An early blood test may come out soon to diagnose the Creutzfeldt-Jakob disease, a human version of the mad cow disease, U.S. scientists said on Thursday.
In the July 7 issue of the journal Science, a research team at the University of Texas Medical Branch at Galveston reported on first animal experiments that may help doctors estimate how many people are infected with the pathogen of the disease.
This rare but fatal brain disease is believed by many scientists to be linked with the Bovine Spongiform Encephalopathy (BSE), or the mad cow disease. The infectious agent for both is a malformed protein called prion.
The pathogen can spread to the brains of people who consume meat from sick cows, and convert healthy brain cells into prions. The " silent" phase of the Creutzfeldt-Jakob disease can last up to 40 years before any obvious symptoms appear.
Scientists are concerned that there may be people who are unaware they have the disease after the mad cow disease outbreak in Britain in 1980s.
According to Claudio Soto, a professor who led this study, early detection of the prions in the blood of infected people will offer a great promise for the early diagnosis of the Creutzfeldt-Jakob disease.
In the study, the researchers inoculated 46 hamsters with scrapie, a sheep version of the spongiform encephalopathy, and used a laboratory process that amplifies the quantity of abnormal prion proteins in the blood to a measurable amount.
Until now, measurable levels of the prion could only be detected in the brain and some lymph tissue late in the course of the disease. But Soto's team used a technique known as protein misfolding cyclic amplification to accelerate the process by which prions convert normal proteins to misshapen infectious forms.
With this technique, the researchers could detect prions in hamsters' blood 40 days after infection, about 74 days before symptoms appeared, according to the study. The disease wasn't detectable in the blood after 80 days, until symptoms appeared.
"With this method, for the first time we have detected prions in what we call the silent phase of infection," Soto said in a statement. Now the team is developing such test for people.
This advance could also help prevent accidental transmission via infected blood transfusions and organ transplants of the prions, the researchers suggested, especially now that some cases seem to have been transmitted by blood transfusion.