Chapter 121

121. The Black Death (4)

Maybe some folks are curious.

The Black Death can infect all mammals, so why does it specifically spread through rats and fleas? The reason is surprisingly simple.

Human immune systems cannot tolerate bacteria in the blood. Human blood must remain completely sterile. When Black Death bacteria circulate in human blood, death is imminent.

Just think about it—almost everyone who gets septicemic plague dies.

So to put it simply…

Fleas don’t easily get infected from biting a person with Black Death. Humans only start having bacteria circulating in their blood right before death, and even then, the concentration is low.

The chances of Black Death bacteria being in the blood a flea eats are slim. But it’s different for rats.

Rats have less thorough immune systems than humans, meaning Black Death bacteria can exist at relatively high concentrations in rat blood.

For Black Death to properly spread, we need rats as intermediate hosts.

Even with fleas as vectors, human-to-human transmission isn’t easy. That’s why we had to kill all the rats.

We did use magic, but the situation resolved faster than expected. In a way, it wasn’t directly related to healing people.

In original history, Black Death didn’t survive as an epidemic into the 20th century. It became a rare disease caused by eating strange animals.

The reason was simple.

Humans realized Black Death spreads because of rats and fleas, and responded accordingly. Improving urban hygiene also meant fewer people got bitten by fleas.

After all that explanation, here’s the conclusion:

Black Death is less contagious than you’d think.

Based on experience this time too, even with fleas as vectors, it didn’t seem to spread well between people. Most patients died within days, so there wasn’t enough time for the plague to properly spread.

Istina seemed confused. My graduate student was cleaning her glasses while just staring blankly at me.

“So… if we get rid of rats, Black Death can’t spread? Is that the whole solution?”

“Yeah.”

“Surprisingly simple, huh.”

There was something I regretted.

No, I didn’t know such magic existed back then.

If I’d known we could gather and kill rats, I would’ve done that first thing. We could’ve resolved the situation a day or two faster.

“Sometimes solutions turn out anticlimactic when you actually lay them out. Not every mystery has a grand answer.”

Istina put her glasses back on and tilted her head curiously.

“Hey Professor, couldn’t we have treated Black Death with penicillin made in the lab? That’s a mass-producible drug, right?”

I shook my head.

Black Death-causing bacteria are mostly gram-negative. Unfortunately, it’s not the kind treatable with penicillin.

“Good thinking… but penicillin is an antibiotic that kills gram-positive bacteria. We can’t guarantee effectiveness against Black Death bacteria.”

This comes down to structure and function issues.

Gram-positive bacteria have thick peptidoglycan layers, which is why they stain positive during gram tests.

Penicillin works by interfering with peptidoglycan synthesis to kill bacteria.

Black Death bacteria are gram-negative, meaning they have thin and less crucial peptidoglycan layers. That’s why penicillin can’t kill Black Death.

I didn’t explain all that though.

“Complicated.”

Istina scribbled something in her notebook.

***

Twenty remaining Black Death patients at the temple.

There were patients showing improvement, but none fully recovered. Even if they had, they wouldn’t be ready to return to daily life yet.

They’ll need to stay in quarantine for now.

The rest of the patients have all passed away.

“So many deaths.”

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

Let’s calculate.

50 patients came to the temple, and only 20 survived. So the mortality rate for this Black Death outbreak was around 60%.

“Most people who get Black Death die. Early antibiotic treatment increases survival odds, but it’s not guaranteed.”

As I mentioned last time, antibiotics must be administered within a day of symptoms starting to properly ensure patient survival.

It was too late to save everyone this time. Still, we managed to prevent a major epidemic, which is fortunate.

Istina muttered something.

“Black Death. A bacterial disease where the bacteria lives in rats, and fleas transfer it from rats to humans. The most effective treatment is euthanasia, along with environmental measures like killing rats…”

Generally correct.

I nodded.

“Yeah.”

“But professor, you suggested euthanasia for patients whose limbs turned black, right?”

“That’s right.”

“What happened to those patients if we didn’t do euthanasia? Don’t remember…”

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

“Professor! Please come immediately!”

Someone was dying at the far end of the ward. Istina rushed toward the voice, and I followed her.

***

The situation wasn’t good.

Whether lucky or unlucky, the patient was still alive. I had been asked what happens if we don’t euthanize patients whose limbs turn black.

This.

“Bring me a tourniquet.”

“Huh? Why?”

The patient’s right hand had completely turned black. The left hand and feet only showed bruising from pinpoint bleeding.

I tied a tourniquet above the patient’s elbow. If the blackened hand had just started rotting, meaning cellular material was entering the bloodstream…

We need to restrict blood flow through the rotten hand as much as possible. Since necrosis has reached near the elbow, we need to amputate the arm itself.

“The patient’s pulse is unstable!”

Hyperkalemia.

Think about it. With an unstable pulse, we need to act within minutes. Hyperkalemia can be treated with calcium gluconate injections. If there are blood clots, we can inject heparin.

What’s important right now is…

“We may need to amputate the arm.”

“Huh?”

The patient, despite being semi-conscious, understandably panicked, but Istina and the temple priest firmly nodded.

There’s no other option.

“Just stabilize the pulse. Let’s move.”

We can’t inject heparin right before surgery, so we have to leave that to fate.

Ideally, I wouldn’t inject calcium gluconate without an ECG, but I have to make a choice. Otherwise, the patient might die from hyperkalemic arrhythmias regardless of the arm.

I injected calcium gluconate while checking the patient’s pulse. The pulse seems to be stabilizing, but it’s hard to tell for sure.

Anyway, the pulse stabilized.

Amputating limbs is an ancient surgical procedure. Though safely removing limbs presents its own challenges…

It’s not particularly difficult surgery.

The operating room was prepared without issue.

I looked at the healer who had called me earlier. Though not quite a collar grab, we needed to have a serious talk. At least from my perspective.

“Why is this?”

“Why are we cutting off the arm now? Shouldn’t it have been removed earlier to prevent arrhythmia? Or were we just letting the patient die?”

I sighed.

“To be fair, I planned to do the surgery today. The patient refused opioids. There were so many patients in the ward… I was going to operate when the professor had time.”

“I understand for now.”

If we had acted faster, the patient might have survived. At the very least, we could have helped them pass peacefully.

“Is anesthesia okay?”

“Yes.”

A knife, boiled and cooled salt water, and a saw were prepared next to the operating table. Soon after, nurses placed the patient on the operating table.

“We’re ready.”

We moved to the operating table. The patient sat there looking very anxious.

“Are you feeling alright, patient?”

“Yes.”

“No palpitations?”

“Not right now.”

We gathered around the patient again. The patient looked at us anxiously. I spoke up reluctantly.

“I’ll get straight to the point since we don’t have time. As you probably know, one of your arms is rotting.”

“It certainly looks that way.”

“Uh… we need to amputate your arm, but even then, we can’t guarantee survival. If you prefer, we can skip the surgery, give you painkillers, and let you rest.”

“I’ll go with the surgery. I can sacrifice my arm and hand, but I have a family to return to…”

This patient previously refused opioids, right? Ultimately, the will to live is most important. If the patient hadn’t wanted to live, they would have already passed.

“Let’s… try amputating the arm then.”

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