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Cite Details

G. Chowell, E. Shim, F. Brauer, P. Diaz-Duenas, J. M. Hyman and C. Castillo-Chavez, "An epidemic model for Acute Hemorrhagic Conjunctivitis: Application to a 2003 outbreak in Mexico", Preprint: LA-UR-04-7961, 2005


We use a simple epidemic model that includes susceptible, infectious, reported, and recovered classes to model an outbreak of Acute Hemorrhagic Conjunctivitis (AHC). Our model considers the impact of under-reporting and behavior changes on the transmission rate and is applied to a recent epidemic of Acute Hemorrhagic Conjunctivitis in Mexico. Model parameters are estimated from a fit to the cumulative number of cases. Epidemi- ological parameters are in agreement with those derived from clinical studies. Our model predicts a “mean time from symptom onset to diagnosis” of 1.43 days (95% CI: 1 − 2.5) which is consistent with an estimate of 1.55 days (95% CI: 1.46 − 1.63) obtained using maximum likelihood methods on the distribution of the “times from symptom onset to diagnosis” of the clinical records of AHC cases reported during the epidemic. Our model predicts that the final epidemic size was under-reported by 38.68%. We estimate that a primary infectious case generates approximately 3 secondary cases (R0 = 2.64, SD 0.65). Furthermore, our model predicts a 36.36% reduction in the transmission rate due to be- havior changes which started to be effective 21.90 (SD 0.19) days after the first reported case. We explore the expected impact of how quickly interventions are implemented and estimate an approximate of 11 person-years of productivity losses from diagnosed cases. Our results are in agreement with current public health policy including informing the population about the presence of the outbreak as quickly as possible, instructing indi- viduals via press releases with public health information on how to avoid contagion, and encouraging infectious individuals to get diagnosed in hospital clinics.

BibTeX Entry

author = {G. Chowell and E. Shim and F. Brauer and P. Diaz-Duenas and J. M. Hyman and C. Castillo-Chavez},
title = {An epidemic model for Acute Hemorrhagic Conjunctivitis: Application to a 2003 outbreak in Mexico},
year = {2005},
urlpdf = {http://math.lanl.gov/~mac/papers/bio/CSBDHC05.pdf},
note = {Preprint: LA-UR-04-7961}