Smallpox and Vaccinia Virus: various articles
How Smallpox Vaccine is made:
The origin of vaccinia virus is unknown.
Controversal question, is Vaccinia Virus a form of smallpox virus?
NOTE: Should smallpox virus be destroyed?
IOM: Selected quotes from Long article re Should smallpox virus be destroyed?
[Smallpox and smallpox virus--200 years since the first vaccination in Norway]
Electron Micrographs of Variola and Varicella�Zoster Virus
Animal poxviruses transmitted from cat to man:
Vaccinia is now apparently becoming a problem:
PCR identification and differentiation of small pox and other orthopoxviruses
Vaccinia has a broad host range
Vaccinia virus [and] different clinical
forms of postvaccinal complications
Viruses potentially derived from recombination of vaccinia ...
Vaccination - A business based on fear by Dr. Buchwald
How Smallpox Vaccine is made:
1: Emerg Infect Dis 2001 Nov-Dec;7(6):920-6
Developing new smallpox vaccines.
Rosenthal SR, Merchlinsky M, Kleppinger C, Goldenthal KL.
CBER/Food and Drug Administration, Rockville, MD 20852, USA.,
rosenthals@cber.fda.gov
New stockpiles of smallpox vaccine are required as a contingency for protecting civilian and
military personnel against deliberate dissemination of smallpox virus by terrorists or unfriendly
governments. The smallpox vaccine in the current stockpile consists of a live animal poxvirus
(Vaccinia virus [VACV]) that was grown on the skin of calves. Because of potential issues
with controlling this earlier manufacturing process, which included scraping VACV lesions
from calfskin, new vaccines are being developed and manufactured by using viral propagation
on well-characterized cell substrates. We describe, from a regulatory perspective, the various
strains of VACV, the adverse events associated with calf lymph-propagated smallpox
vaccine, the issues regarding selection and use of cell substrates for vaccine production, and
the issues involved in demonstrating evidence of safety and efficacy.
PMID: 11747717 [PubMed - indexed for MEDLINE]
Source: http://www.bats.ch/abstr/197k2a13.htm
II.1.3.1 Origin
The origin of vaccinia virus is unknown.
Five hypotheses (Fenner, 1992; Behbehani, 1983) suggest vaccinia virus to be:
1.derived from variola virus by passage in cows
2.derived from variola virus by passage in humans (variolation)
3.derived through hybridisation between cowpox and variola viruses
4.a fossil virus maintained in the laboratory but otherwise extinct
5.derived from cowpox virus by repeated passage on the skin of animals
None of these hypotheses has conclusively been proven.
See source for good article: http://www.bats.ch/abstr/197k2a13.htm
RE: the Controversal question, is Vaccinia Virus a form of smallpox
virus?
Note an article by the IOM
that addressed the question, 'Should Smallpox stocks be distroyed?', has some
good material to help one understand this question. For full article see:
http://www.nap.edu/html/variola_virus/index.html (a selection of quotes
at end of this section.)
Summary:
To put it in a nut shell. The answer to the question above depends not
only on science, but as usual in the vaccination arena, it also depends
upon political and finanacial pressures, plus the all important
perceptions and beliefs about the value of vaccines, the germ theory of
disease, and the germ theory of disease severity.
Or to put it another way:
It is not DNA that answers the question, "Is Vaccina Virus a form of Smallpox Virus", but
rather clinical experience which must anwer the question.
Quotes here are from: http://www.nap.edu/html/variola_virus/index.html,
http://www.nap.edu/html/variola_virus/ch1.html The genomes of both
variola and vaccinia have been sequenced and are 95 percent identical
[6].
Smallpox was eradicated before the development of many modern techniques
of microbiology.
In 1999, only 2 strains of variola major, and only 1 strain of variola
minor had been DNA sequenced.
There are no known natural hosts of vaccinia virus, and its origin is
obscure.
Given the above limited information, the question of whether vaccinia is
smallpox must be answered from its "EFFECTS" (clinical experience) an area hightly fraught
with belief systems.
