Histoplasmosis in Rats and Skunks in Georgia

Cw, Emmons; Hb, Morlan; El, Hill

doi:10.2307/4587147

Cited by 36 publications

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“…Among 13 isolates of NAm Hcc2, 10 genotypes were found, which were very homogeneous with a maximum diversity of 0.38% nucleotide substitutions per nucleotide (Table 4). Isolate H79, taken from a striped skunk in the 1940s (27), grouped with the four NAm Hcc1 isolates, from which it differed by a single T-C transition in 1,577 bp of sequence. H79 is therefore the first nonhuman NAm Hcc1 isolate and predates by 20 years what had been thought to be the initial class 1 isolate, the Downs strain (33).…”

Section: Resultsmentioning

confidence: 99%

Phylogenetic Relationships of Varieties and Geographical Groups of the Human Pathogenic Fungus Histoplasma capsulatum Darling

1999

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The phylogeny of 46 geographically diverse Histoplasma capsulatum isolates representing the three varietiescapsulatum, duboisii, andfarciminosum was evaluated using partial DNA sequences of four protein coding genes. Parsimony and distance analysis of the separate genes were generally congruent and analysis of the combined data identified six clades: (i) class 1 North AmericanH. capsulatum var. capsulatum, (ii) class 2 North American H. capsulatum var.capsulatum, (iii) Central American H. capsulatum var. capsulatum, (iv) South American H. capsulatum var.capsulatum group A, (v) South American H. capsulatum var. capsulatum group B, and (vi)H. capsulatum var. duboisii. Although the clades were generally well supported, the relationships among them were not resolved and the nearest outgroups (Blastomyces andParacoccidioides) were too distant to unequivocally root the H. capsulatum tree. H. capsulatum var. farciminosum was found within the South American H. capsulatum var.capsulatum group A clade. With the exception of the South American H. capsulatum var. capsulatumgroup A clade, genetic distances within clades were an order of magnitude lower than those between clades, and each clade was supported by a number of shared derived nucleotide substitutions, leading to the conclusion that each clade was genetically isolated from the others. Under a phylogenetic species concept based on possession of multiple shared derived characters, as well as concordance of four gene genealogies, H. capsulatum could be considered to harbor six species instead of three varieties.

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Section: Resultsmentioning

confidence: 99%

Phylogenetic Relationships of Varieties and Geographical Groups of the Human Pathogenic Fungus Histoplasma capsulatum Darling

1999

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“…The dramatic increase in recovery of NAm 1 individuals correlated with the AIDS pandemic provides support for this idea. Prior to the pandemic, which began in the early 1980s, NAm 2 was predominant and NAm 1 was represented by only two individuals, H9 [Downs, obtained in 1968 from an 86‐year‐old woman (Gass & Kobayashi 1969)] and H79 [obtained from a striped skunk in the 1940s (Emmons et al . 1949)].…”

Section: Discussionmentioning

confidence: 99%

Phylogeography of the fungal pathogenHistoplasma capsulatum

White²,

et al. 2003

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Until recently, Histoplasma capsulatum was believed to harbour three varieties, var. capsulatum (chiefly a New World human pathogen), var. duboisii (an African human pathogen) and var. farciminosum (an Old World horse pathogen), which varied in clinical manifestations and geographical distribution. We analysed the phylogenetic relationships of 137 individuals representing the three varieties from six continents using DNA sequence variation in four independent protein-coding genes. At least eight clades were idengified: (i) North American class 1 clade; (ii) North American class 2 clade; (iii) Latin American group A clade; (iv) Latin American group B clade; (v) Australian clade; (vi) Netherlands (Indonesian?) clade; (vii) Eurasian clade and (viii) African clade. Seven of eight clades represented genetically isolated groups that may be recognized as phylogenetic species. The sole exception was the Eurasian clade which originated from within the Latin American group A clade. The phylogenetic relationships among the clades made a star phylogeny. Histoplasma capsulatum var. capsulatum individuals were found in all eight clades. The African clade included all of the H. capsulatum var. duboisii individuals as well as individuals of the other two varieties. The 13 individuals of var. farciminosum were distributed among three phylogenetic species. These findings suggest that the three varieties of Histoplasma are phylogenetically meaningless. Instead we have to recognize the existence of genetically distinct geographical populations or phylogenetic species. Combining DNA substitution rates of protein-coding genes with the phylogeny suggests that the radiation of Histoplasma started between 3 and 13 million years ago in Latin America.

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“…In Kenya, H. capsulatum has been isolated from soil, including samples enriched with chicken and bat faeces [55][56][57]. Although evidence exists for the role of rats as environmental reservoirs, current literature is limited to North America, where H. capsulatum was identified in wild rats and soil samples proximal to rat burrows [26,58,59]. Additional research is warranted in the community setting in western Kenya to explore any associations between H. capsulatum exposure and the following variables: frequency and routes of human exposure to rats and their habitats, the location of rat burrows, isolation of H. capsulatum from rats and rat burrows, and the household and environmental factors maintaining rat populations.…”

Section: Plos Neglected Tropical Diseasesmentioning

confidence: 99%

Evidence of Histoplasma capsulatum seropositivity and exploration of risk factors for exposure in Busia county, western Kenya: Analysis of the PAZ dataset

et al. 2023

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Background Despite recognition of histoplasmosis as a disease of national public health concern in Kenya, the burden of Histoplasma capsulatum in the general population remains unknown. This study examined the human seroprevalence of anti-Histoplasma antibody and explored associations between seropositivity and demographic and environmental variables, in Busia county, western Kenya. Methodology Biobanked serum samples and associated data, from a previous cross-sectional survey, were examined. Latex agglutination tests to detect the presence of anti-Histoplasma antibody were performed on serum samples from 670 survey respondents, representing 178 households within 102 sub-locations. Potential epidemiologic risk factors for H. capsulatum exposure were explored using multi-level multivariable logistic regression analysis with household and sub-location included as random effects. Principal findings The apparent sample seroprevalence of anti-Histoplasma antibody was 15.5% (n = 104/670, 95% Confidence Interval (CI) 12.9–18.5%). A multivariable logistic regression model identified increased odds of H. capsulatum seropositivity in respondents reporting rats within the household within the previous 12 months (OR = 2.99 90% CI 1.04–8.55, p = 0.04). Compared to respondents aged 25–34 years, the odds of seropositivity were higher in respondents aged 15–24 years (OR = 2.70 90% CI 1.04–6.97, p = 0.04). Conclusions The seroprevalence result provides a baseline for sample size approximations for future epidemiologic studies of the burden of H. capsulatum exposure in Busia county. The final model explored theoretically plausible risk factors for H. capsulatum exposure in the region. A number of factors may contribute to the complex epidemiological picture impacting H. capsulatum exposure status at the human-animal-environment interface in western Kenya. Focussed H. capsulatum research is warranted to determine the contextual significance of identified associations, and in representative sample populations.

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Histoplasmosis in Rats and Skunks in Georgia

Cited by 36 publications

References 0 publications

Phylogenetic Relationships of Varieties and Geographical Groups of the Human Pathogenic Fungus Histoplasma capsulatum Darling

Phylogenetic Relationships of Varieties and Geographical Groups of the Human Pathogenic Fungus Histoplasma capsulatum Darling

Phylogeography of the fungal pathogenHistoplasma capsulatum

Evidence of Histoplasma capsulatum seropositivity and exploration of risk factors for exposure in Busia county, western Kenya: Analysis of the PAZ dataset

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