In a breakthrough effort to prevent dengue illness, mosquitos infected with the Wolbachia bacterium were released in three major towns in Colombia. Because of this bacteria, the prevalence of disease-spreading mosquitos has reduced. Dengue sickness rates dropped by 94%-97% in places where these genetically engineered mosquitos thrived.
The program was overseen by the World Mosquito Program (WMP), a non-profit organization that has performed analogous studies in nations such as Australia, Brazil, Indonesia, and Vietnam. It was the most significant continuous release of Wolbachia-infected mosquitoes to date when genetically modified mosquitoes were released in one of Colombia’s most heavily inhabited districts.
The findings of the effort were presented by epidemiologist Katie Anders of the World Malaria Program and Monash University at the annual conference of the American Society of Tropical Medicine and Hygiene in Chicago. Infected mosquitos are less likely to transmit illnesses like dengue and Zika. Furthermore, they can pass the bacterium on to future generations.
The end objective is for these genetically modified mosquitos to reproduce with wild mosquitos and spread Wolbachia across the wild mosquito population. The World Mosquito Program (WMP) began releasing these mosquitos in Colombia’s Aburrá Valley in 2015 and plans to continue doing so until the end of 2020. This technique reached 3.3 million people in cities such as Bello, Medelln, and Itagü.
Dengue cases decreased by 95% in Bello and Medelln and 97% in Itagü when complete medication was delivered. There have been no severe dengue epidemics in these areas since the program began. “We’re starting to see the real-world effect of Wolbachia,” said Anders. However, due to natural changes in dengue frequency over time, evaluating the efficacy of such medicines is a challenge.
Alex Perkins, an epidemiologist at Notre Dame, suggested that randomized controlled trials were necessary for assessing the success of these sorts of public health interventions. Even though Wolbachia mosquitoes have shown great promise, the World Health Organization has yet to endorse them formally, and the Vector Control Advisory Group is still investigating the technology.
The WMP aspires to expand and develop in the following years. Over the next decade, a Brazilian factory will mass-produce these genetically engineered mosquitos for distribution in a variety of metropolitan environments. There are still issues to work out, such as how to customize mosquito deployment to the particular ecological and socioeconomic circumstances of different places.
Luciano Moreira, an Oswaldo Cruz Foundation specialist in mosquito-borne diseases and WMP collaborator, emphasized the importance of adapting to the realities of each location, focusing on collaboration with local health authorities, and seeking alternative partners for deployment in areas with limited resources.
Journal Reference
Lenharo, M. (2023). Dengue rates drop after release of modified mosquitoes in Colombia. Retrieved from https://www.nature.com/articles/d41586-023-03346-2
