User:Graham Beards/viruses/History of virology

Source: Wikipedia, the free encyclopedia.

The history of virology – the scientific study of viruses and the infections they cause – begins in the closing years of the 19th century. Although Louis Pasteur and Edward Jenner developed the first vaccines to protect against viral infections, they did not know that viruses existed.

The first evidence of the existence of viruses came from experiments with filters that had pores small enough to retain bacteria. In 1892,

tobacco plant remained infectious to healthy tobacco plants despite having been filtered. Martinus Beijerinck called the filtered, infectious substance a "virus" and this discovery is considered to be the beginning of virology
. In the 20th century many viruses were discovered.

Early virologists

Martinus Beijerinck in his laboratory in 1921

Despite his other successes, Louis Pasteur (1822–1895) was unable to find a causative agent for rabies and speculated about a pathogen too small to be detected using a microscope.[1] In 1884, the French microbiologist Charles Chamberland (1851–1931) invented a filter – known today as the Chamberland filter – that had pores smaller than bacteria. Thus, he could pass a solution containing bacteria through the filter and completely remove them from the solution.[2] In 1892, the Russian biologist

Dmitry Ivanovsky (1864–1920) used this filter to study what is now known as the tobacco mosaic virus. His experiments showed that crushed leaf extracts from infected tobacco plants remain infectious after filtration. Ivanovsky suggested the infection might be caused by a toxin produced by bacteria, but did not pursue the idea.[3]

In 1898, the Dutch microbiologist Martinus Beijerinck (1851–1931) repeated the experiments and became convinced that the filtered solution contained a new form of infectious agent.[4] He observed that the agent multiplied only in cells that were dividing and he called it a contagium vivum fluidum (soluble living germ) and re-introduced the word virus.[3] Beijerinck maintained that viruses were liquid in nature, a theory later discredited by the American biochemist and virologist Wendell Meredith Stanley (1904–1971), who proved they were particles.[3] In the same year Friedrich Loeffler (1852–1915) and Paul Frosch (1860–1928) passed the first animal virus through a similar filter and discovered the cause of foot-and-mouth disease.[5]

In 1881,

William Crawford Gorgas (1854–1920) organised the destruction of the mosquitoes' breeding habitats in Cuba, which dramatically reduced the prevalence of the disease.[7] Gorgas later organised the elimination of the mosquitoes from Panama, which allowed the Panama Canal to be opened in 1914.[8] The virus was finally isolated by Max Theiler (1899–1972) in 1932 who went on to develop a successful vaccine.[9]

By 1928 enough was known about viruses to enable Thomas Milton Rivers (1888–1962) to write the first book about all known viruses and his Filtrable Viruses was published in 1928. Rivers, who survived typhoid fever at the age of twelve, went on to have a distinguished career in virology. He was born in Jonebro, Georgia USA, was awarded a BA degree from Emory College in 1909 and graduated in medicine at Johns Hopkins University in 1915. In 1926, he was invited to speak at a meeting organised by the Society of American Bacteriology where he said for the first time, "Viruses appear to be obligate parasites in the sense that their reproduction is dependent on living cells."[10]

That viruses were particles was not considered unnatural and fitted in nicely with the

the electron microscope in 1931 by the German engineers Ernst Ruska (1906–1988) and Max Knoll (1887–1969),[12] that virus particles, especially bacteriophages, were shown to have a complex structure. The sizes of viruses determined using this new microscope fitted in well with those estimated by filtration experiments. Viruses were expected to be small, but the range of sizes came as a surprise. Some were only a little smaller than the smallest known bacteria, and the smaller viruses were of similar sizes to complex organic molecules.[13]

In 1935, Wendell Stanley examined the tobacco mosaic virus and found it was mostly made of protein.

genes.[16]

