episode_0121

Episode 121. Black Death (4)

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Some people might be curious.

If the Black Death can affect all mammals, why is it transmitted through rats and fleas? The reason is simpler than you might think.

The human immune system cannot tolerate bacteria in the blood. Human blood is kept in a completely sterile state. If the Black Death bacteria were to circulate in a human’s blood, it would be time to die.

This is especially true when you consider that most people who contracted the septicemic plague died.

So, to explain it simply.

It is not easy for a flea that bites a person with the Black Death to contract the plague. The bacteria only start to circulate in the blood when the person is close to death, and the concentration is low.

It is unlikely that the human blood that fleas eat will contain the plague bacteria, but rats are different.

Because mice’s immune systems are less robust than those of humans, the blood of mice infected with the plague can contain quite high concentrations of the bacteria.

In order for the Black Death to spread properly, it needs rats as intermediate hosts.

Even if it was transmitted by fleas, it was not easy for the Black Death to spread from person to person. That’s why we had to kill all the rats.

Even though I used magic, the situation was resolved faster than I thought. In a way, it was a method that had nothing to do with healing people.

Originally, the Black Death did not survive as a plague until the 20th century. It remained only as a rare disease that was contracted by eating strange animals.

The reason was simple.

Humanity realized that the Black Death was a disease spread by rats and fleas, and responded accordingly. Improved sanitation in cities also meant that people were less likely to be bitten by fleas.

I explained it for a long time, but the conclusion is this.

The Black Death is less contagious than expected.

Even in this case, empirically, it did not seem to spread from person to person, even if it was transmitted by fleas. Most of the patients died within a few days, so there was no time for the plague to spread properly.

Istina didn’t seem to understand. My graduate student just looked at me with blank eyes, wiping her glasses with her hand.

“So. If the rats disappear, the Black Death won’t spread? Is that the only solution?”

“Yeah.”

“The solution was simpler than I thought.”

There were things I regretted.

No, I didn’t know there was such magic.

If I had known I could round up and kill the rats, I would have done that as soon as I got here. The situation would have been resolved a day or two sooner.

“Sometimes, right? When you look at it frankly, the conclusion is sometimes a bit disappointing. Not all riddles have great solutions.”

Istina put her glasses back on and tilted her head as if curious.

“But, Professor, couldn’t the Black Death have been cured with lab-made penicillin? That’s a drug that can be mass-produced.”

I shook my head.

The bacteria that cause the Black Death are mostly gram-negative bacteria. Unfortunately, the Black Death was not a type of bacteria that could be treated with penicillin.

“That’s a good idea, but… … Penicillin is an antibiotic that kills gram-positive bacteria. So we can’t guarantee that it will be effective against the plague bacteria.”

This is also a question of structure and function.

Gram-positive bacteria have a thick peptidoglycan layer, and this thick peptidoglycan layer is what makes them appear gram-positive when stained.

Penicillin kills bacteria by interfering with the synthesis of this peptidoglycan.

The Black Death bacillus is a gram-negative bacterium, so its peptidoglycan layer is thin and less important. That’s why penicillin can’t kill the Black Death.

I didn’t explain it like that.

“It’s complicated.”

Istina scribbled something in her notebook.

****

There are twenty plague patients left in the temple.

There were some patients whose symptoms improved, but none of them were completely cured. Even if there were, they would not have been able to return to their daily lives.

We’ll have to stay isolated for the time being.

The rest of the patients all died.

“There are so many dead.”

Istina was flipping through the medical records, counting how many people had died.

Let’s do the math.

Fifty patients came to the temple, and only twenty of them survived. The mortality rate of this plague epidemic must be around 60%.

“People who contract the Black Death usually die. If treated early with antibiotics, the survival rate increases significantly, but that is not certain.”

As I said last time, antibiotics must be administered within a day of the onset of plague symptoms to ensure the patient’s survival.

It’s too late to save everyone who’s been infected, this time. At least we’ve stopped the plague from spreading widely.

Istina muttered something.

