Why do fleas not bite me but bite others? - briefly
Fleas locate hosts by sensing carbon dioxide, body heat and particular skin odors, and individuals who emit weaker or different cues are less attractive to the insects. Consequently, the parasites preferentially bite others whose scent profile or temperature provides a stronger stimulus.
Why do fleas not bite me but bite others? - in detail
Flea feeding behavior depends on host chemistry, skin temperature, and immune response. Individual variation in these factors determines whether a person becomes a target.
Skin surface compounds such as lactic acid, ammonia, and certain fatty acids attract fleas. Higher concentrations of these chemicals create a stronger olfactory cue, prompting the insect to approach and bite. People who produce lower levels of these attractants experience fewer bites.
Body heat influences flea activity. Fleas locate hosts by detecting infrared radiation. Individuals with lower peripheral temperature or reduced heat emission generate a weaker thermal signal, decreasing the likelihood of detection.
Blood type can affect susceptibility. Research indicates that type O blood releases more volatile substances than type A or B, making type O individuals more attractive to fleas. Consequently, people with non‑type O blood may receive fewer bites.
Immune factors also play a role. Some hosts develop rapid histamine release and localized inflammation, which can deter further feeding. Repeated exposure may strengthen this defensive response, reducing bite frequency over time.
Key determinants can be summarized:
- Chemical attractants: lactic acid, urea, fatty acids
- Thermal signature: skin temperature and infrared emission
- Blood group: type O associated with higher attractiveness
- Immune reaction: rapid histamine response limiting feeding
Environmental conditions, such as humidity and the presence of pet hosts, modify these personal factors but do not override them. Understanding the interplay of chemistry, temperature, blood type, and immunity clarifies why certain individuals are rarely bitten while others attract frequent flea activity.