Maryland Lyme - Results National Tick Study- 2018

You Sent In Ticks To Be Tested

The Results Are In!

July 2018- QUOTE- "When the project was initiated, we expected approximately 2,400 submissions; and at times were almost overwhelmed by the actual 16,000-plus!"

STUDY RESULTS

Using citizen science to describe the prevalence and distribution of tick bite and exposure to tick-borne diseases in the United States

Nathan C. Nieto , W. Tanner Porter, Julie C. Wachara, Thomas J. Lowrey, Luke Martin, Peter J. Motyka, Daniel J. Salkeld
Published: July 12, 2018

Link Here To Full Study

Some Notes of Importance

Some selected quotes below that you may find of interest. Please note that some statements were slightly edited (common names of ticks and diseases added, % figures removed, etc.) to make them easier to comprehend. (You know, Lyme brain adjustments.)

Please read the full study if able. It is well done and appreciated. Link Here To Full Study

"We received a total of 12,130 submissions from across the US’ 50 states and Puerto Rico... resulting in a total of 16,080 ticks collected and tested for pathogens."

Ticks were tested for:

A. phagotcytophilum [Anaplasma],

Babesia microti [Babesia],

B. burgdorferi [Borrelia burgdorferi- Lyme disease],

B. miyamotoi [Borrelia miyamotoi- Relapsing Fever Borrelia] .

All four pathogens were detected in:

I. scapularis [deer tick],

D. variabilis [dog tick],

A. americanum [lonestar tick]

"Lyme disease transmission is associated with I. pacificus and I. scapularis, but we observed B. burgdorferi and B. miyamotoi in lone star, Gulf Coast, Pacific Coast and American dog ticks."

"The newly identified human pathogen, B. miyamotoi, exhibited a higher prevalence of infection in western black-legged ticks compared to the eastern congener."

"B. miyamotoi DNA was also identified in I. scapularis [deer tick] populations..."

Other tick species, not currently recognized as competent vectors, were also observed with B. miyamotoi infections:

A. americanum [lonestar tick]

A. maculatum [Gulf Coast Tick]

Amblyomma spp. [Lonestar]

Dermacentor variabilis [Dog Tick]

I. scapularis [lonestar tick] samples contained the highest prevalence of A. phagocytophilum [Anaplasma] infections

Anaplasma DNA was also found in A. americanum, A. maculatum, Amblyomma spp., Dermacentor variabilis, Dermacentor andersoni, and Dermacentor occidentalis.

Lonestar ticks contained the highest prevalence of Babesia microti.

Babesia microti was also detected in I. scapularis [deer tick] and D. variabilis [dog tick].

Co-infections were identified in 0.98% of tested ticks. I. scapularis [deer ticks] accounted for 88.0% (139/158) of these co-infections.

The most common co-infection was between A. phagocytophilum [Anaplasma] and B. burgdorferi [Lyme]. Co-infections with Babesia microti and B. burgdorferi also occurred.

Seven I. scapularis [deer] ticks were infected with triple infections of B. burgdorferi [Lyme]-A. phagocytophilum [Anaplasma]- Babesia microti [Babesia]. No ticks were positive for all four pathogens.

"We believe that utilizing the citizen science potential [the public collecting ticks and submitting them] in a local area could be broadly effective at providing public health managers with a relatively cheap (reduced labor and travel costs) and effective (greater scope) way of determining the risk of particular tick species in a region."

"...we received I. scapularis [deer tick] from 594 counties and 35 US states and I. pacificus in 79 counties from 6 states. These data echo findings from an extensive literature search examining the reported presence of ticks within US counties: I. scapularis [deer tick] in 1,420 counties in 37 states, and I. pacificus [western black-legged tick] in 111 counties and six states.

"... submission of lone star ticks (A. americanum) from northern California, and a single black-legged tick (I. scapularis) from northern Montana which are both locations well outside of the recorded range for these species."