In Pasteur's day, and for many years after his death the word "virus" was used to describe any cause of infectious disease. Painstaking work, by many bacteriologists, soon discovered the cause of numerous infections. However, some infections remained, many of them horrendous, but for which no bacterial cause could be found. These agents were invisible and could only be grown in living animals. The discovery of viruses was the key that unlocked the door that withheld the secrets of the cause of these mysterious infections. And, although Koch's postulates could not be fulfilled for many of these infections, this did not stop the pioneer virologists from looking for viruses in infections for which no other cause could be found.[17]

Bacteriophages

Bacteriophage

Bacteriophages are viruses that infect bacteria. There are over 5,100 types of bacteriophages. They are important in

marine ecology: as the infected bacteria burst, carbon compounds are released back into the environment, which stimulates fresh organic growth. Bacteriophages are useful in scientific research because they are harmless to humans and can be studied easily. These viruses can be a problem in industries that produce food and drugs by fermentation
and depend on healthy bacteria. Some bacterial infections are becoming difficult to control with antibiotics, so there is a growing interest in the use of bacteriophages to treat infections in humans.[18]

The structure of a typical bacteriophage

Discovery

Bacteriophages were discovered in the early 20th century, by the English bacteriologist

Vibrio cholera – the cause of cholera. Whatever it was in the water could be passed through filters that remove bacteria but was destroyed by boiling.[20] Twort discovered the action of bacteriophages on staphylococci bacteria. He noticed that when grown on nutrient agar some colonies of the bacteria became watery or "glassy". He collected some of these watery colonies and passed them through a Chamberland filter to remove the bacteria and discovered that when the filtrate was added to fresh cultures of bacteria, they in turn became watery.[19] He proposed that the agent might be "an amoeba, an ultramicroscopic virus, a living protoplasm, or an enzyme with the power of growth".[20]

Félix d'Herelle (1873–1949) was a mainly self-taught French-Canadian microbiologist. In 1917 he discovered that "an invisible antagonist", when added to bacteria on agar, would produce areas of dead bacteria.[19] The antagonist, now known to be a bacteriophage could pass through a Chamberland filter. He accurately diluted a suspension of these viruses and discovered that the highest dilutions (lowest virus concentrations), rather than killing all the bacteria, formed discrete areas of dead organisms. Counting these areas and multiplying by the dilution factor allowed him to calculate the number of viruses in the original suspension.[21] He realised that he had discovered a new form of virus and later coined the term "bacteriophage".[22][23] Between 1918 and 1921 d'Herelle discovered different types of bacteriophages that could infect several other species of bacteria including Vibrio cholera.

typhoid and cholera, but their promise was forgotten with the development of penicillin.[22] Since the early 1970s, bacteria have continued to develop resistance to antibiotics such as penicillin, and this has led to a renewed interest in the use of bacteriophages to treat serious infections.[25]

Early research

D'Herelle travelled widely to promote the use of bacteriophages in the treatment of bacterial infections. In 1928, he became professor of biology at Yale and founded several research institutes.[26] He was convinced that bacteriophages were viruses despite opposition from established bacteriologists such as the Nobel Prize winner Jules Bordet (1870–1961). Bordet argued that bacteriophages were not viruses but just enzymes released from "lysogenic" bacteria. He said "the invisible world of d'Herelle does not exist".[27] But in the 1930s, the proof that bacteriophages were viruses was provided by Christopher Andrews (1896–1988) and others. They showed that these viruses differed in size and in their chemical and serological properties.

