In Trunks' future that had been destroyed by the Androids, Goku died from a Heart Virus.
Even in the alternate timeline caused by Trunks warning the Z Warriors about the Androids, Goku still contracted the Heart Virus but they already had a cure for it given by Trunks. Yet in both timelines out of all the Z Warriors Goku was the only person to contract it.
Why is this? Was it a targeted attack on him by Dr. Gero (given the timing of when it occurred)? Was Goku's diet a factor or was there something Saiyan wise that made him more susceptible which doesn't apply to Vegeta and half-Saiyans?