Diseases like Zika virus, dengue fever, and chikungunya have been a major health concern in South America for years. Residents have tried to eliminate them by using traditional methods of mosquito control, including insecticides and bed nets, but they were proven to be insufficient in preventing the spread of these diseases.
How Do Mosquitoes Spread Disease?
Mosquito-borne diseases refer to those transmitted to people through the bite of an infected mosquito. Mosquitoes pick up viruses by biting infected people. The infection can be transmitted to the next person when they bite again.
Mosquitoes do not carry pathogens naturally. Instead, they get them from infected people. The diseases spread by these insects can be caused by a parasite, like in the case of malaria, or by a virus, as is the case for Zika fever and other infections. Only female mosquitoes bite humans. Hence, only female mosquitoes can transmit pathogens and cause diseases.
Some agents, like parasites, have been around and produced illness in humans for thousands of years. Others, like Zika and chikungunya viruses, have emerged only very recently. Several factors affect the potential for mosquitoes to proliferate and cause disease on a broader scale. These include human population growth, global travel, and urbanization.
War Against Mosquitoes 202, global dengue cases reached more than 5 million,n with 5,000 reported cases. About 80% of these are in the Americas, according to the latest World Health Organization (WHO report).
The cities of Bello, Medellín, and Itagüí, Colombia, have devised a unique solution to fight the spread of mosquito-carrying diseases. They thought of releasing bacteria-carrying mosquitoes into the environment to reduce the population of disease-carrying mosquitoes.
This is made possible by injecting the mosquito eggs with Wolbachia, an extremely common bacteria that naturally occurs in 50% of insect species, including fruit flies, moths, mosquitoes, butterflies, and dragonflies. It lives inside insect cells and is passed from one generation to the next through the eggs. Independent studies show that Wolbachia poses negligible risks to humans and the environment.
In 2011, mosquitoes that carry Wolbachia were released for the first time into a community in the Cairns region of Australia. After five weeks, scientists discovered that 100% of mosquitoes at Yorkeys Knob and 90% at Gondonvale were carrying Wolbachia. Since then, the World Mosquito Program has planned a strategy to breed large numbers of infected mosquitoes and release them into areas with high rates of mosquito-borne diseases.
The study about Wolbachia was made in 2009 by Scott O'Neill, founder of the World Mosquito Program (WMP). The first achievement using this strategy was transferring the Wolbachia strain to the Aedes aegypti mosquito,o which does not usually carry it.
In the study "Large-scale releases and establishment of wMel Wolbachia in Aedes aegypti mosquitoes throughout the Cities of Bello, Medellín and Itagüí, Colombia," it was revealed that releasing mosquitoes in the cities of Bello, Medellín, and Itagüí led to reduced incidence of dengue by over 94% compared to previous outbreaks. Another study showed that dengue fever decreased by 69%, Zika by 37,% and chikungunya by 59% after bacteria-carrying mosquitoes were released in Niterói.
Check out more news and information on Mosquito-Borne Diseases in Science Times.
