Filariasis is a tropical disease caused by parasitic worms, primarily transmitted through the bites of infected mosquitoes. The most common types of filarial worms are Wuchereria bancrofti, Brugia malayi, and Onchocerca volvulus. These worms can lead to severe health issues, including swelling of the limbs and genitals, a condition known as lymphatic filariasis. The disease is prevalent in many parts of the world, particularly in Africa, Asia, and the Pacific Islands. Symptoms may not appear for years, making early detection challenging. Preventive measures include controlling mosquito populations and using medications to reduce transmission.