In the wake of the outbreak of Zika virus in French Polynesia in 2013, and most recently in Brazil in 2015, major steps in vector control have been proposed by the World Health Organisation (WHO) to eradicate mosquito populations that spread the disease. One such tried and tested method for reducing cases of Dengue fever spread by mosquitoes is the use of genetically modified (GM) male mosquitoes , that when mating with females produce unviable offspring that die before reaching adulthood, hence reducing the mosquito population. The reason the Zika virus has become a major concern is because there is now strong evidence to suggest that the disease causes microcephaly in the babies of pregnant women, causing decreased brain function that results in learning difficulties and often visual and hearing impairment .
AGAINST GM MOSQUITOES
Stakeholders that disapprove of the use of GM mosquitoes include followers of some religions, who refrain from killing or genetically modifying living beings. As well as religious opposition to the use of GM there are also animal rights groups and environmental groups that oppose the use of genetic modification.
From a deontological viewpoint it is clear that the use of GM mosquitoes is unethical and immoral. Deontology holds that decisions should be made considering the factors of one’s duties and other’s rights. It should be clear that we as humans and the dominant race have a duty to conserve the earth and its natural beings and by using GM mosquitoes to kill off an entire species goes completely against this. We also have to consider the rights of the animal. Mosquitoes are classed as pests, however they still serve a purpose in the ecosystems they are part of and as such they should be valued and their rights should be considered as stated by deontology.
From a consequential point of view there is some concern that the reduction of mosquitoes will affect the ecosystem by altering the food chain. Animals affected include insects, spiders, salamanders, frogs, lizards and even migrating birds. Mosquito larvae are also the primary food source of many species of fish, and larvae feed on decaying matter in water that hinders plant growth.
FOR GM MOSQUITOES
Stakeholders that approve the use of GM mosquitoes include the WHO, who proposed their use due to the spread of the Zika virus and Dengue fever and also Oxitec; the commercial company that are developing the GM mosquitoes. It is also clearly in the best interest of sufferers and potential sufferers of the Zika virus that the mosquito population is reduced. Starting in Brazil in 2015 the disease is now widespread, and affects people in South America, Central America, Mexico and the Caribbean.
When using a utilitarian approach to investigate the effects of using GM mosquitoes it hard not to prioritise the large populations of humans living in Zika virus affected countries. Whilst there are at least 15 groups working on Zika vaccines, WHO estimates that it will be at least 18 months before vaccines could be tested in large-scale trials. Vector control using GM mosquitoes would satisfy the people affected, however to also satisfy the stakeholders against the use of genetic engineering there are a number of other methods that can be used. The simplest method of preventing contraction of the disease is by using chemical repellent and covering up exposed skin, especially in the daytime when the Aedes mosquito is most active. Due to the scale of the problem, WHO suggests that using such methods and the use of fogging (spraying pesticides) is not effective enough and so vector control is necessary to a significant scale.
When exploring biological methods of vector control there are a number of methods that avoid GM mosquitoes. In El Salvador, with the strong support of fishing communities, larvae-eating fish are kept in water storage tanks and mosquitos infected with Wolbachia bacteria can be used to produce none viable eggs. This bacterium infects 60% of common animals and does not infect humans or other mammals. Male mosquitos can also be sterilised using low doses of radiation, however whilst this method worked well with eradicating screw-worms in North America, irradiated male mosquitoes are very sickly, and female mosquitoes prefer not to mate with them. Due to this problem and the difficulty of using Wolbachia bacteria, the only effective method of eradicating large populations of mosquitoes is by the use of genetic modification . This is supported by environmental concerns, where above-average rainfall caused by El Niño is expected in parts of South America until May 2016, and could cause floods and increases in diseases spread by mosquitoes. With all these factors considered and the huge population affected, by using a utilitarianism approach it seems favourable to use GM mosquitoes, thereby significantly reducing the spread of disease in South America.
It is not known what the extent of damage would be done on ecosystems if mosquito populations are reduced, however it is believed that the insect would be replaced as another species thrives in its absence. Whilst there is speculation about the damaging effects of vector control, the effects of using pesticides in the environment is thought to be much worse. Research shows that birds in regions of pesticides lay less eggs than those in unaffected regions, and the effect of pesticides that wash into rivers and streams on aquatic life is often devastating.
Another major concern is the cost of research; however the Zika response proposal by the WHO estimates that the cost of vector control, research and coordination is $18.9M (£13.2M). This is considerably less than the cost of surveillance, community engagement, risk communication and care for those affected which is $36.7M (£25.7M) . Welfarism states that the best action is the one that most increases economic well-being, and based on the data above it is clear that the option which most increases economic well-being would be to use the GM mosquitoes as their overall cost is half that which would be required for the other approaches.
28: Fernando Camacho, Guy Pearson, Matt Kirkland, Will Moss