Eye Worm in Human | Loa Loa Filariasis

eye worm

A parasitic eye worm, also known as African eye worm, is known as Loa loa. The infection is called loa loa filariasis. This eye worm parasite is transferred to humans by the bite of deerflies or mango flies, of the genus Chrysops. These flies get infected by biting and sucking the blood of an infected person first. These are most commonly found in the rain forests of Central and West Africa. People traveling from these areas, when bitten with these flies are usually affected. This is a relatively very rare disease. But before we get on the description of the Eye worm or Eye Parasite let’s first look at what are parasites?


Parasites are organism that derives food and nutrition and also lives on the host and thus depends completely on the host. At the expense of the host the parasite derives nutrition and actually survives on the host’s food and shelter. The parasite effectively deprives the host of the nutrition that it needs.

These parasites typically live in or on the bodies of the host organism. Some parasites are also harmful, since they can cause infections. If they are inside the body, such organisms then reach their destination organ, eyes are just such organs i.e. Eye parasites. There can be different types of parasites; Protozoa, helminthes or Ectoparasites.

Symptoms of Eye Parasites

General symptoms of eye parasites are not always very apparent. And they may also be difficult to understand and recognize. These may include inflammation of the eyes, or redness, blurry vision, sensitivity to light, excessive tear production, pain in the eyes, crusting eyelids, retinal scarring, and also blindness or loss of vision

The signs and symptoms of eye parasites are not very apparent in most people, and usually do not even present themselves for days or even months after inoculation. Although with loiasis or African eye worm infection, the most commonly presented are swellings which are non-painful, these may be accompanied with itchiness, around the swelling. These are not persistent, but usually transient meaning that these swellings come and go. The Loa Loa filariasis symptoms may be swellings, itchiness and irritation.

There may be worm in eye symptoms; that is development of an eye worm crawling inside the surface of the eye. There may also be other symptoms like worm crawling under the skin, or swelling in and around the joints, or itching in different parts of the body. These symptoms may present along with high levels of eosinophils in the blood, which can be seen in blood reports. There are different eye parasites in humans, some of which are given below:

Eye Parasites in Humans

Other than loa loa filariasis there are other organisms that can be eye parasites in humans. Acanthamoeba may be such an organism. This organism can effect vision and can be dangerous. Transmission usually is through direct contact in the marine and fresh water environments in which it is present. Another Eye parasite may be toxoplasmosis, present in mostly animal waste especially among pets for example cats. Its transmission is through ingestion, although a thing of concern is that the parasite can be passed in pregnancy from mother to the fetus. As is typical of eye parasites normally do not present with signs or symptoms. Immuno- compromised individuals especially children develop eye worm infections. But if left untreated, they can cause severe scarring or even vision loss.


Seeing worms in eyes would be a terrifying experience, but that’s what happens with Loiasis. This is caused by a helminth parasite, as discussed before mostly found in Africa. T Endemic to the West and Central Africa Loiasis infection is from the filarial nematode called Loa loa. The infection is acquired from the infected fly bite, this parasite is then transferred to the body where it develops and then migrates to different areas and tissues. The produced larvae are called microfilariae. Not only the adult worm, but the larvae as well can cause issues in the eye or vision for example impaired movement of the eyes, sensitivity to the light, vision problems and eye pain.


Another eye parasite or human eye worm can be Gnathostomiasis, this particular helminth or human eye worm is found mostly some parts of South America or Central America, and Africa, Southeast Asia, Japan and Thailand. The transmission of infection of this eye infesting worm is through the mouth that is by ingesting uncooked food or raw food like fish or meat. The eye infesting worm or eye parasite then goes to different parts of your body, eyes included from the gastrointestinal tract. This parasite in eye symptoms can affect the eyes vision partially or even in some cases fully.

River blindness (onchocerciasis)

Onchocerciasis is also an eye worm which is a helminth. These parasites are found in the South and Central Americas, the Middle East and some parts of Africa. This is often also known as river blindness. The larvae enter the body through the bite of a blackfly which is already infected or exposed to the parasite. This eye parasite will burrow into the skin and then develop to adults, where they will reproduce so that they can enter into different organs and tissues. If they reach the eyes, the parasite in eye symptoms maybe that it may cause blindness.

Treating Eye Infections

As is the case with any disease the treatment depends upon the type of infection. Or in this case upon the type of parasite, whether eye parasite removal may be necessary or some eye drops to kill parasites would be a better approach. Although different types of medications including topical and oral are available depending again upon the type of infection and parasite. Diethylcarbamazine, ivermectin, or pyrimethamine usually the medicines used for such eye parasites. While some eye worms can be treated through such medicines. But in some extreme cases eye parasite removal may be the recommended approach. Such is the treatment of eye parasites including loa loa filariasis, river blindness,and or gnathostomiasis.