Formally known as midges but also referred to as punkies, biting midges and sand flies, they are often mistaken for mosquitos or fleas. The insects are usually found in the great outdoors, chomping away at gardeners, hikers, farmers and beachgoers.
The no-see-ums are from the genus Culicoides, and the adults are less than 1/16th of an inch long. Many people associate no-see-ums with beaches, perhaps in the mistaken belief that they are sand flies. But the tiny bugs are found anywhere that has moist soil or fertilizer exposed to the air, including forests, wetlands and farm pastures.
They are active in the early morning and the beginning of the evening of the summer and are particularly active on cloudy days with little to no wind. Any exposed skin is fair game for these critters, but they seem to prefer the legs, arms and back of the neck for their attacks. Adults rarely roam far from the nest, so those encountering a dense area of no-see-ums may find none just a few hundred yards away. Because they aren’t great fliers, windy days likely will keep their presence to a minimum.
No-see-ums feed on flowers, but the female of the species feeds on blood to help her eggs mature into viability. No-see-um eggs are found mostly in moist soil, and favorite breeding grounds include the edges of seashores, ponds, rivers, streams, springs, muddy areas, swamps, tree holes and occasionally accumulated water from air conditioners.
They thrive when the soil has been plowed or otherwise disturbed, creating ideal, moist conditions for the eggs. The no-see-ums lay eggs in standing water, where the larvae feed on decomposing organic matter, quickly becoming pupa and then, within just a few days, they turn into adults who leave the nest in search of food and to mate.
Adult females use their dagger-like mouths to gash holes in your skin -- the better to suck your blood. Like their cousins, the mosquito, the no-see-ums have an anti-coagulant in their saliva. This can cause a major reaction in sensitive people.
Painful Bites – with Infection Potential
The no-see-ums pack a painful wallop out of proportion to their tiny size. Unfortunately, there is no numbing agent in the no-see-um saliva, which means you’ll be aware of being bitten instantly and feel the pain. The bites typically will produce a small red welt, which sometimes manifests into a water-filled blister. That usually develops into an itchy nuisance that can break and bleed. Because no-see-um bites come in batches and tend to be in the same area of the body, you can develop a hot zone of bites quickly.
That’s when the danger of infection looms, and particularly sensitive individuals may develop long-lasting, painful lesions. You may have an allergic reaction that can last up to two weeks if you’re sensitive to bug bites.
Some no-see-ums can carry pathogens that will transmit certain diseases to animals and humans. A species of no-see-um called the Culicoides sonorensis is known to harbor the bluetongue virus, which typically is passed to cattle and sheep.
In humans, no-see-ums can spread parasitic skin worms, an affliction primarily confined to tropical areas. A swarm of bites can lead to a high fever and the onset of itchy bumps. But the pathogens can remain active for months and can develop into a disease called leishmaniasis.
No-see-ums found in Asia and Africa (the genus Phlebotomus) and those in Latin America and the Caribbean (the genus Lutzomya) generally carry the Leishmania parasite. In fact, these bugs carry more than 20 protozoan parasites and can cause severe reactions -- fatal ones, in some cases -- caused by toxins transmitted to major body organs.
Leishmaniasis is estimated by the World Health Organization to affect up to 12 million people in 88 countries, generated an annual two million new cases. The leishmania-carrying no-see-ums are particularly entrenched in Honduras, Belize, Mexico, Hispaniola and Trinidad. In Asia, they are active in Thailand, and in the Middle East, in Egypt.
The problem for those acquiring leishmaniasis is that diagnosis is sometimes difficult. Leishmaniasis is just one of the many tropical diseases that travelers can acquire and accounts for less than 5 percent of tropical diseases. Most physicians in the United States are not particularly well-versed in tropical diseases, so a specialist might be needed to get an accurate diagnosis.
Leishmaniasis features sores that can resemble a small volcano, with a raised edge and central crater. They present with a scab but may not be painful. They may affect nearby glands, particularly if bitten under the arm.
The no-see-um is akin to a flea, in that they seem to communicate and flock to a happy hunting ground, aka you. When no-see-ums find a human with exposed skin, they will often swarm the individual. You can get several bites from an individual no-see-um and will experience several to many bites at once.
Bite Treatments
For just a normal range of no-see-um bites, dermatologists generally recommend topical cortisone creams for treatment or non-steroidal anti-inflammatory drugs like ibuprofen or aspirin. Severe reactions likely will require a doctor visit. For the more serious leishmaniasis, intravenous drugs may be used.
Taking Precautions
If you plan to be walking outdoors during the mid-to-late summer, the height of the no-see-um season, it’s a good idea to coat exposed skin areas (except the face) with a DEET-infused insect repellent, although such sprays are not totally effective in stopping them. Some botanical insect repellents that contain eucalyptus, citronella or other plant-based extracts may work).
Clothing should include long-sleeved shirts, shoes, socks and long pants, plus a hat, particularly those with fine mesh embedded in the fabric. Those with extreme sensitivity should consider head nets, jackets and pants that are certified as no-see-um-proof. Or simply avoid walking in areas or quickly pass through where no-see-ums are likely to breed and be active, which include areas near most bodies of water.
Because they are so tiny, no-see-ums can penetrate most household screens or netting easily. Extremely tight mesh may help keep them out, particularly when treated with insecticides like permethrin. It's recommended to run a fan to keep them blowing in the wind as well.
Just a few precautions when traveling in no-see-um areas can spare you from these annoying creatures. Cover up, don’t linger in areas near standing water and take care never to scratch any welts that develop.