My first acquaintance with North American no see ums was in 1996. A novice to the biting midges, sand flies and the other names by which these tiny biting insects are known I slept in an open boat under the stars.
In the morning I was in excruciating pain and my skin itched like fire. I counted forty three no see ums bites on my left foot and gave up trying to assess the numbers after that. The itching continued for days in all the areas where my blanket had not protected me that night. My feet were swollen. I felt drowsy and I'm sure I had a mild fever. It was a bad start to my vacation.
My medical mind was interested in just what had caused this reaction. No see ums are after all small, often too small to be seen. My experience seemed out of all proportion.
Research has shown that the reaction we have to no see um bites is due to the proteins in their saliva. Most allergic reactions involve our immune system reacting to and attacking invasive proteins. Pollen allergies and food allergies are usually triggered by proteins. No see ums are no different. When the female bites us seeking blood to nourish her eggs, her saliva enters the bite to increase the flow. This creates a local allergic reaction where our immune system triggers a response from an immunoglobulin, IgE to counter the invading protein.
The IgE can cause our natural Mast cells in the tissues surrounding the reaction to release a cascade of chemicals. These include histamine, inflammatory prostaglandins and immune signaling compounds called cytokines which escalate the inflammatory response. These chemicals are very irritating and cause the itching, swelling and fluid leaking associated with no see ums bites.
On top of this the bites can become infected if not washed well.
One bite is bad enough. However no see ums are often seen as dark swarms where their habitat encourages breeding. Any wetland, swamp, water, forest, pond, stream, beach, can be home to thousands. No see ums are particularly active at dawn and in the evenings as the weather warms. The unwary visitor, exposing unprotected skin, can receive multiple bites in minutes. The females will also give multiple bites seeking our blood.
Protection for ourselves and especially our children is essential. Long pants, long sleeved shirts, hats, even specialized no see ums head nets and combination head and shirt all-in-ones are the first line of defense. These netting clothes have tiny netting too small for the 1 millimeter insects to get through.
Insect repellents are valuable although there are health concerns over the effects of the very strong ones on our bodies.
If you are bitten then anything from ice to antihistamines can be used to reduce the itching and pain. Antihistamines can help but only with medical advice. Do not shy away from medical help if you feel you need it, especially for children.
After my experience in 1996 I go out into the no see ums territory with a full set of clothing and an arsenal of first aid.