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. 2018 Jan 22;12(1):e0006174.
doi: 10.1371/journal.pntd.0006174. eCollection 2018 Jan.

Molecular detection of airborne Emergomyces africanus, a thermally dimorphic fungal pathogen, in Cape Town, South Africa

Ilan S Schwartz  1   2 , Josh D McLoud  3 , Dilys Berman  4 , Alfred Botha  5 , Barbra Lerm  5 , Robert Colebunders  2 , Estelle Levetin  3 , Chris Kenyon  6
Affiliations

Molecular detection of airborne Emergomyces africanus, a thermally dimorphic fungal pathogen, in Cape Town, South Africa

Ilan S Schwartz et al. PLoS Negl Trop Dis. .

Erratum in

Abstract

Emergomyces africanus is a thermally dimorphic fungus that causes a systemic mycosis in immunocompromised persons in South Africa. Infection is presumed to follow inhalation of airborne propagules. We developed a quantitative PCR protocol able to detect as few as 5 Es. africanus propagules per day. Samples were collected in Cape Town, South Africa over 50 weeks by a Burkard spore trap with an alternate orifice. We detected Es. africanus in air samples from 34 days (10%) distributed over 11 weeks. These results suggest environmental exposure to airborne Es. africanus propagules occurs more commonly in endemic areas than previously appreciated.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Standard curves from the amplification of 10-fold dilutions of ITS and β-tubulin amplicons.
These curves showed a linear relationship across the whole range (ITS, R2 = 0.99 and β-TUB, R2 = 0.98), between the log10 value of the amplicon concentrations and the threshold cycles. The high coefficient of determination indicated low intra-assay variability. The dotted lines are the 95% CI of the coefficient of determination, which show that there is no significant difference between the 2 standard curves used to generate the mean target copy number per genome.
Fig 2
Fig 2. Standard curve for the SepRef (cuttlefish) inhibition assay (R2 = 0.98).
Fig 3
Fig 3. Mean ITS target number of quantifiable weekly and daily air samples for Es. africanus fit on the standard curve.
Note: Five standards were used to generate the standard curve; however, only three standards are shown in these figures to increase the visibility and separation of the test samples. A) Weekly air samples B) Daily air samples.
Fig 4
Fig 4. Weather conditions in relation to the detection of airborne propagules of Es. africanus.
The number of days per week in which Es. africanus was detected using qPCR is plotted against (A) weekly mean maximum and minimum temperature, (B) wind speed (C) rainfall, and (D) all variables.
See this image and copyright information in PMC

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