During the hot summer, flies become more active. Besides transmitting bacteria, flies can also lay eggs on humans and animals, particularly on patients and elderly individuals who are often bedridden, physically disabled, or lack self-care ability. This can lead to myiasis, a condition caused by the infestation of fly larvae.

Flies lay their eggs on wounds, abrasions, ulcers, or mucous membranes, especially those contaminated with excreta. After hatching, the larvae will burrow into the tissues of humans or other vertebrates, causing open sores, foul-smelling secretions, organ dysfunction, and skin damage. Therefore, nursing homes and places where people with limited self-care ability reside should be particularly vigilant.