Problem formulation for gene drive mosquitoes designed to reduce malaria transmission in Africa: results from four regional consultations 2016–2018

Table 4 Consideration of possible pathways to harm affecting water quality

A Protection goal: water quality
Harm: Ecosystem/aquatic habitat affected
Step	Pathway to harm	Plausibility	Additional information needed
1	Introduction of the gene drive [?]mosquito	Given	A large fraction of habitats are temporary and do not support complex communities^a No additional information is needed
2	Less larvae breeding in the water	Unlikely
3	Larvae containing the new gene are present in the water	Unlikely
4	Aquatic organism populations (e.g., algae and populations (e.g., algae and anaerobic bacteria) increases	Unlikely
5	Toxin production	Unlikely
6	Ecosystem/aquatic habitat affected	Unlikely

B Protection goal: water quality
Harm: Drinking water becomes contaminated
Step	Pathway to harm	Plausibility	Additional information needed
1	Introduction of the gene drive Mosquito	Given	Literature review: other vectors of disease, including information/evidence from other control programmes that have eliminated An. gambiae^b
2	Gene spreads into the mosquito population	Likely
3	Larvae release toxin into the water	Unknown
4	People drink water	Likely
5	People get sick (safe drinking water is reduced)	Unknown

A. Suppression Drive, Case Study #2. B. Modification Drive, Case Study #1
^a[30] provides additional information addressing larval habitats of An. gambiae
^b[31, 32] provide additional information addressing biosafety of genetically modified organism (genetically modified mosquitoes and genetically modified plants)

ISSN: 1475-2875