The pathogenesis of<unk>  infection is dependent on the immune system and inflammatory responses of the host. After infection, the worms mature within 6–8 months, male and female worms mate and then release the microfilariae. These microfilariae can be released for up to 10 years. # The asymptomatic phase usually consists of high microfilaremia infection, and individuals show no symptoms of being infected. This occurs due to cytokine IL-4 suppressing the activity of TH1 cells in the immune system. This can occur for years until the inflammatory reaction rises again. # In the inflammatory (acute) phase, the antigens from the female adult worms elicit inflammatory responses. The worms in the lymph channels disrupt the flow of the lymph, causing lymphedema. The individual exhibits fever, chills, skin infections, painful lymph nodes, and tender skin of the lymphedematous extremity. These symptoms often lessen after 5–7 days. Other symptoms that may occur include orchitis, an inflammation of the testes, which is accompanied by painful, immediate enlargement and epididymitis (inflammation of the spermatic cord). # The obstructive (chronic) phase is marked by lymph varices, lymph scrotum, hydrocele, chyluria (lymph in urine), and elephantiasis. Microfilariae are not normally present in this phase. A key feature of this phase is scar formation from affected tissue areas. Other features include thickening of the skin and elephantiasis, which develops gradually with the attack of the lymphatic system. Elephantiasis affects men mainly in the legs, arms, and scrotum. In women, the legs, arms, and breasts are affected.
Wuchereria bancrofti
Onchocerca volvulus
Schistosoma haematobium
Taenia solium
Schistosoma intercalatum
Echinostoma revolutum
Schistosoma japonicum
Taenia asiatica