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Review
. 2018 Apr;34(4):295-309.
doi: 10.1016/j.pt.2017.12.006. Epub 2018 Jan 11.

The Blacklegged Tick, Ixodes scapularis: An Increasing Public Health Concern

Rebecca J Eisen  1 , Lars Eisen  2
Affiliations
Review

The Blacklegged Tick, Ixodes scapularis: An Increasing Public Health Concern

Rebecca J Eisen et al. Trends Parasitol. 2018 Apr.

Abstract

In the United States, the blacklegged tick, Ixodes scapularis, is a vector of seven human pathogens, including those causing Lyme disease, anaplasmosis, babesiosis, Borrelia miyamotoi disease, Powassan virus disease, and ehrlichiosis associated with Ehrlichia muris eauclarensis. In addition to an accelerated rate of discovery of I. scapularis-borne pathogens over the past two decades, the geographic range of the tick, and incidence and range of I. scapularis-borne disease cases, have increased. Despite knowledge of when and where humans are most at risk of exposure to infected ticks, control of I. scapularis-borne diseases remains a challenge. Human vaccines are not available, and we lack solid evidence for other prevention and control methods to reduce human disease. The way forward is discussed.

Keywords: Ixodes scapularis; control; disease; surveillance.

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Figures

Figure 1
Figure 1
Reported Distribution of Ixodes scapularis in 1996 (A) and 2016 (B); and Reported Cases of Lyme Disease in 2001 (C) and 2015 (D). Counties classified as established, based on <6 individual ticks of a single life stage or >1 life stage reported per county in a year are shown in red. Counties classified as reported based on <6 individual ticks reported in a year are shown in blue. Data from A and B are derived from Dennis et al. [30] and Eisen et al. [6], respectively. In panels C and D, one dot was placed randomly within the county of residence for each reported case. In the far-western United States, Ixodes pacificus serves as a vector of Borrelia burgdorferi.
Figure 2
Figure 2
Timeline Showing Discovery of the Seven Human Pathogens Transmitted by Ixodes scapularis.
Figure 3
Figure 3
Life Cycle of Ixodes scapularis.
Figure 4
Figure 4
Reported Cases of Babesiosis, Anaplasmosis, and Lyme Diseases in the United States, 1996–2016. Source: https://wwwn.cdc.gov/nndss/data-and-statistics.html (last referenced November 13, 2017).
Figure 5
Figure 5
Chain of Events Leading to a Lyme Disease Infection, with Possible Intervention Points for Different Control Approaches.
Figure 6
Figure 6
Desired Characteristics of an Ideal Tick-Borne Disease Prevention Method.
See this image and copyright information in PMC

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