Schamberg's Disease

Loa-loa has been known for over three hundred years and is probably of West African origin. It was first described by Guyot in 1778, and in 1891 Manson found a new species of micro-filaria in the blood of two negroes, in one of whom a worm had crossed the eyeball. This newly discovered parasite showed slight morphological differences from Filaria bancrofti, and it was only found in the blood during the daytime, so Manson called it Filaria dittrna. The mangrove fly was suspected of carrying the larval form of the parasite, and after infection of the human subject development was very slow, and adult worms might not appear for from three to five years. In some recorded cases worms have been found 4 to 5 cm. in length and 0 * 3 mm. thick. They can move 2 to 3 cm. per minute in the loose subcutaneous tissues, and occasionally they cross the ball of the eye. It was supposed that the adult worms moved about until fertilization was accomplished, and then the female found a site near a blood-vessel where she deposited ova so that the young filarie could enter the blood-stream. Worms have been seen at intervals in a single host for fifteen years. The other peculiar feature of loa-loa is the appearance of Calabar swellings, which arise as painless tumours oval or round, up to 8 cm. in diameter, somewhat inflamed, not pitting on pressure and usually disappearing spontaneously in three or four days.