Scientists trace and identify origin of smallpox vaccine strains used in
Civil War

Date:
July 20, 2020
Source:
McMaster University
Summary:
Scientists and historians have pieced together the genomes of old
viruses that were used as vaccination strains during and after
the American Civil War ultimately leading to the eradication
of smallpox.



FULL STORY ========================================================================== Scientists and historians working at McMaster University, the Mu"tter
Museum and the University of Sydney have pieced together the genomes of
old viruses that were used as vaccination strains during and after the
American Civil War ultimately leading to the eradication of smallpox.


========================================================================== Smallpox was one of the most devastating viral diseases ever to
strike humankind, killing about three out of every 10 people who
were infected. Those who survived were frequently disabled, blind or disfigured.

The World Health Organization recently celebrated the 40th anniversary
of the eradication of smallpox, the most successful campaign ever
attempted. As researchers around the world work feverishly to develop a
vaccine against COVID-19, the success of the campaign and the findings
of this paper, outlined the journal Genome Biology, point to the value
of vaccination, say researchers.

They suggest other vaccines are waiting to be discovered among the viral relatives of today's influenza and coronaviruses.

"Understanding the history, the evolution and the ways in which these
viruses can function as vaccines is hugely important in contemporary
times," says evolutionary geneticist Hendrik Poinar, who is director
of the McMaster Ancient DNA Centre, where the work was done, and a
principal investigator at the university's Michael G. DeGroote Institute
for Infectious Disease Research.

"This work points to the importance of looking at the diversity of
these vaccine strains found out in the wild. We don't know how many
could provide cross protection from a wide range of viruses, such as
flus or coronaviruses," he says.

The concept of widespread vaccination dates back to 1796, when English physician Edward Jenner, known for his remarkable contributions to
medicine, observed that exposure to a milder illness (called cowpox)
thought to be transferred from cows with a similar pox-like illness on
their udders to milkmaids, offered protection against future smallpox outbreaks. However, the method and source material used for early smallpox vaccinations remained unstandardized for over a century. While "cowpox"
is often referenced as the source of the first vaccination, little had
been known about the specific origins and diversity of the virus strains
used in early smallpox vaccination programs For their study, researchers
used sophisticated techniques developed at the McMaster Ancient DNA Centre
to reconstruct and analyse the genomes of virus fragments recovered from vaccination kits used during the Civil War era.



==========================================================================
The kits, part of a medical collection at the Mu"tter Museum of the
College of Physicians of Philadelphia, contained lancets and small
glass plates for mixing fluid for vaccines that had been collected from blisters of deliberately infected subjects, and tin boxes with sliding
lids to contain scab material.

The techniques used in this paper resulted in the successful recovery
of viral molecules from both organic sources, such as scab material, but
also from the non-destructive sampling of inorganic materials, such as tin boxes and glass slides, that contained no evidence of organic residues.

This finding opens a new possible field of study into medical history
through the non-destructive examination of materials previously associated
with biological samples.

The researchers were able to determine that in the 1860s and 1870s,
medical practitioners in Philadelphia were using a vaccinia virus strain
that was still being propagated in human subjects. The milder relative
of the deadly smallpox pathogen was introduced into the body, usually by applying pus or scabs to a scratch or cut in the skin, where it helped recipients develop immunity to smallpox.

An overriding concern about vaccine design is how close -- from an
evolutionary standpoint- the vaccine strain must be to the one causing
disease in order to prevent illness. Here, the vaccinia strains used
for vaccination are in fact very distantly related to the virus that
causes smallpox. The slow mutation rate of orthopox viruses (of which
both vaccinia and variola are members) likely allows for this 'distant' protection.

"Vaccination is a wonderful process with a rich medical history that we
should celebrate," says Ana Duggan, a former postdoc in the Department
of Anthropology at McMaster, now at the Public Health Agency of Canada,
who was lead researcher on the study. "Medical museums are incredible repositories of our past and of our collective history. The new tools
we develop in this work allow us to begin to investigate how medical
sources, procedures and techniques have changed through time."

========================================================================== Story Source: Materials provided by McMaster_University. Original written
by Michelle Donovan. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Ana T. Duggan, Jennifer Klunk, Ashleigh F. Porter, Anna N. Dhody,
Robert
Hicks, Geoffrey L. Smith, Margaret Humphreys, Andrea M. McCollum,
Whitni B. Davidson, Kimberly Wilkins, Yu Li, Amanda Burke, Hanna
Polasky, Lowell Flanders, Debi Poinar, Amogelang R. Raphenya, Tammy
T. Y. Lau, Brian Alcock, Andrew G. McArthur, G. Brian Golding,
Edward C. Holmes, Hendrik N. Poinar. The origins and genomic
diversity of American Civil War Era smallpox vaccine strains. Genome
Biology, 2020; 21 (1) DOI: 10.1186/ s13059-020-02079-z ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200720093253.htm

--- up 5 days, 1 hour, 54 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)