Onchocercosis occurs mainly in Africa, mainly in the equatorial zone, some South American countries and the Arabian Peninsula. The more common name for this dangerous, parasitic disease is river blindness, because it can lead to partial or complete blindness.

River blindness( onchocerkoza ) is caused by parasites from the nematode speciesOnchocerca volvulus , which are transmitted (vector) by a small black hair of the genusSimulium . It lives in river areas, mainly in Africa in the equatorial zone, in South America (some areas of Brazil, Colombia, Ecuador, Bolivia) and mainly in Yemen on the Arabian Peninsula. Infection occurs as a result of a bite - the insect feeds on blood, and at the same time the nematodes penetrate the human skin. There, after about a year, they reach their adult form (a single filaria can be even several dozen centimeters long), which is capable of assembling larvae (microfilariae) living in human tissues.

River blindness (onchocercosis): symptoms

The first disturbing symptoms, indicating the possibility of infection with the parasiteOnchocerca volvulus , concern the skin. It begins to itch (itching mainly affects the lower body, thighs and buttocks), there are changes in the form of subcutaneous lumps or urticaria, with visible, erythematous-edema changes on the body. In the course of onchocerciosis, there is a sowda - lichenous atrophic dermatitis on the limbs or the trunk. These are asymmetrical, itchy, discolored lesions of excessively keratinized, flaky epidermis. The loss of hair and sweat glands, along with the enlargement of the lymph nodes in the groin, causes them to be referred to as "hanging groin". With time, the skin becomes saggy, aging quickly, because the larvae destroy collagen and elastin, which are responsible for its firmness. There may also be lumps under the skin that you can feel with your fingers. These are adult parasites gathered in one place, which can live up to 15 years and produce more microfilariae. The skin becomes discolored, ulcers may also appear on it, which peel over time, and local swellings as a result of a malfunctioning lymphatic system.

Another,a symptomatic symptom of river blindness is enlargement of the lymph nodes. It is the body's response to the inflammation taking place within it. If the disease is not diagnosed and treatment is not initiated at an early stage, further infection of the body occurs.

The characteristic symptoms of river blindness are those affecting the eyes: conjunctivitis and iris inflammation, changes inside the eyeball (e.g. on the retina), corneal opacity, and with time also its hardening. It turns out that the most dangerous are dead nematodes around which inflammation forms. This can lead to irreversible changes in the organ of vision - to partial or even complete blindness.

River blindness (onchocercosis): research

To be absolutely sure that we are dealing with river blindness, doctors perform a number of tests. The simplest is a skin biopsy and placing a fragment of it in a special solution, where you can observe the nematodes moving through the microscope. Sometimes, surgical removal of the subcutaneous tumor is also performed and checking whether there are adult specimens of the parasite there. Yet another method is to examine the anterior segment and the fundus, where you can see the nematodes and the inflammation around them. In the advanced stage of river blindness, the symptoms are so characteristic that the tests are only a formal confirmation of the disease.

River blindness (onchocercosis): treatment

The primary drug for onchocercosis is ivermectin. It is usually administered once every six months, and the treatment lasts at least 15 years (as long as an adult parasite lives). In practice, the drug is taken for life, because it does not kill adult parasites, but only the larvae. Ideally, treatment is started in the early stages of the disease, then there is a greater chance of inhibiting its progress, and the symptoms will be limited only to the skin or lymph nodes, and will not affect the eye. Scientists are currently working to develop a drug that will fight adult nematodes, but also to create a vaccine that would prevent this dangerous disease.

River blindness (onchocerkosis): prevention

The easiest way to avoid parasite infestation that causes river blindness is to avoid places where the commonSimuliumlive. They do not have the ability to move too far (usually about several hundred meters), therefore their area of ​​occurrence is limited. However, if we find ourselves in areas where they can be found, it is worth taking care of the appropriate outfit - wearing clothes with long sleeves, long pants, covering the ankles,head. You can also use ready-to-buy anti-fluff preparations or natural essential oils with the scent of vanilla and eucalyptus, because they do not like these smells.

Category:

Parasitic diseases