Chapter 16 #2
“All protein molecules are long chains of specific amino acids held together by peptide bonds,” Laurie began, mimicking Jack by leaning forward to be better heard.
“Because each protein is an invariable sequence of amino acids, each molecule ends up having a very specific physical shape, which is vitally important as it is a protein’s three-dimensional shape that determines its function, like acting as a catalyst for a vital chemical reaction.
Normal prions are unique proteins that are necessary for the function of the neurons in our brains but which can be coaxed to assume a nonfunctioning shape even though this nonfunctioning shape is the exact same molecule in terms of its amino acid structure.
This aberrant shaped prion has the ability, when it comes in contact with the normal prion, to cause the normal prion to change its shape.
This newly reshaped form can go on to alter another normal prion creating a chain reaction, or it can combine with other misshapen molecules to form fibrils and amyloid plaques.
Currently the thought is that these fibrils and plaques ultimately interrupt brain function and kill the neuron. ”
“Well said,” Jack complimented and even clapped quietly.
“These bad protein prions, once they get on the scene, cause the normal, good prions to change to a dysfunctional state, which eventually kills the neuron, causing a progressive neurogenerative disease. So, let’s review.
We’re dealing here with an unknown neurodegenerative disease caused by a particular infectious prion.
Okay, now let’s talk about transmission.
Bob and Melanie, this is your area of expertise being out there in the clinical trenches, so to speak.
What can you tell us? Have you any thoughts, knowing the patients and their families as well as you do? ”
Bob and Melanie exchanged a quick, mildly nervous glance after which Melanie responded, “I’m not sure exactly what you mean by ‘transmission’.”
“Simply, how do we think these people have gotten this disease,” Jack explained.
“We have to figure that out if we are going to have any chance of stopping this outbreak, if it is an outbreak. For the moment we are going to consider it an outbreak. My understanding is that all twelve cases and potentially the two more you will be seeing today have all occurred in the last month or so and they all live here, in Essex Falls.”
“Yes, that’s correct,” Melanie said. “Obviously we’ve had our share of Alzheimer’s patients over the years, but seeing this many with such similar, rapidly developing symptoms is definitely new for us, especially with three progressing to death within weeks.”
“It’s shocking, the more I think about it,” Bob added.
“I guess the idea of how they’ve gotten this disease hadn’t occurred to me,” Melanie said, “but I suppose it should have. What I’m remembering from courses I’ve taken over the years is that the three main methods of getting a disease are ‘acquired,’ ‘familial,’ and ‘sporadic.’ We can immediately eliminate the ‘sporadic’ because that requires a very specific random mutation and the chances of that happening suddenly in this many people is almost zero.
We can also eliminate familial because only two of the twelve patients are related in any way and that’s by marriage, not by genetics.
So, we are left with it being acquired.”
“My thoughts exactly,” Jack said. “Mad cow disease was acquired by eating cows infected with a specific infectious prion. Could something like that be involved here in Essex Falls? These patients of yours had to have gotten their infectious prions from someplace.”
“I can’t imagine,” Bob said. “You’re talking about someone having an infected herd of cattle.”
“Something like that,” Jack said. “But I don’t think it has to be necessarily beef.
Maybe it could be pork or even chicken. My guess is that all live animals, particularly mammals, have prions.
We’ll have to ask Christine if it’s possible for other species’ prions to be infectious for us humans.
They must be, or at least some, because those were definitely cow prions that killed all those people in England during the mad cow outbreak. ”
“I suppose Melanie and I can start asking those infected families about their eating habits,” Bob said. “We can find out if they share any unique similarities.”
“What about wild deer?” Laurie asked. “I’ve heard they can be carriers. When is deer hunting season here?”
“That’s not until the fall,” Bob said.
“I suppose it could be deer meat coming out of someone’s freezer,” Laurie suggested. And then she shook her head in discouragement. “Narrowing it down to an ‘acquired’ infection is still much too broad to be helpful. There’re just too many possibilities.”
“But we still have to try,” Jack said. “Let’s move on to location. Has there been any thought given to where the individual cases occurred?”
“What do you mean?” Bob questioned, wrinkling his forehead. “They’ve all been here, in Essex Falls.”
“That I understand,” Jack said. “But what I’m asking is where in Essex Falls.
The most famous epidemiological case in the history of medicine was John Snow’s triumph in London.
He was the doctor who figured out that a mid-nineteenth-century cholera epidemic that was raging in the city wasn’t coming from ‘bad air’ as most people thought but rather from one specific water well, and by shutting it down, he stopped the outbreak. ”
“Okay, fair enough,” Bob said. “We’ll get a map of the town and locate all twelve cases and even add the two I’m seeing today if need be. Unfortunately, I can’t imagine it’s going to helpful. I already know that all the original dozen live here in town and the town is obviously not that big.”
“Okay,” Jack said, raising his hands as if surrendering. “I’ve said my piece. You are all excused now.” Everyone laughed, including Jack. “If everyone is finished with lunch, I want to get back to the Hiram House because my basketball buddy from the city, Warren, should be here any minute.”
“Can we take a few minutes to look at the brain slides from Barker and Hughes,” Laurie suggested. “Would you be okay with that, Jack?”
“I suppose,” Jack said. “If we make it fast.”
“Would that be a problem, Bob?” Laurie asked.
“No, not at all,” Bob said. “Only that I’ll be embarrassed. I’m afraid they aren’t very good. Melanie and I are just learning to make slides and use the staining properly.”
“What stains did you use?” Laurie asked.
“The recommended silver and Congo red,” Bob said. “But it’s not just the staining that’s the problem. It’s that the sections are too thick.”
“I’d still like to see them,” Laurie said as everyone got to their feet and then filed out of the diner into the warm late July afternoon.