In 1940, the first electron micrograph image of a bacteriophage was published and this silenced sceptics who had argued that bacteriophages were relatively simple enzymes and not viruses.[28] Numerous other types of bacteriophages were quickly discovered and were shown to infect bacteria wherever they are found. But this early research was interrupted by World War II. Even d'Herelle was silenced. Despite his Canadian citizenship, he was interned by the Vichy Government until the end of the war.[29] Knowledge of bacteriophages increased in the 1940s following the formation of the Phage Group by scientists throughout the US. Among the members was Max Delbrück (1906–1981) who founded a course on bacteriophages at Cold Spring Harbor Laboratory.[25] Other key members of the Phage Group included Salvador Luria (1912–1991) and Alfred Hershey (1908–1997). During the 1950s, Hershey and Chase made important discoveries on the replication of DNA during their studies on a bacteriophage called T2. Together with Delbruck they were jointly awarded the 1969 Nobel Prize in Physiology or Medicine "for their discoveries concerning the replication mechanism and the genetic structure of viruses".[30] Since then, the study of bacteriophages has provided insights into the switching on and off of genes, and a useful mechanism for introducing foreign genes into bacteria and many other fundamental mechanisms of molecular biology.[31]

20th century

By the end of the 19th century, viruses were defined in terms of their infectivity, their ability to be filtered, and their requirement for living hosts. Up until this time, viruses had only been grown in plants and animals, but in 1906, Ross Granville Harrison (1870–1959) invented a method for growing tissue in lymph,[32] and, in 1913, E Steinhardt, C Israeli, and RA Lambert used this method to grow vaccinia virus in fragments of guinea pig corneal tissue.[33] In 1928, HB and MC Maitland grew vaccinia virus in suspensions of minced hens' kidneys.[34] Their method was not widely adopted until the 1950s, when poliovirus was grown on a large scale for vaccine production.[35]

At the turn of the 20th century, evidence for the existence of viruses was obtained from experiments with filters that had pores too small for bacteria to pass through; the term "filterable virus" was coined to describe them.[36] Although the modern concept of a virus was at that time slowly beginning to gain acceptance, the word is ancient. In Latin it means a "slimy liquid, poison offensive odour or taste", and it first appears in the medical literature in the 18th century to describe a poisonous fluid.[37]

Electron micrograph of the rod-shaped particles of tobacco mosaic virus that are too small to be seen using a light microscope

In 1882, Adolf Mayer (1843–1942) described a condition of tobacco plants, which he called "mosaic disease" ("mozaïkziekte"). The diseased plants had variegated leaves that were mottled.[38] He excluded the possibility of a fungal infection and could not detect any bacterium and speculated that a "soluble, enzyme-like infectious principle was involved".[39] He did not pursue his idea any further, and it was the filtration experiments of Ivanovsky and Beijerinck that suggested the cause was a previously unrecognised infectious agent. After tobacco mosaic was recognized as a virus disease, virus infections of many other plants were discovered.[39]

The importance of tobacco mosaic virus in the history of virology cannot be overstated. It was the first virus to be discovered, and the first to be

Robley Williams showed that purified tobacco mosaic virus RNA and its coat protein can assemble by themselves to form functional viruses, suggesting that this simple mechanism was probably the means through which viruses were created within their host cells.[41]

By 1935 many plant diseases were thought to be caused by viruses. In 1922,

vectors
and transmit virus to plants. In the following decade many diseases of plants were shown to be caused by viruses that were carried by insects and in 1939, Francis Holmes, a pioneer in plant virology,[42] described 129 viruses that caused disease of plants.[43]

A modern electron microscope

Until the 1930s most scientists believed that viruses were small bacteria, but following the invention of the electron microscope in 1938 they were shown to be completely different, to a degree that not all scientists were convinced they were anything other than accumulations of toxic proteins. The situation changed radically when it was discovered that viruses contain genetic material in the form of DNA or RNA.[44] Once they were recognised as distinct biological entities they were soon shown to be the cause of numerous infections of plants, animals, and even of bacteria.[45]

Of the many diseases of humans that were discovered to be caused by viruses in the 20th century only one, smallpox, has been eradicated. Two others – measles and poliomyelitis – could be, but the diseases caused by viruses such as HIV and influenza virus have proved to be more difficult to control.

arboviruses, are presenting new challenges.[47]

Late 20th century

The second half of the 20th century was the golden age of virus discovery and most of the 2,000 recognised species of animal, plant, and bacterial viruses were discovered during these years.