"For example, babesiosis has been reported in 15/18 states where the disease is reportable, and predominantly in just seven states (97% of cases in just Connecticut, Massachusetts, Minnesota, New Jersey, New York, Rhode Island, and Wisconsin). We observed Babesia microti in several states where this pathogen is not a reportable disease..."

"In addition, the tick submissions confirm that babesiosis is a rare disease in the west coast; however the diversity of Babesia organisms in the west is likely unrealized (e.g., Washington, Oregon and California)."

"... our data identified a number of B. burgdorferi positive larvae which contradicts evidence the spirochete has limited, if any transovarial transmission."

"Special thanks to all the citizen scientists across the US who provided tick samples."

Link Here To Full Study

Results From National Tick Study- 2018

B. burgdorferi DNA was also identified in A. americanum, with the highest prevalence of 4.8% (1/21, CI = 0.2–25.9) in larval ticks, followed by 1.4% (24/1754, CI = 0.9–2.0) in adults and 0.7% (2/299, CI = 0.9–2.0) in nymphs (overall prevalence of 1.2% (27 / 2078, CI = 0.9–1.9). Amblyomma spp., nymphs and larvae (2.1%, 14/661, CI = 1.2–3.6) and an A. maculatumadult (5.2%, 1/21, CI = 0.3–28.1) tested positive for B. burgdorferi, as did D. occidentalis(0.8%, 2/264, CI = 0.1–3) and D. variabilis (0.9%, 54/5853, CI = 0.7–1.2).

The newly identified human pathogen, B. miyamotoi, exhibited a higher prevalence of infection in western black-legged ticks compared to the eastern congener. In the western US, prevalence was highest in larval I. pacificus ticks (5.9%, 1/17, CI = 0.3–30.8), followed by adults (1.8%, 33/1785, CI = 1.3–2.6), and nymphs (0.9%, 2/225, CI = 0.2–3.5), and an overall prevalence of 1.8% (N = 36/2027, 1.8%, CI = 1.3–2.5).

B. miyamotoi DNA was also identified in I. scapularis populations (1.3%, 60/467, CI = 1.0–1.7), with the highest prevalence in larvae (2.0%, 2/98, CI = 0.4–7.9), followed by adult ticks (1.4%, 41/2,997, CI = 1.0–1.9), and nymphs (1.1%, 17/1,560, CI = 0.7–1.8). Other tick species, not currently recognized as competent vectors, were also observed with B. miyamotoi infections: A. americanum (1.3%, 28/2078, CI = 0.9–2), an A. maculatum adult (4.8%, 1/21, CI = 0.2–25.9), Amblyomma spp. (1.4%, 9/661,CI = 0.7–2.7), and D. variabilis(0.4%, 24/5853, CI = 0.3–0.6).

I. scapularis samples contained the highest prevalence of A. phagocytophilum infections (4.1%, 191/4671, CI = 3.5–4.7) with adult ticks accounting for the highest prevalence (5.1%, 153/2,997, CI = 4.4–6.0), followed by nymphs (2.4%, 38/1560, CI = 1.8–3.4). I. pacificus also harbored A. phagocytophilum (1.1%, 23/2,033, CI = 0.7–1.7); prevalence was 1.2% in adult ticks (21/1,785, CI = 0.7–1.8) and 0.9% in nymphs (2/225, CI = 0.2–3.5). A. phagocytophilumDNA was also found in A. americanum adults (0.3%, 6/2078, CI = 0.1–0.7%), an A. maculatum adult (4.8%, 1/21, CI = 0.2–25.9), Amblyomma spp. (nymphs) (0.5%, 3/661 CI = 0.1–1.4). D. variabilis (0.5%, 28/5853, CI = 0.3–0.7%), D. andersoni (0.8%, 1/132 CI = 0–4.8), and D. occidentalis (0.4%, 1/264, 0–2.4) also had a low prevalence of A. phagocytophilum.

