“Sand fleas” is a common name referring to several tiny, biting organisms found in beach environments. In many coastal areas, the term refers to biting midges, also known as “no-see-ums” or sand flies, which are small insects that feed on blood. It may also refer to chigoe fleas, which can burrow into the skin, or harmless beach hoppers, which are small crustaceans that do not bite humans. Given the potential for painful, itchy reactions, understanding how to prevent contact with these pests is important for anyone spending time near the water. This article focuses on practical strategies to minimize exposure to the biting varieties of these beach dwellers.
Topical and Physical Barriers
Applying an effective topical repellent to exposed skin creates a chemical barrier that deters biting insects. The most effective active ingredients include DEET, picaridin, and oil of lemon eucalyptus (OLE), the only plant-based ingredient recommended by the Centers for Disease Control and Prevention (CDC). DEET concentrations between 20% and 40% offer long-lasting protection. Picaridin in a 20% formulation is comparable in efficacy and does not damage synthetic materials like plastics. For oil of lemon eucalyptus, a concentration of 30% or greater is recommended.
Repellent should be applied to all exposed skin and reapplied after swimming or excessive sweating, as water can quickly wash away the protective layer. Lotion-based formulations may offer longer protection than sprays or aerosols, as they adhere more consistently to the skin. Always read the label and follow the manufacturer’s directions, especially when applying products to children.
Physical barriers formed by clothing are just as important as chemical ones. Wearing long-sleeved shirts and long pants made of tightly woven fabric can block the tiny mouthparts of biting midges. Light-colored, loose-fitting garments are often recommended, as they make the wearer less conspicuous to some insects and reduce the chance of biting through the material. Tucking pants into socks and wearing closed-toe shoes provides an additional layer of defense for the ankles and feet, which are frequent targets.
Avoiding Peak Activity Times and Habitats
Modifying your behavior based on when and where the pests are most active significantly reduces the risk of bites. Biting midges are most active during calm conditions, particularly around dawn and dusk, though they may continue to bite throughout the night or on overcast days. Avoiding the beach or sandy areas during these twilight hours is a highly effective preventative measure. The emergence of adult midges is sometimes associated with new and full moon phases, suggesting local knowledge of peak activity is helpful.
Biting midges and chigoe fleas thrive in specific environments, making habitat avoidance important. They are often found in damp, sandy soil, areas near water bodies, and places with moist, decaying leaf material or seaweed debris. Staying on dry, exposed sand away from the high-tide line, mangrove swamps, or estuarine areas minimizes contact. Because these insects are close to the ground, using an elevated beach chair or a thick blanket instead of sitting directly on the sand creates physical separation from their habitat.
Securing Shelters and Gear
Protecting temporary shelters and personal gear is a necessary step to prevent bites and stop the pests from being carried home. Standard mosquito netting is often insufficient to stop tiny biting midges, which are often less than 2 millimeters long. Tents, caravans, and windows should be screened with a fine mesh (such as a 30 x 20 weave or 0.6mm hole size) to physically exclude the smaller insects. For permanent structures, fine-mesh flyscreens can be made more effective by applying a residual surface spray insecticide to the screen itself.
Pre-treating clothing and gear with permethrin provides a long-lasting defense, offering protection for up to six weeks or six washes. Permethrin is an insecticide that bonds to fabric fibers, killing or repelling insects that land on the material, but it should never be applied directly to the skin. This treatment is best used on outdoor gear like tents, backpacks, hats, and the cuffs of pants and socks.
Upon returning from an infested area, a strict post-exposure protocol prevents bringing the insects into your dwelling. Towels, blankets, and shoes that have been in contact with the sand should be vigorously shaken out outdoors before entering a vehicle or home. All clothing worn during the outing should be removed and immediately washed in hot water to eliminate any hitchhiking insects or eggs.