§3.307. Presumptive service connection for chronic, tropical, or prisoner-of-war related disease, disease associated with exposure to certain herbicide agents, or disease associated with exposure to contaminants in the water supply at Camp Lejeune; wartime and service on or after January 1, 1947.

General. A chronic, tropical, or prisoner of war related disease, a disease associated with exposure to certain herbicide agents, or a disease associated with exposure to contaminants in the water supply at Camp Lejeune listed in § 3.309 will be considered to have been incurred in or aggravated by service under the circumstances outlined in this section even though there is no evidence of such disease during the period of service. No condition other than one listed in § 3.309(a) will be considered chronic.

Evidentiary basis. The factual basis may be established by medical evidence, competent lay evidence or both. Medical evidence should set forth the physical findings and symptomatology elicited by examination within the applicable period. Lay evidence should describe the material and relevant facts as to the veteran's disability observed within such period, not merely conclusions based upon opinion. The chronicity and continuity factors outlined in § 3.303(b) will be considered. The diseases listed in § 3.309(a) will be accepted as chronic, even though diagnosed as acute because of insidious inception and chronic development, except: (1) Where they result from intercurrent causes, for example, cerebral hemorrhage due to injury, or active nephritis or acute endocarditis due to intercurrent infection (with or without identification of the pathogenic micro-organism); or (2) where a disease is the result of drug ingestion or a complication of some other condition not related to service. Thus, leukemia will be accepted as a chronic disease whether diagnosed as acute or chronic. Unless the clinical picture is clear otherwise, consideration will be given as to whether an acute condition is an exacerbation of a chronic disease.

Prohibition of certain presumptions. No presumptions may be invoked on the basis of advancement of the disease when first definitely diagnosed for the purpose of showing its existence to a degree of 10 percent within the applicable period. This will not be interpreted as requiring that the disease be diagnosed in the presumptive period, but only that there be then shown by acceptable medical or lay evidence characteristic manifestations of the disease to the required degree, followed without unreasonable time lapse by definite diagnosis. Symptomatology shown in the prescribed period may have no particular significance when first observed, but in the light of subsequent developments it may gain considerable significance. Cases in which a chronic condition is shown to exist within a short time following the applicable presumptive period, but without evidence of manifestations within the period, should be developed to determine whether there was symptomatology which in retrospect may be identified and evaluated as manifestation of the chronic disease to the required 10-percent degree.