Biocontrol, short for biological control, is a method of using living organisms, often microbes or insects, to manage a pest or disease-causing pathogen. These biological control organisms usually are natural enemies (predators, pathogens or competitors) of the unwanted pest or pathogen. Examples include introducing lady beetles to control aphids in the garden, using goats or sheep to control weeds, or having a housecat to control rats and mice. Biocontrol has a long-standing history of use for insect pest management, including by releasing sterile insects to reduce or eliminate wild populations of that insect.
Potential applications of genetic biocontrol
Genetic biocontrol approaches use genetic engineering to implement or supplement biocontrol. There are many possible applications of genetic biocontrol across public health, agriculture and conservation. For example, genetic biocontrol can be used to reduce the reproductive capacity of insects in the wild. Genetic biocontrol also could potentially be used to raise insects that do not acquire or transmit a disease, which could help to protect human, livestock and wildlife health. In the area of public health, there is evidence from laboratory experiments that genetic biocontrol approaches can reduce populations of disease-carrying mosquitoes.
Gene drive approaches
Some possible genetic biocontrol approaches are gene drive approaches. Gene drive is a natural phenomenon in which a genetic element spreads more quickly in a population of organisms that breed with each other than would otherwise be expected, because of a “drive” mechanism. Many different drive mechanisms are found in nature, including those where a gene is inherited at a higher rate than others, those where organisms that inherit only one of a pair of genes don’t survive or produce fewer offspring, and those that limit which organisms can successfully breed with each other. Genetic biocontrol may make it possible to use gene drive approaches for genetic biocontrol. For example, if there is a set of genes that prevents an insect from acquiring or spreading a disease, a gene drive approach may be able to spread those genes into a wild population of that insect. Gene drive approaches may also be able to spread genes that decrease the size of a wild population of an insect that spreads diseases. Gene drive could help to make genetic biocontrol more widely accessible and cost-effective.
Gene drive approaches for public health
There have been many decades of research into the potential of gene drive approaches to reduce the transmission of human and animal diseases that are spread by mosquitoes. Scientists have identified genes that, in laboratory mosquitoes, decrease the ability of mosquitoes to carry disease (population modification) or to produce offspring (population suppression). They have also developed gene drive approaches that rapidly spread these genes in populations of laboratory mosquitoes (see figure). So far, these approaches have not been tested outside of the laboratory, but computer simulation modeling predicts both approaches have great promise for preventing disease. Out of thousands of species of mosquitoes, only a small number of species carry the dozens of deadly and disabling diseases known to be transmitted by mosquitoes. These mosquito-borne diseases include malaria and viral diseases such as dengue, chikungunya, Zika and yellow fever. Currently, the GeneConvene Global Collaborative focuses on the potential for gene drive approaches to reduce malaria transmission by Anopheles mosquitoes in Africa, where more than 90 percent of malaria deaths occur. Contact us to support current activities, or to discuss opportunities for GeneConvene to address other potential applications of genetic biocontrol approaches for public health.