BIODEFENCE
MUTATIONS T
Far Leſt : Dramatically improved imaging of the surface of a cell. Orange areas correspond to the bacterial lipopolysaccharide derived from
E.coli and the green area show the cell’s TLR4 receptors.
Leſt : An image of the AIDS Virus.
hroughout history, plagues have had a huge impact upon human populations. The fi rst that researchers are confi dent about is the Justinian Plague
that claimed around 100 million lives across Asia, Africa and Europe between AD 542 and ASD
546.The most recent large-scale outbreak occurred in 1967 when 6,004 cases were notifi ed to the World Health Organisation (WHO). Over the period from 1954 to 1997 the WHO was notifi ed of 80,613 cases and 6,587 deaths. It also was a time when three notable increases in plague activity were detected. For terrorist groups focused on
creating a weapon of terror these orders
disease was spread in the air. At the time London was a city noted for its ‘miasma’. At its peak the Great Plague claimed
7,165 people in a week, claiming a total of over 100,000 lives in total. Despite the portrayal of the Great Plague as a mass killer that was ended by the Great Fire, two-thirds of the population survived. Attempts to classify those who died into various socio-economic categories also failed. The plague was not just caught by poor people. Today the AIDS virus has been viewed
by many (and by some, for reasons of prejudice) to be the modern-day equiva- lent of the Great Plague. According to the United States Agency for International Development around 7,400 people a day contract the AIDS virus and 5,000 die. Since its inception it also believes that
of magnitude in fatalities hold an attraction, despite the diffi culties that exist in developing such viruses as eff ective weapons. In the UK such is the concern about this form of pandemic that in the National Risk Register they are rated at the highest level of impact. Recently several viruses have been
detected that have caused alarm. In February 2013 several new cases of the Severe Acute Respiratory Syndrome (SARS) virus were detected in the UK which had resulted in fi ve dying people. While not as severe as previous outbreaks, it nonetheless highlights how new viral mutations can develop and spread to humans.
Why did so many survive? Throughout human history however one thing has puzzled many physicians. Why do some people survive? In London during the Great Plague of the 17th century the authorities took drastic measures to halt the spread of the disease. People where literally chained up in their houses once someone in the household had contracted plague. This consigned whole families to die. But others survived. In the absence of any understanding of the impact of genetic mutation such conundrums baffl ed scientists in the immediate aſt ermath of the Great Plague. In trying to understand what helped some individuals survive, those involved at the time latched onto other possible causes of plague. They did not under- stand the process by which people became infected. Many thought that the
25 million have succumbed to its deadly impact on the human immune system. Today around 40 million people are believed to be infected with the virus. While that pales in comparison with the estimates of between 75 and 200 million people dying from the Black Death, the AIDS fi gure is still large. Yet despite the scale of the AIDS death toll people exposed to the disease do survive.
Mutation versus disease The idea of ‘mutation’ is easily stereotyped. Mutants have a specifi c depiction in the media and in history that have oſt en elicited specifi c negative reactions from the public. They are rarely seen through a positive lens despite the Oxford English Dictionary off ering a fairly bland defi nition: “the changing form of the structure of a gene, resulting in a variant form which may be transmitted to subsequent generations, caused by the alteration of single base units in DNA, or the deletion, insertion, or rearrangement of larger sections of genes or chromosomes.” Today, as a result of the Human
Genome Project, our scientifi c understanding of the impact of such mutations is considerably improved. In 2003 the publication of this vast scientifi c eff ort aſt er 13 years of international collaboration showed that there are between 20,000 to 25,000 genes and 3 billion chemical base pairs in human DNA. With all these various component parts, it is perhaps to be expected that not all mutations have a negative outcome. To date, over 10,000 disease-causing mutations of the human
CBNW 2013/02 81
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100