A Scab Story

August 4, 2014 Karie Youngdahl

Man with smallpox, early 1900s, The Historical Medical Library of The College of Physicians of PhiladelphiaToday's blog post is by Robert D. Hicks, PhD, Director, Mütter Museum/Historical Medical Library, William Maul Measey Chair for the History of Medicine, The College of Physicians of Philadelphia.

The World Health Organization has been debating the future of smallpox. The debate concerns what to do with existing stocks of infectious smallpox virus given its eradication from the planet decades ago, one of the most significant public health achievements ever. Assuming a method could be devised to dispose of these smallpox stocks safely to avoid their being used as a terrorist weapon, can we be assured that all of it has been destroyed? Is destruction a good thing, since future technologies may be able to elicit from virus samples answers to fundamental questions about epidemic diseases, their origins, evolution, and treatment? What if possibly infectious samples of smallpox still exist . . . in museums and libraries?

In 2011, the Virginia Historical Society in Richmond displayed some “bizarre bits” from its collection, including a cigar once owned by Confederate President Jefferson Davis and an 1876 letter containing a smallpox scab.[i] The author of the letter, a son writing to his father, pinned to it a smallpox scab taken from the arm of a child, intending the scab to be used to inoculate up to a dozen persons. Visitors who saw the scab—or “crust,” in 19th-century parlance—became nervous and called the Centers for Disease Control and Prevention (CDC), who came calling in biohazard suits. Upon analysis of the specimen, biologists detected “virus from the smallpox vaccine” but without “the deadly disease virus itself.” CDC eventually returned the scab to Richmond following irradiation to ensure its safety.

Even if the scab did not present a threat, it furnished possible research value. “No one knows precisely which viruses were used in vaccines historically,” according to Dr. Inger Damon, Chief, Poxvirus and Rabies Branch, CDC.[ii] The smallpox scab, then, holds promise as a historic biomedical artifact of use to on-going epidemiological research. Once in the human body, smallpox—or variola—can become a stable and resilient virus and may survive the death of the host, but for how long and under what circumstances, no one knows. And scabs might be ideal biological time capsules. A sufferer’s body erupts in smallpox pustules; the pustules burst; blood clots at the pustule site; proteins form a net around the emerging scab, encapsulating the virus. Centuries ago, bits of scab were inserted into the bodies of live hosts via skin cuts in the hope that recipients would develop and survive a milder form of the disease, a technique called variolation. Upon recovery, the host human becomes immune to renewed smallpox infection.[iii]

The Richmond case was not the first. A librarian at the Fogelson Library, College of Sante Fe, New Mexico, found an envelope tucked into an 1888 medical treatise with a handwritten label identifying the contents as vaccination scabs collected from children, signed by the book’s author.[iv] The library consulted the National Museum of Civil War Medicine in Frederick, Maryland, for an explanation of the practice of vaccination during the 19th century and then contacted a forensic anthropologist who called the CDC. The FBI duly recovered the envelope and, after ascertaining that the sample was placed in the book during the19th century and not recently by a would-be terrorist, conveyed the scabs to the CDC and into the gloved hands of the redoubtable Dr. Damon. Although she thought that the viability of the scabs “highly unlikely,” Dr. Damon was excited to consider their value in drawing a “genetic portrait of the virus” in an evolutionary context.[v] Old smallpox scabs most likely are not a public health threat, then, but they very likely have research value in constructing a genomic lineage for the disease. Without these old survivals in museums and libraries, researchers would be limited to samples in laboratories including the oldest viable variola from 1939 in determining a lineage.[vi]

Outside of libraries and museums, archaeologists are encountering disease manifestations that might present an infection risk. Archaeologists examining 19th-century burials at Spitalfields, London, found “pustules and scabs on a desiccated body.”[vii] After World Health Organization officials descended on the site and vaccinated everyone associated with the excavation, they found that “no viable organisms” remained within the body. One researcher has found that hot and humid conditions militate against the survival of Variola major over time, the amount of virus particles dropping steeply after only a few years. Nevertheless, “[d]ried scabs may harbor viable smallpox viruses even after decades or centuries of interment.”[viii] In 2011, archaeologists in Queens, New York, uncovered a corpse of an African American woman of the 19th century with visible pustules, enclosed in a metal coffin, presumably intended to contain the disease.[ix] CDC analyzed tissue and found no virus remaining. What about the chance of survivability in corpses from frozen places? Says virologist Peter Jahrling, “I think it’s plausible to imagine that virus might exist in mummies in cold crypts.”[x]

