What is an example of a good virus?

While many viruses can cause illness, there are also some viruses that can have beneficial effects. For example, some viruses can help to control populations of harmful insects, while others can be used to create vaccines. One specific example of a good virus is the bacteriophage, which is a virus that infects and kills bacteria. Bacteriophages can be used to treat bacterial infections, such as those caused by E. coli or Salmonella. They are particularly useful in cases where antibiotics are not effective. Bacteriophages have been used successfully in both human and veterinary medicine, and they offer the advantage of being able to target specific types of bacteria without harming other beneficial bacteria in the body.