What does a subcutaneous mite look like on a rat? - briefly
A subcutaneous mite presents as a tiny, pale, dome‑shaped nodule under the rat’s skin, typically 1–2 mm in diameter, sometimes showing a minute punctum where the parasite breathes. The overlying skin is thin and slightly raised, and the mite itself is a microscopic, oval arthropod with short legs.
What does a subcutaneous mite look like on a rat? - in detail
A subcutaneous mite embedded in a laboratory or wild rodent appears as a small, elongated body measuring 0.2–0.5 mm in length. The cuticle is smooth, translucent to pale brown, allowing internal organs to be faintly visible under magnification. The anterior region bears a pair of chelicerae and a dorsal shield (propodosoma) that may be slightly raised. Posteriorly, the opisthosoma tapers and ends in a pointed terminal spine or sucker, depending on the species.
Key visual characteristics:
- Coloration: Light amber or yellowish, sometimes with a faint reddish hue if engorged with blood.
- Shape: Cylindrical to slightly flattened, with a rounded anterior and a narrowed posterior.
- Surface texture: Glossy, lacking setae or prominent ornamentation; microscopic examination may reveal fine cuticular striations.
- Movement: Limited locomotion; the mite remains largely immobile within the host’s subdermal tissue, occasionally shifting in response to host movement.
When the mite is alive, its abdomen may appear distended due to blood feeding, giving a bulging, sausage‑like profile beneath the skin. The surrounding tissue often shows a localized swelling or nodule, sometimes accompanied by a thin, translucent capsule formed by host connective tissue. Histological sections reveal the mite’s mouthparts penetrating the dermal layer, with a small feeding tube inserted into host capillaries.
Diagnostic imaging (e.g., dermoscopy or stereomicroscopy) typically shows a well‑defined, oval silhouette beneath the epidermis, contrasting with the surrounding pinkish tissue. In advanced cases, the mite’s exoskeleton may calcify, producing a harder, whitish core visible on radiographs.
Overall, the mite’s appearance combines a minute, smooth, lightly pigmented body with a characteristic tapered tail, situated within a localized subdermal swelling that may be palpable as a firm nodule.