To illustrate that smallpox vaccine can be associated with smallpox
cases, where the individual is susceptable before hand, look at the
'smallpox' and 'vaccinia' case photos at:
http://www.bt.cdc.gov/Agent/Smallpox/SmallpoxImages.asp Graphic
clinical images of smallpox.
http://www.bt.cdc.gov/Agent/Smallpox/VaccineImages.asp,
Graphic clinical images of smallpox.
Does the upper composite photo show a different disease than the the lower composite
photo?
Soc Hist Med 1996 Apr;9(1):117-9
Should smallpox virus be destroyed? The relevance of
the origins of
vaccinia virus.
Baxby D.
Department of Medical Microbiology, University of
Liverpool.
The fate of surviving stocks of smallpox virus is
still uncertain, and it is important that arguments
in favour of retention or destruction should present
balanced evidence. This article balances the
view, probably incorrect and possibly alarmist
presented earlier in this Journal by Peter Razzell,
that vaccinia and cowpox viruses were derived from
smallpox virus. The generally accepted
alternative view that all three viruses are
independent species and that smallpox virus could not
emerge through simple mutation of the other two is
presented, together with appropriate
literature citations.
A quote from the IOM article, "...responses to orthopoxvirus
infections in humans comes from studies of human subjects in
immune-deficient states who are subsequently vaccinated with vaccinia
virus. In children with immunological defects in cell-mediated immunity,
vaccinia virus replicates without restriction, resulting in a
continually progressive primary lesion, persistent viremia, and
widespread secondary viral infection of many organs."
More quotes snipped from:
http://www.nap.edu/html/variola_virus/index.html
Assessment of Future Scientific Needs for
Live
Variola
Virus
Committee on the Assessment of Future Scientific Needs for Live
Variola Virus
Board on Global Health
INSTITUTE OF MEDICINE
NATIONAL ACADEMY PRESS
Washington, D.C. 1999
http://www.nap.edu/html/variola_virus/ch1.html
The genomes of both variola and vaccinia have been sequenced
and are 95 percent identical [6].
The genes involved in DNA replication, gene expression, and assembly of
new virions are located mainly in the center of the DNA genome. Studies
from many laboratories
with different strains of poxviruses have shown that the genes involved
in virus-host interactions are located near the ends [7,8]. It is there
that most of the differences among the genomes of the poxviruses are
found--in those regions determining the interactions with the immune
system of the host. Investigations of these
interactions are likely to provide fundamental insights into human
biology and the functioning of the human immune system. Studies of other
viruses provide extensive
support for this belief [5]. One notable example is the wholly
unexpected finding that proteins within the endoplasmic reticulum can
be targeted for destruction and transported into the cytoplasm by
virus-encoded gene products [9].
Smallpox was eradicated before the development of many modern techniques
of microbiology. As these tools emerged, they were generally applied to
studies of
pathogens posing current health threats. Partly as a result of the
successful eradication of smallpox, therefore, modern analytical
techniques have not been applied to enhance understanding of the
pathogenesis of variola virus in the human host.
http://www.nap.edu/html/variola_virus/ch2.html
Vaccinia Virus. Vaccinia virus has been propagated by humans for use as
a smallpox vaccine for the past 200 years. There are no known natural
hosts of vaccinia virus,
and its origin is obscure. All present strains of vaccinia virus are
genetically related, although they exhibit different biological
properties in the laboratory. Most strains have a wide host range in
experimental animals, and all exhibit rapid growth on the
chorioallantoic membrane cultures. Since the early 1980s, strains of
vaccinia have been engineered to express genetic information for other
viral and bacterial antigens or
immunomodulatory proteins. Vaccination against smallpox is most
effective by infection of the skin with vaccinia virus, followed by
extension of replication to the lymph nodes and spleen, which elicits
cell-mediated and humoral immune responses that provide protection
against infection with variola virus.
http://www.nap.edu/html/variola_virus/ch3.html
The human immune response to viruses is a complicated process about
which much has yet to be discovered. Furthermore, knowledge of
interactions between the immune system and variola virus is limited
because modern techniques for the study of immune responses
were developed after smallpox was eradicated.
