Fall 2003 Volume 16, Number 2	A Talk with Richard Johnson: Down the Prion Path Johnson offers perspective as a valued U.S. Advisor on mad cow and more.
	Little did neurologist Richard Johnson know that his seeing kuru patients in the highlands of Papua New Guinea-a postdoc's chance encounter with transmissible spongiform encephalitis (TSE)-would put him on a path toward expertise in the prion diseases. "The situation was nothing short of astonishing," he says of the fate of the New Guinea natives who spread kuru via the ritual of consuming newly dead relatives.
During the next 40 years, Johnson published more than 250 papers on both inflammatory and demyelinating ills of the nervous system-MS, AIDS, West Nile and measles, to name a few. Students and colleagues call him "the father of neurovirology." But he's never done prion research. He has, however, dealt with prion disease patients in Hopkins' neurology clinic, mostly those with Creutzfeldt-Jakob disease (CJD). And because Johnson's work as a virologist parallels that of many prion researchers, he's come to know the key scientists in the field. He's been both guide and advocate to TSE's handmaidens. His summary articles are widely read. Now a world expert, Johnson heads the foremost U.S. committee on TSE, one the Institute of Medicine has set up to advise Congress. Q.Is it difficult to diagnose Creutz-feldt-Jakob disease? A. We see three or four patients with CJD every year, far more than most hospitals. You look for rapid, progressive dementia, difficulty walking, cognitive problems and the spasms called myoclonic jerking. Clearly the hardest diagnosis is an early one. Sometimes home clinicians are flummoxed and send us patients. But the delay works in our favor. One fellow, I remember, didn't begin myoclonic jerking until he was in the ambulance on his way here. We needed just one look, really, and knew. Still, patients may be atypical. That's why you do a proper neuro exam and spinal tap to look for the breakdown protein 14-3-3; you do repeat EEGs. A specific, weighted MRI is helpful. We also, rarely, do confirmatory brain biopsies. But we're careful. One patient scheduled for a biopsy, we found, had syphilis. Another exhibited CJD symptoms but with bizarre behavior. Turned out she had bismuth poisoning from popping Pepto Bismol tablets. Q. What's the incubation time for CJD? Or for its variant (vCJD), the human version of mad cow? A Nobody's sure for CJD or vCJD. Kuru, we know, ranges from four to 40 years. That's because three elderly ladies in New Guinea died 40 years after cannibalism was suppressed. Q. Are fears of getting mad cow here warranted? A. The risk is minuscule. Five thousand U.S. citizens die every year from typical foodborne diseases. The number who die of U.S. mad cow is zero. On a picnic, the safest thing to eat may be a well-done hamburger. Q. . Now that one animal in Washington state had mad cow, is that in your mind when you examine patients? A. Definitely, though we ask questions that could help spot any prion disease: Did you have human growth hormone injections as a child? Grafts during surgery? Were you in the army in Europe? Our personnel ate British beef then. Q. If you thought we had a case of vCJD, would you send the patient to the CDC? A. There'd be no need. I'd examine the patient here without a gown or a mask, same way you do a person with HIV or with no infectious disease. Wash your hands afterward. You only use gloves to enter an orifice. But I've seen people overreact: You have some nice little babysitting grandmother. Next day she's diagnosed with CJD and, boom-she's isolated and everyone's swathed in masks and gowns. The family's terrified. And there's no reason for it. Q. Are we missing cases of mad cow in people? A. Perhaps. If this country had a first-rate autopsy system, we'd be better off. I feel strongly that we won't learn if vCJD or other spongiform encepha-lopathies exist in this country until we do more autopsies. Part of the problem is expense-HMOs often don't pay for them. And contacts tell me that some hospitals and pathologists refuse to perform autopsies for suspected prion disease. Fortunately, the CDC has set up a network of free autopsies for suspected CJD patients. Q. What else would you advise? A. We should watch what gets into the grocery store. Obviously, you don't process brains and spinal cords. But gut and lymphoid tissue are also infective. Get rid of it! The British removed beef offal from food in 1989. I'd hate to think what's in scrapple. Also, we need to monitor nutritional supplements. People are out there legally selling raw ground cow brains as health pills. Q. What worries you most? A. Chronic wasting disease (CWD). It's a spongiform encephalopathy of wildlife, mostly out West. Only a handful of people in this country work on it. Now, mad cow is transferred by feed, and there's no sign of transmission from animal to animal. But CWD is different. It apparently crosses species, from mule deer to regular deer or elk. Deer share pastures with cattle and sheep. Scary? You bet. I recently ate at a Baltimore restaurant that had elk on the menu. I had beef instead.