One mosquito bite, zoomed in Cross-section of the skin under a feeding mosquito. Its mouthpart passes through the stratum corneum, epidermis and dermis to a small blood vessel. Saliva goes in with it, and any germ in the saliva is carried off in the blood. ONE BITE, ZOOMED IN PHASE 1 · HEALTHY CROSS-SECTION, NOT TO SCALE Mouthpart Slides through the skin to a vessel. Stratum corneum The outer barrier of flat, dead cells. Epidermis Living skin cells. Dermis Collagen and small blood vessels. Saliva + germ Goes in with the mouthpart. Blood vessel Any germ is carried off in the blood.

Mosquito- and tick-borne disease: R&R Lotion, Vector-Borne Diseases: Causes, Prevention & Treatment, white paper, p. 6. Illustration for education only.