PERCHE’
RICREARE IL VIRUS
DEL VAIOLO
IN LABORATORIO?
Il
virologo David Evans [a destra] e il ricercatore associato Ryan Noyce.
Nel gennaio del 2018,
veniva pubblicata su una rivista scientifica, la notizia [https://www.folio.ca/creation-of-synthetic-horsepox-virus-could-lead-to-more-effective-smallpox-vaccine/], già apparsa su Science [https://www.sciencemag.org/news/2017/07/how-canadian-researchers-reconstituted-extinct-poxvirus-100000-using-mail-order-dna], nel luglio del 2017,
che alcuni ricercatori canadesi dell’Università di Alberta, coordinati dal
virologo David Evans, avevano creato il virus del vaiolo in laboratorio e
avevano pubblicato on-line, all’interno
di un articolo scientifico sulla prestigiosa rivista PloS ONE la procedura per ottenerlo.
Per creare il virus
del vaiolo, denominato horsepox virus [Hpvx],
i virologi avevano acquistato sul Web,
da comporre come pezzi di un puzzle, singoli frammenti di DNA,
costati 100mila dollari e finanziati dalla Tonix,
un’azienda farmaceutica di New York, [https://www.youtube.com/watch?v=lDEgg8L13qY].
Lo studio canadese e
la sua pubblicazione sull'acquisto on-line di frammenti di DNA, usati poi per
costruire una versione sintetica del virus del vaiolo, aveva fatto molto
discutere la comunità scientifica.
Thomas Inglesby, direttore del Center
for Health Security della Johns
Hopkins University Bloomberg School of Public Health, aveva dichiarato:
“Il mondo è ora più vulnerabile al vaiolo.”
E Andreas Nitsche del Robert Koch
Institute:
“Se qualcuno vuole ricostruire un altro virus simile ora trova le
istruzioni per farlo in un solo posto.”
Il vaiolo è stato responsabile di circa 300
milioni di morti nel secolo scorso.
L’ultima vittima diretta del virus fu Janet Parker, una fotografa di medicina,
che, nel 1978, entrò in contatto con un campione di vaiolo, in un laboratorio
della Birmingham Medical School.
Il direttore del laboratorio, Henry Bedson, si suicidò prima che la morte
di Parker fosse confermata, per il rimorso di avere fatto uscire il virus dalla
struttura. Dopo il contagio, la fotografa era entrata in contatto con molte
persone, ma solo la madre della fotografa contrasse il vaiolo e ne fu, poi,
curata.
Un anno dopo l’accaduto, il vaiolo fu considerato ufficialmente eradicato
dall’Organizzazione Mondiale della Sanità,
e dopo un acceso dibattito – con i Paesi più colpiti dall’epidemia che
premevano per la totale soppressione dei campioni, considerati una potenziale
minaccia – si decise di custodire due campioni del virus da studiare in caso di
improvvise recrudescenze della malattia presso i Centers for Disease Control
and Prevention di Atlanta, negli Stati Uniti, e il Centro di Ricerca Statale di Virologia e Biotecnologia [Vector] di Koltsovo,
nella zona di Novosibirsk, in Siberia.
Il lunedì 16 settembre scorso, una fuga di
gas aveva causato una esplosione e un incendio all’interno del Centro di Ricerca Statale di Virologia e Biotecnologia [Vector] di Koltsovo.
La Vector aveva dichiarato che il settore interessato
dall’incidente non era coinvolto in ricerche scientifiche e non conteneva
materiale a rischio biologico.
Ma perché ricreare il
virus del vaiolo in laboratorio?
Qualunque gruppo terroristico potrebbe acquistare, con facilità, su Internet agenti patogeni utili alla
realizzazione di armi batteriologiche!
E questo, a causa dell’assenza di regole certe che impediscano l’acquisto
in Rete di virus mortali per l’uomo.
Come sia facile realizzare un’arma batteriologica lo aveva, già, dimostrato,
nel 2006, il quotidiano britannico The
Guardian, che non aveva fatto altro che acquistare su Internet una piccola sequenza di DNA del virus del vaiolo.
The Guardian aveva,
infatti, acquistato on-line la sequenza di DNA
dalla VH Bio Ltd, una società con sede
a Gateshead, in Gran Bretagna, che forniva strumentazioni e sostanze chimiche
usate nei laboratori genetici.
Attraverso una semplice mail
il quotidiano si era garantito una sequenza di 78 lettere di DNA della proteina del vaiolo, al modico
prezzo di 33 sterline e 8 centesimi, più 7 sterline di spese postali [https://www.repubblica.it/2006/06/sezioni/esteri/guerra-batteriologica/guerra-batteriologica/guerra-batteriologica.htm].
Daniela Zini
James Randerson, Tighter
laws needed on sale of DNA samples, says research chief, The Guardian, 15
giugno 2006
One of the country’s leading
scientists yesterday called on the government to draw up new laws to regulate
companies that sell DNA samples which could be used to manufacture a biological
weapon.
Colin Blakemore, chief executive
of the Medical Research Council, said foolproof protection was needed to
prevent potentially dangerous material getting into the wrong hands. His
comments were endorsed by other senior scientists and follow a Guardian
investigation that revealed the ease with which a potential terrorist could buy
such materials on the internet. The Guardian was able to order a small fragment
of DNA from the variola virus, the virus that causes smallpox.
