World Health Organization Comments About Genetically Modified Mosquitoes

The term “genetically modified” to many are dirty words. Genetically modified or GM is controversial today because the science is little understood, and the pushback from consumer advocacy groups is severe.

What GM Is and the Sad Tale of Golden Rice

The definition of GM is the alteration of the DNA of a plant or animal using bioengineering techniques where genetic information from one species is transferred to another unrelated or related species for the purpose of enhancing specific desirable traits.

GM staple crops like corn, soybean, and wheat have been developed to combat drought, and insect and weed infestations to improve yields. Companies like Bayer and Dow have taken out patents and created rules for the use of their GM seeds. The anti-Monsanto (now owned by Bayer) movement heads up those opposed to GM largely because of these chemical companies’ practices in enforcing patent protection.

But there are other GM examples far different than the Monsanto experience. For example, a genetic modification to rice developed in 2000, at the Swiss Federal Institute of Technology, in Zurich, added a beta carotene gene to the plant. The end product is called Golden Rice. The biofortification meant growers could switch to Golden Rice away from traditional rice varieties found in Bangladesh, China, India, and other South Asian countries to address a health problem endemic to the region. There is a Vitamin A deficiency in the diet of many South Asians who rely almost exclusively on three meals of rice per day for nutrition. Traditional rice lacks beta carotene which when ingested turns into Vitamin A necessary for normal cell development and vision. Vitamin A deficiency in South Asia is linked to a million premature deaths and 500,000 cases of blindness in children annually. By creating rice containing beta carotene these two catastrophes would be averted. Better yet the developers of the rice made the seed freely available to farmers who were then encouraged to save Golden Rice seeds for replanting every year. Golden Rice was created without a profit motive. So wouldn’t you think that resistance to it would be negligible? Not so. In the two decades since its invention, Golden Rice has been attacked by environmentalists, organic food activists, government regulators, and NGOs like Greenpeace. Why? Because Golden Rice is a GM product. As a result, child mortality numbers and child blindness from Vitamin A deficiency remain endemic in South Asia.

WHO GM Guidance

The World Health Organization (WHO) comments extensively on GM foods. A whole section of its website is devoted to the subject. It discusses safety, environmental risk, the public debate, and regulatory issues governing planting, sale and international distribution of GM foods. It also looks at biochemical and biopharmaceutical companies that are in the business of creating GM crops and foods for profit, and the challenges faced by farmers to own the GM seeds produced by them when they plant. It notes that current GM foods available today have passed all safety assessments regarding risk to human health. But the assurances from the WHO site fall on many deaf ears.

So what happens when GM biotechnology is deployed to deal with the scourge of insect-borne diseases? The same levels of resistance, unfortunately. And we are talking about mosquitoes being the targeted species, not harmless butterflies or honey bees.

Better late than never the WHO is weighing in on GM mosquitoes at last. Mosquitoes, states the latest report, are described as “the deadliest animal on earth.” They transmit malaria, dengue, West Nile virus, chikungunya, yellow fever and Zika and cause 700 million infections annually. Areas, where mosquito-borne infectious diseases spread, are home to billions. In dengue areas, for example, 2.5 billion people reside. And dengue is the fastest-growing mosquito-borne disease with a 3,000% rise in incidents over the last 50 years.

Where malaria incidences are in decline because of the deployment of an army of mosquito control mechanisms the world is in better shape. But based on my family’s experience of a few years aog when we vacationed in Cuba, our defences remain reactive and primitive. Where we stayed in Varadero, airplanes carrying insecticides spread aerosol insecticides over the landscape several times in just one week. We were advised to stay by the pool in the morning and not go down to the beach until the aerosol vapours cleared.

For many countries tending with mosquito-borne infectious diseases, insecticides remain the primary tools of combat. The problem in continuing to use them is biological resistance. The more you spray, the mosquitoes that survive pass on that ability to their progeny. The result today, is that in more than 75% of countries fighting malaria transmission by this type of program using four different classes of insecticides, we are seeing decreasing effectiveness when deployed.

The idea behind modifying mosquitoes genetically was conceived of several decades ago. The first GM mosquitoes were unleashed only in laboratories. But only recently have GM mosquito trials been tested in limited pilot projects. After more than a decade of fighting to get regulatory approval and public acceptance, Oxitec, a British biotechnology company, has received permission to release its GM mosquito in a U.S. trial. Prior to the May 2021 release, the company has demonstrated success in Brazil, Panama, the Cayman Islands, and Malaysia with no ill effects.

The U.S. trial in the Florida Keys is aimed at the wild population of Aedes aegypti, the mosquito species known to spread Zika, dengue, chikungunya and yellow fever. ALl the Oxitec GM mosquitoes are male and when released are competing for the favours of the wild female population. The mating of the two produces larval offspring of both sexes.But the GM modification contains a gene that allows only the non-biting males to pass turn into adults while killing all females while they are still larvae. The males then carry the modified gene with them and mate with other wild females. The end result should see a decline in the Aedes aegypti mosquito population.

An analogy that may make sense to those who condemn GM anything may be of some help. Think of the current COVID-19 pandemic. We tried to combat the disease with defensive measures after people were originally infected. We put on masks, isolated, and washed our hands. But over 3 million documented deaths happened just in 2020 alone. It was as if we were applying insecticides to the disease after it was already out and circulating in the human population. At the same time, our GM equivalent strategy was the development of vaccines which in time will cause the virus population to shrink.

The WHO, in issuing its latest GM guidance states that as a novel control, GM mosquitoes may be added to the current arsenal of tools to fight insect-borne diseases. Still a maybe. But maybe may soon be replaced by absolutely once testing moves beyond current pilot programs like the one launched in Florida last month. After it and a few more, we should have enough data to validate this GM strategy and other gene drive technologies like CRISPR/Cas9 and come up with criteria and rules for their safe use.