Old Dominion University Tick Research Update 2014 Chelsea Wright Department of Biological Sciences Old Dominion University
Study Objectives Long-term study of tick population ecology in Hampton Roads area Collect ticks from the field Determine populations of ticks in Hampton Roads that carry pathogens Mathematical modeling and simulation to determine high-risk areas and best control methods
Tick Collection Methods Flagging vegetation Rodent live-trapping Hunt check stations Road kill convenience Veterinarian data Human volunteers Bird mist netting Reptile sampling
2014 Flagging Sites
Flagging Effort Flagging effort remained at a level similar to last year Sampling Frequency April through October Core sites weekly All others biweekly November through February Core sites biweekly All others monthly
Effort
Ticks/100m2 30 25 Amblyomma americanum (lone star tick) Larvae Nymphs Adults 20 15 10 5 0 Apr Jun Aug Oct Apr Jun Aug Oct Mar May Jul Sep Nov May Jul Sep Nov Apr Jun Aug Oct 2010 2011 2012 2013 2014
Ticks/100m2 6 Amblyomma americanum (without larvae) 5 Nymphs Adults 4 3 2 1 0 Apr Jun Aug Oct Apr Jun Aug Oct Mar May Jul Sep Nov May Jul Sep Nov Apr Jun Aug Oct 2010 2011 2012 2013 2014 *big lone star year*
Apr May Jun Jul Aug Sep Apr May Jun Jul Aug Mar Apr May Jun Jul Aug Sep Apr May Jun Jul Aug Sep Apr May Jun Jul Aug Sep Preliminary data Do Not Reprint Ticks/100m2 0.35 Dermacentor variabilis (American dog tick) 0.3 Adults 0.25 0.2 0.15 0.1 0.05 0 2010 2011 2012 2013 2014
Ticks/100m2 0.1 Ixodes scapularis (blacklegged tick) 0.09 Nymphs Adults 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Apr Jun Aug Oct Apr Jun Aug Oct Dec Mar May Jul Sep Nov Jan Apr Jun Aug Oct Dec Mar May Jul Sep Nov 2010 2011 2012 2013 2014
Apr May Jun Jul Aug Sep Oct Nov Apr May Jun Jul Aug Sep Oct Apr May Jun Jul Aug Sep Oct Apr May Jun Jul Aug Sep Oct Apr May Jun Jul Aug Sep Oct Preliminary data Do Not Reprint Ticks/100m2 0.14 Ixodes affinis 0.12 Nymphs Adults 0.1 0.08 0.06 0.04 0.02 0 2010 2011 2012 2013 2014
Ticks/100m2 0.06 Nymphs Amblyomma maculatum (Gulf Coast tick) Adults 0.05 0.04 0.03 0.02 0.01 0 May Jun Jul Aug Sep Apr May Jun Jul Aug Sep Mar Apr May Jun Jul Aug Sep Apr May Jun Jul Aug Sep Apr May Jun Jul Aug 2010 2011 2012 2013 2014
State Sweep 2014: Tracking Range- Expanding Species
State Sweep Two tick species have been recently introduced into Virginia: Amblyomma maculatum and Ixodes affinis To map the spread of these ticks, every city and county in central and eastern Virginia is sampled during the month of June
State Sweep
State Sweep Amblyomma maculatum (Gulf Coast tick) has been found intermittently in a variety of counties (not shown) and consistently in a variety of counties (darker blue for more recent discoveries).
Amblyomma maculatum Delaware data: David Florin (USUHS). Western Virginia data: David Gaines (VDH). North Carolina data: Varela-Stokes AS, Paddock CD, Engber B, Toliver M. Rickettsia parkeri in Amblyomma maculatum ticks, North Carolina, USA, 2009 2010. Emerg Infect Dis. 2011 Dec [date cited]. http://dx.doi.org/10.3201/eid1712.110789
Ixodes affinis Ixodes affinis has been found throughout the coastal plain. Once found, this species appears to remain. Darker red indicates more recently discovered.
Ixodes affinis North Carolina data: Harrison, B.A., W.H. Rayburn Jr., M. Toliver, E.E. Powell, B.R. Engber, L.A. Durden, R.G. Robbins, B.F. Prendergast, and P.B. Whitt. 2010. Recent discovery of widespread Ixodes affinis (Acari: Ixodidae) distribution in North Carolina with implications for Lyme disease studies. J. Vector Ecol. 25: 174-179.
Rickettsia parkeri in A. americanum Rickettsia parkeri causes spotted fever illness in humans High prevalence of R. parkeri in Virginia Gulf Coast tick populations 43-56% in southeastern Virginia (Wright et al. 2011, Nadolny et al. 2014) 41% in northern VA (Fornadel et al. 2011) Is R. parkeri spilling over into lone star tick populations?
Rickettsia parkeri in A. americanum Sampled VA counties from June 8 th June 22 nd 2014 Lone star adults collected from 29 of 33 counties sampled Individual adults tested for R. parkeri using qpcr of ompb (Jiang et al. 2012) 320 ticks (1-29 ticks per county) were tested 2 ticks (1 male, 1 female) were positive for R. parkeri Mathews County Northampton County
R. parkeri Spillover
Ticks from animals Additional effort this year to expand search for ticks from medium and large mammals Worked with wildlife rehabbers, wildlife biologists and others
Ticks from small mammals (2011-2014) Host Total Percent with number ticks Cotton Rat 154 41.56% 4.56 Golden Mouse 14 50.00% 1.57 House mouse 58 24.14% 5.71 Harvest Mouse 80 15.00% 2.00 Marsh Rice Rat 50 70.00% 5.43 Shrew 90 23.33% 15.24 Meadow Vole 96 56.25% 3.54 White Footed Mouse Average ticks per host with ticks 24 37.50% 8.33
Host Dog Ticks Lone Star Black-legged Gulf Coast Ixodes Other ticks Ticks Ticks Ticks affinis Total Black Bear 2 23 3 0 0 0 28 Cat 27 60 66 1 0 24 178 Coyote 3 38 0 0 0 1 42 Deer 0 526 1408 7 321 Winter ticks 40 2302 Dog 50 155 21 1 1 Brown dog tick 3 231 Feral Hog 78 162 14 1 1 Brown dog tick 0 256 Gray Fox 0 0 5 0 0 0 5 Gray Squirrel 0 1 0 0 0 0 1 Groundhog 0 7 0 0 0 0 7 Horse 0 4 0 0 0 0 4 Opossum 11 8 0 0 0 0 19 Rabbit 0 1 2 0 27 Rabbit ticks 0 3 Raccoon 58 27 18 0 2 Winter ticks, 25 Raccoon ticks 0 130 Red Fox 10 1 0 0 0 0 11 Grand Total 239 1013 1537 10 30 68 3247
Summary Southeastern Virginia tick community dominated by Amblyomma americanum Small yet well-established populations of Ixodes affinis and Amblyomma maculatum increasingly found in Virginia Rickettsia parkeri present in Virginia A. americanum Implications for human disease?
Acknowledgements Graduate students: Lindsey Bidder, Robyn Nadolny, Erin Heller, Amy Johnson, Pamela Kelman, Sharon Vaturi, Alexis White Faculty: Holly Gaff, Wayne Hynes, David Gauthier, Eric Walters, Daniel Sonenshine And the tireless effort of more than 30 undergrad lab and field assistants