Image Gallery: Ticks of the Northeastern United States

Figure 1A Male (A) and nymphal (B) deer ticks (Ixodes dammini), also known as blacklegged ticks or the northern clade of Ixodes scapularis.^1,2 These ticks are distinguished by their oval shape and dark black legs and mouthparts. The female tick has a small black dorsal shield and a red body, whereas the male tick has a black dorsal shield covering its entire body. Deer ticks are typically found in the northeastern United States from Virginia north into Canada, as well as in Wisconsin and Minnesota, though their range is rapidly expanding.^3,4 They serve as the vectors for Lyme disease (Borrelia burgdorferi),⁵ anaplasmosis (Anaplasma phagocytophilum),⁶ babesiosis (Babesia microti),⁷ Borrelia miyamotoi,⁸ ehrlichiosis (Ehrlichia muris),⁹ and deer tick virus encephalitis (a subtype of Powassan virus).¹⁰ All active stages, except for the adult male, feed on a variety of animals.

Figure 1B Male (A) and nymphal (B) deer ticks (Ixodes dammini), also known as blacklegged ticks or the northern clade of Ixodes scapularis.^1,2 These ticks are distinguished by their oval shape and dark black legs and mouthparts. The female tick has a small black dorsal shield and a red body, whereas the male tick has a black dorsal shield covering its entire body. Deer ticks are typically found in the northeastern United States from Virginia north into Canada, as well as in Wisconsin and Minnesota, though their range is rapidly expanding.^3,4 They serve as the vectors for Lyme disease (Borrelia burgdorferi),⁵ anaplasmosis (Anaplasma phagocytophilum),⁶ babesiosis (Babesia microti),⁷ Borrelia miyamotoi,⁸ ehrlichiosis (Ehrlichia muris),⁹ and deer tick virus encephalitis (a subtype of Powassan virus).¹⁰ All active stages, except for the adult male, feed on a variety of animals.

Figure 2 American dog tick (Dermacentor variabilis), also known as the wood tick. These ticks are large and dark brown with "painted" designs on the back. Female ticks are brown with a painted dorsal shield extending halfway down the abdomen, whereas the male tick's painted dorsal shield extends the entire length of the tick. The range of the American dog tick extends widely east of the Rocky Mountains and along the western coast of California, as well as into Canada and Mexico. They are a vector for Rocky Mountain spotted fever (Rickettsia rickettsii)¹¹ and tularemia (Francisella tularensis).¹² Larval and nymphal American dog ticks rarely feed on hosts other than rodents and thus are not usually found on humans or companion animals.

Figure 3 Ovipositing American dog tick. Because a single egg batch can consist of more than 4000 eggs, host-directed preventive tick control measures are crucial.

Figure 4A Male lone star tick (Amblyomma americanum). These ticks are distinguished by their reddish-brown color, long mouthparts, and round shape.

Figure 4B Female lone star tick (Amblyomma americanum). These ticks are distinguished by their reddish-brown color, long mouthparts, and round shape. The female tick has a distinctive white spot on its dorsal shield.

Figure 4C Nymphal lone star tick (Amblyomma americanum). These ticks are distinguished by their reddish-brown color, long mouthparts, and round shape. Lone star ticks are common throughout the southern, south-central, and eastern United States, though they are rapidly expanding their range into New England. These ticks are vectors for ehrlichiosis (Ehrlichia chaffeensis and Ehrichia ewingii),⁶ tularemia (Francisella tularensis),¹² and Rocky Mountain spotted fever (Rickettsia rickettsii).¹¹ All active life stages feed on humans and companion animals.