...
The best information on the relative importance of cell-mediated and
humoral immune responses to orthopoxvirus infections in humans comes
from studies of human subjects in immune-deficient states who are
subsequently vaccinated with vaccinia virus. In children with
immunological defects in cell-mediated immunity, vaccinia virus
replicates without restriction, resulting in a continually progressive
primary lesion, persistent viremia, and widespread secondary viral
infection of many organs. In patients with thymic dysplasia and
partially or completely intact immunoglobulin-synthesizing capacity
(Nezelof's syndrome), the progression is slower and less persistent, but
usually results in death. Delayed-type hypersensitivity reactions are
not evoked in patients with progressive vaccinia, nor can their
peripheral blood lymphocytes be stimulated to
undergo mitosis by exposure to inactivated vaccinia virus. Although
neutralizing antibody is sometimes present in the serum, its presence
does not prevent the development of progressive vaccinia if
cell-mediated immunity is defective.
All orthopoxviruses induce cross-protective immunity in susceptible
laboratory animals. Indeed, that is one of the ways of identifying
members of the genus and is the basis for currently available vaccines.
Among the orthopoxviruses that infect humans, cowpox and vaccinia
viruses usually produce only local lesions and minimal systemic
disturbance. Variola and monkeypox viruses cause serious systemic
disturbance with high case-fatality rates. [It should be noted that it may be
sanitation and nutritional status which determines severity and case-fatality far
more than the virus...]
The process of inoculating smallpox material is called variolation to
distinguish it from vaccination, which uses cowpox or vaccinia virus.
After variolation of the skin, a primary lesion develops at the
inoculation site on about the third day, and satellite pustules are
common. But the rash is usually much less severe than with naturally
occurring smallpox. Historically, case-fatality rates were between 0.5
and 2 percent after variolation, compared with 20 to 30 percent from
natural smallpox. Since the virus material used was not attenuated, it
was possible for those receiving variolation to
transmit ordinary smallpox to susceptible contacts.
Because of its extreme virulence, variola virus must be
handled in
maximum containment facilities (BSL-4). These facilities consist of
a separate building or clearly isolated section of a building with a
sealed internal shell. Outer and inner change rooms separated by a
shower are provided for personnel entering and exiting the facility. A
double-doored autoclave, fumigation chamber, or ventilated airlock
is provided for passage of materials not brought into the facility
through the change room. Sewer and ventilation lines contain
high-efficiency particulate air (HEPA) filters. Special individual
supply and exhaust air ventilation is provided for laboratory workers,
and pressure differentials are maintained to ensure the inward flow
of air toward areas where the potential for hazard is highest [17].
Chapter 9
Bioinformatics
Although possession of the viral genome sequence does not yield total
knowledge about the integrated biology, virulence, or transmissibility
of a virus, much can be learned from a variety of studies based on these
sequences. An important question is the variability of genetic
information (DNA sequence) among different isolates of the virus
obtained from patients in different geographic locations, although
available collections are not well-ordered sets of variola virus
strains. Multiple clones or PCR products should be sequenced to assess
diversity. Significant differences are known to exist between the
sequences of variola major and minor, but the extent of the variation
and the importance of the identified differences for virulence in each
of the two subspecies or even within individual isolates have not been
determined [36]. The extent and consistency of sequence variability
might provide essential clues to the pathogenesis, virulence, and
evolution of the virus and the nature of the infection. For example, a
recent outbreak of monkeypox exhibited somewhat greater human-to-human
transmission than had been the case in the past. However, preliminary
results from sequencing of DNA fragments of monkeypox virus isolates
obtained at various times since 1970 suggest that the virus has changed
very little over this period. Thus at present, there is no clear
evidence that the rate of human-to-human transmission of monkeypox is
likely to increase [37]. DNA sequence information from a characteristic
set of variola virus isolates could enhance our capability to assess
whether human monkeypox is evolving trans-mission characteristics
similar to those of smallpox. Variola virus stocks need to be retained
until a sufficient number have been cloned, or PCR amplifications have
been obtained and analyzed.
