Blood parasite Bloodstream microfilaria 2023-03-19T14:37:40Z Filariasis is an infectious parasitic disease caused by roundworms that belong to the family Filarioidea. These are spread by bloodfeeding insects such as black flies and mosquitoes. Eight known filarial nematodes use humans as their definitive hosts. See Figure 1 of PMID:32313484. Presence of filaria in the blood stream. Filariasis is a common cause of elephantiasis in Coastal Districts of India. The initial manifestations are repeated episodes of fever with chills and rigor, lymphadenopathy which gradually progress to elephantiasis. In India filarial infestation is commonly caused by W. bancrofti and Brugia malayi, the former responsible for almost 98 percent of all cases.