Final answer:
The presence of a herpes simplex virus infection in an HIV patient is an indication to increase nutritional intake to support the immune system, despite their CD4 T-cell count being at a safe level.
Step-by-step explanation:
A nurse assessing a client with HIV should identify the presence of a herpes simplex virus infection as an indication to increase the client's nutritional intake. This is because opportunistic infections like herpes simplex can occur when the immune system is compromised, requiring an increased nutritional intake to support the immune system and overall health. Although a CD4 T-cell count of 700/mm3 suggests the patient's infection is likely in the first stage and their disease is relatively well-managed, the presence of an opportunistic infection indicates a stressed immune system. An undiagnosable HIV viral load and increased body mass do not necessarily imply a need for increased nutrition.