I wouldn't have picked it up if I'd known what it was. As I scooped the scrap of black velvet out of my car's trunk and turned to toss it into the trash, it gained a sort of skeletal substance, scrabbled at my fingers and struggled to unfurl. It was a bat. I dropped it. The bat lay on its back on the ground, wings spread and mouth agape, and I contemplated our mutual dilemma: The bat was clearly sick; I didn't want to get sick. That nagging concern led me to talk about my late-June bat encounter, first in casual conversation with friends, then less casually with my doctor. And it ultimately triggered a series of ER visits (four so far) and follow-up calls from animal control and city health department officials, all to guard against a possibility of which I was first just vaguely aware: A bat bite can cause rabies. The only way to know for sure whether my bat was rabid would have been to take it to a lab and have it tested. I didn't have a glove to pick it up or a bag to put it in. I tried, ineffectually, to scoop the distressed creature onto the dog's Frisbee and put it back into the car to take it to the doctor's office. But it flapped and gaped at me, and I wondered whether it might bite me in self-defense. And what if it regained its ability to fly in my car or, worse still, in the doctor's waiting room, launching aerial attacks on the already sick? So I left the bat where it lay and went to wash my hands. Thoroughly. Then I put the episode to the back of my mind. I love the bats that fly out into the early night sky, swooping to feast on a diet of various twilight pests like moths and maybe mosquitoes by the thousand every hour. (Just think, thousands fewer itchy bites; thousands fewer chances of getting West Nile virus.) During daylight hours, I've taken friends to see them in a relative's barn, hunched along the dark beams like rows of inverted little nuns. Once in a while, we collect their droppings to fertilize the garden. They are our allies -- unless, of course, they're rabid. Which was the possibility raised again a couple of days later by a friend who is a doctor. His words of warning sent me to the Internet, where I began a crash course on bats. Like other mammals, bats can carry the rabies virus and spread it in their saliva, usually into bite wounds or open cuts. It can take weeks for symptoms to develop; once they do, they progress inexorably from a fever and headache to anxiety, delirium and finally heart failure. Along the way, people typically develop the haunting fear of water that gave the disease its Latin name -- hydrophobia. Rabies is extremely rare in people, though as many as 40,000 Americans get treatment every year to prevent the disease after coming into contact with an animal that might be infected. Bats are the source of most of the recent human cases in the United States, according to the Centers for Disease Control and Prevention. A biologist from Bat Conservation International told me that the vast majority of bats are rabies-free, but there are signs to watch for: Any bat that is active by day or unable to fly, the CDC says, is far more likely to be rabid. That was my bat. I shouldn't consider hand-washing adequate protection, my doctor-friend said. Our family physician concurred, more forcefully. But his office doesn't carry the vaccine. Which is why I found myself sitting in a Baltimore hospital's emergency room four days after the encounter, with a note on my chart: 'Picked up sick bat.' As if I'd picked it up because I felt sorry for it. Rabies treatment is considered urgent, but it's hardly an emergency, so my case didn't trigger alarms with the busy ER triage nurse. I waited among people far needier than I was. As evening dragged into night, I wondered: Were we making too much fuss about my having simply handled a bat? That's what I asked the doctor when I finally got to see him. I hadn't felt a bite, I told him; I had a couple of scratches on my hand, but they were more likely caused by the (vaccinated) family dog than the bat. Was this a big waste of money and of time -- his as well as mine? The doctor eyed me quizzically: 'We're dealing with an entirely preventable, completely incurable disease,' he cautioned. 'Let's do the shots,' I said. The so-called post-exposure treatment is no longer a 20-shots-in-the-stomach ordeal. In recent years, the number of injections of rabies vaccine has come down to five over the course of a month, usually given in the muscle of the upper arm. (I got two of mine in the thigh.) And in June, the Advisory Committee on Immunization Practices reduced the number of recommended shots to four over two weeks. A little more disconcerting were several injections of human rabies immune globulin I was given on that first visit; they go into open wounds or the site of the bite, which, as the ER doctor said, is almost always on fingers. I watched the nurse force as much fluid as he could into the scratches on my ring finger, creating a liquid bubble under my skin. In the weeks that followed, as I got my successive injections of vaccine, I heard more bat lore. There was the mysterious 1995 case of a child asleep in a room in which a bat was flying around. The child's aunt captured the bat without waking her niece, who bore no signs of a bite. But a month later, the 4-year-old fell ill, was found to have rabies and died. The bat's body was retrieved; it tested positive for the disease. The bat biologist told me another spooky story of a couple of scientists in a bat-filled cave who developed rabies even though they apparently had no physical contact with the creatures. On the theory that they had inhaled airborne rabid bat saliva, he said, researchers in enclosed bat-infested areas are now advised to wear respirators. The medical community has become 'hinky about bats,' as the ER doctor put it, and that has led to what can seem like extreme caution. Our neighbors had bats in the attic, and the whole family got shots. On one of my visits to the hospital, a nurse told me about having to vaccinate an entire boys' soccer team after a single bat flew worrisomely low among the players. There's now a national vaccine shortage, the nurse told me. Finding the right response can be tricky when you consider the perils of leaving somebody unvaccinated -- a point emphasized to me by officials from animal control and the city health department, who made separate follow-up calls to make sure nobody else was at risk from my bat. Bats' teeth are very fine, the community health nurse told me: People sometimes don't know they've been bitten. (I remembered the white needles lining the gaping mouth.) Was anyone asleep where I found the bat, she asked? (No.) Or drunk? (No again.) Could anyone else have touched the bat? Yes. My husband had been loading junk from a barn into our car just before I found the bat. He probably picked it up, too. He's getting his own set of shots. 