Parasite infestations occur when harmful organisms, known as parasites, invade a host, often causing health issues. Common parasites include lice, fleas, and ticks, which can affect both humans and animals. These organisms rely on their hosts for nourishment and can lead to discomfort, skin irritations, or more serious diseases. Infestations can happen in various environments, such as homes, gardens, or farms. Prevention methods include maintaining cleanliness, using protective measures like insect repellent, and regularly checking pets for signs of parasites. Early detection and treatment are essential to minimize health risks associated with these infestations.