Range Expansion of Tick Disease Vectors in North America
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.