LOA LOA

Loa Loa



Loa loa (the causative agent of loiasis)

Loa Loa

The Loa loa or "African eye worm is a worm that infects humans quite peculiar, is a type of nematode and shaped wire. Located in the hot and humid regions of West Africa where it is so endemic. It may seem unusual, but millions are infected with this parasite. Loa loa, (the causative agent of loiasis) is a filarial nematode transmitted by the bite of Chrysops tabanid flies. The larvae mature into adult worms that travel around the patient's subcutaneous tissue and occasionally in the subconjunctival space. The cycle of infection continues when a non-infected deerfly takes blood from a microfilaremic human host. [1]

Their life cycle begins in two different species of flies that feed on human blood (known as horse flies). There, in the trunk of the Flies, is the loa loa. When one of these fly bites a human being, not only brings a bit of blood but in return will leave a small gift on the skin: Loa loa larvae. These larvae are inserted under the skin through the wound that caused the flies to feed and remain in the subcutaneous tissue. That will start to grow, to become an adult without any clinical manifestation. The dimensions that can reach the adult is 7 cm long and 0.5 mm in diameter and can stay up to 17 years in a person. Females tend to be significantly larger than males. It can take months or years after infection until the individual reaches adulthood and begins to show some kind of signal. They move through the tissue at a speed of 60 cm per hour, which is necessary for the females and males can be found somewhere on the person and have offspring, the microfilariae. These pass into the bloodstream through the capillaries following a daily routine that is exactly the same in which the flies bite people to feed. With a rigorous routine, the microfilariae migrate into the blood from 10 am to 4 pm. If it happens that a gadfly takes to feed and makes contact with one of the microfilariae pass the digestive tract of this and later spread to more people with the next bite, thus closing the life cycle of Loa loa. Other microfilariae, which have not contacted any Tabano, return to the lungs where they will await the next day to return to the blood with the same schedule as always.

Symptoms

The symptoms usually appear until about a year after the bite, the parasites take time to reach adulthood. The males measure from 2 to 3.5 cm. while females can reach 7 cm, with 0.5 mm in diameter. The worm moves freely in the subcutaneous tissue, producing transient swelling in the limbs of less than 30 mm in diameter to stay 2 to 3 days, called Calabar swellings. These swellings appear as pruritic nodule areas that present with pain and are the result of the patient's allergic reaction against the parasite and its ...