What happens to a tick when it becomes engorged with blood on a cat? - briefly
When a tick feeds on a cat and becomes engorged, its abdomen expands dramatically, the cuticle softens, and the insect reaches the point where it will detach. After dropping off, it seeks a protected environment to molt into the next life stage.
What happens to a tick when it becomes engorged with blood on a cat? - in detail
When a tick attaches to a cat and begins feeding, its mouthparts anchor into the skin and a feeding tube, the hypostome, penetrates the dermis. Saliva containing anticoagulants, anti‑inflammatory agents, and immunomodulatory proteins is injected to keep blood flowing and to dampen the host’s immune response. The tick’s gut expands dramatically as it ingests plasma and red blood cells. During the engorgement phase, the abdomen can increase severalfold in volume, changing from a flat, oval shape to a rounded, balloon‑like form that often protrudes from the cat’s fur.
Physiological changes inside the tick include:
- Rapid uptake of plasma through a series of cuticular pores, followed by concentration of erythrocytes in the midgut.
- Activation of digestive enzymes that break down hemoglobin and other blood proteins.
- Synthesis of proteins for cuticle expansion, allowing the exoskeleton to stretch without rupturing.
- Accumulation of waste products, which are later expelled during the subsequent molt or detachment.
The cat experiences localized inflammation at the bite site, often manifesting as a small, raised lesion. The tick remains attached for several days, typically 3‑7, until it reaches maximal engorgement. At that point, the tick detaches spontaneously or is groomed off by the cat. After detachment, the engorged tick drops to the ground, where it seeks a sheltered environment to complete its life stage, often undergoing a molt to the next developmental stage (larva → nymph → adult) depending on its current stage.
If the tick is not removed promptly, prolonged feeding increases the risk of pathogen transmission, such as Bartonella, Ehrlichia, or Cytauxzoon felis. The enlarged tick also becomes more conspicuous, facilitating detection and removal by owners or veterinary professionals.