HIV AND VISNA
There have long been allegations that HIV contains fragments of
other retroviruses, or appears to be a splicing of other viruses.
Different theories have proposed that it contains segments of
HTLV (a leukemia retrovirus, the first human retrovirus that
was discovered by Robert Gallo), or BIV (bovine leukemia
virus), or visna (a sheep retrovirus).
Only a few things seem clear. All of these viruses have significant
similarities. SIV is genetically closer to HIV, than are
these other viruses. These facts do not answer all the
questions as to the ancestry of the viruses, or whether they are
natural, or not.
There has been at least one study to suggest that SIV appears
to be descended from HIV, rather than vice-versa (I will
document this in another post). It is possible that both are
relatively recent descendents of a common ancestor.
Phylogenetic trees can show which subgroups of viruses
bear the most similarity to each other, but cannot in themselves
prove ancestral relationships.
Determination of whether a virus contains fragments of other
viruses is a matter of statistical analysis. It would possible,
for example, for HIV to have identifiable splices of
other viruses, even if it is overall closer to SIV.
These are questions for future investigation. For now, my goal
has been just to get a better handle on animal retroviruses
that are similar to HIV, the order in which they were discovered,
how much is known about them, what record of lab experimentation
is publicly available.
Under the category of retroviruses, there is a subclass known
as "lentiviruses" (meaning "slow" viruses, that take a long time
to incubate). Mammal lentiviruses include EIAV (horses),
BIV (cattle), CAEV (goats), visna (sheep), PUMA and FIV
(cats), and SIV (monkeys/chimps).
The large number of viruses would seem to suggest that they
are very old. However, this theory raises some puzzles.
For instance, why were they not noticed earlier? Visna is
among the oldest- the first known outbreak was around 1930,
in Iceland. The virus was first identified in the 1949.
Visna was not something that would likely go unnoticed.
The outbreak in Iceland was obvious and explosive.
Similarly, SIV is now widespread among primates, and is present
in most species of monkeys. Monkeys and chimps from all over
the world were used were used extensively for research, in the
decades preceding AIDS. Viruses similar to HIV, such as FELV and
visna, were well-known, and their structure was identified
in detail (see reference to follow). There had been extensive
attempts to identify and catalogue animal viruses (another
topic for future discussion). Why would the viruses not
have been discovered earlier?
These are not viruses that stayed confined in "remote
villages". Somehow, we have to explain viruses that
jumped species and jumped oceans and continents, from Iceland to
Australia to Africa to Europe and the U.S., yet were little
noticed..
There are such things as wild cattle and sheep, but most are
domesticated. This would lead you to imagine that explosive
and deadly new viral epidemics would not go unnoticed.
These viruses sometimes are not fatal, but often are. It is not
simply a matter that they were harmless variations of
viruses. We would have to explain why viruses that were
supposed "harmless" in most species, suddenly turned
malignant in multiple species, at the same time.
Presumably, all of the lentiviruses trace back to a common
ancestor- one of the more interesting questions. The phylogenetic
trees are today drawn without any identifiable root.
We go to great lengths to imagine how humans may have
picked up a monkey virus, by tribes drinking monkey blood,
etc. It is even more interesting to imagine the link that spread
a virus between say, cattle and monkeys.
It conjures slightly humorous images of Farmer Brown
inviting his brother, Jungle Jim, out to the farm, where his
pet monkey, Bonzo, got into a fight with Bessie the cow.
Blood was everywhere. It must have been awful.
After all, we are talking about viruses that do not spread
by casual contact, even if the animals had casual contact,
which they do not. They are not predators of each other, they
do not have sex with each other.
You might imagine some common vector such as insects,
but we have been assured that insects cannot transfer HIV,
and are not likely to do so in the future, even if HIV were
to mutate significantly.
You might suppose that humans are the most common
link among all the animals, but we supposedly got our
virus variant as the last in line.
Another interesting observation is that most of the mammal
lentviruses are spread by milk, sometimes, spread primarily
by milk. Humans, consumers of goat's milk, sheep's milk,
cow's milk, sometimes unpasteurized, have presumably been
exposed to other animal lentiviruses many times. If the viruses
are truly ancient, it is rather odd that we never became infected
with deadly disease, until very recently.
Certainly, it is conceivable that all of these animal retroviruses
are relatively recent, just like the epidemic of HIV. HIV has
a phenomenal mutation rate, and has infected tens of millions
of humans in the span of a few decades. There multiple
strains of HIV in humans, already. Perhaps, among other
mammals, it is just more of the same story.
To try to sort out this mess, I tried to focus on what seemed like
the first known lentivirus, visna.
I've been told visna itself may have had origins in German
biological war research/testing, but I have no information
on this, yet. I've also been told that EIAV may be older,
but again, I am still looking into this.
It was clear however, that the initial visna outbreak was
would have been well known, and of interest, to anyone
doing biological war research, any time after 1930.
One cannot exactly search for what secret research might
have been done with visna. Next best is to try to find out
how much was known in the public arena, and when, and
what kind of published experiments were done with visna.
This effort, in itself, was very revealing and unsettling.
It certainly lends credence to the notion that visna could
have been manipulated with destructive results.
For the rest of this essay, I refer to studies that are listed
in the "PUBMED" database.
First, it is clear that there was *extensive* interest and
research involving visna, before the AIDS epidemic.
I found dozens of published experiments, looking just at
a limited time frame in the 60's and 70's. No doubt, the
total experiments numbered at least in the hundreds- a great
deal of interest, for a infection that was rare among sheep,
and had already been eradicated in Iceland.