Bovine virus diarrhea was discovered,[50] which is still possibly the commonest pathogen of cattle throughout the world[51]
and in 1957, equine arterivirus was discovered.
Howard Temin (1934–1994) described the first retrovirus.[58] Reverse transcriptase, the key enzyme that retroviruses use to translate their RNA into DNA, was first described in 1970, independently by Howard Temin and David Baltimore (b. 1938).[59] This was important to the development of antiviral drugs – a key turning-point in the history of viral infections.[60] In 1983 Luc Montagnier (b. 1932) and his team at the Pasteur Institute
in France, first isolated the retrovirus now called HIV.[61] New viruses and strains of viruses were discovered in every decade of the second half of the 20th century. These discoveries have continued in the 21st century as new viral diseases such as
SARS[62] and nipah virus[63] have emerged. Despite scientists' achievements over the past one hundred years, viruses continue to pose new threats and challenges.[64]

Table 1. Some of the many viruses that were discovered in the 20th century

Year Virus References
1908 poliovirus [65]
1911 Rous sarcoma virus [66]
1915 bacteriophage of staphylococci [19]
1917 bacteriophage of shigellae [19]
1918 bacteriophage of salmonellae [21]
1927 yellow fever virus [67]
1930 western equine encephalitis virus [68]
1933
eastern equine encephalitis virus
 [68]
1934 mumps virus [69]
1935 Japanese encephalitis virus [70]
1943
Dengue
virus 		[71]
1949 enteroviruses [72]
1952 Varicella zoster virus [53]
1953
adenovirus
 [73]
1954
measles virus
 [55]
1956 paramyxoviruses, rhinovirus [54][56]
1958
monkeypox
 [74]
1962 rubella virus [75]
1963 hepatitis B virus [76]
1964 Epstein–Barr virus [77]
1965 retroviruses [78]
1966 Lassa fever virus [79]
1967 Marburg virus [80]
1972 norovirus [81]
1973
hepatitis A virus
 [82][83]
1975 parvovirus B19 [84]
1976 Ebola virus [85]
1980 human T-lymphotropic virus 1 [86]
1982 human T-lymphotropic virus 2 [86]
1983 HIV [87]
1986 human herpesvirus 6 [88]
1989 hepatitis C virus [89]
1990
Human herpesvirus 7
 [90]
1994 henipavirus [91]
1997 Anelloviridae [92]

21st century

As humans have changed their behaviour during the course of history, so have viruses. In ancient times the human population was too small for pandemics to occur and, in the case of some viruses, too small for them to survive. 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.[93][94] Like smallpox, some viral diseases might be conquered, but others, such as SARS will continue to present new challenges.[95] Although vaccines are still the most powerful weapon against viruses, in recent decades antiviral drugs have been developed to specifically target viruses as they replicate in their hosts.[96] The 2009 influenza pandemic showed how rapidly new strains of viruses continue to spread around the world, despite our efforts to contain them.[97] Advances in virus discovery and control continue to be made.

papillomaviruses
that cause cervical cancer was developed between 2002 and 2006.
human T lymphotropic viruses 3 and 4 were discovered.[101] And, in 2008 the WHO Global Polio Eradication Initiative was re-launched with a plan to eradicate poliomyelitis by 2015.[102]


