The symptoms suggest lack of establishment, which means the root system didn't establish and some sort of environmental stress (usually under- or over-watering) caused the plant's demise. The only infectious disease that tends to be associated with the loss of a fairly new plant is root rot when the soil is poorly-drained or the plant is watered too often (or receives too much extra water from sources like a nearby roof downspout outlet).

This individual is not salvageable, but we suggest replacing it with a different evergreen since spruces are not well-adapted to our climate in the mid-Atlantic outside of a few pockets of native spruce growing in the higher-elevation Appalachian mountains. Those that are used in home landscaping tend to succumb in time to one or more fungal infections that heat stress makes them more susceptible to. (These infections are not remedied with the use of a fungicide.)

For the remaining spruces, make sure they're only being watered when the soil becomes somewhat dry to the touch at a depth of about six inches within their root zone. Were the roots loosened well upon planting? If not, that can make it harder for plants to establish and for soil moisture levels within and outside of the root ball to even-out; when moisture levels are very uneven this can stress or kill roots.

Miri