The filarial worm is a type of parasitic roundworm belonging to the family Filariidae. These worms are primarily transmitted to humans through the bites of infected mosquitoes or other blood-feeding insects. Once inside the human body, they can cause various diseases, including lymphatic filariasis, which leads to severe swelling and discomfort. Filarial worms can live for several years in the human lymphatic system, where they reproduce and release microfilariae into the bloodstream. These microfilariae can then be picked up by another mosquito, continuing the cycle of transmission. Effective treatments and preventive measures are essential to control the spread of these parasites.