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Tracing histoplasmosis genomic epidemiology and species occurrence across the USA
Bernardo Guerra Tenório1, Daniel R Kollath2, Lalitha Gade3
1Faculty of Medicine, University of Brasília, Brasília, Brazil.
Abstract:
ABSTRACTHistoplasmosis is an endemic mycosis in North America frequently reported along the Ohio and Mississippi River Valleys, although autochthonous cases occur in non-endemic areas. In the United States, the disease is provoked by two genetically distinct clades of Histoplasma capsulatum sensu lato, Histoplasma mississippiense (Nam1) and H. ohiense (Nam2). To bridge the molecular epidemiological gap, we genotyped 93 Histoplasma isolates (62 novel genomes) including clinical, environmental, and veterinarian samples from a broader geographical range by whole-genome sequencing, followed by evolutionary and species niche modelling analyses. We show that histoplasmosis is caused by two major lineages, H. ohiense and H. mississippiense; with sporadic cases caused by H. suramericanum in California and Texas. While H. ohiense is prevalent in eastern states, H. mississipiense was found to be prevalent in the central and western portions of the United States, but also geographically overlapping in some areas suggesting that these species might co-occur. Species Niche Modelling revealed that H. ohiense thrives in places with warmer and drier conditions, while H. mississippiense is endemic to areas with cooler temperatures and more precipitation. In addition, we predicted multiple areas of secondary contact zones where the two species co-occur, potentially facilitating gene exchange and hybridization. This study provides the most comprehensive understanding of the genomic epidemiology of histoplasmosis in the USA and lays a blueprint for the study of invasive fungal diseases.
Insights
Histoplasmosis in the USA is caused by two main lineages, Histoplasma ohiense and Histoplasma mississippiense. Their geographical distribution and environmental preferences were mapped using genomic data, revealing potential for hybridization.
Area of Science:
- Mycology
- Genomic Epidemiology
- Infectious Diseases
Background:
- Histoplasmosis is an endemic mycosis in North America, primarily along the Ohio and Mississippi River Valleys.
- Two distinct clades of Histoplasma capsulatum sensu lato, Histoplasma mississippiense (Nam1) and H. ohiense (Nam2), cause disease in the United States.
- Understanding the molecular epidemiology and geographical distribution of these fungal lineages is crucial for public health.
Purpose of the Study:
- To bridge the molecular epidemiological gap of histoplasmosis in the USA.
- To genotype Histoplasma isolates from a broad geographical range using whole-genome sequencing.
- To analyze evolutionary relationships and model species niches for accurate disease mapping.
Main Methods:
- Whole-genome sequencing of 93 Histoplasma isolates (62 novel genomes) from clinical, environmental, and veterinary sources.
- Evolutionary analyses to determine phylogenetic relationships between isolates.
- Species Niche Modelling to predict habitat preferences and distribution patterns.
Main Results:
- Histoplasmosis is caused by two major lineages: H. ohiense (prevalent in eastern states) and H. mississippiense (prevalent in central and western US).
- Sporadic cases are linked to H. suramericanum in California and Texas.
- H. ohiense prefers warmer, drier conditions, while H. mississippiense thrives in cooler, wetter environments, with overlapping zones identified.
Conclusions:
- This study provides the most comprehensive genomic epidemiology of histoplasmosis in the USA.
- Identified distinct geographical distributions and niche preferences for H. ohiense and H. mississippiense.
- Predicted secondary contact zones suggest potential for gene exchange and hybridization, impacting future disease dynamics.
