Clinical and Molecular Epidemiology of Histoplasma capsulatum in Quebec, Canada
Bibliographic record
Abstract
Background. Histoplasma capsulatum (HC) comprises 8 phylogenetically distinct clades as defined by multilocus sequence typing (MLST). Limited animal data suggest that virulence of North American and Latin American strains of HC may differ, hypothetically accounting for unique clinical features observed in cohorts from different locations. Differential clinical disease has never been studied in patients with genotype-defined histoplasmosis. Methods. We conducted a retrospective cohort study including all culture-proven histoplasmosis cases from 4 university-affiliated hospitals in Quebec (Canada), between 1988 and 2013. HC isolates were genotyped using MLST. Demographic and clinical data were independently collected by chart review. Results. A total of 63 patients were included in this preliminary analysis. The median age was 42 years (range 21–81 years), and a majority of patients were male (n = 49, 77.8%). Forty-six (73.0%) patients were immunocompromised as a result of HIV infection (n = 28), solid organ transplantation (n = 8), rheumatologic disease (n = 6) or others (n = 4). Disseminated progressive histoplasmosis (DPH) was observed in 39 (61.9%) patients, while 16 (25.4%) and 5 (7.9%) patients presented with acute and chronic pulmonary forms, respectively. HC isolates were identified as North American 2 (NAm2), Latin American A (LAmA) and other clades in 31 (49.2%), 26 (41.3%) and 6 (9.5%) patients, respectively. Ten patients were born in South America, while 12 had reportedly traveled to this area. Patients infected with LAmA were younger (mean 40.2 versus 49.4 year-old; p = 0.02) and were more likely to be infected with HIV (17/26 versus 6/31; p = 0.005). There was a tendency towards an association between DPH and LAmA infection (p = 0.10). No significant differences were observed between NAm2 and LAmA infections with regards to clinical manifestations and outcomes (mortality, admission to intensive care unit and use of amphotericin B). Conclusion. We did not confirm distinct clinical features between NAm2 and LAmA histoplasmosis, although the study was underpowered to detect small differences. In our endemic region, a significant proportion of culture-proven histoplasmosis was not indigenous (travel- or immigration-associated). Disclosures. All authors: No reported disclosures.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".