Old Dominion University Tick Research Update Chelsea Wright Department of Biological Sciences Old Dominion University

Transcription

1 Old Dominion University Tick Research Update 2014 Chelsea Wright Department of Biological Sciences Old Dominion University

2 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

3 Tick Collection Methods Flagging vegetation Rodent live-trapping Hunt check stations Road kill convenience Veterinarian data Human volunteers Bird mist netting Reptile sampling

4 2014 Flagging Sites

5 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

6 Effort

7

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9 Ticks/100m Amblyomma americanum (lone star tick) Larvae Nymphs Adults Apr Jun Aug Oct Apr Jun Aug Oct Mar May Jul Sep Nov May Jul Sep Nov Apr Jun Aug Oct

10 Ticks/100m2 6 Amblyomma americanum (without larvae) 5 Nymphs Adults Apr Jun Aug Oct Apr Jun Aug Oct Mar May Jul Sep Nov May Jul Sep Nov Apr Jun Aug Oct *big lone star year*

11 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/100m Dermacentor variabilis (American dog tick) 0.3 Adults

12 Ticks/100m2 0.1 Ixodes scapularis (blacklegged tick) 0.09 Nymphs Adults 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

13 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/100m Ixodes affinis 0.12 Nymphs Adults

14 Ticks/100m Nymphs Amblyomma maculatum (Gulf Coast tick) Adults 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

15 State Sweep 2014: Tracking Range- Expanding Species

16 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

17 State Sweep

18 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).

19 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, Emerg Infect Dis Dec [date cited].

20 Ixodes affinis Ixodes affinis has been found throughout the coastal plain. Once found, this species appears to remain. Darker red indicates more recently discovered.

21 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 Recent discovery of widespread Ixodes affinis (Acari: Ixodidae) distribution in North Carolina with implications for Lyme disease studies. J. Vector Ecol. 25:

22 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?

23 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

24 R. parkeri Spillover

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26 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

27 Ticks from small mammals ( ) Host Total Percent with number ticks Cotton Rat % 4.56 Golden Mouse % 1.57 House mouse % 5.71 Harvest Mouse % 2.00 Marsh Rice Rat % 5.43 Shrew % Meadow Vole % 3.54 White Footed Mouse Average ticks per host with ticks % 8.33

28 Host Dog Ticks Lone Star Black-legged Gulf Coast Ixodes Other ticks Ticks Ticks Ticks affinis Total Black Bear Cat Coyote Deer Winter ticks Dog Brown dog tick Feral Hog Brown dog tick Gray Fox Gray Squirrel Groundhog Horse Opossum Rabbit Rabbit ticks 0 3 Raccoon Winter ticks, 25 Raccoon ticks Red Fox Grand Total

29 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?

30 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