[Last Modified: ]
[Amblyomma spp.] [Dermacentor spp.] [Ixodes spp.] [Ornithodoros spp.] [Rhipicephalus spp.]

Members of the genus, Ixodes, are known vectors of Borrelia burgdorferi (Lyme disease), Babesia spp. (babesiosis), human granulocytic ehrlichiosis (HGE), and Russian spring-summer encephalitis virus.  In North America, the two most important species medically are I. scapularis and I. pacificus.  Adults are characterized by having mouthparts longer than the basis capituli, a lack of festoons, an inornate dorsal shield without eyes, and an inverted, U-shaped anal groove.

A	B

A: Larva (A), nymph (B), adult male (C), adult female (D), and engorged adult female with eggs (E) of I. scapularis.  Image courtesy of James Occi.
B: Adult female, adult male, nymph and larva of I. scapularis.  Image courtesy of Dr. Marc Dolan.

C	D

C: Ventral view of a nymph of Ixodes sp.  Image courtesy of the Washington State Public Health Laboratories.
D: Higher-magnification of the specimen in Figure C, showing a spiracular plate (SP) and the inverted, U-shaped anal groove (AG).  Notice also the absence of festoons.

E	F

E, F: Dorsal (Figure E) and ventral (Figure F) views of the specimen in Figure C, showing a close-up of the anterior region.  Notice the hypostome (HY) and palps (PA) are long, in relation to the basis capituli (BC).