Newsgroup: it.scienza.medicina
Titolo: [&] review libri sul virus dell'influenza e la strage del 1918, da Nature Genetics

volume 24 no. 2 p 111
Flu times two
Reviewed by Brian W.J. Mahy
National Center for InfectiousDiseases, Centers for Disease Control and
Prevention, Atlanta, Georgia 30333, USA
Flu: The Story of the Great Influenza Pandemic of 1918 and the Searchfor
the Virus That Caused It
By GinaKolata Farrar, Straus and Giroux, $25.00 (US). ISBN
0-374-15706-5, 1999
The genetic material of the type A influenza virus, the only one of
thethree types that is known to cause pandemic influenza, consists of
eight segmentsof single-stranded RNA encoding ten proteins. The most
important surface antigen,haemagglutinin (an attachment protein), has
considerable diversity, generatedby mutation and subsequent selection of
antigenic variants that can evadethe host's antibody response. Variation
in another surface protein, neuraminidase,may also assist in immune
evasion. This 'antigenic drift' necessitates theproduction of new
influenza vaccines every year. New variants of influenzaalso arise
through genetic reassortment between a human influenza virus andanother
influenza A virus (usually an avian or swine virus). When the RNAsegment
encoding haemagglutinin is replaced by one of distinct
antigenicity(described as a new subtype), and when such a reassorted
virus is highly transmissibleamong humans, the virus spreads rapidly and
may cause a global pandemic. Whethersuch a reassortment event was
responsible for the appearance of the 1918 virus(H1 subtype) is unknown,
but it seems to have been involved in generatingthe Asian influenza
pandemic in 1957 (H2 subtype) and the Hong Kong influenzapandemic in
1968 (H3 subtype). There is now considerable concern among
virologiststhat a new subtype could appear at any time. As detailed in
two recent bookson the 1918 outbreak, Catching Cold, by Pete Davies, and
Flu,by Gina Kolata, new technologies have allowed a re-examination of
the 1918pandemic as well as some of the events that followed.
Influenza viruses were first isolated from swine by Richard Shope in
1931 and from humans by Smith, Andrewes and Laidlaw in 1933. The
pandemic of 1918caused an estimated 25 million deaths worldwide, and
over the 50-year periodfollowing virus isolation (until the discovery of
HIV), more work was carriedout on the properties and replication of
influenza than on any other viralpathogen. But a major unsolved question
has been why the 1918 influenza virus,popularly known as 'Spanish flu',
was so highly pathogenic. Records from theperiod suggest that this
particular strain was unique in its propensity tocause fatal pneumonia,
especially in young adults.
Although attempts were made in the 1950s to isolate the 1918 strain
ofinfluenza from victims buried in conditions in which the virus might
haveremained viable, such as the Alaskan permafrost region, these
efforts wereunsuccessful. The more recent availability of PCR to amplify
the viral RNA,both from formalin-fixed tissues and from tissue samples
taken recently fromvictims buried in the permafrost since 1918, has
provided the complete sequenceof the gene encoding haemagglutinin and
should soon lead to determinationof the sequences of the other nine
genes of the 1918 virus.
The story behind this recent success has been recounted in Catching Cold
and Flu, which rely heavily upon the historical accounts providedby
Alfred Crosby's definitive work, America's Forgotten Pandemic
(publishedin 1989), for their descriptions of the events in 1918. The
books agree onmost of the facts concerning several recent influenza
investigations. Theseinvestigations include, in both books, the 1997
incident when six of eighteenpersons infected with an avian influenza
virus (H5 subtype) died in Hong Kong;the attempt to find the 1918
influenza virus in the remains of eight minersburied in the Norwegian
permafrost in Svalbard; and the superb work carriedout by Jeffery
Taubenberger's group at the Armed Forces Institute of Pathologyin
Washington in which the RNA of the 1918 virus was amplified and
sequencedfrom formalin-preserved tissue specimens of two United States
soldiers. Alsodetailed is the remarkable story of Johan Hultin, who
single-handedly wentto Alaska and retrieved tissue specimens from an
influenza victim who hadbeen buried in the permafrost since 1918. The
Taubenberger group used RNAfrom this victim to corroborate their
findings from the formalin-fixed tissues(A.H. Reid et al. Proc. Natl
Acad. Sci. USA 96, 1651-1656; 1999).
Both books are popular accounts written more for the interested lay
readerthan for the scientist. Flu emphasizes events in the US, and it
containsan interesting and detailed account of the abortive attempt
during PresidentFord's administration to vaccinate the entire US
population against swineflu and the litigation nightmare that ensued.
Catching Cold offersa useful account of the recent development of
anti-influenza drugs which havebeen designed on the basis of new
knowledge of the three-dimensional structureof neuraminidase. Davies
calls these "plug drugs" because they are built toplug a cleft on the
neuraminidase surface and stop its enzymatic function.
There are many lessons to be learned in Flu and Catching Cold which may
be of value in preparing for the inevitable future pandemicsof
influenza. Both books express well the sense of excitement in
uncoveringthe mystery of the 1918 influenza virus. But the story is not
yet over. Thesequence of the haemagglutinin gene did not provide any
obvious clues as towhy the virus was so pathogenic. It remains to be
seen whether answers tothis question will come from the sequences of the
other nine genes. Thus thedefinitive account of the 1918 influenza
pandemic has yet to be written.
Copyright 2000 Nature America Inc.
-- 
Ciao, Carlo Fusco

 By GinaKolata Farrar, Straus and Giroux, $25.00 (US). ISBN
Questa Gina Kolata (nome e cognome: si scrivono staccati) è la stessa che
pubblicò quell'articolo che portò alla ribalta mondiale il nome di Folkman,
e che per tale ragione venne ribattezzata "Gina speriKolata".  ;-))
Ottima comunque la recensione di quei due libri... thanks!
Bye,
  -= Ginzo =-


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=B8ao
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-- 
Ciao, Carlo Fusco
* Quegli strani simboli che vedi qui sopra costituiscono una firma *
* digitale. Impara anche tu a farne uso insieme alla crittografia  *
* nelle tue mail private, e` molto importante: 
http://www.pgpi.com
 *

 (se ci sono problemi contattatemia via email, please).
Mi sa che non hai letto bene la mia esposizione minima della netiquette...
comunque, per stavolta faccio uno strappo alla regola e invio questo post
anche nella tua mailbox.
Bye,
  -= Ginzo =-

 anche nella tua mailbox.
Non e` che ho fatto una domanda e voglio la risposta a casa perche` non
mi va di seguire il ng. In questo caso si tratta di una cosa che non ha
senso svolgere come publico dibattito (cioe` sapere se qualcuno si
scoccia se io assumo un certo comportamento sul ng) e ne ho richiesto
l'invio in forma privata per rispetto nei confronti del resto del mondo.
Rinnovo la domanda con maggiore precisione, e` un problema se io posto
cose che so per certo non essere reperibili se non dietro pagamento in
dollaroni sul ng quando le trovo interessanti, anche se non ho un
particolare motivo per aprire un thread? La risposta dove vi pare, anche
se per me e` piu` corretta se me la spedite a casa. Thanks.
A prosito di comunicazioni solo via email approfitto per dire che se
qualcuno ha bisogno di un particolare paper e non puo` averlo in altro
modo puo` senzaltro richiedermelo *via email* (vedi sopra) e cerchero`
di farglielo avere elettronicamente in tempi ragionevoli.
-- 
Ciao, Carlo Fusco