How does an encephalitic tick look after a bite? - briefly
After feeding, the tick’s body expands, turning a bright reddish‑brown and becoming engorged, often obscuring its original shape. The mouthparts stay embedded, and the insect appears as a smooth, dome‑shaped lesion on the skin.
How does an encephalitic tick look after a bite? - in detail
After feeding, a tick capable of transmitting encephalitis undergoes distinct visual changes that can be observed without magnification. The insect expands dramatically, increasing its body length up to three times the size of an unfed specimen. The abdomen becomes distended, taking on a balloon‑like shape that dominates the overall silhouette. Color shifts from a light brown or gray in the unfed stage to a darker, reddish‑brown hue as blood fills the gut. The cuticle stretches, creating fine wrinkles across the dorsal surface.
Key external features include:
- Mouthparts: The capitulum remains visible at the anterior end, often appearing as a small, dark, hooked structure that anchors the tick to the host’s skin.
- Legs: All eight legs stay attached and may appear splayed outward to support the enlarged body; they retain their original segmentation and dark coloration.
- Scutum (if present): In hard‑tick species, the scutum does not expand, so it appears as a rigid, lighter patch on the dorsal side, contrasting with the engorged abdomen.
The bite site on the host’s skin typically shows:
- A tiny puncture wound, often less than 1 mm in diameter.
- A faint, circular erythema surrounding the entry point; the redness may be uniform or slightly raised.
- Occasionally, a small crust or scab forms as the wound heals.
Differences between life stages are notable. Nymphs, after a blood meal, measure roughly 2–5 mm in length, while adult females can reach 10–12 mm when fully engorged. Males rarely become heavily engorged; their abdomen remains relatively small and elongated.
In summary, the post‑bite appearance includes a markedly swollen, darkened abdomen, visible mouthparts, splayed legs, and a subtle skin lesion at the attachment site. These characteristics enable identification of an engorged, potentially encephalitic tick without specialized equipment.