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The Worst Disease in Human History

2023-09-15 · explainer · Hank · 5:27 · watch on YouTube

Topic: Health (also: Global development) · mode: Explainer · tags: heavy topic, civic or action cta

Hank explains why tuberculosis, the deadliest infectious disease for most of human history, is so hard to fight: its thick waxy cell wall resists antibiotics, aids biofilms and resistance, and slows growth, which makes culture diagnosis slow; so molecular test cartridges must get cheap, and he calls Danaher and Cepheid allies against TB in getting them to $5.

What is said

The parts of the video and what is said in each (★ — how much it matters to the video).

00:00:00 — Tuberculosis as the deadliest infectious disease, and Hank's own old guesses

  • ★ Hank says a couple of years ago he would probably have guessed malaria, then AIDS, as the deadliest infectious disease, and needed a hint to reach tuberculosis. (hedged) — 00:00:00 · malaria, tuberculosis
  • ★★★ Hank says tuberculosis has been the deadliest infectious disease for like 99% of the last 10,000 years, overtaken only every once in a while by the Spanish flu, the Black Death or, very briefly, COVID. — 00:00:12 · tuberculosis, COVID-19 pandemic

00:00:29 — TB as possibly the oldest infectious disease, John as the expert, a specific bacterium

  • ★★ Hank says tuberculosis has now taken back its title as deadliest infectious disease and is a strong contender for the oldest infectious disease. — 00:00:29 · tuberculosis
  • ★ Hank says he would love to read a John Green book about tuberculosis; John is definitely the expert on it. — 00:00:35 · John Green
  • ★★ Hank says he once thought tuberculosis, like pneumonia, described symptoms rather than a specific disease, but it is caused by a specific bacterium. — 00:00:44 · tuberculosis

00:00:58 — The thick waxy cell wall: antibiotics, biofilms, resistance and slow replication

  • ★★★ Hank says the tuberculosis bacterium's weirdly thick cell wall, made largely of waxy fats, is its secret weapon, making TB harder to fight in many different ways. — 00:00:58 · tuberculosis
  • ★★ Hank says the thick wall keeps antibiotics out, and many antibiotics work by breaking bacterial cell walls, which differ from human cell membranes, so they work less well on TB's unusual wall. — 00:01:27
  • ★★ Hank says scientists think the wall makes it easier for TB to form strong biofilms, which keep out antibiotics and immune cells and let TB hold on in the body for a long time. (hedged) — 00:01:56
  • ★★ Hank says a bigger, weirder cell wall gives more places for antibiotic resistance to evolve; this is called cell wall remodeling, and TB is good at it. — 00:02:26
  • ★★ Hank says the complicated wall is hard to manufacture, so TB replicates much more slowly than most bacteria. — 00:02:36 · tuberculosis

00:02:55 — Slow growth makes culture-based diagnosis and resistance testing slow and laborious

  • ★★ Hank says many antibiotics target fast-replicating cells, so they are less good at attacking slow-replicating tuberculosis. — 00:02:55 · tuberculosis
  • ★★ Hank says that to treat TB one must find out whether a person has it, what kind and which antibiotics it resists, by growing bacteria from their spit in a petri dish. — 00:03:02 · tuberculosis
  • ★★ Hank says a well-fed E. coli colony doubles every 20 minutes, while for tuberculosis doubling takes about a day. — 00:03:24 · tuberculosis
  • ★★ Hank says diagnosing TB and testing its resistance means culturing it many times against different antibiotics, which takes much labor, time, petri dishes and space. — 00:03:31 · tuberculosis

00:03:53 — Molecular cartridge tests for TB and resistance, and why their cost matters

  • ★★ Hank says that would be fine if a thousand people a year got tuberculosis, but about 10 million people a year get it. — 00:03:53 · tuberculosis
  • ★★★ Hank says sequencing many TB strains revealed the resistance sequences, so a machine can run a sample through a cartridge that shows both whether it is TB and whether it is drug-resistant. — 00:03:56
  • ★ Hank says the machine runs many different tests for many diseases all over the world. — 00:04:15
  • ★★★ Hank says because TB is the deadliest infectious disease, hits poor communities, and kills millions a year while disabling more, the tests' cost must be as low as possible, especially for multidrug-resistant TB. — 00:04:22 · tuberculosis

00:04:52 — Appeal to Danaher and Cepheid for $5 MDR-TB cartridges: allies against TB; sign-off

  • ★★ Hank says that, since TB is so good at evolving resistance, cutting test costs is needed to save lives and for everyone's safety, and he thinks it can be done. — 00:04:52
  • ★★★ Hank says the people at Danaher and Cepheid, despite their pricing targets, can look hard at the spreadsheets, ask what is right, and get MDR-TB cartridges to about $5. — 00:04:58
  • ★★★ Hank says campaigners and the companies are not enemies but allies: the enemy is tuberculosis. — 00:05:21 · tuberculosis

In the description and comments

  • ★★ The description asks viewers to check out TBFighters.org to help get the TB test price down to $5. — video description
  • ★★ The description calls Danaher and the campaigners allies in the fight against TB who do not always agree on how best to fight it. — video description
  • ★★ The description adds that TB may replicate slowly for evolutionary advantage too: possibly, having lived with humans so long, it evolved to linger rather than kill quickly. (hedged) — video description · tuberculosis

Threads in this video

Where the stories that moved here went next

Mentioned

Central: cell wall · tuberculosis

Also: Organizations: Cepheid · Danaher Corporation

Concepts: Antibiotic · antimicrobial resistance · Bacteria · biofilm · DNA sequencing · Escherichia coli · HIV/AIDS · immune system · infectious disease · malaria · multidrug-resistant tuberculosis · pneumonia

Events: Black Death · COVID-19 pandemic · Spanish flu

Products: GeneXpert

Only in the description or credits: evolution · TBFighters

Also centred on cell wall: Correcting a Mistake in Everything Is Tuberculosis · 50 x 50 Science

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