VARIABILITY OF VARIOLA VIRUS
While the complete genomic sequences of a few variola virus isolates are
available, the overall scope of such information remains limited. As
noted in Chapter 5, the complete genome DNA of variola major virus
Bangladesh-1975 (GenBank #L22579) has been
sequenced from clones with about sixfold redundancy. The variola major
virus India-1967
(GenBank X69198) genome, except for a small region at each DNA terminal,
and the variola minor alastrim virus Brazil-1966 genome (EMBLY167080)
also have been sequenced, with about twofold redundancy. The samples in
the CDC and VECTOR repositories do not, however, represent a complete
archive of characterized strains from the different outbreaks in recent
history.1
Although the sequences of the above strains are not entirely identical,
they are nearly so. Direct sequence comparison of the Bangladesh-1975
and India-1967 strains shows that the viruses are 99.2 percent identical
throughout the entire genome (see Figure 9-1) [6, 36, 38]. While in one
sense this finding argues for relatively little variability,
that conclusion should be tempered by the following considerations. Most
of the differences are clustered in the terminal regions of the viral
genome.
Those regions contain genes that frequently are not essential for viral
replication, yet typically are associated with pathogenesis, interact
with the immune system, and affect virulence and host range. While only
18 of 200 proteins in the entire genome differ
significantly between the Bangladesh and India strains, 7 of 30 open
reading frames at the left terminus and 8 of 22 open reading frames near
the right terminus show variation between the two viruses [36]. It must
be remembered that a very minor change -- a single base addition or
deletion or a single amino acid coded by a genecan lead
to profound effects in the corresponding proteins that determine
variations in virulence. Moreover, available sequence data have been
derived from plaque-purified
isolates whose DNA was cloned into plasmids, and there are sparse or no
data on
heterogeneity within individual isolates, the effect of cloning in
bacteria, or the heterogeneity in strains other than those discussed
above.
Chapter 10
Understanding of the Biology of Variola Virus
As noted earlier, smallpox was eradicated prior to the modern age of
cell and molecular biology, virology, and immunology. Therefore, the
basics of viral replication, determinants of viral virulence, and
pathogenesis of the disease are not as well understood as they are for
other pathogens.
Chapter 12
... increased knowledge of variola infection has been limited largely to
the cloning and complete sequencing of two strains of variola major from
the Asian subcontinent, partial sequencing of one strain of variola
major, and one strain of variola minor from
Latin America. In addition, a few genes of other strains have been
sequenced.
For whole article:
http://www.nap.edu/html/variola_virus/index.html
1: Tidsskr Nor Laegeforen 2001 Dec 10;121(30):3546-50
[Smallpox and smallpox virus--200 years since the
first vaccination in Norway]
[Article in Norwegian]
Tryland M.
Norges veterinaerhogskole Institutt for arktisk
veterinaermedisin 9292 Tromso.
morten.tryland@veths.no
In December 1801, the first vaccination against
smallpox in Norway took place. Vaccine
material came from Denmark, England, Ireland, and
other countries; it was also obtained from a
few local cowpox cases. What mattered was the effect,
not the origin. Several reports indicate
that variola virus itself, the cause of smallpox, was
also used for human vaccination after
passages through cows and horses. A vaccine institute
for production of vaccine in calves was
established in Kristiania in 1891. Cowpox was once a
rare disease in cattle, but a total of
70,985 bovine cases were reported between 1889 and
1928. The source of infection was
thought to be humans vaccinated against smallpox.
Pox-like diseases were also registered in
horses, pigs, sheep, goats and dogs at that time.
