What does an encephalitis tick look like? - briefly
Encephalitis‑transmitting ticks are small, oval arachnids about 2–3 mm long when unfed, reddish‑brown on the dorsal side with a darker scutum and a lighter ventral surface, and they expand to roughly 5–10 mm after a blood meal. They possess eight legs, a flattened body, and are typically identified as Ixodes species common in temperate regions.
What does an encephalitis tick look like? - in detail
Encephalitis‑transmitting ticks belong primarily to the Ixodes genus, especially Ixodes scapularis (the black‑legged tick) and Ixodes ricinus (the castor bean tick). Adult specimens measure 3–5 mm in length when unfed and expand to 8–10 mm after a blood meal. The dorsal surface is covered by a dark, shield‑shaped scutum that contrasts with a lighter‑colored abdomen. The scutum’s outline is oval, with a smooth edge and no distinct patterns, distinguishing it from other hard‑tick species that may display ornate markings.
Key visual characteristics include:
- Body coloration: Dark brown to black dorsal shield; reddish‑brown or pale ventral surface.
- Legs: Eight legs, each about twice the body length; legs are pale with fine, short hairs.
- Mouthparts: Prominent capitulum extending forward; palps are shorter than the chelicerae, giving a “stiletto” appearance.
- Eyes: Two small, pigmented eyes positioned near the scutum’s anterior margin.
- Engorgement changes: After feeding, the abdomen becomes markedly distended, taking on a rounded, balloon‑like shape while the scutum remains unchanged in size.
Larval and nymph stages are considerably smaller (0.5–1 mm for larvae, 1.5–2 mm for nymphs) and exhibit a similar coloration pattern but lack a fully developed scutum. Nymphs retain the dark dorsal shield, whereas larvae possess a uniformly colored body without a distinct scutum. Recognizing these morphological details aids in accurate identification and timely removal, reducing the risk of encephalitic infection.