PRISON OFFICIALS have a tough job. They deal day in and day out with very troubled, frequently violent people, and they often lack the facilities, resources, personnel and community support to do a first-rate job of rehabilitating the inmates in their custody. As a minimum, though, they are responsible for the welfare of their charges and, in particular, for their safety. In this connection, assaults by one prisoner on another are a common problem and a major headache. Fights, homosexual rape and even murder take place within prison walls. Now there is something else, something frighteningly dangerous to worry about: AIDS.

Jerome Baker, who is serving two sentences for armed robbery in an Arlington jail, was notified last week that he carries the AIDS virus. Mr. Baker had requested a test after he was bitten by his cell mate, who is infected. It is possible that the virus entered Mr. Baker's bloodstream when his skin was broken during the attack. He also points out that his cell mate had bleeding mouth sores and had shared his cup and toothbrush. It is also possible that Mr. Baker was infected before he even entered the jail. Because many inmates are intravenous drug users and that is a high-risk group for AIDS, he might also have contracted the infection from an intimate contact with some other inmate.

Prisoners have already filed lawsuits in three states seeking protection from AIDS carriers with whom they are incarcerated. In Arlington, it is the policy of corrections officials not to tell prisoners that another inmate is a carrier, not to segregate carriers unless there has already been dangerous behavior, and not to test inmates routinely, or even on request.

Is this fair to those in custody who have not been infected? We think it is not. Granted, this problem has come up rather suddenly and steps to protect the prison population are still in the planning stages, but those plans must be accelerated. Prisoners are wards of society. They do not have the freedom to decide where to eat and sleep or the right to choose those with whom they must live in close contact. They must be protected and so must the families to whom they will eventually return. "It's truly going to be a headache," says Arlington Sheriff James Gondless of the need to test and perhaps separate inmates. But the inexorable deadliness of the infection makes a swift and effective response by prison officials imperative.