Which disease is primarily transmitted by blackflies?

Onchocerciasis is primarily transmitted by blackflies, specifically those belonging to the Simulium genus. This parasitic disease is caused by the filarial worm Onchocerca volvulus, which is transmitted through the bites of infected blackflies. The blackflies breed in fast-flowing rivers and streams, and their bite can lead to severe health issues such as skin rashes, itching, and, in the worst cases, blindness due to the damage caused by the adult worms and their microfilariae.

The relationship between blackflies and onchocerciasis is well-documented, as the female blackfly acquires the bacteria when it feeds on a person infected with the disease, and then transmits it to other individuals through subsequent bites. Understanding the cycle of transmission is crucial for disease control and prevention strategies in affected areas.