Compulsory vaccination continued in Norway
until 1976; smallpox is now eradicated. During the
last decades, however, cowpox virus
infections have re-emerged among zoo animals,
domestic cats and humans in Western Europe,
with small wild rodents and shrews as wildlife
reservoirs. Vaccinia virus is also met with new
interest as a vector in recombinant vaccines. Given
the fact that the human population no longer
has immunity against orthopoxviruses and the new
possible exposure through pets and wildlife, it
may be appropriate to reflect on poxvirus history in
Norway in the light of the present situation.
black and white graphic of
Electron Micrographs of Variola Virus
(Panel A, x200,000) and Varicella�Zoster Virus
(Panel B, x200,000).
Diagnosis and Management of Smallpox at:
http://content.nejm.org/cgi/content/full/346/17/1300 - -
NEJM Volume 346:1300-1308 April 25, 2002 Number 1
google search for SMALLPOX images [several hundred]
http://images.google.com/images?q=smallpox&ie=ISO-8859-1&hl=en
1: Zentralbl Veterinarmed [B] 1991 Aug;38(6):421-31
Animal poxviruses transmitted from cat to man:
current event with lethal end.
Czerny CP, Eis-Hubinger AM, Mayr A, Schneweis KE, Pfeiff B.
Institute of Medical Microbiology, Infectious- and
Epidemic Diseases, Veterinary Faculty,
Ludwig-Maximilians-University, Munich.
We report about the infection of an 18-year-old man
with an orthopox virus (OPV) which was
transmitted by a cat. The infectious route from cat
to man could be proved by epidemiological,
virological and serological methods. The
corresponding techniques are described. The patient
had not been vaccinated against smallpox and was
intensively immunosuppressed by medication
on account of a severe endogeneous eczema combined
with an allergic asthma bronchiale. A
cyclic poxvirus disease developed with a generalised,
partly confluent pox virus exanthema
disseminated over the body. The clinical symptoms
were similar to a "variola pustulosa
haemorrhagica". The young man died of a lung embolism
in the course of the intensive medical
therapy. The haemorrhagic character of the pox virus
pustules with central necrosis (pox navel)
could be reproduced in the rabbit skin and on
chorioallantois membranes. The pox virus isolated
from the patient could be differentiated from
variola, vaccinia and monkeypox virus. It is a
member of the group of "cowpox-like viruses". The
environmental importance of these OPVs is
discussed.
PMID: 1659066 [PubMed - indexed for MEDLINE]
Vaccinia is now apparently becoming a problem:
1: Virology 2000 Nov 25;277(2):439-49
An emergent poxvirus from humans and cattle in Rio de
Janeiro State:
Cantagalo virus may derive from Brazilian smallpox
vaccine.
Damaso CR, Esposito JJ, Condit RC, Moussatche N.
Laboratorio de Biologia Molecular de Virus, Instituto
de Biofisica Carlos Chagas Filho, CCS,
Rio de Janeiro, RJ 21941-900, Brazil.
The biological properties of poxvirus isolates from
skin lesions on dairy cows and milkers during
recent exanthem episodes in Cantagalo County, Rio de
Janeiro State, Brazil, were more like
vaccinia virus (VV) than cowpox virus. PCR
amplification of the hemagglutinin (HA) gene
substantiated the isolate classification as an Old
World orthopoxvirus, and alignment of the HA
sequences with those of other orthopoxviruses
indicated that all the isolates represented a single
strain of VV, which we have designated Cantagalo
virus (CTGV). HA sequences of the
Brazilian smallpox vaccine strain (VV-IOC), used over
20 years ago, and CTGV showed
98.2% identity; phylogeny inference of CTGV, VV-IOC,
and 12 VV strains placed VV-IOC
and CTGV together in a distinct clade. Viral DNA
restriction patterns and protein profiles
showed a few differences between VV-IOC and CTGV.
Together, the data suggested that
CTGV may have derived from VV-IOC by persisting in an
indigenous animal(s), accumulating
polymorphisms, and now emerging in cattle and milkers
as CTGV. CTGV may represent the
first case of long-term persistence of vaccinia in
the New World. Copyright 2000 Academic
Press.
