Water

Onchocerciasis – An Overview

Onchocerciasis

is a parasitic infection primarily caused by the filarial worm, Onchocerca volvulus. This disease is also known as

‘river blindness’

. The mosquitoes breed in the river water. Hence, this disease is known as ‘river blindness’. Onchocerciasis is spread via bites of the infected blackflies belonging to the Simulium species. These blackflies carry the immature larva’s of the parasite from a infected individual to another individual. The larvae forms nodule in the subcutaneous tissue of the human body and mature into adult worms. The adult female worm releases nearly 1000 microfilariae after mating everyday. The microfilariae move in the body and after they die, they cause complications like skin depigmentation, intense itching, lesions, skin rashes and blindness. Read on to know more about onchocerciasis.

Most of the countries have implemented preventive measures to control onchocerciasis by spraying insecticide on the blackflies breeding sites. Additionally, a drug is used which eradicates the microfilariae, alleviates the symptoms and minimizes the transmission. By the year of 2010, an international effort aims at bringing the annual treatment with this specific drug to all people who are susceptible.

Classification of Onchocerciasis

This parasitic disease is divided into the following types or phases:

  • Sowda

    – This is a localized form of the disease. It is a cutaneous condition.

  • Mal morando

    – This is a cutaneous (skin) condition in which inflammation occurs along with hyperpigmentation.

  • Erisipela de la costa

    – This is an acute phase which leads to swelling of the face accompanied with itching and erythema. This infection leads to many types of skin changes. These changes depend on the geographical locations and vary accordingly. This is seen mostly in South and Central America.

Magnitude of Onchocerciasis

In most of the African countries, this disease is the leading cause of blindness. This is prevalent in Central and West Africa as well. As per the estimation, nearly half a million people become blind due to onchocerciasis.

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