What does a diseased tick look like? - briefly
Ticks infected with pathogens often become engorged, showing a pale or grayish body with a darker, sometimes cracked, dorsal shield. Additional signs include discoloration or a waxy coating on the cuticle.
What does a diseased tick look like? - in detail
A tick that carries a pathogen often shows visual changes that distinguish it from a healthy specimen. These alterations are most apparent on the dorsal shield (scutum) and the ventral side, where discoloration, swelling, or abnormal texture may appear.
- Color shift: Infected individuals frequently develop a darker, almost black coloration of the scutum, sometimes with mottled patches of brown or gray. The change results from hemolymph accumulation and tissue degradation caused by the pathogen.
- Swelling: The abdomen can become markedly enlarged, giving the tick a balloon‑like profile. This distension is due to rapid blood intake combined with impaired digestion and fluid retention associated with infection.
- Surface texture: The exoskeleton may lose its typical smoothness, becoming rough or cracked. In some cases, a thin, opaque film of exudate forms on the cuticle, especially around the mouthparts.
- Mouthpart deformation: The hypostome and palps can appear swollen or misshapen, reflecting tissue inflammation. This deformation may impede attachment but also signals internal pathology.
- Leg and sensory organ changes: Legs may appear splayed or less coordinated, and the sensory Haller’s organ can be obscured by debris or fungal growth that often accompanies disease vectors.
Microscopic examination can reveal additional signs, such as the presence of spirochetes or protozoan cysts within the tick’s hemocoel, and an increased density of bacterial colonies on the cuticle surface. Together, these macroscopic and microscopic characteristics provide reliable indicators that a tick is diseased.