My experience of bats is limited to Oz, where they're grouped into the microbats (about the size of a flying mouse) that are insectivorous and flying foxes (about the size of a not very large flying cat) that are fructivores. Some biologists reckon the evolutionary histories of the two groups are vastly different.

When I was involved in bat banding (several decades ago) there was concern that many bat populations in the Top End had migratory patterns overlapping those in Papua New Guinea, where there was "rabies" as well as overlapping those of bat populations south of the Top End. There is no rabies in Oz so our efforts were encouraged.

Subsequent events have indicated that the PNG "rabies" is more likely to be the Lyssa virus that Foolestroupe mentioned; the two infections are in the same group, apparently. While the microbats are most unlikely to bite through an adult's skin, repeated handling of bats while banding them can gradually erode your skin so that blood is eventually drawn, but I've never heard of either type of bat biting people in Oz.

It appears that Lyssa virus and Hendra virus are both transmitted from bats by being exposed to their urine; they urinate while flying as well as when they're roosting. It is believed exposure to urine mist is the method by which bats in populations are also infected. This resonates with some info I picked up years ago about a cave in the US that was used by a large bat colony; people who entered this cave had to wear SCBA (or CABA) and full hazmat gear to prevent being infected with rabies, as it was carried in the urine mist from the colony.

The guano in caves and mines colonised by bats is often full of Histoplasmosis spores, which stay dormant until inhaled by a warm blooded animal. The fungal spores then germinate in the lungs and, basically, take over the alveolar cavities competing with the pulmonary tissue for oxygen. Untreated, it is fatal. A geologist friend of mine copped it while investigating an old adit and, fortunately, had it correctly diagnosed by his GP (who is also mine). Considering there are only one or two cases per decade in Oz, this earned our GP some praise; the xrays of my geologist mate's lungs looked like a space full of cobwebs; his mate had also copped an infection and required ICU treatment for several weeks. Poultry manure can also harbour Histoplasmosis, so beware.

Cheers, Rowan