Syndemic
The worst of the 20th century influenza pandemics was the 1918 pandemic, where between 20-40 percent of the world’s population became ill between 40-100 million people died. More people died of the so-called Spanish flu (caused by the H1N1 viral strain) pandemic in the single year of 1918 than during all four-years of the Black Death. The pandemic had devastating effects as disease spread along trade and shipping routes and other corridors of human movement until it had circled the globe. InIndia, the mortality rate reached 50 per 1,000 population. Arriving during the closing phase of the World War I, the pandemic impacted mobilized national armies. Half of U.S. soldiers who died in the "Great War," for example, were victims of influenza. It is estimated that almost ¾ of a million Americans died during the pandemic. In part, the death toll during the pandemic was caused by viral pneumonia characterized by extensive bleeding in the lungs resulting in suffocation. Many victims died within 48 hours of the appearance of the first symptom. It was not uncommon for people who appeared to be quite healthy in the morning to have died by sunset. Among those who survived the first several days, however, many died of secondary bacterial pneumonia. It has been argued that countless numbers of those who expired quickly from the disease were co-infected with tuberculosis, which would explain the notable plummet in TB cases after 1918.
Demography of Scotland
With a population of 4.8 million in 1911, Scotland sent 690,000 men to First World War, of whom 74,000 died in combat or from disease, and 150,000 were seriously wounded. Thus, although Scots were only 10 percent of the British population, they made up 15 per cent of the national armed forces and eventually accounted for 20 per cent of the dead. While emigration began to tail off in England and Wales after the First World War, it continued apace in Scotland, with 400,000 Scots, ten per cent of the population, estimated to have left the country between 1921 and 1931. When the Great Depression hit in the 1930s there were no easily available jobs in the US and Canada and emigration fell to less than 50,000 a year, bringing to an end the period of mass migrations that had opened in the mid-18th century. This contributed to the growth of the population, which reached a peak of 5,240,800 in 1974. Thereafter it began to fall slowly, moving down to 5,062,940 in 2000. There was also a decrease in some urban populations as a result of policies of slum clearance, overspill and relocation to new towns, with the population of Glasgow falling from over a million in 1951 to 629,000 in 2001. Rural areas also saw a loss of population, particularly the Highlands and Hebrides.