RACA Journal October 2020 | Page 37

Getting Technical VIRAL PANDEMICS PRIOR TO COVID-19 By Charles Nicolson CHARLES NICOLSON Charles Nicolson has a physics and chemistry degree from Natal University which he subsequently put to good use by applying speciality chemicals in mining and industrial processes where water is a major factor. This created an enduring interest in water technology, a passion that expanded to the HVAC industry in 1984 when he joined BHT Water Treatment. Since then, water technology in HVAC water circuits has continued to be an abiding interest. Examples of diseases caused by viruses in humans include smallpox, the common cold, various types of influenza, measles, mumps, hepatitis, Ebola, poliomyelitis, HIV(AIDS), SARS, and others. To-date, none of these have been completely eradicated, although specific vaccines and treatments have been developed which greatly diminish the severity of infections which, in turn, reduce symptoms and disease-related damages accordingly. Viral diseases infecting humans tend to become epidemic (widespread) and then expand further becoming pandemic (world-wide). The most devastating, although thankfully short-lived lethal pandemic in modern times, was the 1918/19 flu pandemic also known as The Spanish Flu. This was a particularly deadly influenza pandemic caused by the H1N1 influenza A virus. Figure 1: Electron micrograph of a re-created 1918 influenza virus. The origin of the name ‘Spanish Flu’ comes from when it spread out from France into Spain in November 1918 during the final stages of World War 1. Spain was not involved in the war, having remained neutral, Spanish newspapers were therefore not under censorship and were able to report on one of the deadliest pandemics in human history. The first wave was a typical flu epidemic. Those most at risk were the infirm and elderly, while younger, healthier people mostly recovered. When a second wave began, the virus had mutated to a much more deadly form. October 1918 was the month having the highest fatality rate of the entire pandemic occurring during a period when the flu killed more people in 24 weeks than HIV/ AIDS killed in 24 years. By the time a third wave started during 1919, the virus had become a pandemic reaching as far south as Australia. At the beginning of 1920 a more minor fourth wave occurred but only in isolated areas around the world where mortality rates were very low. The overall death toll is estimated to have been in the range of 17 million to 50 million, although possibly as high as 100 million, making it one of the deadliest pandemics in recorded human history. During the relatively short three-to-four year period of the Spanish Flu, another viral disease which had begun at least a thousand years earlier, was continuing a slower but inexorable spreading into a pandemic which afflicted virtually every corner of the earth directly or indirectly – poliomyelitis. Many people, the writer included, have vivid personal memories of poliomyelitis in South Africa during the late 1940s and early 1950s. Memories of injections every 4 hours, day and night comprising substantial quantities of yellow liquid penicillin – not pleasant memories, but overladen with gratitude for dedicated people like Jonas Salk whose name will be always remembered for pioneering and developing the first successful anti-polio vaccine. Although no major polio epidemics were recorded before the 20th century, the disease has caused paralysis and death for much of human history. It was only in the 1900s that epidemics began to occur in Europe followed by increasingly widespread epidemics in the US. By 1910, polio epidemics became regular events throughout www.hvacronline.co.za RACA Journal I October 2020 35