), and move to the proboscis and into the saliva in its third larval stage (J3.). Maturation takes about seven days. The black fly takes another blood meal, passing the larvae into the next human hosts blood. The larvae migrate to the subcutaneous tissue and undergo two more molts. They form nodules as they mature into adult worms over six to 12 months. After maturing, adult male worms mate with female worms in the subcutaneous tissue to produce between 700 and 1,500 microfilaria per day. The microfilaria migrate to the skin during the day, and the black flies only feed in the day, so the parasite is in a prime position for the female fly to ingest it. Black flies take blood meals to ingest these microfilaria to restart the cycle. Diagnosis
Diagnosis can be made by skin biopsy (with or without PCR) or antibody testing. Classification
Onchocerciasis causes different kinds of skin changes, which vary in different geographic regions; it may be divided into the following phases or types:: 440–441 
Erisipela de la costa
An acute phase, it is characterized by swelling of the face, with erythema and itching. : 440  This skin change, erisípela de la costa, of acute onchocerciasis is most commonly seen among victims in Central and South America.Mal morando
This cutaneous condition is characterized by inflammation accompanied by hyperpigmentation. : 440 
Sowda
A cutaneous condition, it is a localized type of onchocerciasis.
Findings of a phylogenetic study in the mid-90s are consistent with an introduction to the New World in this manner. DNA sequences of savannah and rainforest strains in Africa differ, while American strains are identical to savannah strains in western Africa. The microfilarial parasite that causes the disease was first identified in 1874 by an Irish naval surgeon, John ONeill, who was seeking to identify the cause of a common skin disease along the west coast of Africa, known as "craw-craw". Rudolf Leuckart, a German zoologist, later examined specimens of the same filarial worm sent from Africa by a German missionary doctor in 1890 and named the organism Filaria volvulus.Rodolfo Robles and Rafael Pacheco in Guatemala first mentioned the ocular form of the disease in the Americas about 1915. They described a tropical worm infection with adult Onchocerca that included inflammation of the skin, especially the face (erisipela de la costa), and eyes. The disease, commonly called the "filarial blinding disease", and later referred to as "Robles disease", was common among coffee plantation workers. Manifestations included subcutaneous nodules, anterior eye lesions, and dermatitis. Robles sent specimens to Émile Brumpt, a French parasitologist, who named it O. caecutiens in 1919, indicating the parasite caused blindness (Latin "caecus" meaning blind). The disease was also reported as being common in Mexico.