The people who concern themselves with the disease of rabies have some good news and some bad news. The good news is for Washington area residents -- the 2-year-old epidemic of rabies here has largely passed through.

This, unfortunately, is bad news for counties east and north of here, including Howard, Calvert and Baltimore.

The rabies epidemic has by no means completely abated here, however, says Thomas B. Ferguson, director of the Montgomery County Department of Animal Control and Humane Treatment, and it remains a threat to human life and the pet population.

Also, he says, if you are going to risk rabies this year, it is more apt to involve your house cat than your dog or a wild animal. "People know they have to get rabies shots for their dog," he says. "They think nobody will notice it if they fail to get shots for their nice, gentle little kitty."

Rabies is an infection of the central nervous system caused by a virus present in the saliva of infected animals. It is usually transmitted by bites, although it can be transmitted when the saliva of a rabid animal enters a cut or open sore.

In extremely rare cases -- only two have been reported, and they are not documented -- rabies may be transmitted through the air, according to Dr. Joseph McDade of the federal Centers for Disease Control in Atlanta.

Four cases of human-to-human transmission have been reported, all involving corneal transplants from the eyes of people who died of a neurologic illness that was unspecified until after the rabies appeared.

Generally, rabies is carried in the wild by bats, skunks, foxes and other warm-blooded animals. Squirrels and other rodents, and opossums, seem to be immune. "Why they don't get it is something we're all trying to answer," McDade says.

Raccoons account for 85 percent of the reported cases of rabies in the wild.

Humans rarely survive rabies once symptoms have begun, which is 30 to 50 days after exposure in most animals. In dogs it is a much broader period, usually 14 to 60 days.

Rabies symptoms in humans are suspected if, in a few weeks (or a few months) after exposure, the person gets depressed, restless, feels abnormal sensations around the site of exposure, develops headaches, fever, malaise, nausea, sore throat or loss of appetite.

In later stages the victim develops unusual sensititivy to sound, light and temperature changes, muscle stiffness, increased salivation, and then, in later stages, irrational excitement alternating with calmness (sort of how Sir Francis Chichester described how it felt to sail alone around the world in a small boat), and then convulsions, throat spasms and hydrophobia, the classic symptom where the victim has a pathological fear of water.

Cardiac or respiratory failure occurs within a week after appearance of symptoms, as a rule, according to Patricia Randall of the National Institute of Allergy and Infectious Diseases (NIAID), and if anybody does survive this stage, a fatal, progressive paralysis sets in. In human rabies resulting from the bite of a rabid vampire bat, excitement and hydrophobia are usually absent, and the pre-death symptoms start with the creeping paralysis.

A lot of people die from rabies abroad, particularly in Asia, but not in this country, where government agencies frequently collaborate with private resources to keep people aware of the disease and how to avoid it. Since 1960, there have been five or fewer rabies deaths a year in the United States. The exact number abroad is not known, but McDade says "we are talking about thousands of cases a year in the developing and underdeveloped nations."

The best way to avoid rabies, of course, is to keep the domestic animal population vaccinated. Most people are good about their dogs, says Montgomery's Tom Ferguson, but silly about their cats. The laws in the area jurisdictions require that you have them all vaccinated, but, Ferguson points out, a lot of people think they have "house" cats and that, since the kitty spends most of its time on your lap, it doesn't need a shot. The fact is, Ferguson says, that the cat will be out mixing it up with a rabid raccoon at the garbage can as soon as it's let out for a nightly whatever.

Wild animal rabies has been epidemic in this area since 1983, when the District of Columbia reported 162 cases of animal rabies, compared with five in 1982. Virginia had 625 confirmed cases, and Maryland 787. Far and away the greatest number of these cases were in raccoons.

In 1983, 5,878 cases of rabies were reported in the United States, according to NIAID, and 2,146 of these were in the South Atlantic states, including Maryland, Virginia, Delaware, North and South Carolina, Georgia and Florida. Of those South Atlantic cases, 1,768 were in raccoons, and of those 732 were in Maryland, a big state for rabid animals, it turns out, with Virginia hard on its heels with 545 rabid racoons.

Rabies in domestic animals that year consisted of one rabid cat in the District, nine in Maryland and six in Virginia. There were no rabies cases reported in dogs for the year, the last for which complete figures are available.

How the current epidemic got its start here is a matter of conjecture, including the theories that a single rabid raccoon migrated from North Carolina, or a single dumb hunter transported a rabid, perhaps dead, raccoon into Maryland with the disease in it.

Maryland figures show that it is leaving the immediate Washington area and heading east and north.

In 1983 there were 434 cases of rabies in Montgomery County, 16 in Prince George's County and none in Calvert County. The next year Montgomery had dropped to 119 cases, Prince George's had grown to 239 and Calvert had a single case. This year, so far, Montgomery has held to 14 cases, while Prince George's has had to 53, a slower pace than last year, while Calvert has increased to 11 cases, Ferguson reported.

During the same period Baltimore County, also to the east and north, reported three cases in 1983, 54 in 1984, and 112 so far this year.

These figures are skewed somewhat, Ferguson points out, because in the more rural areas not all rabies cases are reported. "Out there," Ferguson says, "a rabid raccoon comes around, somebody shoots it and they dispose of it, and that's the end of it. Case closed."

Both Ferguson and Randall advise people to stay alert, keep pets supervised and inoculated, keep the garbage and trash tightly covered, make sure a steel animal barrier is in place on the chimney to keep raccoons from making your home their home, and routinely use soap and water, as if you didn't already, on bites or scratches inflicted by your own or somebody else's pets. If you are bitten by a wild animal, seek professional help. Rabies Film

The National Institute of Allergy and Infectious Diseases has just completed a dramatic 28-minute film called "Rabies Alert," which will be available this fall for use by schools and organizations at no charge. The movie, produced by NIAID and the state of Maryland, includes a documentary follow-through of how one fluffy kitten led to the need to inoculate 20 people, five of them in one Maryland family, against rabies. The cat died. The message: vaccinate your cat, too. To borrow the film, call 496-5717.