PMID: 11080491 [PubMed - indexed for MEDLINE]
J Clin Microbiol 1995 Aug;33(8):2069-76
PCR strategy for identification and differentiation
of small pox and other orthopoxviruses.
Ropp SL, Jin Q, Knight JC, Massung RF, Esposito JJ.
Division of Viral and Rickettsial Disease, Centers
for Disease Control and Prevention, Atlanta,
Georgia 30333, USA.
Rapid identification and differentiation of
orthopoxviruses by PCR were achieved with primers
based on genome sequences encoding the hemagglutinin
(HA) protein, an infected-cell
membrane antigen that distinguishes orthopoxviruses
from other poxvirus genera. The initial
identification step used a primer pair of consensus
sequences for amplifying an HA DNA
fragment from the three known North American
orthopoxviruses (raccoonpox, skunkpox, and
volepox viruses), and a second pair for amplifying
virtually the entire HA open reading frame of
the Eurasian-African orthopoxviruses (variola,
vaccinia, cowpox, monkeypox, camelpox,
ectromelia, and gerbilpox viruses). RsaI digest
electropherograms of the amplified DNAs of the
former subgroup provided species differentiation, and
TaqI digests differentiated the
Eurasian-African orthopoxviruses, including vaccinia
virus from the vaccinia virus subspecies
buffalopox virus. Endonuclease HhaI digest patterns
distinguished smallpox variola major viruses
from alastrim variola minor viruses. For the
Eurasian-African orthopoxviruses, a confirmatory
step that used a set of higher-sequence-homology
primers was developed to provide sensitivity
to discern individual virus HA DNAs from
cross-contaminated orthopoxvirus DNA samples;
TaqI and HhaI digestions of the individual amplified
HA DNAs confirmed virus identity. Finally,
a set of primers and modified PCR conditions were
developed on the basis of base sequence
differences within the HA genes of the 10 species,
which enabled production of a single DNA
fragment of a particular size that indicated the
specific species.
PMID: 7559950 [PubMed - indexed for MEDLINE]
Source:
http://www.bats.ch/abstr/197k2a1.htm
What happens when vaccinia is released into the environment?
Vaccinia has a broad host range, and unlike some other members of the
orthopoxvirus family, is not indigenous to European wild life so far. Once
released it might persist in the environment with unpredictable fate and
effects.
The wide dissemination of vaccinia-based vaccine resulting from extensive use
increases the probability of vaccinia recombination with other
orthopoxviruses present in target and nontarget animals. The vaccinia virus
has been used most successfully for the vaccination against smallpox in
humans, but has, in rare instances, caused serious adverse effects.
Before launching any type of vaccination programme against sylvatic rabies,
thorough studies on the chosen vaccine (recombinant or live attenuated virus)
efficacy as well as on its cost/risk analysis are necessary. The cyclic
nature of rabies epizootics makes comparisons of efficacy drawn from field
studies a difficult task (Anderson, 1991; Brochier et al., 1990; Brochier et
al., 1991).
It is not within the scope of this report to evaluate efficacy and cost/risk
factors. Criticism against the wildlife rabies vaccination programme exists
(Mc Nally, 1994; Bruggemann, 1993), however, European and North American
authorities and most virologists plead for this preventive measure. Finally,
before releasing any genetically modified organism into the environment,
economic, social and ethical concerns also should be carefully addressed.
Zh Mikrobiol Epidemiol Immunobiol 1979 Nov;(11):73-8
[Participation of vaccinia virus in the pathogenesis of different clinical
forms of postvaccinal complications. I. Frequency of vaccinia virus
detection in the vaccinated who have usual and complicated reactions to
vaccination]
[Article in Russian]
Gurvich EB, Movsesiants AA, Stepanenkova LP.
