The date of Aragorn's birth appears only in The History of Middle-earth volume XII, The Peoples of Middle-earth. It cannot therefore be considered completely reliable.
The details of Aragorn's loss are sketchy at best. The Lord of the Rings tells us only that 'it is said' that he was slain by wolves (Appendix A I (iii)). A selection of the notes behind this comment appear in The Peoples of Middle-earth (volume 12 of The History of Middle-earth), which variously suggest that he was lost while on a hunt, or at the hands of Orcs, or (as in the final version) was slain by wolves. It is not easy to piece together a coherent account from this, but probably the most consistent reading would be that he was lost while out hunting the very wolves that turned on him and slew him.