HONG KONG, June 28 (Reuters) - A newly discovered virus that is probably carried by bats has caused acute respiratory disease in three members of the same family in Malaysia, scientists said.

Bats are carriers of a number of viruses, including SARS that killed about 800 people globally in 2003, Nipah that killed more than 100 people in Malaysia in 1999 and the Hendra virus which killed 1 person and 14 horses in Australia in 1994.

Writing in the July issue of the Proceedings of the National Academy of Sciences, scientists in Malaysia and Australia said they isolated a previously unknown virus from a 39-year-old army clerk in Malacca, Malaysia, who fell sick in March 2006.

The issue was published online this week.

The man developed high fever, loss of appetite, fatigue and acute respiratory illness about a week after a bat flew into his home as he was watching television in the living room.

The creature flew "frantically" for two to three minutes in the living room before flying out the same door through which it entered, the report said.

Two of his five children, an 11-year-old daughter and a 6-year-old son, developed milder symptoms a week after the man fell ill. All three have since recovered.

Virus samples taken from the three of them proved identical and have since been named the Melaka virus. The researchers say it belongs to the family of reoviruses, which were first found in humans in the early 1950s.

"Melaka virus is a unique orthoreovirus capable of infecting and causing disease in humans. The infection of multiple members in the same family and the delayed onset by one week of clinical symptoms of the two children strongly suggest human-to-human transmission," the scientists wrote.

While the researchers have no direct evidence showing that the Melaka virus originates from bats, later analyses found it was closely related to the Pulau virus, another reovirus isolated in 1999 from fruit bats on Tioman island in Malaysia.

They also detected Melaka virus antibodies in recent tests of serum samples collected between 2001 and 2002, from volunteers from Tioman island, indicating these people had been infected previously by the virus.

The batch of serum was originally collected for surveillance against the Nipah virus.

Looking ahead, the researchers said identification of the Melaka virus would help doctors better diagnose the cause for respiratory tract illnesses (RTI), which are among the symptoms seen in SARS and bird flu patients.

"When severe RTI patients (are admitted to) hospital, it is important not only to exclude SARS or highly pathogenic avian influenza, but also to accurately determine the causative agent so that a targeted treatment regimen can be implemented," they said.

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