The virological examination of 1365 samples taken
from 469 children vaccinated against smallpox revealed considerable differences in the
frequency and the time of vaccinia virus detection in different clinical forms of postvaccinal
pathology as compared with uncomplicated vaccinal process. During the postvaccinal period
taking its normal course vaccinia virus was isolated from 7.3% of children only from the pharynx
till day 8 following vaccination. In generalized and creeping vaccinia the virus was
isolated from 71.4% of children, in postvaccinal encephalitis from 57.1% of children, in vaccinal
angina frove-mentioned complications vaccinia virus was detected in the samples obtained from the
patients till days 24, 35, 15 and 24 respectively. The etiopathogenetic role of vaccinia
virus in a number of postvaccinal complications is discussed.
PMID: 42243 [PubMed - indexed for MEDLINE]
http://www.bats.ch/abstr/197intro.htm
Tools for safety assessment Vaccinia-derived recombinant rabies vaccine
http://www.bats.ch/abstr/197k2a5.htm Following quote is from:
II.5. Viruses potentially derived from recombination of
VRG in the field
Recombination between two viruses (either by homologous recombination or by direct ligation of
viral genomic DNA) can occur only if both viruses infect the same cell. Therefore the host ranges
and the tissue tropisms of the viruses in question must overlap.
Whereas poxviruses recombine easily with other members of the same genus, their recombination
with viruses belonging to other families is not very likely. Because virus-specific promoter sequences
are required for transcription, the effective transfer of genetic material from a poxvirus is expected to
take place only if the recipient organism is another poxvirus, preferably of the same genus.
Moreover, poxviruses, African swine fever virus, and to some extent iridoviruses are the only DNA
viruses which replicate in the cytoplasm of the infected host cell (Fenner et al., 1989).
...
The outcome from the recombination of two viruses cannot be predicted. It is even possible that
progeny viruses with increased virulence compared to both parental viruses can result (for example:
the spontaneous generation of malignant rabbit fibroma virus). There is experimental evidence on the
generation of recombinant viruses with increased virulence. In one experiment, mice were either
inoculated (footpad) simultaneously with two weakly neuroinvasive herpes simplex virus type 1
strains or with each strain alone (Javier et al. 1986). A total of 62% of mice having received a 1 : 1
mixture of the viruses died, whereas mice having received a similar or 100-fold higher dose of each
individual strain alone survived. Of the 14 viruses isolated from the brains of 10 mice that had died,
11 were recombinants. Among the recombinants, 3 were lethal when reapplied to the footpads of
mice. Henderson et al. (1990) also observed increased virulence in sheep after coinoculation of two
avirulent vaccine strains of pseudorabies virus (alpha-herpesvirus). Other examples of recombination
resulting in viruses with increased virulence compared to both parental strains were reviewed by
Hahn (1992) and Kaplan (1989)
Dr. G. Buchwald wrote in his book
"Vaccination - A business based on fear" page 25,
Quote
It turned out that the material produced and used for vaccination did
contained neither cowpox viruses or did it contain the human smallpox
virus,
but that it in fact contained viruses which until then had been unknown and
which were later called "smallpox virus vacciniae" or "vaccine viruses".
This virus- up to that time unknown - has never been found in nature and is
therefore only known to exist in the vaccine. At the time it was claimed
that the cowpox virus had - while artificially propagated - changed into
the
vaccine virus. A dispute among the vaccine doctors was the result. German
doctors claimed it was possible to change the cowpox virus into the vaccine
virus by artificial propagation. Others disputed such a possibility and
were
of the opinion that the two forms of viruses were two completely different
entities. The Frenchman Chaveau was the chief proponent of this opinion,
together with numerous French and English authors. It turned out that these
viruses are indeed two different entities and that it is not possible to
modify cowpox viruses into vaccine viruses or back the other way during
propagation. In other words, the claims made by "researchers" that they had
succeeded in breeding vaccine viruses from cowpox viruses were a
fabrication. It is with this vaccine material - which does not occur in
free nature, of which the origin is unknown, which is completely unknown
quantity and of which it can only be said "its origin vanishes in the
darkness of the past "- that we have vaccinated millions of our children
with for the past 100 years! Unquote
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