Behseta, S

Talamantes, J

Zender, CS

eScholarship - University of California

UC IrvineUC Irvine Previously Published WorksTitleDoes climate control valley fever incidence in California?Permalinkhttps://escholarship.org/uc/item/4w91v1gsAuthorsZender, CSTalamantes, JBehseta, SPublication Date2007-12-01 Peer reviewedeScholarship.org Powered by the California Digital LibraryUniversity of CaliforniaDoes Climate Control Valley Fever Incidence inCalifornia?Charlie Zender1, Jorge Talamantes2, and Sam Behseta31Department of Earth System Science, University of California, Irvine2Department of Physics and Geology, California State University, Bakersfield3Department of Mathmatics, California State University, BakersfieldContributions from:F. Beltran (CSUB), E. Chaput (KCDPH), K. Emery (KCDPH),T. Larwood, R. Reynolds (USGS), S. Sebesta (CDHS), U. Urbina (CSUB)Presented to: American Meteorological Society 2007 Annual Meeting, San Antonio TX(Web: http://dust.ess.uci.edu/smn/smn ccd ams 200701.pdf)Figure 1: Lifecycle of coccidioidomycosis (CourtesyKent Kuehl, Bakersfield Californian)Valley fever (coccidioidomyco-sis, or “cocci”) caused by C. im-mitis, a fungus which• has two lifecycle phases– Saprophytic– Parasitic• is dislodged from soils bymechanical disturbancesMultiple climate connections:1. C. immitis blooms in moistconditions2. C. immitis is drought-tolerant3. VF infection vector is wind-borne dustFigure 2: Endemic regions of coccidioidomycosisEndemic regions:• Only in the Americas• Found, Argentina 1892• Found, San Francisco 1894• Isolated, San Joaquin Val-ley 1930sToll on Kern County:• Incidence N0 = 500 [# yr−1],N = 85 [# yr−1 (100,000)−1](about 0.1 % yr−1)• Dissemination ∼ 5%• Death ∼ 1%• Economic cost $5–25 M yr−1(Pappagianis, 1988; Jinadu,1995; Barnato et al., 2001)1960 1970 1980 1990 2000010020030040050060070080090010001100N (# year -1  100, 000-1)0500100015002000250030003500N0 (# year-1)Figure 3: Annual incidence N [# yr−1 (100,000)−1] (solid line) and total number of reported cases N0 [# yr−1](dashed line) of valley fever in Kern County from 1960–2002 (Zender and Talamantes, 2006).1. MethodsPrevious studies demonstrate strong climate-incidence links in AZ:1. Kolivras and Comrie (2003): Antecedent Precipitation P and surfacetemperature explain up to 50% incidence anomalies2. Komatsu et al. (2003): Cumulative 7-month P explains up to 75% ofmonthly 1998–2001 incidence3. Comrie (2005): Previous summer P and current PM10 explains up to80% of 1992–2003 incidenceWe examine wind, precipitation, temperature links to CA incidence:1. Test autoregression-corrected monthly incidence anomalies for signifi-cant lag correlations with wind U , precipitation P , and temperature Tanomalies (Zender and Talamantes, 2006)2. Use Generalized Auto Regressive Moving Average (GARMA) tech-nique to construct predictive models based on antecedent incidence,climate, and both (Talamantes et al., 2007)             02040N__ (# month-1100, 000-1) (a)             0204060P (mmmonth-1)(b)             234U (m s-1 ) (c)             280290300310T (K) (d)J F M A M J J A S O N D J99610001004p s (mb)(e)Figure 4: Annual cycle of coccidioidomycosis incidence and potential climate risk factors from 1980–2002.Shown are monthly mean (a) incidence N̄ [# mo−1 (100,000)−1] (b) precipitation P̄ [mm mo−1], (c) windspeed Ū [m s−1], (d) surface temperature T̄s [K], (e) surface pressure p̄s [mb] (Zender and Talamantes, 2006).0 6 12 18 24Months by which Environmental Factor Leads Incidence-0.2-0.10.00.10.2Correlation Coefficient rTs*U*P*P*ps*ps*0 6 12 18 24Months by which Precipitation Leads Incidence-0.4-0.20.00.20.4Correlation Coefficient rABDCEFGFigure 5: (a) Lag correlation coefficient r between valley fever incidence anomaly N∗ and climate anomaliesP ∗, U∗, T ∗s , and p∗s . Plusses (+) and squares () indicate confidence statistics p better than 5% and 1%,respectively. (b) Lag correlation of N∗ and P ∗ for seven different periods bracketing the 1991-1995 epidemic(Zender and Talamantes, 2006).Results:1. Valley fever incidence is highly significantly (p < 0.01) correlated (r =0.04) with precipitation nine months earlier (i.e., previous wet season)2. Climate anomalies explain < 5% of VF incidence anomaliesFigure 6: Reported weekly valley fever incidence (new cases per 100,000 population) in Kern County, Cali-fornia (solid lines) from Jan. 1996 to Dec. 2003 and three GARMA models: (a) full model, (b) prior incidencemodel, and (c) environmental model (Talamantes et al., 2007).1. Incidence 1, 2, 4, and 26 weeks prior skillfully predicts N2. Prior weather adds negligible skill to VF prediction2. ConclusionsKern County California valley fever results:• Climate does not (directly) control VF in Kern County• Valley fever incidence is highly significantly (p < 0.01) correlated withprevious wet season precipitation• Climate anomalies explain < 5% of VF incidence anomalies• Prior incidence is best known VF predictorAttribution of Kern County VF anomalies:• 1991-1995 epidemic and 2001–present surge consistent with non-climaticcauses, e.g., anthropogenic activities such as excavationFuture Work:• Examine other predictors (e.g., PM10, cumulative rainfall)• Apply techniques to understand AZ/CA differences3. ReferencesReferencesBarnato, A. E., G. D. Sanders, and D. K. Owens (2001), Cost-effectivenessof a potential vaccine for Coccidioides immitis, Emerging Infectious Dis-eases, 7(5), 797–806.Comrie, A. C. (2005), Climate factors influencing Coccidioidomycosis sea-sonality and outbreaks, Environmental Health Perspectives, 113(6), 688–692, doi:10.1289/ehp.7786.Jinadu, B. A. (1995), Valley Fever Task Force report on the control of Coc-cidioides immitis, Tech. rep., Kern County Health Department, Bakers-field, CA.Kolivras, K. N., and A. C. Comrie (2003), Modeling valley fever (coccid-ioidomycosis) incidence on the basis of climate conditions, Int. J. Biome-teorol., 47, 87–101, doi:10.1007/s00,484–002–0155–x.Komatsu, K., et al. (2003), Increase in coccidioidomycosis — Arizona,1998–2001, Morbidity and Mortality Weekly Report, 52(6), 109–112.Pappagianis, D. (1988), Epidemiology of coccidioidomycosis, in Currenttopics in medical mycology, vol. 2, edited by M. McGinnis, pp. 199–238,Springer Verlag, New York, New York.Talamantes, J., S. Behseta, and C. S. Zender (2007), Statistical modeling ofvalley fever data in Kern County, California, In Press in Int. J. Biometeo-rol.Zender, C. S., and J. Talamantes (2006), Environmental factors controllingvalley fever incidence in Kern County, California, Int. J. Biometeorol.,50(3), 174–182, doi:10.1007/s00,484–005–0007–6.

Does climate control valley fever incidence in California?

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