"Reaction" - what is it, definition of the term
A response, in chemical and biological contexts, is a measurable change in a system provoked by an external stimulus; it entails the transformation of initial substances into distinct products, the redistribution of energy, and the activation of signaling or metabolic pathways that alter the system’s state.
Detailed information
Ticks, bugs, lice and fleas are hematophagous arthropods that trigger immediate physiological changes in the host. Their saliva contains anticoagulants, vasodilators and immunomodulatory proteins that facilitate blood ingestion. The host’s skin reacts with erythema, edema and pruritus within minutes to hours after the bite. These manifestations result from histamine release, prostaglandin synthesis and activation of sensory nerve endings.
Systemic effects may develop when pathogens are transmitted during feeding. Common agents include Borrelia spp. (tick‑borne Lyme disease), Rickettsia spp. (flea‑borne typhus), Bartonella spp. (lice‑borne trench fever) and various viruses carried by bugs. The ensuing immune response involves cytokine production, acute‑phase protein elevation and, in severe cases, organ‑specific inflammation. Early detection relies on recognizing characteristic rash patterns, fever spikes and laboratory markers such as elevated C‑reactive protein or leukocytosis.
Preventive measures focus on interrupting the contact chain. Effective strategies comprise:
- Regular inspection of skin and clothing after potential exposure.
- Use of insect‑repellent formulations containing DEET, picaridin or IR3535.
- Maintenance of environmental hygiene, including washing bedding at high temperatures and applying residual insecticides to pet habitats.
- Prompt removal of attached arthropods with fine‑point tweezers, grasping close to the skin to avoid mouthpart rupture.
Therapeutic interventions depend on the severity and pathogen involved. Localized symptoms respond to topical corticosteroids and antihistamines. Systemic infections require antimicrobial agents selected according to susceptibility profiles—doxycycline for many rickettsial diseases, amoxicillin for early Lyme disease, and appropriate antiparasitic drugs for lice infestations. Monitoring for complications, such as secondary bacterial infection or neuroinflammation, is essential for optimal outcomes.