1918 Flu

The death toll from the Spanish flu was somewhere between 20 million and 100 million worldwide, after the end of WWI. It was partly so high because  so many of the countries infected had been decimated by war, but it is hard to determine how many people really died due to a lack of documentation. If such  a disease emerged again today, it would kill more people in a year than heart disease, cancer, stroke, lung disease, AIDs and Alzheimer’s disease combined.

Spanish flu has largely been forgetting due to occurring so soon after the upheaval of the deaths of 9 million soldiers and a further 9 million civilians during WWI.

The name itself is deceptive- it did not origin in Spain, nor was it most devastating to Spain. However, Spain immediately started reporting about the disease. It is unknown where the virus originated from, but it may well be from the Far East, and it was spread by the active troops across Europe.

In 2005, scientists from the USofA processed the genetic code of the 1918 flu virus; the sample was taken by extraction from a female patient buried in Alaskan permafrost. The pandemic was found to have been caused by gradual genetic changes from a flu virus that had originated in birds.

Flu most frequently effects humans, birds and pigs. Interspecies infections can quite easily lead to deaths, even in otherwise mild strains.

Symptoms

Typical Spanish flu symptoms included:

  • Spots over cheek bones within hours of admission to wards
  • Cyanosis (skin turning blue) extending across he face from the ears
  • Starting to struggle for breath within hours
  • Sudden collapse
  • Infection of the lungs by other diseases in addition

The collapses were especially common. In South America, a mine operator collapsed at control of a lift and sent at least 20 miners plummeting back down the mine shaft to their deaths.

Spanish Flu death-causing symptoms included:

  • Bleeding from the nose and ears
  • Swollen hearts
  • Solidified lungs weighing up to 6x their normal weight
  • Accumulation of fluid in delicate tissues such as the lungs

Clogged up lungs from the disease would have offered little ability for gas exchange across the lung surface by the volume of water. Thus the patient would have drowned; it was called  “Drowning death”.

It was common for those who survived the initial infection to then be infected by another disease, such as pneumonia, which would then kill them.

Causes of symptoms: 

The influenza virus weakens respiratory epithelia and cilia (a type of cell that wafts dirt out of the lungs), and immune cell dysfunction, leaving them weakened to other infections.

Distinguishing features

Most influenza break outs focus upon the young and old, and have the greatest death toll upon these age groups, due to having a weaker immune system. The Spanish flu also specifically targeted young healthy adults.

One theory for this was “cytokine storming”. Cytokines are small chemicals used to signal between various white blood cell types to co-ordinate fighting infections. Cytokines work a lot like hormones, and travel through the blood. They encourage inflammation, swelling, increasing vasopermeability (ability for chemicals to move through blood vessels) and attract other white blood cells. This fights infection, but sometimes damages organ tissue. It can lead, eventually, to internal scarring and organ failure.

Cytokine storms are thus when the cytokines overreact to a pathogen and this can lead to deaths.

Infection

All strains of flu are viruses, and belong to the family orthomyxovirus. Influenza A is the worst sort of the virus group. Its genome includes genes for the coding of only 10 proteins. 2 of these- haemoggluttin and neuraminidase are the most important, and flu strains tend to be named after these. The Spanish flu and 2009’s swine flu were both H1N1. H2N3, H5N1 (Bird flu) and H7N7 are all common strains.

Haemoggluttin binds receptors on the outside of the virus with the membrane of the target cell. Neuraminidase lets new viruses formed within the cell leave and move out to attack further cells.

Viruses have to integrate their genetic material into a host cell. They themselves have RNA, rather than DNA, so have to have specialised enzymes to convert their RNA into DNA. The host cell then incorporates this DNA into its own nucleus- much the same way that a computer will absorb the coding to produce certain types of virus itself. When the host produces its own proteins, it also produces copies of the virus proteins, which eventually combine to form more viruses- this continues until the host cell has used up all its contents in the worst case scenario. Typically, viruses will be released gradually from the host cell over time.

Treatment

The viruses of Haemoggluttin and Neurominidase can be extracted. Each year this is done to produce a new flu vaccination. The body can then produce antibodies specific to those proteins, and learn how to tackle the virus more effectively if it should enter the body. However, the viruses always mutate over the year, so new jabs have to be developed frequently.

They are also individually targeted by other jabs. TamiFlu is an example of this. The UK government spent £500 million on TamiFlu during the swine flu outbreak of 2009- but in practice, for many, this does little more than just paracetamol to relieve symptoms.

Finding one set treatment is hard, as mutations in the virus genome mean an antibody that works one year may well not by the start of the next. The body has to constantly adapt to every new strain.

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