  1. PMID 12758285. {{cite journal}}: Unknown parameter |month= ignored (help); line feed character in |journal= at position 13 (help
    )
  2. ^ Shors, pp.76–77
  3. ^
    ISBN 0-340-66316-2.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  4. ISBN 1-4051-3645-6.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  5. ISBN 0-12-375146-2
    .
  6. PMID 2684378. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  7. PMID 11482006
    .
  8. PMID 2673502. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  9. PMID 20589188. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  10. ^ Frank L. Horsfall Jnr.(1965) "Thomas Milton Rivers (1888–1962)—A biographical memoir" The National Academy of Sciences Washington D.C. Retrieved 3 December 2010.
  11. ^ *In 1887, Buist visualised one of the largest, Vaccinia virus, by optical microscopy after staining it. Vaccinia was not known to be a virus at that time. (Buist J.B.(1887) Vaccinia and Variola: a study of their life history Churchill, London)
  12. ^ From Nobel Lectures, Physics 1981–1990, (1993) Editor-in-Charge Tore Frängsmyr, Editor Gösta Ekspång, World Scientific Publishing Co., Singapore.
  13. ISBN 0-521-26056-6.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  14. PMID 17756690
    .
  15. PMID 17788438
    .
  16. ISBN 0-7637-5963-5
    .
  17. ISBN 0-521-26056-6.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  18. ^ Shors pp. 588–604
  19. ^ a b c d e Shors, p. 589
  20. ^
    ISBN 0-12-375146-2
    .
  21. ^
    PMID 17855060. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  22. ^
    ISBN 0-12-375146-2
    .
  23. ^ "The antagonistic microbe can never be cultivated in media in the absence of the dysentery bacillus. It does not attack heat-killed dysentery bacilli, but is cultivated perfectly in a suspension of washed cells in physiological saline. This indicates that the anti dysentery microbe is an obligate bacteriophage". Felix d'Herelle (1917) An invisible microbe that is antagonistic to the dysentery bacillus (1917) Comptes rendus Acad. Sci. Paris Retrieved on 2 December 2010
  24. ISBN 0-12-375146-2
    .
  25. ^ a b Shors, p.591
  26. ISBN 0-7637-2932-9
    .
  27. ISBN 0-12-375146-2
    .
  28. ISBN 0-12-375146-2. {{cite book}}: line feed character in |title= at position 21 (help
    )
  29. ISBN 0-12-375146-2
    .
  30. ^ Nobel Organisation
  31. ISBN 0-12-375146-2
    .
  32. ^ J. S. Nicholas, Ross Granville Harrison 1870—1959 A Biographical Memoir, National Academy of Sciences, 1961, Retrieved on December 4, 2010
  33. ^ Steinhardt, E; Israeli, C; and Lambert, R.A. (1913) "Studies on the cultivation of the virus of vaccinia" J. Inf Dis. 13, 294–300
  34. PMID 13475780. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  35. ISBN 0-340-66316-2.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  36. ^ Crawford, p. 14
  37. ^ Baker p. 55
  38. ^ Mayer A (1882) Over de moza¨ıkziekte van de tabak: voorloopige mededeeling. Tijdschr Landbouwkunde Groningen 2: 359–364 (In German)
  39. ^
    PMID 16732421. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  40. PMID 18702397. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  41. ISBN 1-4051-3645-6.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  42. PMID 11718380. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link
    )
  43. ^ name="Shors 563 ">Shors, p. 563
  44. ^ Crawford, p. 15
  45. ^ Oldstone, pp. 22–40
  46. ^ Baker p. 70
  47. ^ Levins, pp. 123–125, 157–168, 195–198, 199–205 and others
  48. PMID 18446425
    .
  49. ^ Frederick A Murphy (2008) "Discoverers and Discoveries", International Committee on Taxonomy of Viruses
  50. PMID 20995890. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link
    )
  51. PMID 20197026.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  52. PMID 13397177. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link
    )
  53. ^
    PMID 8545033. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  54. ^ a b c Schmidt AC, Johnson TR, Openshaw PJ, Braciale TJ, Falsey AR, Anderson LJ, Wertz GW, Groothuis JR, Prince GA, Melero JA, Graham BS (2004). "Respiratory syncytial virus and other pneumoviruses: a review of the international symposium —RSV 2003". Virus Research. 106 (1): 1–13.
    PMID 15522442. {{cite journal}}: Unknown parameter |month= ignored (help); line feed character in |title= at position 93 (help)CS1 maint: multiple names: authors list (link
    )
  55. ^
    PMID 19203111
    .
  56. ^