Amblyomma americanum ticks contained the highest prevalence of Bab. microti (2.5%, 51/2078, CI = 2.5–3.2), with adults accounting for the highest prevalence of 2.6% (46/1754, CI = 1.9–3.5), followed by nymphs at 1.7% (5/299, CI = 0.6–4.0), and Amblyomma spp. nymphs (1.4%, 9/656, CI = 0.7–2.7). Bab. microti was also detected in I. scapularis (1.8%, 86/4671, CI = 1.5–2.3), with adults having a prevalence of 2.1% (64/2997, CI = 1.7–2.7) followed by 1.3% in nymphs (20/1,560, CI = 0.8–2.0). A low prevalence of Bab. microti was observed in D. variabilis (0.2%, 10/5,850, CI = 0.1–0.3).

Co-infections were identified in 0.98% (N = 158, CI = 0.8–1.2) of tested ticks, and I. scapularis accounted for 88.0% (139/158) of these co-infections. The most common co-infection was between A. phagocytophilum and B. burgdorferi, with an overall prevalence of 0.5% (83 / 16080, CI = 0.4–0.6%) and specifically in I. scapularis, 1.7% (79/4671, CI = 1.3–2.1). Co-infections with Bab. microti and B. burgdorferi also occurred with an overall prevalence of 0.2% (N = 36, CI = 0.2–0.3) and in I. scapularis, 0.7% (34/4,671, CI = 0.5–1.0). Co-infections were predominantly found in adult ticks (81.6%, 129/158, CI = 74.5–87.2). In addition, seven I. scapularis ticks were infected with triple infections of B. burgdorferi-A. phagocytophilum-Bab. microti (0.1%, 7/4671, CI = 0.07–0.3). No ticks were positive for all four pathogens.

Our data on geographic distributions of tick exposures corroborate and expand previously published records on tick distribution ranges. For example, we received I. scapularis from 594 counties and 35 US states and I. pacificus in 79 counties from 6 states. These data echo findings from an extensive literature search examining the reported presence of ticks within US counties: I. scapularis in 1,420 counties in 37 states, and I. pacificus in 111 counties and six states [12]. It therefore seems feasible that citizen science contributions can augment our scientific knowledge of where and when ticks are biting humans and animals, and perhaps can address our current inability to properly define current tick and pathogen geographic distributions, as well as to monitor changes in the ranges over time [12].

For the most part, surveillance for pathogens also mirrored conventional perspectives on tick-borne diseases but our citizen-science based database also allows insights that are not available from the typical chains of information that rely on notifiable disease status by state. For example, babesiosis has been reported in 15/18 states where the disease is reportable, and predominantly in just seven states (97% of cases in just Connecticut, Massachusetts, Minnesota, New Jersey, New York, Rhode Island, and Wisconsin) [40]. We observed Bab. microti in several states where this pathogen is not a reportable disease (Table 3), and so although our data do not necessarily reflect an increase in geographical distribution, they do provide additional insight on the ecology and epidemiology of the disease.

Additionally, our data identified a number of B. burgdorferi positive larvae which contradicts evidence the spirochete has limited, if any transovarial transmission.

Lyme disease transmission is associated with I. pacificus and I. scapularis, but we observed B. burgdorferi and B. miyamotoi in lone star, Gulf Coast, Pacific Coast and American dog ticks. However, these observations are presumably because these tick species feed on the reservoir hosts for these pathogens; these data do not on their own provide evidence that the tick species are involved in disease transmission. Indeed, xenodiagnostic experiments have failed to demonstrate viable pathogen transmission of B. burgdorferi by lone star or American dog ticks [47–49]. Previous studies have observed Babesia in lone star ticks, and suggested the potential for vector competence, but experimental studies are required to confirm pathogen transmission cycles in particular tick studies [49].

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0199644

Last Updated- April 2019

Lucy Barnes

AfterTheBite@gmail.com