From 2004 -- that awful transplant story

ATLANTA, Georgia (CNN) -- Rabies spread by organs taken from an infected donor has killed three transplant recipients, the Centers for Disease Control and Prevention said Thursday.

"This has never happened before," said Dr. Mitch Cohen, an infectious disease expert at the CDC, in a conference call with reporters.

A fourth recipient died during the actual transplant operation, before there was time to develop the disease, officials said.

Rabies was also determined to be responsible for the death of the organ donor.

The unprecedented case began nearly two months ago, shortly after an Arkansas man suffered a brain hemorrhage and died at Christus Saint Michael Healthcare Center in Texarkana, Texas.

The man's lungs, kidneys and liver were transplanted May 4.

The impact of the virus began to emerge within weeks.

The liver recipient died June 7; one kidney recipient died June 8 and the other kidney recipient died June 21. The patient who died was undergoing lung transplant surgery.

Though the risk of person-to-person transmission of rabies is low, the disease is nearly always fatal.

Health officials urged anyone who may have had contact with the infected patients to be tested for rabies, and patients at five hospitals were being sought.

In addition to the Texarkana hospital, the other facilities are Baylor University Medical Center in Dallas; the University of Alabama-Birmingham Hospital; Wadley Regional Medical Center, Texarkana, Texas; and Good Shepherd Medical Center Longview, Texas.

Cohen said rabies typically occurs in just one to three people in the United States in any given year, and is most often transmitted by the bite of an infected mammal.

Based on laboratory tests, health experts said they believe a bat infected the organ donor.

Rabies tests are not routine donor screening tests, Virginia McBride, public health organ donation specialist with the Health Resources and Services Administration, said.

The number of tests is limited because doctors have only about six hours from the time a patient is declared brain-dead until the transplantation must begin for the organs to maintain viability.

Potential donors are tested for other infectious diseases such as HIV, hepatitis B and C and syphilis, she said.

Person-to-person rabies transmission has been reported in only two cases, both of which occurred in Ethiopia via contact with saliva, Cohen said. One infection resulted from a bite, the other a kiss, he added.