    PMID 3039038. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  57. PMID 18298788. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  58. PMID 9001412. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  59. PMID 4348509. {{cite journal}}: |access-date= requires |url= (help
    )
  60. PMID 20018391. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  61. ^ Barré-Sinoussi F, Chermann JC, Rey F, Nugeyre MT, Chamaret S, Gruest J, Dauguet C, Axler-Blin C, Vézinet-Brun F, Rouzioux C, Rozenbaum W, Montagnier L (1983). "Isolation of a T-lymphotropic retrovirus from a patient at risk for acquired immune deficiency syndrome (AIDS)". Science. 220 (4599): 868–71.
    PMID 6189183. {{cite journal}}: Unknown parameter |month= ignored (help); line feed character in |title= at position 30 (help)CS1 maint: multiple names: authors list (link
    )
  62. PMID 21116811
    .
  63. PMID 11334748. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link
    )
  64. ISBN 0-12-375147-0
    .
  65. doi:[https://doi.org/10.1007%2Fs00705-010-0778-%0A%0Ax
    10.1007/s00705-010-0778- x].
    PMID 20683737. {{cite journal}}: Check |doi= value (help); Unknown parameter |month= ignored (help); line feed character in |doi= at position 25 (help
    )
  66. PMID 20503720
    .
  67. PMID 20513550. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  68. ^
    PMID 19775836. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  69. PMID 19870227. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  70. PMID 20132860. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  71. PMID 20513545. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  72. PMID 8024744. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  73. ISBN 0-7817-6060-7.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  74. PMID 1331540. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  75. PMID 3890105
    .
  76. PMID 16190102. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  77. PMID 4288580. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link
    )
  78. PMID 15682876. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  79. doi:[https://doi.org/10.1007%2F0-387-%0A%0A33026-7_4
    10.1007/0-387- 33026-7_4].
    PMID 16802617. {{cite journal}}: Check |doi= value (help); line feed character in |doi= at position 15 (help
    )
  80. PMID 20513546. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link
    )
  81. PMID 10804141. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  82. PMID 186236.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  83. PMID 6307916.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  84. PMID 6117755. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  85. PMID 21084112. {{cite journal}}: Unknown parameter |month= ignored (help
    )Epub ahead of print
  86. ^
    PMID 16155599. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  87. PMID 20152474. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  88. PMID 15653828. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link
    )
  89. PMID 2523562. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link
    )
  90. PMID 20335188. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  91. PMID 18511217. {{cite journal}}: Unknown parameter |month= ignored (help
    )
  92. PMID 19230554
    .
  93. ^ Karlen, p. 229
  94. ^ Mahy, (b) p. 585
  95. ^ Dobson, p. 202
  96. ^ Carter, p. 315
  97. PMID 20568566
    .
  98. ^ van den Hoogen BG, Bestebroer TM, Osterhaus AD, Fouchier RA (2002). "Analysis of the genomic sequence of a human metapneumovirus". Virology. 295 (1): 119–32.
    PMID 12033771. {{cite journal}}: Unknown parameter |month= ignored (help); line feed character in |author= at position 48 (help)CS1 maint: multiple names: authors list (link
    )
  99. PMID 17972339. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link
    )
  100. ^ Xiao C, Kuznetsov YG, Sun S, Hafenstein SL, Kostyuchenko VA, Chipman PR, Suzan-Monti M, Raoult D, McPherson A, Rossmann MG (2009). Sugden, Bill (ed.). "Structural studies of the giant mimivirus". PLoS Biology. 7 (4): e92.
    PMID 19402750. {{cite journal}}: Unknown parameter |month= ignored (help); line feed character in |author= at position 44 (help)CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link
    )
  101. PMID 15911757. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link
    )
  102. PMID 20455167
    .
Retrieved from "https://en.wikipedia.org/w/index.php?title=User:Graham_Beards/viruses/History_of_virology&oldid=935874768"