People do not take issue with doing something against malaria but with the proposed method.
How could it be stopped if something went wrong? It's not like a chemical agent that you just stop applying when you notice adverse effects. This is a living thing. Living things can procreate, mutate, enter new niches and the only deciding factor is the rate of reproduction. Life doesn't optimize for killing malaria-carrying mosquitoes, it optimizes for rate of reproduction and survival. As soon as there is a mutation that can extend the niche to another target, this will happen. And getting such a match doesn't have to be via a mutation on the fungus either, it can also be one of the target, making it susceptible to it.
How do you make sure these things don't happen? I'm worried that the answer is that you can't.
(Edit: I'm not even talking about engineered organisms, just have a look at a list of invasive species)
How could it be stopped if something went wrong? It's not like a chemical agent that you just stop applying when you notice adverse effects. This is a living thing. Living things can procreate, mutate, enter new niches and the only deciding factor is the rate of reproduction. Life doesn't optimize for killing malaria-carrying mosquitoes, it optimizes for rate of reproduction and survival. As soon as there is a mutation that can extend the niche to another target, this will happen. And getting such a match doesn't have to be via a mutation on the fungus either, it can also be one of the target, making it susceptible to it.
How do you make sure these things don't happen? I'm worried that the answer is that you can't.
(Edit: I'm not even talking about engineered organisms, just have a look at a list of invasive species)