Paracoccidioides
MICROBIOLOGY
- Paracoccidioides species
- P. brasiliensis species complex:
- P. brasiliensis (also known as S1a and S1b)
- P. americana (PS2)
- P. restrepiensis (PS3)
- P. venezuelensis (PS4)
- P. lutzii
- P. brasiliensis species complex:
- Geographic distribution:
- Most cases occur in Brazil, but the range is as far north as Mexico.
- P. brasiliensis, P. americana (PS2) and P. lutzi: found across South America.
- P. restrepiensis and P. venezuelensis: found in Colombia and Venezuela respectively.
- Significant differences in annual incidence rates reported among Brazilian states (range 0.7 to 40 cases per 100,000 inhabitants)[2].
- Most cases occur in Brazil, but the range is as far north as Mexico.
- Ecological associations: Mostly in rural and peri-urban environments.
- Humid, rainy, forested areas near rivers
- Agricultural (especially coffee and tobacco crops)
- Armadillo hunting
- Large-scale construction projects (e.g., hydroelectric dams) that disturb soil.
- Morphology (dimorphic nature)
- Mycelium phase (mold): this is the form found in the environment and when samples are cultured at 25C. Hyphae and conidia.
- Yeast phase: This is the form found in tissues and body fluids and when samples are cultured at 37C
- Pathogenesis:
- Infectious propagules (conidia) produced by the environmental mycelium phase are inhaled by accidental hosts (humans and armadillos are the main ones).
- The transition from conidia to yeast phase occurs in the lungs.
- Most infected individuals will control infection with T cell-driven granuloma formation and will not develop clinical disease.
- Acute/subacute (“juvenile”) form: This occurs in children and young adults whose T cells responses are unable to control the infection.
- Occurs weeks to months after initial exposure.
- Chronic (“adult”) form: >80% of cases
- Quiescent fungus in granuloma that had previously been controlled becomes active long after the initial infection.
- Predisposing factors:
- Gender: The male to female ratio is ~22:1. One reason is that circulating estrogens inhibit the transformation of the aspirated conidia into yeast cells.
- Genetic variables: the presence of certain MHC antigens (HLA-A9, HLA-B13 and C4B*-Q0) and the IL12RB1 641AA genotype are associated with risk for developing the disease.
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Last updated: July 4, 2021
Citation
, Shmuel Shoham. "Paracoccidioides." Johns Hopkins ABX Guide, The Johns Hopkins University, 2021. Pediatrics Central, peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540737/all/Paracoccidioides.
S. Paracoccidioides. Johns Hopkins ABX Guide. The Johns Hopkins University; 2021. https://peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540737/all/Paracoccidioides. Accessed December 7, 2024.
, S. (2021). Paracoccidioides. In Johns Hopkins ABX Guide. The Johns Hopkins University. https://peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540737/all/Paracoccidioides
S. Paracoccidioides [Internet]. In: Johns Hopkins ABX Guide. The Johns Hopkins University; 2021. [cited 2024 December 07]. Available from: https://peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540737/all/Paracoccidioides.
* Article titles in AMA citation format should be in sentence-case
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