The disease all Washington fears has surfaced once again. It is apparently caused by coming in contact with a dirty deed, although it is sometimes falsely linked to what is otherwise a slow period for the press. Whatever the cause, it is here again. I am talking of the dreaded Acquired Amnesia Syndrome.

It has decimated the Reagan administration. Presidential aides and other high-ranking officials usually considered sharp as a tack now cannot recall if they ever saw a black book, about three inches high, containing Jimmy Carter's briefing materials for his debate with Ronald Reagan.

The book in question disappeared from, of all places, the White House, and materialized in, of all places, the office of David Stockman who used it in pre-debate rehearsals. Stockman, a man for details, played Carter and Reagan, a man for the big picture, played Reagan which is what they have been doing ever since.

You would think a book that helped Reagan to disabuse cynics of the notion that he is intellectually unqualified for the presidency would be remembered by key Reagan aides. Ah, but you have not allowed for the dreaded, albeit convenient, Acquired Amnesia Syndrome. It turns out that no one can remember how the book got from the White House to Stockman's office and, after that, who actually saw or--God forbid!--touched the awful thing.

White House Chief of Staff James A. Baker III said it is his "best recollection" that William J. Casey, then a senior official in the Reagan campaign and now the mere director of the CIA, somehow came up with the book. Casey, for his part, said he had "no recollection" of the thing.

David Gergen, the White House communications director, said he did not see the book, but could recall some pages, although, to tell the truth and cross his heart, the material was not very valuable. Stockman, however, said he not only remembered the book, but that it had been "useful."

Another former campaign aide, Myles Martel, said he too remembered the book. He also remembered telling Frank Hodsell, now chairman of the National Endowment for the Arts, that it was unethical to have it and it should be returned. Hodsell, a victim of Acquired Amnesia Syndrome, said he could not recall such a conversation, although he and Martel might have talked about it "in passing."

Of all the previous examples of Washington amnesia, these are among the most tragic. Even in a town accustomed to seeing otherwise keen minds turn to mush at the mere posing of an awkward question and recalling, of course, a parade of Watergate witnesses who could, alas, remember nothing, this sudden outburst of I-can-not-recall is something to behold.

The document in question, after all, is not a mere collection of a few papers. It is a hefty notebook, the first page of which is entitled "Debate Briefing Material--Domestic" and which contains chapters like these: Answer and Rebuttal Objectives; Answer and Rebuttal Themes; Carter--Answers and Responses; Carter--Response to Reagan Statements; Key Lines to Use; Questions for Carter to Ask Reagan.

You can see that such a book, far from being of modest use, would instead represent a bonanza to the Reagan camp and that its arrival would be eagerly anticipated. Unless, of course, the thing really did come sailing over the transom, there were key members of the Reagan campaign team, now key members of the government, who either thought there was nothing unethical or illegal about using a stolen Carter campaign document or--worse--did not care.

But, alas, afflicted with Acquired Amnesia Syndrome, these people are unable to tell us who they are. Not that it matters. Their amnesia matches that of the public and the press, from whom the story of the alleged theft has elicited not so much as a yawn..

Reagan aides can take comfort in the fact that Americans have forgotten the lessons of the past and once again seem willing to permit politicians an ethical standard unworthy of the people they have been chosen to govern. This is the kind of thinking that produced Vietnam and Watergate.

But who remembers?