Worldwide seasonal variation in search volume for cutaneous warts from 2004 to 2019

To the Editor: Several dermatologic conditions show seasonal variation, including visits for actinic keratosis, acne, and folliculitis.1Hancox J.G. Sheridan S.C. Feldman S.R. Fleischer A.B. Seasonal variation of disease in USA: a study office from 1990 to 1998.Int J Dermatol. 2004; 43: 6-11Crossref PubMed Scopus (66) Google Scholar In well-known case molluscum contagiosum, environmental behaviors that facilitate contact fomite viral transmission2Centers Disease Control PreventionMolluscum contagiosum: risk factors: who is at infection?.https://www.cdc.gov/poxvirus/molluscum-contagiosum/risk.htmlDate: 2018Date accessed: August 16, 2019Google may give rise clinically apparent seasonality. By analogy, human papillomavirus serotypes responsible cutaneous warts plausibly similar variation. Trends (https://trends.google.com/) publicly available resource presents monthly search volume data since 2004,3Carneiro H.A. Mylonakis E. trends: web-based tool real-time surveillance outbreaks.Clin Infect Dis. 2009; 49: 1557-1564Crossref (445) it has been used assess incidences various diseases.3Carneiro We an exploratory worldwide country-specific 2004 through 2018 “wart,” “genital wart” (GW), “molluscum contagiosum” (MC) topics.4Trends HelpCompare terms.https://support.google.com/trends/answer/4359550?hl=enDate normalizes time place origin reports relative index (SVI) scaled 0 100. Cross-correlation time-delay analyses were performed using R Stats Package, version 3.5.1 (R Core Team, Vienna, Austria). The MC wart series showed clear seasonality, with consistent 12-month period oscillation (Fig 1). Accordingly, cross-correlation between was high (r = 0.89). Graphically, components approximately biphasic, both more clearly than GW (Supplemental Fig 1, A-C; via Mendeley http://doi.org/10.17632/4wrt3rp3fh.2). Graphically seasonality present United States, Canada, Mexico, Spain, Kingdom, Netherlands, Poland, Ukraine, Russia, Japan, Australia, Argentina (and borderline Chile) but absent Romania, Iran, Kazakhstan, Philippines, Kenya, South Africa, Ecuador, Colombia, Peru, Brazil. Among countries displaying none data. Pairwise comparison major contributors by hemisphere (United Argentina, Australia) 2) phase inversion SVI oscillations across equator.Fig 2Country-specific topic northern (orange) southern (blue) hemispheres, 2019. Note noise reduction Australia after 2011 update Google's geographic assignment process. SVI, Search index.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Time-delay analysis maximum zero lag latitude-concordant pairs States/Japan, Argentina/Australia; r 0.88 0.56, respectively) 1 half-period latitude-discordant States/Argentina, Japan/Australia; 0.65). Whereas natural (weather) shows 6-month shift Northern Southern Hemispheres, these observations are underlying this analysis, SVIs warts—but not GW—showed marked yearly cyclic spanning several continents showing equatorial variability. These provide evidence suggestive global, ubiquitous, internet extragenital raise question corresponding epidemiologic Wart might arise independent incidence, behavioral trends skin exposure self-interest could influence knowledge-seeking abnormalities like warts. However, myriad factors also merit consideration as potential modulators activity transmissibility.5Dostrovsky A. Even-Paz Z. pathogenesis diseases.Arch 1961; 84: 750-758Crossref (2) Internet trend designs face unique challenges. Making inferences relevant complex difficult, we suggest such ours be considered directly representative only public information seeking. Additionally, precise compositions topics (unlike raw terms) available. Where share conceptual overlap, topics, represents inherent limitation use