In the United States, female mosquitoes are responsible for transmitting West Nile or the Zika virus while obtaining blood to feed their young. They also spread heartworms and Eastern Equine Encephalitis. According to the Centers for Disease Control and Prevention, the case numbers rise each year. Worldwide, mosquitoes spread the Chikungunya virus, dengue fever and malaria. However, recently, scientists from the Imperial College in London have successfully devised the means to eliminate the disease-carrying pests.
In a laboratory setting, researchers were able to bring about the collapse of a housed population of mosquitoes using CRISPR gene editing. By altering specific genes, the group was able to change the genetics throughout the population that spanned multiple generations. The technique was aimed at reducing female mosquito reproduction.
Female pass on various disease processes by biting an infected host. As they go on to the next target, they also transfer the bacteria, virus or parasite responsible for causing illness. Creating vaccinations for the disease processes that mosquitoes carry is a long and difficult process. The effort may take three to four decades. However, by eradicating the cause of the problem, it will be possible to greatly reduce the number of illness cases in a significantly less amount of time.
By using CRISPR, scientists are able to add, change or delete specific gene sequences. The London study involved locating the doublesex gene, which determines whether the insect becomes male or female. Once female mosquitoes have two copies of the altered gene, they exhibit female and male characteristics. Affected insects do not lay eggs and thus, have no need to bite. After eight generations, there were no longer any female mosquitoes in the population. The insects were also unable to develop a resistance to the treatment, which occurred in previous studies.
Although achieving promising results, the researchers report that it could be up to 10 years before the technology would be ready to test in a real-world setting. Many factors come into play before the method might prove useful. There are more than 3,000 species of mosquitoes worldwide. Food sources and predators in various locations must also be assessed.
Scientists from Kansas State University are pleased with the London report. They shared that genetic manipulation has long been considered in an effort to combat the mosquito-borne illness problem. With the introduction of CRISPR, the science is coming closer to becoming a reality.