Filariasis is a parasitic disease caused by an infection with roundworms of the Filarioidea type. These are spread by blood-feeding insects such as black flies and mosquitoes. They belong to the group of diseases called helminthiases. These parasites exist in the wild in subtropical parts of southern Asia, Africa, the South Pacific, and parts of South America. One does not acquire them in temperate areas like Europe or the United States.Eight known filarial worms have humans as a definitive host. These are divided into three groups according to the part of the body they affect:

Lymphatic filariasis is caused by the worms Wuchereria bancrofti, Brugia malayi, and Brugia timori. These worms occupy the lymphatic system, including the lymph nodes; in chronic cases, these worms lead to the syndrome of elephantiasis. Subcutaneous filariasis is caused by Loa loa (the eye worm), Mansonella streptocerca, and Onchocerca volvulus. These worms occupy the layer just under the skin. L. loa causes Loa loa filariasis, while O. volvulus causes river blindness. Serous cavity filariasis is caused by the worms Mansonella perstans and Mansonella ozzardi, which occupy the serous cavity of the abdomen. Dirofilaria immitis, the dog heartworm, rarely infects humans.The adult worms, which usually stay in one tissue, release early larval forms known as microfilariae into the persons blood. These circulating microfilariae can be taken up during a blood meal by an insect vector; in the vector, they develop into infective larvae that can be spread to another person.
Among recent-onset users individual rates of dependency were higher for smoking (3.4 times) and much higher for injecting. Women were 3.3 times more likely to become dependent, compared with men. Users who started at ages 12 or 13 were four times as likely to become dependent compared to those who started between ages 18 and 20.However, a study of non-deviant users in Amsterdam found a "relative absence of destructive and compulsive use patterns over a ten year period" and concluded that cocaine users can and do exercise control. "Our respondents applied two basic types of controls to themselves: 1) restricting use to certain situations and to emotional states in which cocaines effects would be most positive, and 2) limiting mode of ingestion to snorting of modest amounts of cocaine, staying below 2.5 grams a week for some, and below 0.5 grams a week for most. Nevertheless, those whose use level exceeded 2.5 grams a week all returned to lower levels". Treatment
Therapy
Twelve-step programs such as Cocaine Anonymous (modeled on Alcoholics Anonymous) have been widely used to help those with cocaine addiction. Cognitive behavioral therapy (CBT), dialectical behavior therapy (DBT), rational emotive behavior therapy (REBT), and motivational interviewing (MI) can be especially powerful approaches to treating cocaine addiction. Cognitive behavioral therapy (CBT) combined with motivational therapy (MT) have proven to be more helpful than 12 step programs in treating cocaine dependency. However, both these approaches have a fairly low success rate as research suggests that the withdrawal symptoms can last for several weeks.