Scientists have found the mysterious MERS virus in a bat in Saudi Arabia.

An international research team said the bat virus is an exact match to the first known human case of Middle East respiratory syndrome. The sample was collected from within a few miles of that patient’s home.

The discovery reported Wednesday is considered an important development in the search for the origin of MERS, a deadly respiratory illness that is worrying health officials around the world.

But it’s likely that something else — perhaps another animal — is spreading the virus directly to humans, said Dr. Ziad Memish, Saudi Arabia’s Deputy Minister of Health and lead author of the report.

Since it was identified last September, the respiratory illness has sickened nearly 100 people, most of them in Saudi Arabia and the Middle East. About half of them died.

No cases have been reported in the United States.

Bats have been a suspected carrier of the virus for some time because they are known to carry viruses similar to MERS. They also harbor other deadly viruses, including rabies and SARS.

Still, discovery of a genetic match doesn’t mean bats are the direct culprit.

“There is no evidence of direct exposure to bats in the majority of human cases of MERS,” Memish said in a statement.

Signs of MERS-like viruses have been reported in other animals, including camels. The researchers are investigating other species, said Dr. W. Ian Lipkin of Columbia University, another study author.

“This is but the first chapter” in the global team’s investigation, Lipkin said in a statement.

The researchers collected more than 1,000 samples from seven bat species in Saudi Arabia. The exact match was seen in a fecal sample from an Egyptian Tomb Bat.