“That’s a start. Dr. Elliot, you see anything worth noting?”
Claire focused her eyepiece and gazed at the field of tissue. She was able to identify most of the cells, based on what she remembered from medical school histology classes years before. She recognized star-shaped astrocytes, and the presence of macrophages-the cleanup crew, whose function is to tidy up after infection. She also saw what Rothstein had noticed: there were swirls of granulation tissue or scarring, possibly the aftermath of acute inflammation.
Reaching for the slide position knob, she shifted the field, scanning new cells.
An unfamiliar pattern appeared under her gaze, a swirl of fibrous matter several cells thick, forming a microscopic rind of tissue. “I see encapsulation here,” she said. “A layer of scar tissue. Is this a cyst, maybe? Some sort of infectious process that his immune system managed to wall off and encase?”
“You’re getting warm. Remember the CT scan?”
“Yes. It looked like he had a discrete brain mass, with calcifications.”
“An MRI was done here after transfer,” said Rothstein. “It showed essentially the same thing. A discrete lesion, encapsulated, with calcifications.”
“Right,” said Clevenger. “And what Dr. Elliot has just identified is the cyst wall. Scar tissue formed by the body’s immune system, surrounding and closing off the infection.”
“Infection by what organism?” asked Rothstein, raising his head to look at Clevenger.
“Well, that’s the mystery here, isn’t it?”
Slowly Claire moved the slide, shifting the field again. What appeared through her eyepiece was so startling her gaze froze in amazement. “What on earth is this?” she said.
Clevenger made a sound of almost childish delight. “You found it!”
“Yes, but I don’t know what it is.”
Rothstein pressed his face back to the eyepiece. “My god. I don’t know what it is, either.”
“Describe it for us, Dr. Elliot,” said Clevenger.
Claire was silent for a moment as she shifted the position knob and slowly scanned the field. What she saw was a strangely twisted architecture, partially calcified. “It’s some sort of degraded tissue. I don’t know if this is all artifact or what-it’s as if some organism collapsed into an accordion shape, and then became petrified.”
“Good. Good!” said Clevenger. “I like that description-petrified. Like a fossil.”
“Yes, but of what?”
“Back off, look at the larger picture.”
She reduced magnification, trying to get an overall view. The shape took more complete form, became a spiral that had ‘folded upon itself. The realization of what she was looking at made her straighten in shock and stare at Clevenger.
“It’s some sort of parasite,” she said.
“Yeah! And isn’t it cool?”
“What on earth was a parasite doing in my patient’s brain?” said Rothstein.
“It’s probably been there for years. Invaded the gray matter, caused a temporary encephalitis. The immune system launched an inflammatory response. You get an influx of white blood cells, eosinophils, everything the host can muster to fight back. Eventually the host wins, and his body walls off the critter, encases it in granulation tissue, forming a sort of cyst. The parasite dies.
Parts of it become calcified-petrified, if you will. Years later, that’s what you have left.” He nodded at the microscope. “A dead parasite, trapped in an envelope of scar tissue. It’s probably the reason behind his seizures. The mass effect of that little pocket of dead worm and scar.”
“What parasite are we talking about?” asked Claire. “The only one I can think of that invades the brain is cysticercus.”
“Exactly. I can’t conclusively identify this species-it’s too far degraded. But this is almost certainly the disease cysticercosis, caused by the larva of Taenia solium. The pork tapeworm.”
Rothstein looked disbelieving. “I thought Taenia solium was only found in underdeveloped countries.”
“For the most part it is. You’ll find it in Mexico, South America, sometimes in Africa and Asia. That’s why I was so excited when I saw that slide. To find a case of cysticercosis here, in northern Maine, is unbelievable. It’s definitely worth an article in The New England Journal of Medicine. What we need to figure out is when and where he got exposed to pork tapeworm eggs?’
“There’s nothing in his history about foreign travel,” said Claire. “He told me he’s lived all his life in this state.”
“Which would make it a truly unusual case. I’ll run antibody tests to confirm this is the right diagnosis. If it is Taenia solium, he’ll have a positive ELISA test on his serum and CSE Is there any history of an initial inflammatory response? Symptoms that might tell us when he was first infected?”
“What symptoms, specifically?” asked Rothstein.
“It could be a clinical picture as dramatic as full-blown meningitis or encephalitis. Or new onset epilepsy.”
“His first seizures occurred sometime before age eighteen”
“That’s one clue.”
“What other symptoms might show up?”
“Subtler signs, possibly. It can mimic brain tumors, cause a variety of psychiatric disorders.”
The back of Claire’s neck was suddenly tingling. “Violent behavior?” she asked.
“Possibly,” said Clevenger. “I didn’t see that specifically mentioned in my references. But it could be a sign of acute illness.”
“When Warren Emerson was fourteen years old,” said Claire, “he murdered both his parents.”
The men stared at her. “I didn’t know that,” said Rothstein. “You never mentioned it.”
“It wasn’t relevant to his medical condition. At least, I didn’t think so.” She looked down at the microscope, the image of the parasite still vivid in her mind. An initial infection of parasitic eggs, followed by symptoms of encephalitis. irritability. Even violence.
“It’s been a long time since medical school,” she said. “I don’t remember much about Taenia solium. What’s the life cycle of this organism?”
“Taenia solium is a cestode,” said Clevenger. “A tapeworm that usually lives in the intestinal tract of its host. People get it by eating undercooked pork that’s been infected with the larvae. The larva has sucking caps that hook on to the wall of the human small intestine, which is where it sets up housekeeping, absorbing food. The worms can live there for decades without causing symptoms, and grow as long as three meters-over nine feet long! Sometimes the worms will be passed or expelled. You can imagine what it’d be like to wake up one morning and find one of those critters lying in the sheets with you.”
Rothstein and Claire exchanged slightly nauseated glances. “Sweet dreams,” muttered Rothstein.
“So how does the larva reach the brain?” asked Claire.
“It happens during a different part of the worm’s life cycle. After the worm matures to adulthood in the human intestine, it begins to produce eggs. When those eggs are passed, they contaminate soil and food sources. People ingest them, the eggs hatch and penetrate the intestinal wall, and are then carried through the bloodstream to any number of organs, including the brain. There, after a few months, they develop into larvae. But it’s a dead end, because they can’t grow in that confined space, without nutrients. So they just sit there until they die, forming little cystlike pockets in the brain. The cause of this patient’s seizures?’
“You said these eggs contaminate the soil,” said Claire. “How long can the eggs stay alive outside of a host?”
“A number of weeks.”
“What about in water? Could they stay alive in a lake, for instance?”
“It’s not mentioned in any of my reference books, but I suppose it’s possible.”
“Would the Taenia solium ELISA test be a screen for infection? Because we should order it on another patient. A boy at the Maine Youth Center.”
“You think there’s another case in this state?”
“Maybe a number of other cases in Tranquility It would explain why so many of our children are suddenly showing violent behavior.”
“An epidemic of cysticercosis in Maine?” Rothstein looked skeptical. Claire’s excitement was rising. “Both the boys I admitted had the same abnormality in their white blood cell count: a high percentage of eosinophils. At the
