Discovering the Distribution of Ticks and Tickborne Illness in North Carolina
Alexis M Barbarin1, Carl Williams1, Gideon Wasserberg2, Michael Reiskind3, Steven Seagle4
division of Public Health, North Carolina Department of Health and Human Services; 2University of North Carolina at Greensboro; 3North Carolina State University; Appalachian State University
Introduction
Results
Figure 2. Incidence of confirmed human cases of Lyme disease in
North Carolina.
Vector-borne diseases (VBD) represent a historical and evolving threat
to the residents of North Carolina. The southern expansion of Lyme
disease from the northeast into southern Virginia, Tennessee and North
Carolina has generated renewed interest in understanding the phenology
and distribution of Ixodes scapularis ticks in the southern states. Due
to limited entomological surveillance in previous years, it is unclear
where, geographically, traditional tick vector species are located in North
Carolina, particularly the Lyme disease (LD) vector, Ixodes scapularis. To
gather this information the Division of Public Health developed a series
of collaborations with the Centers for Disease Control and Prevention
(CDC) in Fort Collins, Colorado, key university partners, and the NC State
Laboratory of Public Health to understand of the ecology and distribution
of Ixodes ticks and their infection rates in North Carolina.
Methods
Counties of interest: Alleghany, Ashe, Buncombe, Carroll, Chatham,
Johnston, Madison, Mitchell, Onslow, Rockingham, Stokes, Surry,
Wake, Watauga, Wilkes, Yadkin and Yancey.
University Partners: University of North Carolina at Greensboro,
North Carolina State University, and Appalachian State University.
Tick surveillance:
Table 1. Percentage of Ixodes ticks infected with pathogens by county.
County
(# tested)
Borrelia
burgdorferi
(%+>
Borrelia
miyamotoi
(%+)
Anaplasma
phagocytophilum
(%+>
Alleghany (93)
24%
1%
1%
Ashe (81)
23%
1%
6%
Buncombe (39)
15%
1%
0%
Chatham (2)
0%
0%
0%
Johnson (4)
50%
0%
0%
Madison (27)
7%
0%
0%
Mitchell (75)
0%
0%
5%
Onslow (7)
0%
0%
0%
Rockingham (65)
3%
0%
0%
Stokes (8)
13%
0%
0%
Surry (34)
0%
0%
0%
Wake (1)
0%
0%
0%
Watauga (39)
15%
0%
8%
Wilkes (16)
13%
0%
0%
Yadkin (2)
0%
0%
0%
Yancey (48)
0%
0%
0%
Confirmed Cases of Lyme Disease
by County of Residence (2016 - 2019)
Average Incidence per
100,000 Population
СЦ)
0.0 -2.1
2.2-70
71-13.9
14.0 - 40.5
(^3 None
n-258
State Center for Health Statistics
Conclusions
Flagging/dragging was conducted in at least two sites per county;
once during August - December; once during April - July.
A minimum of 500 m sampled per session, per site using a
standardized cloth and a Global Positioning System (GPS).
Ixodes ticks were stored in 95% ethanol and sent to the Centers
for Disease Control and Prevention (CDC) Division of Vector-
Borne Diseases for pathogen testing1.
The pathogen panel included tests for: Borrelia burgdorferi,
B. mayonii, B. miycmotoi, Ana plasma phagocytophilum and
Babesia microti.
Figure 1. Percentage of Ixodes ticks infected with B. burgdorferi
by county.
Borrelia burgdorferi Infected Ixodes Ticks
Collected via Flagging/Dragging (2016 - 2019)
Neither Borrelia mayonii nor Babesia microti were found in any of
the ticks collected by university partners and tested for pathogens
by CDC. Additionally, A. phagoctyophilum was found in very low
levels. Ongoing surveillance is needed to document potential
emergence of these pathogens, and rate of co-infection in ticks.
Human incidence of Lyme disease and counties with higher
numbers of B. burgdorferi infected ticks appear to overlap,
particularly in the western part of North Carolina.
Both entomologic and human surveillance indicate that the
northwestern portion of North Carolina is an emerging area for
Lyme disease; health care professionals and the public must be
educated appropriately.
Despite sampling efforts being standardized across counties,
entomologic surveillance of eastern North Carolina detected few
I. scapularis.
Further entomologic data are necessary to characterize risk of
infection with B. burdgorferi based on tick life stage and seasonality.
Acknowledgements
Total ticks tested = 541
We would like to thank the Eisen lab at the Centers for Disease
Control and Prevention, Division of Vector-borne Diseases for all of
their assistance with tick pathogen testing. We would like to thank
Dianne Enright and the State Center for Health Statistics for the
generation of the maps. We would also like to thank CDC ELC for
funding tick surveillance in North Carolina.
Reference: Graham CB, Maes SE, Hojgaard A, Fleshman AC, Sheldon SW, Eisen RJ. (2018). A molecular algorithm to detect and
human pathogens infecting Ixodes scapularis and Ixodes pacificus (Acari: Ixodidae). Ticks Tick-borne Dis. 9, 390-403.
NC DEPARTMENT OF
HEALTH AND
HUMAN SERVICES
