Mystery illness claims 4 lives in Texas

Officials confirmed Tuesday four patients in the U.S. state of Texas have died of a mysterious flu- like illness, local media reported.

A total of eight confirmed patients, ranging in age from 41 to 68, were admitted to hospital with flu symptoms in Montgomery County, but tests for influenza were negative, the website of the Houston Chronicle reported.

Jennifer Nichols-Contella, spokeswoman for the Montgomery County Public Health District, told the Chronicle four of the eight have died. She said officials are monitoring the situation and waiting on further lab results.

No details were available Tuesday on the dates of the deaths or hospitalizations, she said. Two of the surviving patients are " very sick," and doctors are being advised to use extra precaution to prevent it from spreading, other media quoted unnamed sources as saying.

Although the Montgomery County patients did not test positive for influenza, this is the heart of the U.S. flu season, which typically peaks in January or February, health officials here warn. They recommend a yearly flu vaccine for everyone 6 months of age and older.

During the week ending Dec. 7, four U.S. states -- Texas, Louisiana, Alabama and Mississippi -- reported high levels of influenza-like illness, according to the federal Centers for Disease Control and Prevention.