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Volume 22, Number 11—November 2016
Research

Epidemiology of La Crosse Virus Emergence, Appalachia Region, United States

Sharon BewickComments to Author , Folashade Agusto, Justin M. Calabrese, Ephantus J. Muturi, and William F. Fagan
Author affiliations: University of Maryland, College Park, Maryland, USA (S. Bewick, W.F. Fagan); University of Kansas, Lawrence, Kansas, USA (F. Agusto); Smithsonian Conservation Biology Institute, Front Royal, Virginia, USA (J.M. Calabrese); Illinois Natural History Survey, Champaign, Illinois, USA (E.J. Muturi)

Main Article

Table

Summary statistics for epidemiologic metrics of LACV, based on Latin hypercube sampling analysis of the full dynamic model*

Variable Tree-hole model Tiger model Tree-hole/tiger model†
Parameter sets with LACV persistence, %
46
0.20
24
End-of-season host seroprevalence rate, %
Mean 89 79 84
Median 99 88 97
Maximum
100
100
100
Midseason host seroprevalence rate, %
Mean 65 12 18
Median 74 8.9 12
Maximum
100
38
98
Peak no. infected mosquitoes, per hectare
Mean 32 58 23
Median 22 50 16
Maximum
331
200
222
Peak mosquito infection rate, %
Mean 4.5 1.6 1.9
Median 3.5 1.5 1.3
Maximum
27
5.3
15
Average mosquito infection rate, %
Mean 2.0 0.44 0.80
Median 1.6 0.33 0.57
Maximum
13
1.8
6.8
Maximum human transmission, infections per month per person per hectare
Mean 15 59 14
Median 8.6 40 7.9
Maximum
251
247
221
Timing of peak human transmission
Mean Aug 14 Sep 21 Aug 23
Median Aug 10 Sep 28 Aug 21
Earliest Jun 21 Aug 26 Jun 26
Latest
Sep 30‡
Sep 30‡
Sep 30‡
End-of-season egg infection rates, %
Mean 0.63 0.08 0.28
Median 0.49 0.07 0.20
Maximum 5.0 0.32 2.2

*All metrics beyond the first row are only calculated for the subset of simulations that gave infected mosquitoes. LAVC, La Crosse virus.
†We avoid reporting minimum values since these are likely to depend on the threshold that we selected for determining disease persistence (see LAC Dynamics, at http://www.clfs.umd.edu/biology/faganlab/disease-ecology.html).
‡In these systems, the abundance of infected mosquitoes was still increasing at the end of the season, indicating that infection rates do not slow before the decline in mosquitoes at the end of the summer.

Main Article

Page created: October 18, 2016
Page updated: October 18, 2016
Page reviewed: October 18, 2016
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
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