Question: Is it possible to alter a pathogen and make it target specific organisms like another pathogen

Ingmar Schoen answered on 7 Nov 2022:

Theoretically this might be possible for some selected cases, but it is a very difficult task to do in the lab.

Normally, pathogens evolve by natural selection. This means that small spontaneous changes happen, and if these changes make the pathogen ‘fitter’ (=it can infect or multiply more easily), then it survives other pathogen variants. A good example for this are the different Covid strains.

Normally, a lot of these smaller changes have to add up before a pathogen can infect other organisms. Even if it is known what lets a pathogen infect another organism, it is quite unlikely that by simply integrating these features into another pathogen (by genetic manipulations) that the other pathogen will be able to infect this organism.

What is much easier is to take a pathogen and make it harmless by introducing some genetic changes that prevent it from multiplying. Such manipulated viruses can be used as vehicles to deliver gene therapies (=DNA drugs) to help cure some diseases.