Final answer:
To prevent the spread of respiratory syncytial virus (RSV), the appropriate nursing action would be for the nurse to wear a mask when caring for the infected infant.
Step-by-step explanation:
Respiratory syncytial virus (RSV) is highly contagious and can be spread through respiratory droplets from coughing and sneezing. It can also survive on environmental surfaces, making indirect transmission possible. Therefore, when caring for an infant with RSV, it is important for the nurse to wear a mask to protect themselves and others from potential exposure. This precaution helps to reduce the risk of spreading the virus to other patients and healthcare workers.