(a) Any injury sustained by a volunteer or volunteer leader while he or she is located abroad is deemed proximately caused by Peace Corps employment and will be found by OWCP to have been sustained in the performance of duty, and any illness contracted while that volunteer is located abroad will be found by OWCP to be proximately caused by the employment unless the evidence establishes:

(1) The injury or illness was caused by the claimant's willful misconduct, intent to bring about the injury or death of self or another, or was proximately caused by the intoxication by alcohol or illegal drugs of the injured claimant; or

(2) The illness is shown to have pre-existed the period of service abroad; or

(3) The injury or illness claimed is a manifestation of symptoms of, or consequent to, a pre-existing congenital defect or abnormality.

(b) If the OWCP finds that the evidence indicates that the injury or illness may not have been sustained in the performance of duty due to the circumstances enumerated in paragraph (a)(2) and (3) of this section, the claimant may still prove his claim by the submittal of substantial and probative evidence that such injury or illness was sustained in the performance of duty with the Peace Corps.

(c) If an injury or illness, or episode thereof, comes within one of the exceptions described in paragraph (a)(2) or (3) of this section, the claimant may nonetheless be entitled to compensation. This will be so provided he or she meets the burden of proving by the submittal of substantial, probative and rationalized medical evidence that the illness or injury was proximately caused by factors or conditions of Peace Corps service, or that it was materially aggravated, accelerated or precipitated by factors of Peace Corps service; if the injury or illness was temporarily aggravated by factors of Peace Corps service, disability compensation is payable for the period of such aggravation.