“Black Death. It is a disease caused by bacteria, and the Black Death bacteria are in rats, and fleas transmit the bacteria from rats to humans. The most effective treatment is euthanasia, and environmental quarantine and prevention such as killing rats… … .”

That was mostly correct.

I nodded.

“Yeah.”

“But, Professor, you suggested that patients whose limbs have turned black be euthanized, right?”

“That’s right.”

“Those patients. Didn’t you tell them what would happen if they didn’t get euthanized? I remember… … .”

Someone shouted from the other side of the ward. Probably one of the priests working at the temple. Istina and I turned our heads.

“Professor! You need to come now!”

Someone was dying on the other side of the ward. Istina ran towards the voice and I chased after her.

****

Things weren’t going well.

Fortunately or unfortunately, the patient was still alive. His limbs had turned black, so I asked what would happen if we didn’t euthanize him.

It becomes like this.

“Bring your belt.”

“Yes? Why?”

The patient’s right hand was completely discolored black. The left hand and feet still had bruises from petechial hemorrhages.

I tied a bandage around the patient’s upper arm. If the patient’s blackened hand had just begun to rot, and if the cellular material was seeping into the bloodstream… … .

We need to limit the blood flowing through the rotten hand as much as possible. The necrosis has spread to the elbow area, so the arm itself needs to be amputated now.

“The patient’s pulse is unstable!”

Hyperkalemia.

Let’s think about it. If the pulse is unstable, you need to act within minutes. Hyperkalemia can be treated with calcium gluconate injections. If there is a blood clot, you can inject heparin.

What’s important now is… … .

“I think I’ll have to cut off your arm.”

“Yes?”

The patient was understandably frightened even though he was still unconscious, but Istina and the priests of the temple nodded resolutely.

There is no other way.

“Just hold on to your Mac and let’s move on.”

Since we can’t inject heparin right before surgery, we have to leave that up to God.

I didn’t want to inject calcium gluconate in a situation where there was no electrocardiogram, but I had to make a choice. If I continued like this, I would die from hyperkalemic arrhythmia, including my arm.

I took the patient’s pulse while injecting calcium gluconate. The pulse seemed to be stabilizing… … It was hard to tell for sure.

First of all, Mac is stable.

Amputating limbs is a surgical procedure that has been performed for a very long time. Doing it safely is a different matter, though.

It is not a particularly difficult surgery.

The operating room was being prepared without a hitch.

I looked at the healer who had called me earlier. It wasn’t quite a situation where I had to grab him by the collar, but it was a situation where I had to fight him. At least in my opinion.

I grabbed the healer and moved aside, to a place where the patient would have a hard time hearing the conversation.

“Why are you like that?”

“Why did you cut off that patient’s arm now? If you had cut off the arm earlier, wouldn’t the arrhythmia not have occurred? Or was it because he was going to die anyway, so you just left him alone?”

I sighed.

“Not an excuse. I was originally planning to have the surgery today. The patient refused opium. There were so many patients in the ward. I was going to ask the professor when he had time and then have the surgery.”

“Okay, I understand.”

If we had responded quickly, he might have survived. At least we could have sent him off comfortably.

“Are you saying that anesthesia is okay?”

“Oh, yes.”

A knife, boiled and cooled salt water, and a saw were prepared next to the operating table. After a while, the nurses helped the patient onto the operating table.

“Ready to go.”

We moved to the operating table. The patient was sitting there with a very anxious expression.

“Is the patient okay?”

“Yes.”

“No heart palpitations?”

“Not available now.”

We rushed back to the patient. The patient looked at us with an anxious expression. I opened my mouth with difficulty.

“I don’t have much time, so I’ll just get to the point. As you know, one of the patient’s arms is rotting away.”

“It looks like that.”

“Yes. We need to amputate the patient’s arm, but even if we do, we cannot guarantee survival. If you want, we can skip the surgery, and we will give you painkillers, so you can rest well.”

“I’m going to have surgery. I can give up my arms and hands, but I have a home to go back to… … .”

This patient said he had previously refused opium. Ultimately, the will to survive is what matters most. If the patient had not wanted to live, he would have already died.

“Let’s cut off the arm… … then.”