Social history of viruses
Viruses of plants and livestock also increased, and as humans became dependent on agriculture and farming, diseases such as potyviruses of potatoes and rinderpest of cattle had devastating consequences.
[23] The Antonine Plague of 165–180 CE, another probable smallpox pandemic, wiped out around five million people in the Roman Empire, which included Britain, Europe, the Middle East and North Africa.
[24] The pandemic began after Roman soldiers who were sent to suppress an uprising in what is now Iraq, plundered the city of Seleucia on the river Tigris and at the same time were infected.
[32] The rapidly growing population of Europe and the rising concentrations of people in its towns and cities became a fertile ground for many infectious and contagious diseases, of which the Black Death – a bacterial infection – is probably the most notorious.
[37] The Crusades and the Muslim conquests aided the spread of smallpox, which was the cause of frequent epidemics in Europe following its introduction to the continent between the fifth and seventh centuries.
[42] A short time after Henry Tudor's victory at the Battle of Bosworth on 22 August 1485, his army suddenly went down with "the English sweat", which contemporary observers described as a new disease.
[48] The disease – which killed tens of thousands of people – was probably influenza[49] or a similar viral infection,[50] but records from the time when medicine was not a science can be unreliable.
[1] In the 150 years that followed Columbus's arrival in 1492, the Native American population of North America was reduced by 80 per cent from diseases, including measles, smallpox and influenza.
[92] Jenner knew of a local belief that dairy workers who had contracted a relatively mild infection called cowpox were immune to smallpox.
Celsus, in the first century AD, first recorded the symptom called hydrophobia and suggested that the saliva of infected animals and humans contained a slime or poison – to describe this he invented the word "virus".
[106] Later Pasteur wrote, "as the death of this child appeared inevitable, I decided, not without deep and severe unease ... to try out on Joseph Meister the procedure, which had consistently worked on dogs".
In the 20th and 21st century increasing population densities, revolutionary changes in agriculture and farming methods, and high speed travel have contributed to the spread of new viruses and the re-appearance of old ones.
[139] Before the September 11 attacks on the United States in 2001, the World Health Organization proposed the destruction of all the known remaining stocks of smallpox virus that were kept in laboratories in the US and Russia.
[145] Measles is still a major problem in densely populated, less-developed countries with high birth rates and lacking effective vaccination campaigns.
[170] In 1988 the World Health Organization along with others launched the Global Polio Eradication Initiative, and by 1994 the Americas were declared to be free of disease, followed by the Pacific region in 2000 and Europe in 2003.
This led the World Health Assembly to pass a 1987 resolution, which stated that HIV is "a naturally occurring [virus] of undetermined geographic origin".
[187] Debates on the ethics of provision and cost of anti-retroviral drugs, particularly in poorer countries, have highlighted inequalities in healthcare and stimulated far-reaching legislative changes.
[190] When influenza virus undergoes a genetic shift many humans have no immunity to the new strain, and if the population of susceptible individuals is high enough to maintain the chain of infection, pandemics occur.
[199] New strains of influenza virus often originate in East Asia; in rural China the concentration of ducks, pigs, and humans in close proximity is the highest in the world.
The prevalence of the disease increased in Asia, and in 1957 Thailand had to appeal for aid because so many buffaloes had died that the paddy fields could not be prepared for rice growing.
The virus has infected animals, mainly ungulates, in Africa since ancient times and was probably brought to the Americas in the 19th century by imported livestock.
[252] In the 1920s the sugarbeet growers in the western US suffered huge economic loss caused by damage done to their crops by the leafhopper-transmitted beet curly top virus.
[260] Even without mutation, it is always possible that some hitherto obscure parasitic organism may escape its accustomed ecological niche and expose the dense populations that have become so conspicuous a feature of the earth to some fresh and perchance devastating mortality.
[277] Governments were not prepared for the scale of the pandemic and worldwide, virology and epidemiology experts were complacent with regards to the efficiency of existing testing and monitoring systems.
The virus, which is carried by mosquitoes and birds, caused outbreaks of infection in North Africa and the Middle East in the 1950s and by the 1960s horses in Europe were also affected.
The largest outbreak in humans occurred in 1974 in Cape Province, South Africa and 10,000 people became ill.[280] An increasing frequency of epidemics and epizootics (in horses) began in 1996, around the Mediterranean basin, and by 1999 the virus had reached New York City.
[280] In the US, mosquitoes carry the highest amounts of virus in late summer, and the number of cases of the disease increases in mid July to early September.
[281] In Europe, many outbreaks have occurred; in 2000 a surveillance programme began in the UK to monitor the incidence of the virus in humans, dead birds, mosquitoes and horses.
[295] The beginning of the 21st century saw an increase in the global awareness of devastating epidemics in developing countries, which, in previous decades had passed relatively unnoticed by the international health community.
[309] Most of this DNA is no longer functional, but some of these viruses have brought with them novel genes that are important in human development,[312][313][314] and could aid the immune system's B cells destroy tumours.
