Comment by saulrh

Something like 30 out of the 500 anopheles species are capable of carrying malaria. Of those, only those two matter, because the rest won't bite humans. Eradicating those two would be sufficient and another species (that doesn't bite humans) would take over. "Bites Humans" is furthermore not a strong enough competitive advantage to overcome any attempts to eradicate a successor that picks up the disease-ridden malarial torch.