What does a tick inject when it bites? - briefly
A tick injects saliva that contains anticoagulants, anesthetic compounds, and enzymes to suppress the host’s immune response. These components enable prolonged blood feeding and can carry disease‑causing pathogens such as Borrelia bacteria.
What does a tick inject when it bites? - in detail
When a tick attaches to a host, it inserts saliva into the feeding site. The saliva contains a complex mixture of biologically active molecules that facilitate blood ingestion and protect the parasite from host defenses.
The principal constituents are:
- Anticoagulants – proteins such as tick anticoagulant peptide (TAP) and ixolaris inhibit thrombin and factor Xa, preventing clot formation and maintaining fluid flow.
- Platelet‑inhibiting agents – apyrase hydrolyzes ADP, reducing platelet aggregation; other factors block platelet‑activating receptors.
- Immunomodulators – salivary proteins like Salp15 bind to host CD4⁺ T‑cells, suppressing cytokine production; complement‑inhibiting proteins interfere with the complement cascade, diminishing inflammatory responses.
- Analgesics and anti‑inflammatory compounds – prostaglandin E₂ and histamine‑binding proteins lower pain perception and reduce swelling at the bite site.
- Enzymes – metalloproteases degrade extracellular matrix components, facilitating mouthpart penetration and tissue remodeling.
- Pathogen transmission agents – when infected, ticks deliver bacteria, viruses, or protozoa embedded in the saliva, including Borrelia burgdorferi (Lyme disease), Anaplasma phagocytophilum (anaplasmosis), Rickettsia spp., and tick‑borne encephalitis virus.
The coordinated action of these molecules creates a localized environment where blood remains unclotted, immune detection is dampened, and the host experiences minimal discomfort, thereby maximizing the tick’s feeding efficiency and increasing the likelihood of pathogen transfer.