Having lived through a global pandemic, I thought I would do a little research into plagues. Apparently modern genetic studies can identify the sources of historical plagues. Very clever. Here are my findings.

Plagues ordered by severity

1	Black Death (bubonic plague) 1331 Deaths: 200 million Origin: China. Transferred to Crimea, then to Italy.
2	New World Smallpox 1520 Deaths: 56 million Origin: Possibly Egypt more than 3000 years ago. Endemic disease introduced to the Americas by the Spanish and Australia by the British.
3	Spanish flu 1918 Deaths: 50 million Origin: No definitive answer. Candidates include China, Europe or North America. China has published many scientific papers purporting to show it wasn’t them. There have been three subsequent outbreaks in North America, known as Swine flu.
4	HIV 1981 Deaths: 32 million Origin: West Africa
5	Plague of Justinian (bubonic plague) 541 Deaths: 13 million Origin: China. Transferred to Egypt and then Constantinople.
6	The Third Plague (bubonic plague) 1855 Deaths: 12 million Origin: China
7	Covid-19 2020 Deaths: 4 million (June 2021) Origin: China. Became the ninth worst pandemic in human history in July 2020. The eighth worst in October 2020. The seventh worst in January 2021.
8	Asian flu 1957 Deaths: 2 million Origin: China
9	Hong Kong flu 1968 Deaths: 1 million Origin: China
10	Swine flu 2009 Deaths: 0.5 million Origin: Mexico

Six out of these ten originated in China. Three of these were Bubonic plague, but only one of these ignited in China. The other two were exported before they became a pandemic.

Spanish flu and swine flu were probably originally caught through contact with pigs. Asian flu through contact with birds. Hong Kong flu was from pigs who had contact with birds.

Both HIV and Covid-19 were probably caught from eating something that wasn’t cooked properly (best candidates being chimps and bats, respectively).

Smallpox evolved in rats between 68,000 and 16,000 years ago.

Everything you never wanted to know about



Being a history, epidemiology and eulogy for a very nasty little fucker indeed...

by Nick Fryer

Originating in the Far East, smallpox came to Europe in the bloodstreams of the Crusaders.

By the eightennth century one in ten Europeans died of the pox, and 95% of those who survived infancy had contracted it at some time. About half had permanent scars, and many were blinded.

Vaccine before Jenner
The simplest protection against scarring was to inspect the skin for pustule formation and scratching them, which would localise infection.

Deliberate infection with mild strains was the most common attmept to prevent the disease. The Chinese snorted powdered scabs, while Arabs tended to inject the things subcutaneously with a needle. Nutshells were used to transport the pustule material.

and then, suddenly...
In 1796 Edward Jenner, having proved that previous vaccine techniques failed to raise the customary infection in people who had had cowpox, as well as those who had been exposed to smallpox, deliberatey infected eight-year-old Jamie Phipps. Remarkably, this live human trial was carried out without the involvement of ethics committees or priests. Once the cowpox had passed Jamie endured exposure to smallpox, and failed to contract the disease. I hope he got at least a lollipop.

Pasteur's discovery a century later that a virus (or bacterium) grown in a host other than its usual target often loses its virulence gave use mass-producible vaccine.

Us against them
By the fifties numbers of smallpox cases were down to 2 million per year, mostly among India's urban poor.

WHO declared war in 1973. The vaccine was mass-produced and 150,000 people were employed to hunt smallpox down. India was declared free of smallpox in 1977.

Never turn your back...
On July 25, 1978, at the University of Birmingham in England, a medical photographer contracted the disease, which had escaped from the lab upstairs. Her condition was diagnosed by the head of the lab, a prominent virologist, who was also the man responsible for ensuring that no escapes of this kind occurred. He cut his own throat. She died five days later of the disease. To date, these are the last two know deaths from smallpox.

This DNA malarky, what's it all about?
Well it all seems rather complicated and I'm not sure I'd ever understand it. I'm not sure I do now. However I did read a rather helpful article, called "The Genetic Code: Arbitrary?" from the book Metamagical Themas by Douglas Hofstadter. I took some notes, drew some little diagrams, and now, here, is my take on DNA...

DNA is that wonderful double helix molecule that we all have in us, and is the code for life. As a code, the DNA is read by an enzyme called an RNA polymerase. The DNA's code is written in letters of nucleotides. In a DNA there are only 4 different letters or nucleotides. These letters are A, T, C & G, and are combined in threes to make words. There are 64 different triplets possible (AAT, ATC, AGC etc.). An enzyme creates RNA from reading the DNA. This is called transcription. It "transcribes" the DNA letters into corresponding, but different RNA lettering. A, T, C & G (in DNA speak) creates U, A, G & C (in RNA speak) respectively.

So now we are stuck with some RNA, and are no closer to anything actually happening. And where did this enzyme come from? Read on...

There is mRNA and there is tRNA. The mRNA, much like DNA, carries triplets of nucleotides. Each of these triplets is a codon. Each codon corresponds to an amino acid. There are 64 different codons, but only 20 different amino acids. So more that one codon can correspond to the same amino acid. Amino acids have names like phenylalanine, leucine and proline.

Protein, the building blocks of life, is made from long chains of amino acids joined by peptide bonds. The process to get from the instructions for making protein (written on the mRNA) to the actual protein is called translation. This involves a ribosome (a codon reader) moving along the mRNA and reading the codons. It then matches codons, with anti-codons. These anti-codons, are actually part of the tRNA. Attached on the other end of the tRNA is the corresponding amino acid to the codon being read. The ribosome then breaks off the amino acid from the tRNA and attaches to the chain of amino acids it is constructing.

The tRNA is then released and gets re-attached to its anti-codon's corresponding amino acid by an enzyme. This enzyme (a synthetase) is attracted by the DHU loop of the tRNA.

This whole process gives us protein. There are 2 types of protein: there are enzymes, which do everything inside a cell, and other more passive protein, which is the building blocks on which things are done.

All protein has a tertiary shape. Essentially the long chain is tightly curled up around itself, in a very specific shape. Enzymes have active sites on them, which also have a very specific shape. These active sites correspond with the tertiary shapes of the proteins and allow the enzyme to grab and move other proteins. Only appropriate proteins will fit into the shape of these active sites.

And that's about it... Well, it helped me.