Biggest Threat to Zika? Mosquito Love.
As of November 18th, the World Health Organization (W.H.O.) declared that Zika is no longer a global emergency. However, Dr. Peter Salama, executive director of the W.H.O.’s health emergency programs, stated that “we are not downgrading the importance of Zika. We are sending the message that Zika is here to stay, and the W.H.O response is here to stay.”
Though the W.H.O. has downgraded the threat of Zika, combating Zika remains a goal of the global health community. At the end of October 2016, $18 million was put towards a project to release millions of genetically modified Aedes aegypti mosquitoes. These mosquitoes were infected with a bacteria called Wolbachia to mate with Aedes aegypti mosquitos that transmit Zika, as well as Dengue and Chikungunya.
Theoretically, when these modified mosquitoes breed with mosquitoes in the wild, the following generation will inherit Wolbachia and will be unable to transmit Zika and other diseases. As these mosquitoes continue to mate and pass down the bacteria to future generations, these diseases should reduce dramatically. It will affect future mosquito generations and will be a long run benefit to citizens living in countries with high incidence of Zika.
The Wolbachia bacteria is found in 60% of insect species worldwide, and it does not infect humans. Wolbachia normally does not infect the Aedes aegypti mosquito either, but researchers have found a way to inject Wolbachia into Aedes aegypti mosquito eggs as seen in this video. A program called the Eliminate Dengue Program has tried this method in several randomized control trials in Australia, Brazil, Colombia, Indonesia, and Vietnam, and each program has found success. They discovered that these modified mosquitos can stem the spread of Dengue, and they are even more effective at curtailing Zika.
This project is funded by several international organizations and governments including the Bill and Melinda Gates Foundation, the Welcome Trust, and the governments of the U.S., the U.K., Brazil and Colombia. These mosquitoes have been tested in small trials in the suburbs of Rio de Janiero, Brazil, and Antioquia, Colombia. With this funding, scientists will expand into bigger sections of those cities in early 2017, reaching about 2.5 million residents in each city.
The Eliminate Dengue Program investigators will study the impact of these Wolbachia infected mosquitoes over the next two to three years to see if incidences of Zika, and other Aedes aegypti transmitted diseases, are indeed reduced.
Zika was reported in Brazil in mid-2015 and has since spread rapidly. As of November 2016, the CDC reports that there has been a total of 4,255 cases of Zika in the United States, with 4,115 cases being travel-associated. There is also, currently no vaccine. Zika has gone through the test of the 2016 Rio Olympics and faded from much of society’s memory eclipsed by the recent U.S. election. However, it remains a global threat, especially due to the associated microcephaly birth defects. To address the global spread of Zika, creative strides like this should continue to be made.
Rohini Ravi is a Masters of Public Policy Student at Duke University focusing on global health and international development.