A recurrence of an injury, disease or illness oftentimes is mistaken for a new injury. If after an injured federal worker returns to work and experiences spontaneous return of the symptoms of a previous injury or occupational disease without an intervening cause, then one may be experiencing a recurrence of an injury. Essentially, there was no new inciting event that happened to cause the return or increase of the disability. In such a situation, one would file the OWCP claim as a CA-2a. However, if there was an intervening cause or event that causes return of the symptoms it would be a new injury claim using the OWCP CA-1 form.