Range Expansion of Tick Disease Vectors in North America: Implications for Spread of Tick-Borne Disease.

Daniel Sonenshine

doi:10.3390/ijerph15030478

Abstract

Ticks are the major vectors of most disease-causing agents to humans, companion animals and wildlife. Moreover, ticks transmit a greater variety of pathogenic agents than any other blood-feeding arthropod. Ticks have been expanding their geographic ranges in recent decades largely due to climate change. Furthermore, tick populations in many areas of their past and even newly established localities have increased in abundance. These dynamic changes present new and increasing severe public health threats to humans, livestock and companion animals in areas where they were previously unknown or were considered to be of minor importance. Here in this review, the geographic status of four representative tick species are discussed in relation to these public health concerns, namely, the American dog tick, Dermacentor variabilis, the lone star tick, Amblyomma americanum, the Gulf Coast Tick, Amblyomma maculatum and the black-legged tick, Ixodes scapularis. Both biotic and abiotic factors that may influence future range expansion and successful colony formation in new habitats are discussed.

Highlights

Ticks are notorious as vectors of disease-causing agents to humans, companion animals and wildlife
Models predict that areas with suitable climate for D. variabilis could increase by approximately 50%, it is not known whether suitable habitats, especially deciduous forests and hosts will likely resulting in northward expansion throughout most of Canada [20]
The ability of immature stages of this tick to feed on a wide variety of ground feeding birds, as well as various small mammals such as rats, mice and voles and the ability of the adult stages to feed on cattle, swine, white-tailed deer and other mammals suggest that finding suitable hosts will not be a factor limiting its northward and western range expansion

Summary

Introduction

Ticks are notorious as vectors of disease-causing agents to humans, companion animals and wildlife. Res. Public Health 2018, 15, 478 brushy and forested habitats throughout most of the central and eastern United States from Florida to several areas of southern Canada; (2) the Rocky Mountain wood tick, Dermacentor andersoni, found in the northwestern United States and the Canadian Rocky Mountains; (3) the lone star tick, Amblyomma americanum, present in most regions of the eastern and midwestern U.S.; (4) the Gulf. Amblyomma maculatum, present in the Gulf Coast states, midwestern and south Atlantic states of the U.S In contrast, examples of tick species with very broad (and expanding) geographic and host ranges are the black-legged tick Ixodes scapularis in North America, the closely related sheep tick, I. ricinus, found mostly throughout most of Europe, United Kingdom and localities in North Africa, and the taiga tick, I. persulcatus, found in eastern Europe and northern Asia. This review will consider four tick species in North America, D. variabilis, A. americanum, A. maculatum and I. scapularis, for an in-depth examination of their geographic range expansion and some of the factors influencing its progress

Impediments to Range Expansion

Selected North American Ticks and Range Expansion

Findings

Conclusions