According to the Centers for Disease Control and Prevention (CDC) in the United States an experimental rabies treatment that saved the life of a Wisconsin teenager in 2004 has failed to help other children infected with the deadly virus.
The rabies-therapy called the Wisconsin Protocol was first tried in 2004 when 15 year old Jeanna Giese was admitted to hospital with a range of unusual symptoms which doctors took six days to understand why she was ill.
Giese had among other things blurred vision, limb tremors, and slurred speech; a month before she had been bitten by a bat.
Doctors immediately used drugs to induce a coma, used a ventilator to keep her breathing and gave her the antiviral drug ribavirin.
Giese survived, made a full recovery and became the first known victim to do so who had not received a rabies vaccination.
The Wisconsin protocol rabies-therapy protocol has however failed three other youngsters, according to the CDC.
A 10-year-old Indiana girl in Indiana developed symptoms starting with pain in her arm and it was days before her mother remembered that the girl had reported having been bitten by a bat that flew into her window the previous June.
The CDC says the rabies strain identified from her system was a variant associated with the silver-haired bat, Lasionycteris noctivagans.
In the second fatal case, an 11-year-old boy , a recent immigrant from the Philippines had apparently been bitten by a rabid dog in the Philippines, maybe two years before.
The rabies gene sequences isolated from the boy were "similar to those of a canine rabies virus variant from the Philippines says the CDC.
Both children died despite the Wisconsin protocol being applied along with another child from Texas, a 16-year-old boy.
The CDC says those failures indicate that the Wisconsin protocol must be started as early as possible in the disease course and along with other experts they are calling for an "enhanced clinical awareness" of rabies and suggest it should be included in the differential diagnosis of "any unexplained acute, rapidly progressive viral encephalitis."
The CDC report states that while the incubation period for rabies is usually one to three months, longer periods have been documented.
Charles Rupprecht, Ph.D., chief of the CDC's rabies program says speed is of the essence in suspected rabies cases but other possible factors include the strain of the virus and variations in the way the drugs are used.
The report is published in the current issue of Morbidity and Mortality Weekly.