infections
Loiasis
Transmission of loiasis
Loiasis is transmitted when an infected African deer fly or horse fly bites a person and deposits larvae of the worm. The larvae enter through the bite wound and mature into adult worms in the tissues under the skin (subcutaneous tissues). The adult worms travel in tissues under the skin and under the clear mucous membrane that covers the eyes. Adult worms may be about 1 to 3 inches (3 to 7 centimeters) long. The adult worms produce immature worm larvae (called microfilariae) that circulate in the bloodstream during the day and stay in the lungs at night. The infection is spread when the infected person is bitten by a fly during the day, when microfilariae are in the bloodstream. The fly then transmits larvae of the worm when it bites another person. 