicron samples, likely due to altered VOC profiles in vaccinated individuals. While proof-of-concept feasibility was demonstrated with a line-up protocol for detecting asymptomatic scent, detection dogs should not currently be recommended for large-scale screening; the findings underscore the need for standardized protocols and variant-specific retraining.

Dogs can detect volatile organic compounds (VOCs) associated with infectious diseases, but their ability to distinguish between symptomatic and asymptomatic SARS-CoV-2 infections has not been fully established. In this study, eight naïve dogs began training with either symptomatic or asymptomatic Delta samples; seven reached the testing phase and were then evaluated on the alternate group to assess cross-generalization. Training initially used a yes/no protocol but was adapted to a line-up design after poor performance. When presented with novel Delta samples, dogs significantly discriminated them from controls, achieving a mean sensitivity of 71% and specificity of 51%, with no difference between training groups. In contrast, performance dropped when dogs were tested with asymptomatic Omicron samples from vaccinated individuals, with a mean sensitivity of 55%. These results show that dogs can generalize across symptomatic and asymptomatic COVID-19 cases for the Delta variant but fail to detect Omicron reliably, likely due to altered VOC profiles in vaccinated individuals. While proof-of-concept feasibility was demonstrated with a line up protocol for detecting asymptomatic scent, detection dogs should not currently be recommended for large-scale screening, but findings underscore the need for standardized protocols and variant-specific retraining.

INTRODUCTION: Breath testing has become a widely used tool to diagnose small intestinal bacterial overgrowths (SIBOs) and intestinal methanogen overgrowths (IMOs) in clinical settings. Owing to the heterogeneity in clinical manifestations and lack of standardization among centers performing breath testing, SIBO and IMO can be easily overlooked by the clinician. We studied the prevalence and symptoms of SIBO/IMO in French patients referred for breath testing after seeking medical advice. METHODS: Breath test data and symptoms of 331 patients were assessed for SIBO/IMO using the H₂/CH₄ lactulose breath test (LBT). Wilcoxon test or χ² test were used to compare patients with SIBO/IMO with patients without SIBO/IMO. LBT positive patients (H₂+, CH₄+, and CH₄+/H₂+) were compared using Kruskal-Wallis test for continuous data or χ² test for categorical data. RESULTS: Among the 186 (68.1%) patients tested positive for an overgrowth with 40.3%, 47.3%, and 12.4% for H₂+, CH₄+ and CH₄+/H₂+, respectively, the presence of diarrhea was significantly increased in hydrogen type overgrowths (P < 0.001). No significant difference according to age, gender, and symptoms was associated with a positive test except for joint pain that was less prevalent among LBT positive patients (P = 0.038). In 86.5% of IMOs, positivity with CH₄ values ≥10 ppm could be identified at baseline. DISCUSSION: There are little discriminating symptoms that can help the clinician to identify patients likely to have a SIBO/IMO. However, SIBO/IMOs remain a common disorder widely underdiagnosed that need further studies to better apprehend functional bowel disorders.

Background: Patients with long-COVID often complain of continuous fatigue, myalgia, sleep problems, cognitive dysfunction, and post-exertional malaise. No data are available on EMG recording of evoked myopotentials (M-waves) or exercise-induced alterations in long-COVID patients, providing evidence of muscle membrane fatigue. Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) develops in more than half of patients after an infectious disease, particularly viral diseases. A large proportion (around 70%) of these patients have neuromuscular disorders with M-wave alterations during and after exercise. Our hypothesis was that M-wave alterations would be also found in long-COVID patients, in association with neuromuscular symptoms, similar to ME/CFS. Methods: This retrospective observational ColGEM (Covid LonG Encéphalomyelite Myalgique) study compared 59 patients with long-COVID and 55 ME/CFS patients with a history of severe infection who presented before the COVID pandemic. All of these patients underwent the same protocol consisting of a questionnaire focusing on neural and neuromuscular disorders and M-wave recording in the rectus femoris muscle before, during, and 10 min after a progressive cycling exercise. Maximal handgrip strength (MHGS) and maximal exercise power were also measured. The frequency of symptoms and magnitude of M-wave changes in the two groups were compared using non-parametric and parametric tests. Results: The frequency of fatigue, myalgia, sleep problems, cognitive dysfunction, and post-exertional malaise as well as the magnitude of exercise-induced M-wave alterations were the same in the two groups. By contrast, digestive problems were less present in long-COVID. M-wave alterations were greater in ME/CFS patients as in those with long-COVID when the highest muscle strength and highest exercise performance were measured. Conclusions: These high clinical and biological similarities between long-COVID and ME/CFS support the hypothesis that SARS-Cov-2 infection can cause ME/CFS symptoms. Trial registration Registered retrospectively.

Background: Identifying a specific threshold level of SARS-CoV-2 antibodies that confers protection in immunocompromised patients has been very challenging. The aim was to assess the threshold of 264 binding antibody units (BAU)/ml using four different SARS-CoV-2 antibody assays (Abbott, Beckman, Roche, and Siemens) and to establish a new optimal threshold of protection for each of the four antibody assays. Methods: This study was performed on data retrieved from 69 individuals, who received at least one dose of the Pfizer/BioNTech BNT162b2 or Moderna COVID-19 vaccine (Spikevax) at the Alphabio Laboratory in Marseille, France (European Hospital, Alphabio – Biogroup). The results were compared to the percent inhibition calculated using a functional surrogate of a standardized virus neutralization test (Genscript). Results: Samples from 69 patients were analyzed. For a reference cutoff of 264 BAU/ml, assays showed moderate to good overall concordance with Genscript: 87% concordance for Abbott, 78% for Beckman, 75% for Roche, and 88% for Siemens. Overall concordance increased consistently after applying new thresholds, i.e., 148 BAU/ml (Abbott), 48 (Beckman), 559 (Roche), and 270 (Siemens). Conclusion: We suggest specific adjusted thresholds (BAU/ml) for the four commercial antibody assays that are used to assess pre-exposure prophylaxis in immunocompromised patients.

Mastocytosis is an orphan disease associated with many systemic symptoms, chronic handicap, and potentially marked social consequences despite improved therapies. In this study, the authors aimed to measure the effect of 2 hypnosis sessions on mastocytosis symptoms in a clinical setting. Questionnaires (pain, flushes, energy, digestive symptoms, quality of life, perceived symptom severity, and global impression of change) were completed pre- and posthypnosis intervention. Data from 20 patients were analyzed (mean age: 53.3 years, 75% female). Compared to baseline assessment, patients exhibited a significant improvement immediately after the first and second hypnosis sessions with regard to the number of days with abdominal pain, abdominal pain intensity and fatigue (p = .03 and p = .005; p = .05 and p = .02; p = .034, and p = .039, respectively). Perceived severity of symptoms was significantly improved throughout the study (p = .0075). Long-term improvement in global impression of change was observed in half the responders (8/16). Patients with mastocytosis had an improvement in disabling symptoms with the impact of hypnotic intervention persisting at 1 month. Several patients experienced long-term improvement.

In order to assess the ability of older patient with Colorectal Cancer (CRC) to receive chemotherapy, a Comprehensive Geriatric Assessment (CGA) is recommended before the final therapeutic decision.