In 2004, archaeologists excavating in Siberia located a grave of five 300-year-old frozen mummies. Preliminary analysis of tissue samples suggested sudden death due to disease.[xi] Molecular study of DNA in the tissue found much degradation in the samples. While the samples flagged no viability or infection risk, they may have furnished a hugely important historical insight. Smallpox virus comes in two major variants: Variola major, and Variola minor and other related strains from West Africa.[xii] The variola DNA in the corpse represented a strain that may date as early as AD120 or as late as AD928 and “could be a direct progenitor of modern viral strains or a member of an ancient lineage that did not cause outbreaks in the 20th century.”[xiii]

Museums, libraries, and archaeology institutions, then, should observe collections management policies that address possible disease-retaining biological matter. Although live smallpox virus has, by international agreement, been confined to two storage facilities, one in Russia and the other in Georgia at CDC, small quantities of smallpox surface even where handling protocols should be most stringent: the National Institutes of Health campus in Bethesda, Maryland.[xiv] There, a scientist cleaning out a storage area found vials of smallpox from the 1950s. The CDC subsequently determined that smallpox DNA can be identified in some of the vials; however, at this writing officials have not determined if the samples are live and present an infection risk. Although NIH, consequently, has undertaken an exhaustive inventory of all biological specimens within its care, eliminating a disease from the world and keeping it eliminated are no small tasks.

How does this all add up? Readers who are museum or library employees: If you find an early vaccination crust, call CDC. Ask that testing not destroy the sample, if possible, and if CDC declares no infection risk, ask what storage or display protocols ought to be observed with an irradiated, safe scab. Readers who are virologists, geneticists, or epidemiologists: Consider the bio-history of the sample and what it may say about the mutation of viruses over time and think of ways to use historical data to illuminate current infection patterns. Readers who are emergency responders: Don’t get too excited that a museum, library, or archaeology department has an old smallpox crust, but safely and non-destructively convey it to CDC and vaccinate everyone concerned. And don’t forget to blog about it.

Acknowledgment: I am grateful to Tom Fekete, MD, Section Chief, Infectious Diseases; Associate Professor, Microbiology and Immunology; and Executive Vice Chair for Clinical Affairs, Department of Medicine, Temple University, for information which contributed to this blogpost.


[i] Betsy McKay, “’Bizarre Bits’ Exhibition Took a Strange Turn When Feds Arrived,” The Wall Street Journal (on-line), May 19, 2011. Accessed July 23, 2014.

[ii] Ibid.

[iii] Sue Reardon, “Infectious diseases: Smallpox watch,” Nature 509, Issue 7498 (May 1, 2014), pp. 22-24; Accessed July 24, 2014.

[iv] “Century-old smallpox scabs in N.M. envelope,” USA Today, December 26, 2003. Accessed July 23, 2014.

[v] Ibid.

[vi] Reardon, “Infectious diseases.”

[vii] David A. Poirer and Kenneth L. Feder, Dangerous Places: Health, Safety, and Archaeology (Westport, Connecticut: Greenwood Publishing Group, 2001), p.98.

[viii] Ibid.

[ix] Reardon, “Infectious diseases.”

[x] Quoted in Reardon, “Infectious diseases.”

[xi] Philipe Biagini et al., “Variola Virus in a 300-Year-Old Siberian Mummy,” The New England Journal of Medicine 367:21 (November 22, 2012), pp. 2057-2059.

[xii] Ibid., p. 2057.

[xiii] Ibid., p. 2059.

[xiv] Lena H. Sun, Brady Dennis, “Smallpox vials, decades old, found in storage room at NIH campus in Bethesda,” The Washington Post, July 8, 2014. Accessed July 28, at http://www.washingtonpost.com/national/health-science/smallpox-vials-found-in-storage-room-of-nih-campus-in-bethesda/2014/07/08/bfdc284a-06d2-11e4-8a6a-19355c7e870a_story.html..