Clinical manifestations are often delayed for months or years and can continue for up to 17 years. They are caused by migration of the adult worm through the subcutaneous and deeper tissues of the body, leading to recurring or Calabar swellings. Allergic reactions, arthritis and neurological symptoms can occur. Diagnosis may be complicated by the presence of other filarial infections, especially onchocerciasis. The microfilarial have a day-time periodicity.