Integrated saliva-mediated self-cleaning and wound-healing mechanisms in animals: a hypothesis

Abstract

Background: Animals are continuously exposed to environmental contaminants, microbial agents, ectoparasites, and minor injuries, yet many species maintain hygiene and recover from superficial wounds without external intervention.

Objective: This hypothesis manuscript proposes an integrated innate defense model in which grooming behavior, saliva-derived antimicrobial and wound-repair factors, tear antimicrobial activity, and sebaceous secretions act together to support self-cleaning and tissue repair.

Proposed mechanism: Animal saliva contains bioactive components, including lysozyme, lactoferrin, histatins, immunoglobulins, and growth factors, that may contribute to microbial control and wound healing when animals lick their skin, fur, or wounds. Tear secretions similarly contain antimicrobial proteins that protect the ocular surface and assist in debris clearance, whereas grooming behavior distributes saliva and skin lipids while mechanically removing dirt and parasites.

Hypothesis: These interacting behavioral, biochemical, and physiological pathways may be especially active during rest periods, when animals are undisturbed and able to groom. The proposed framework suggests that saliva-mediated grooming, tear antimicrobial activity, and skin secretions constitute a coordinated, evolutionarily conserved innate defense system that contributes to hygiene maintenance, infection prevention, and wound repair.

Research needs: Further comparative and mechanistic studies are needed to test this model and to explore whether saliva-derived antimicrobial and healing compounds can inform bio-inspired veterinary and biomedical therapeutic strategies.