Tick Surveillance in Loudoun County, VA Spring Lauren Lochstampfor Andy Lima VMCA, February 12, 2014

Transcription

1 Tick Surveillance in Loudoun County, VA Spring 2013 Lauren Lochstampfor Andy Lima VMCA, February 12, 2014

2 Introduction High incidence of Lyme in Loudoun County, VA cases cases (18% of state total) (34% of state total) Loudoun County Parks receive over 780,000 visits annually, the County population is about 337, Official resolution and proclamation by BoS declaring 2012 Lyme Disease Awareness Year 10 point action plan to mitigate Lyme disease in Loudoun County

3 10 Point Action Plan Create Lyme Disease Commission Lyme survey to determine risk factors Study cost and feasibility Spraying in County parks 4 poster deer stations Outreach Link on County website Educational material for different age groups Lyme Education Forums Monthly newspaper articles List of doctors specializing in Lyme Information for homeowner yard spraying Lyme education for children enrolled in Parks and Rec activities

4 How Clarke came into the picture Spring 2012 Pilot tick spraying in Parks Fall 2012 Recommendation for evaluation of parks to determine if blacklegged ticks are present in proposed spray areas Winter 2013 RFP issued for Lyme disease mitigation strategy for possible tick spraying Spring 2013 Clarke awarded contract for tick surveillance in Loudoun County Parks

5 Determining Lyme Disease Risk 27 parks visited during March parks not recommended for surveillance due to lack of tick habitat or restricted access. Identify areas within each park with high, medium, and low risk for encountering blacklegged ticks. Identify areas of general tick habitat and areas of human use Determine locations for surveillance activities

6 Most Parks Contain Athletic Fields

7 Edges and more Edges

8 A Nature Preserve

9 Miles of Riverfront Trails

10 Risk Maps

11 Beginning Surveillance 23 parks selected for weekly trapping and dragging. Surveillance focused on tick habitat in close proximity to the human use areas. Blacklegged ticks were pooled by each drag site for testing Surveillance routes were created by regions The River Trails Ashburn The Northwest The Southwest

12 Preparations

13 Such a Drag

14 Dragging

15 Trapping

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17 Continued Surveillance Dragging only continued at 19 parks from epiweeks Total collections from traps and drags in Loudoun County parks, 4/8/2013 5/10/2013 Total Ixodes scapularis Total Amblyomma americanum Total Dermacentor variabilis Male Female Nymph Male Female Nymph Male Female Nymph Total # ticks % 54% 11% 33% 23% 44% 60% 39% 0%

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19 Species Weekly average (traps only) Ixodes scapularis 2 Amblyomma americanum 283 Dermacentor variabilis 7

20 Species Weekly average (drags only) Ixodes scapularis 32 Amblyomma americanum 319 Dermacentor variabilis 282

21 Species Weekly average (traps and drags) Ixodes scapularis 31 Amblyomma americanum 538 Dermacentor variabilis 208

22 Loudoun County Tick Summary--DRAGS ONLY Species Total (drags only) Proportion of Total (drags only) Avg. per epiweek (drags only) Ixodes scapularis % 32 Amblyomma americanum % 319 Dermacentor variabilis % 282 Tick Totals Loudoun County tick summary--traps ONLY Species Total (traps only) Proportion of Total (traps only) Avg. per epiweek (traps only) Ixodes scapularis % 2 Amblyomma americanum % 283 Dermacentor variabilis % 7 Tick Totals Loudoun County tick summary--traps and DRAGS Species Total # ticks (traps and drags) Proportion of total (traps and drags) Avg. per epiweek (traps and drags) Ixodes scapularis % 31 Amblyomma americanum % 538 Dermacentor variabilis % 208 Tick Totals

23 Amblyomma americanum snapshot Most common species in Loudoun County parks 1131 collected during 44 trap nights 1275 collected from 149 drags male female hunting feeding style. Aggressive. Actively pursue hosts via CO 2 detection. catholic feeders this means all welcoming. They will feed on many different hosts. Attached nymph on Lima

24 Dermacentor variabilis snapshot Second most common species collected 28 collected during 44 trap nights (epiweek 15 and 16) 1157 collected from 149 drags 4/8/2013 5/10/2013 male female

25 Ixodes scapularis snapshot Least common species collected 7 collected during 44 trap nights (epiweek 15 and 16) 129 collected from 149 drags 4/8/2013 5/10/2013 nymph male female nymph male female Follow Andy Lima on Instagram to see pics like this

26 Ixodes scapularis testing methods Johns Hopkins University, PCR lab Doug Norris, PhD I. scapularis pooled by park and individual drag sites (no bloodfeds) Up to 5 adults per pool Up to 10 nymphs per pool *Note: pooling does not give a true infection rate. For determination of true infection rates, individual testing is required.

27 Ixodes scapularis testing results 137 I. scapularis collected from epiweek (4/8/2013 5/10/2013) 69 pools tested for B. burgdorferi 43 pools positive (64%) MIR: 31% MLE: 46%

28 Amblyomma maculatum Single male collected from on 5/1/2013 First known collection from Loudoun County, VA??? 700+ acres of land in various stages of succession Park is next to a landfill Bird dispersal? Vultures? Dermacentor variabilis (male) Amblyomma maculatum (male) Amblyomma americanum (male)

29 Picking up Hitchikers Never a good idea!

30 Thanks and Credits! Andrew Lima Fairfax County DCIP Dr. David Goodfriend Loudoun County Health Dept. Steve Torpy Loudoun County Parks and Recreation Patrick Patterson Clarke Francis Valera - Clarke