Coccidioidomycosis incidence in Arizona predicted by seasonal precipitation

James D. Tamerius, Andrew Comrie

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

The environmental mechanisms that determine the inter-annual and seasonal variability in incidence of coccidioidomycosis are unclear. In this study, we use Arizona coccidioidomycosis case data for 1995-2006 to generate a timeseries of monthly estimates of exposure rates in Maricopa County, AZ and Pima County, AZ. We reveal a seasonal autocorrelation structure for exposure rates in both Maricopa County and Pima County which indicates that exposure rates are strongly related from the fall to the spring. An abrupt end to this autocorrelation relationship occurs near the the onset of the summer precipitation season and increasing exposure rates related to the subsequent season. The identification of the autocorrelation structure enabled us to construct a "primary" exposure season that spans August-March and a "secondary" season that spans April-June which are then used in subsequent analyses. We show that October-December precipitation is positively associated with rates of exposure for the primary exposure season in both Maricopa County (R = 0.72, p = 0.012) and Pima County (R = 0.69, p = 0.019). In addition, exposure rates during the primary exposure seasons are negatively associated with concurrent precipitation in Maricopa (R = -0.79, p = 0.004) and Pima (R = -0.64, p = 0.019), possibly due to reduced spore dispersion. These associations enabled the generation of models to estimate exposure rates for the primary exposure season. The models explain 69% (p = 0.009) and 54% (p = 0.045) of the variance in the study period for Maricopa and Pima counties, respectively. We did not find any significant predictors for exposure rates during the secondary season. This study builds on previous studies examining the causes of temporal fluctuations in coccidioidomycosis, and corroborates the "grow and blow" hypothesis.

Original languageEnglish (US)
Article numbere21009
JournalPLoS One
Volume6
Issue number6
DOIs
StatePublished - 2011

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coccidioidomycosis
Coccidioidomycosis
Potassium Iodide
primary contact
incidence
Autocorrelation
Incidence
autocorrelation
Spores
spores
seasonal variation

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Coccidioidomycosis incidence in Arizona predicted by seasonal precipitation. / Tamerius, James D.; Comrie, Andrew.

In: PLoS One, Vol. 6, No. 6, e21009, 2011.

Research output: Contribution to journalArticle

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