Human Achievement of the Day: Fighting Mosquito-Borne Diseases with Technology

For millennia, mosquitos have wreaked havoc on mankind, passing along myriad deadly or debilitating diseases. Mankind’s clever interventions—from screened windows to pesticides—have helped greatly control mosquito-transmitted diseases in developed nations. Until recently, the hope of getting such diseases under control in poor developing nations any time soon appeared dim. But thanks to some new technologies in this field, there’s cause for some optimism.

Ultimately, economic growth offers the best solution in these nations because it would allow them to transition to sealed homes with modern heating and air conditioning and windows with screens—separating man from mosquito for much of the time. In addition, modern agricultural practices would mean, fewer people would be needed to produce food, allowing more people to work indoors. And wealth would also make it affordable for people to access insect repellants—such as DEET—for when they are outdoors, and for local governments to impellent full-time mosquito vector control personnel.

But until then, charitable and private organizations are providing research and funding for a host of activities, including the development of medicines and mosquito control technologies that may help developing nations at their current state of development. 

Among these innovations is the recent release of a vaccine that may help fight Dengue. Dengue is one of the most serious and widespread mosquito-borne disease and the world (Malaria is the other). Dengue is most prevalent in Asia, but has become a global problem in recent years, spreading to the Americas. The World Health Organization reports:

Up to 50 million infections occur annually with 500 000 cases of dengue haemorrhagic fever and 22,000 deaths mainly among children. Prior to 1970, only 9 countries had experienced cases of dengue haemorrhagic fever (DHF); since then the number has increased more than 4-fold and continues to rise.

After 20 years in development, this year the French pharmaceutical company Sanofi Pasteur released Dengvaxia®, a Dengue vaccine that works for people aged 9-45 years old. According to Sanofi: “Dengvaxia® was shown to reduce dengue due to all four serotypes in two-thirds of the participants and prevent 8 out of 10 hospitalizations and up to 93% of severe dengue cases.” While it may not be a complete solution, it could have enormous value as one of the critical tools in the fight against Dengue.

The Wall Street Journal reports that this year, the Philippine government has purchased enough of the vaccine to treat one million school children in the most high risk areas of the Philippines starting in April. Sanofi plans to produce enough to treat 100 million people next year around the world. This year, the vaccine is also approved for use in Mexico, Brazil and El Salvador.

Sanofi’s CEO says that it will now turn its attention to developing a vaccine to address the Zika virus, which has emerged as a serious issue in recent years, particularly in 2015 when it appeared in Brazil. Zika and Dengue viruses are similar and hopefully, research for the Dengue vaccine will also have value for developing of the Zika vaccine.

In addition to the development of this vaccine, other innovators are using mosquitos themselves to fight viruses they carry. Among these are genetically modified mosquitos, such as those developed by a British company called Oxitec.

The company explains how their mosquitos can reduce populations of the Aedes aegypti mosquito, which carries both Dengue and the Zika viruses:

Oxitec has used genetic modification to create ‘sterile’ male insects which seek out and mate with females. After an Oxitec mosquito has successfully mated with a wild female, any offspring that result will not survive to adulthood, so the mosquito population declines. … By applying the Oxitec Control Programme to an area, the mosquito population in that area can be dramatically reduced or eliminated.

Field trials indicate that genetically modified mosquitos offer much promise in the battle against mosquito borne diseases. “Genetic engineering approaches are the kinds of breakthroughs that could spell the beginning of the end for malaria, dengue, Zika and other mosquito-borne diseases and relegate them largely to the history books, as medical science has done for smallpox and polio,” explains Henry I Miller, M.D., in Forbes.

But that’s not all of the new technologies in play. Researchers with an international nonprofit program called Eliminate Dengue are injecting mosquitoes with a bacteria called Wolbachia that reduces the ability of mosquitos to pass virus to human’s particularly Dengue, Zika, chikungunya and yellow fever. When female mosquitoes containing Wolbachia breed, they pass the bacteria on to their off spring.

According to Eliminate Dengue, about 60 percent of insects naturally carry this bacteria, except it is not present in the species of mosquitos that transmit Dengue and Zika—the Aedes aegypti.

Once it’s inserted and mosquitoes released, the bacteria can spread throughout local mosquito populations, thereby reducing disease risks. The Eliminate Dengue research team are testing various strains the bacteria to find the ones that are most effective in blocking disease transmission.

Field trials in Australia look promising. And even better news is the fact that these researchers also say Wolbachia also has the potential to block transmission of malaria parasites, which are protozoan rather than viruses.

The development and deployment of such new mosquito fighting technologies is critical in a world where other options are being taken off the table because of misinformation and anti-technology activism. In particular, there are fewer and fewer pesticides available for public health uses because of hype and misinformation about the risks. These pesticides, including DDT, can and should play a role but politics often prevents effective use. Activists even attack larvicides, which are a safe and effective and key tool for mosquito control programs. Applied to water, larvicides prevent mosquito larvae from developing into adult misquotes.

With any luck, the mankind’s innovative spirit will allow us to rise above regressive, anti-technology forces. Otherwise these regressive forces will keep us in a dark age—and allow millions of people annually to continue suffering from mosquito-borne diseases.