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Flies Are More Dangerous Than You Think!

Flies Can Cause Blindness?!Flies are one of the filthiest insects in the world. In fact, according to an entomologist, which is someone who studies insects, named Ron Harrison, Ph.D., they’re twice as filthy as cockroaches!

You may not have always known that last part (we didn’t either), but we’re sure that you already know that flies are notorious for carrying and transmitting all sorts of disease-causing pathogens. They’re known to spread about 65 known diseases, including Dysentery, Salmonellosis, Typhoid fever, Tuberculosis, Cholera, and an infection that causes blindness, known as Onchocerciasis.


What’s Onchocerciasis?

Onchocerciasis, commonly known as river blindness, is an infection caused by a parasitic worm known as Onchocerca volvulus. As you probably may have already guessed, the infection is spread by none other than flies, blackflies to be exact.

According to the Centers for Disease Control and Prevention, the World Health Organization (WHO) stated that in the year 2013, about 25 million people went blind from Onchocerciasis. Who knows how many are suffering from the infection today.


How Do You Get River Blindness?

Flies Can Cause Blindness?!When a blackfly feeds from an infected person, it also picks up Onchercerca larvae, which then migrate into its muscles, where the larvae will continue to develop. After 10 to 12 days, the larvae become infective to humans and migrate to the blackfly’s mouth, where they lie in wait of their next victim.

On the fly’s next blood meal, the larvae are injected into human skin and mature into adult worms in about 3 months to a year. They can form visible bumps under the skin, usually near joints and muscles, and live up to 15 years in the human body.


Where is River Blindness Most Common?

Last year, WHO said that 205 million people were living in areas known to have Onchocerca-infected blackflies. However, Onchocerciasis or river blindness is found to be most common in Western Africa, Central Africa, Yemen, and Latin America (Brazil, Colombia, Ecuador, Mexico, Guatemala, and Venezuela). In the United States and Europe, the disease is rare but can be brought in by people who travel to and from endemic countries.


What Are the Symptoms of River Blindness?

Flies Can Cause Blindness?!It’s possible for infected people to not experience any symptoms nor show outward signs of infection. Sometimes the larvae can live inside the body without triggering a response from the immune system. However, most people do have symptoms, like intense itching, itchy skin rashes, bumps beneath the skin, skin irritation or swelling, and discolored patches of skin.

As the infection progresses, eye symptoms may start to appear. This can include gradual vision loss, reddening of the eyes, eye pain, light sensitivity, and clouding of the front surface of the eye. These issues happen as a response of larvae dying inside the eye area. The good news is, when treated in time, they can be reversed. If left untreated for a long time, however, the damage becomes permanent.


How Is River Blindness Treated?

Treatment will depend on the severity of the infection. If caught early, river blindness is normally treated with the anti-parasitic drug ivermectin, which is known as the most effective medication used against the disease. In more advanced cases, eye surgery may be required.

Common surgeries include corneal transplant (where the damaged cornea is replaced with a healthy one from a donor), cataract removal (where the clouded eye lens is removed and replaced with a new one), and glaucoma surgery that may involve laser treatment or a small cut in the eye to reduce pressure.


How Can River Blindness Be Prevented?

Flies Can Cause Blindness?!Unfortunately, there’s no vaccine for river blindness, so the best way to prevent yourself from getting infected is to make sure your environment is free of flies. If you live in, or travel to, endemic locations, make sure that you protect yourself with an insect repellent at all times.

Aside from people, there are cases where pets have fallen victim to river blindness, too. So for your furry friend’s safety, it’s best that you protect them with bug spray, as well, especially if you often take them with you outdoors or on trips. You can check out our favorite ones for pets here.

Additionally, try to avoid streams, rivers, and other fast-flowing bodies of water, since blackflies generally breed in those areas. Another useful tip is to wear light-colored clothing because blackflies seem to be drawn to dark colors.


Have you heard about river blindness before?