“It is obviously a worry that
fragments of a potentially very dangerous pathogen can be obtained as easily as
your investigation suggests,” said Professor Blakemore. “This is one area where
legislation or new regulation might be appropriate.”
He said it was naive to think
that self-regulation by scientists and the industry would be sufficient. “What
we are looking for is foolproof protection against highly unusual behaviour and
I don’t think that codes of conduct are the right way to approach that,” he
said.
Alistair Hay, of Leeds
University, an expert on biological and chemical weapons who advises the police
and government, said: “I think it would first be important to get industry to
put its house in order.” If that failed, he said there would be a need for
legislation.
Mark Walport, director of the
Wellcome Trust, the UK’s largest research charity said the risks should be
weighed against the need for research.
Geoffrey Smith, a smallpox
expert at Imperial College, London, pointed out that a short sequence of
variola virus may be similar or identical to a sequence from a closely related
and harmless relative. But he said companies should check orders from
customers. “It’s sensible that requests [for DNA] are screened for sequences
that match a known pathogen.”
A spokesperson for the Royal
Society said there were already stringent regulations on micro-organisms, but
added: “Science faces the challenge of identifying measures that can be taken
to reduce risk without jeopardising the potential benefits from research
advances.”
A dilemma for scientists is
how much data should be shared publicly. Once the sequence of a virus genome is
known, it is possible to manufacture the virus itself, said Prof Blakemore. The
genome for smallpox is already freely available so it is too late to control
access to it, he said [https://www.theguardian.com/science/2006/jun/15/medicalresearch.terrorism].
James
Randerson, Did anyone order smallpox?, The Guardian, 23 giugno 2006.
The smallpox virus last wreaked havoc on the
human population in 1977 before a World Health Organisation programme
eradicated it from the planet. It now exists only in government laboratories in
the US and Russia.
But ordering part of this long-dead pathogen’s
DNA proved easier than anyone dared imagine. All it took was a invented company
name, a mobile phone number, a free email address and a house in north London
to receive the order by post.
The investigation makes clear that anyone,
without attempting to prove a link to a legitimate research organisation, can
order DNA sequences from any potential pathogen without fear of extensive
questioning. In our case VH Bio Ltd did not realise it was supplying part of
the smallpox genome, but many scientists argue that it is the responsibility of
companies selling custom-made pieces of DNA to check their orders for
potentially dangerous sequences.
Without modifications that prevented the strand
ordered by the Guardian ever forming part of a functional gene, it would
probably have fallen foul of the Anti-Terrorism, Crime and Security Act 2001.
This lists so-called Schedule 5 pathogens and toxins, including smallpox virus,
ebola virus and the plague bacterium. It is illegal to keep or use these, along
with any DNA “associated with the pathogenicity of the micro-organism”, without
first notifying the authorities.
Last November New Scientist magazine surveyed 12
gene synthesis companies in North America and Europe. Only five said they
always screened their orders for suspect sequences, and three said they never
did. These were all doing relatively large-scale synthesis, providing sequences
a few hundred letters long, but there are many more companies such as VH Bio
Ltd which make so-called oligonucleotides, sequences around 100 letters or smaller.
Of three UK-based sequencing companies other
than VH Bio Ltd canvassed by the Guardian, one did not screen customers or
sequences, one carried out checks on customers only, and a third checked
customers and had carried out a pilot study on screening DNA orders but is not
currently doing so. Screening shorter sequences is more difficult because a
chance match to a suspect piece of DNA is more likely. “Because they are short,
sequence screening can pick those up, but the false positive rate is high,”
said Robert Jones at Craic Computing in Seattle, which produces software to
screen sequence orders against a database of DNA from nasty pathogens.
The Guardian’s investigation has sparked calls
for DNA synthesis companies to be better regulated.
Edward Hammond, a biological weapons expert with
the Sunshine Project, an NGO that campaigns against the development of
biological weapons, said: “The most worrisome thing . . . is that [the field of
synthetic biology] is going to enable people to create potentially very
dangerous diseases that don’t otherwise exist or to re-create ones that have
been wiped off the face of the Earth.”
The emerging science of synthetic biology holds
great potential for medicine and other fields. There are, for example, research
projects to develop synthetic bacteria that seek and invade tumour cells, and
yeast cells that produce a malaria drug.
Eckard Wimmer at the State University of New
York in Stony Brook said the 2002 experiment to make polio virus from scratch
by stitching together short strands of DNA was fairly easy. “We did it as a
wake-up call,” he said. “It’s surprising to me, after all these discussions for
at least four years, that no more urgent recommendation has gone out to these
companies saying that if you don’t [carry out more rigorous checks] you may be
in trouble,” he said.
At a synthetic biology conference in Berkeley,
California, last month delegates discussed how to minimise misuse of the
technology. Delegates are currently consulting on four “resolutions”, which include
an effort to develop improved and freely available software tools to screen DNA
orders for potentially dangerous sequences and a pledge to “encourage
individuals and organisations to avoid patronising companies that do not
systematically check their DNA synthesis orders”.
But synthetic biologists have defended their
efforts to regulate the field. “If scientists are willing to get the ball
rolling when few others are acting, then they should be encouraged,” said
George Church, a leading synthetic biologist at Harvard. He argued that
voluntary regulation would would be quicker than legislation and would not
preclude new laws [https://www.theguardian.com/science/2006/jun/23/weaponstechnology.guardianweekly].
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