If a veteran served in a tropical location and later developed a tropical disease known to come from that location, it can be considered service-connected as long as it manifests to 10% within 1 year of serving in the tropical location.

Now some of the diseases on this VA Presumptive List have incubation periods (the time between infection and the manifestation of symptoms). If the disease is medically known to have such a lengthy incubation period that the symptoms don’t begin until after the 1-year limit, it is still considered service-connected.