Second, it is clear that the detailed structure of visna was well
known, well before the AIDS epidemic. In order to realize this,
you don't need even to look at the abstract: the convenient
title alone makes the point:
Harter DH.
The detailed structure of visna-maedi virus.
Front Biol. 1976;44:45-60. No abstract available.
Pautrat G, et al.
[Study of the structure of Visna virus by electron microscopy].
C R Acad Sci Hebd Seances Acad Sci D. 1971 Aug 9;273(6):653-5.
PMID: 5001143; UI: 72047938.
Visna is quite similar to HIV. If its structure was known in detail,
then why was it such a painful and prolonged effort to identify
HIV?
Third, it is clear that researchers were attempting
to infect human cells with visna, well before AIDS broke out.
It could be argued that any such experiment of this type carries
a degree of irresponsibility. Any time that you expose a virus
to a new host, there is a danger that the virus will adapt to that
host, and create a new strain of virus.
Macintyre EH, et al. A modification in the response of human
astrocytes to visna virus. Am J Vet Res. 1974 Sep;35(9):1161-3.
PMID: 4370842; UI: 75021753.
Macintyre EH, et al.
Visna virus infection of sheep and human cells in vitro--an
ultrastructural study. J Cell Sci. 1973 Jul;13(1):173-91. No abstract
available. PMID: 4354152; UI: 73250349.
MacIntyre EH, et al.
Morphological transformation of human astrocytes by visna virus with
complete virus production. Nature New Biol. 1972 May 24;
237(73):111-3. PMID: 4503847; UI: 72204414.
Macintyre EH, et al.
The establishment of a line of visna virus-producing human astrocytes
(V-1181N1). Med Res Eng. 1972;11(4):7-13. PMID: 4370460;
UI: 75016059.
Macintyre EH, et al.
Prolonged culture of Visna virus in human astrocytes.
Beitr Pathol. 1974 Jul;152(2):163-78. No abstract available.
PMID: 4369072; UI: 74306244.
The human "astrocytes" refer to cells in human nerve tissue.
Fourth, it is interesting that researchers were experimenting
with visna and simian (monkey) tissues, also. Remember that
monkey kidney tissues are suspect in the contamination of
vaccines. Many lab monkeys were released back into the
wild intentionally, because of "no sign of disease".
For AIDS-like viruses, with long incubation periods, this
is in hindsight a major mistake. At the time, it helped
satisfy animal-rights concerns.
August MJ, et al.
Visna virus-induced fusion of continous simian kidney cells.
Arch Gesamte Virusforsch. 1974;44(2):92-101. No abstract available.
PMID: 4365045; UI: 74250024.
Fifth, researchers were studying visna's interaction with the immune
system:
Panitch H, et al.
Pathogenesis of visna. III. Immune responses to central nervous system
antigens in experimental allergic encephalomyelitis and visna. Lab
Invest. 1976 Nov;35(5):452-60. PMID: 186662; UI: 77054769.
Lab Invest 1976 Nov;35(5):444-51
Pathogenesis of visna. II. Effect of immunosuppression upon early
central
nervous system lesions.
Nathanson N, Panitch H, Palsson PA, Petursson G, Georgsson G
Lastly, it is clear that researchers were experimenting with other
cross-species transfers: sheep, goats, mice, cattle. They were attempting
also to induce tumors and cancers (references to "oncogenic", and
"sarcoma"):
Tamalet J, et al.
[Morphological and biochemical analogies of Visna virus with oncogenic
RNA viruses] pp. 19-26. Monograph. 1976 Aug 23; . English; French. No
abstract available. PMID: 180153; UI: 76215618.
Lycke E, et al.
Tumor incidence in Visna virus inoculated mice.
Experientia. 1976 Apr 15;32(4):514-5.
PMID: 178528; UI: 76187733.
Thormar H.
Visna-maedi virus infection in cell cultures and in laboratory animals.
Front Biol. 1976;44:97-114. Review. No abstract available.
PMID: 182563; UI: 76257981.
Sharma DN, et al.
Jaagziekte & maedi of sheep & goats transmitted in laboratory animals.
Indian J Exp Biol. 1974 Jan;12(1):95-6. No abstract available.
PMID: 4372169; UI: 75040295.
Haase AT, et al.
A comparison of the high molecular weight RNAs of visna virus and Rous
sarcoma virus. Virology. 1974 Jan;57(1):259-70. No abstract available.
PMID: 4362024; UI: 74130620.
Haase AT, et al.
Characterization of the nucleic acid product of the visna virus RNA
dependent DNA polymerase. Virology. 1974 Jan;57(1):251-8. No abstract
available. PMID: 4131957; UI: 74130619.
Boothe AD, et al.
Ultrastructural studies of a visna-like syncytia-producing virus from
cattle with lymphocytosis. J Virol. 1974 Jan;13(1):197-204. No abstract
available. PMID: 4129840; UI: 74086415.
Haase AT, et al.
Demonstration of a DNA provirus in the lytic growth of visna virus.
Nature New Biol. 1973 Oct 24;245(147):237-9. No abstract available.
PMID: 4127186; UI: 74023815.
Why are so many viruses crossing species, and creating deadly new
epidemics in modern times? The reader is encouraged to read the titles
and abstracts of a great many experiments such as the above. You will
not need a pHD in microbiology in order to gain a quite valid epiphany
on the subject.
Tom Keske
Boston, Mass.
