Possible encephalitis cases in WA

Encephalitis-like symptoms suffered by two West Australian teenagers from the same high school appear to be unrelated and coincidental, the Country Health Service says.

Two Broome Senior High School students were flown to Perth by the Royal Flying Doctors Service on Wednesday after they became "very unwell with impaired consciousness" over the space of five days, physician Jeanette Ward said.

"On the basis of clinical judgment at the time, there was a raised index of suspicion that the symptoms could have been caused by an influenza virus, which is known to be a very rare cause of encephalitis," Dr Ward said.

"As the situation evolves, it appears possible that influenza virus may have caused the symptoms in one of the cases, but not the other."

She said the cause of the illnesses in the two students remained unclear, and it appeared they were coincidental and unrelated.

Dr Ward said there was no evidence to suggest either of the students had an infection that would put others at risk, but a notice was issued to the high school as a precautionary measure.

Further testing is under way.