By John-Erik Stig Hansen.
John‐Erik Stig Hansen, M.D., D.M.Sc. is the Director of the National Centre for Biological Defence, Statens Serum Institut, Denmark.
Long before infectious diseases in the 19th century was recognized to be caused by microorganisms, disease was used as a weapon of war. Several accounts have indicated that water supplies were contaminated by throwing carcasses of animals or men in wells or that plague infested corpses were thrown into besieged cities. From the 18th century written sources indicate that British forces spread smallpox among Indians in North America by distributing unwashed blankets from an infirmary which resulted in a smallpox epidemic among the Indians.2 The first account of a biological attack may, however, be far older. The fifth and sixth plague that harassed the Egyptians of The Old Testament is described in Exodus, chapter 9, verses 1‐11:
1 Then the Lord said to Moses, "Go to Pharaoh and tell him: Thus says the Lord, the God of the Hebrews: Let my people go to worship me.
2 If you refuse to let them go and persist in holding them,
3 I warn you, the Lord will afflict all your livestock in the field‐‐your horses, asses, camels, herds and flocks‐‐with a very severe pestilence.
4 But the Lord will distinguish between the livestock of Israel and that of Egypt, so that none belonging to the Israelites will die."
5 And setting a definite time, the Lord added, "Tomorrow the Lord shall do this in the land."
6 And on the next day the Lord did so. All the livestock of the Egyptians died, but not one beast belonging to the Israelites.
7 But though Pharaoh's messengers informed him that not even one beast belonging to the Israelites had died, he still remained obdurate and would not let the people go.
8 Then the Lord said to Moses and Aaron, "Take a double handful of soot from a furnace, and in the presence of Pharaoh let Moses scatter it toward the sky
9 It will then turn into fine dust over the whole land of Egypt and cause festering boils on man and beast throughout the land."
10 So they took soot from a furnace and stood in the presence of Pharaoh. Moses scattered it toward the sky, and it caused festering boils on man and beast.
11 The magicians could not stand in Moses' presence, for there were boils on the magicians no less than on the rest of the Egyptians. The fifth plague (v. 1‐7) describes an outbreak of serious disease with high mortality among livestock. The sixth plague (v. 8‐11) describes a deliberate release causing disease among both animals and men characterized by festering boils. The mortality rate is not indicated but morbidity is at least so severe that the afflicted were incapacitated. This sixth plague seems to fulfill the criteria for a biological attack, but there are several uncertainties. First, it is uncertain which microorganism was used; second, it is unclear how the Israelites acquired the biological agent; and third, it is unknown why only the Egyptians and not also the Israelites were affected.
The microorganism of the sixth plague is naturally not identified in the text, so any identification will remain tentative. Apparently it is a microorganism that can be dispersed by air (v. 10: ‘scattered it toward the sky’) and that results in a skin manifestation (v. 10: ‘festering boils’). Most microorganisms which have not been modified through modern techniques of weaponization have a fairly low environmental stability especially in the climatic conditions ‐ heat, ultraviolet radiation ‐ that are natural to the Middle East. Sporulating bacteria like Bacillus anthracis are however endemic to the Middle East and these have an environmental stability that exceeds years.2 The symptoms described could fit with a number of infectious diseases caused by different microorganisms either contagious between humans or transmitted by vectors. However, if the mode of dispersal is taken into account, the environmental stability and the symptoms could indicate that the sixth plague was caused by Bacillus anthracis with a primary coetaneous manifestation. This disease is not contagious and has an untreated mortality of approximately 20%.4 After an open air dispersal of B. anthracis spores, a number of inhalation anthrax cases would be expected to occur among those that were exposed to particles in the range of 1‐5 micrometers, while those that were contaminated with spores on skin or clothes would be expected to present with symptoms of classical coetaneous anthrax: Papules of the skin especially in places of abrasion or small defects followed by painless ulcers with red rims and a black bottom (eschar), locally swollen lymph nodes and finally in severe cases septicemia and death. Naturally occurring anthrax infection is predominantly coetaneous, and even with the very finely manufactured anthrax powder used in the U.S. letter incidents in 2001 half of the disease cases presented with coetaneous anthrax.4 In the account of the sixth plague nothing is mentioned about secondary cases which would fit with non‐contagious anthrax, but neither is there any mention of a rapidly progressing pneumonia‐like illness, which would be expected after a deliberate air‐borne release of a B. anthracis aerosol resulting in inhalation anthrax. This latter omission may of course be due to a lack of detail in the account but it may also be due to a relative rarity of inhalational illness as would be the case if the particles in the antrax containing dust were too large to pass into the lower airways. In the account of the Exodus the dispersal is described as scattering fine dust into the air. Moses had acquired this fine dust from the soot of a furnace. The furnace in question is not described. However, if the account of the fifth plague – a disease killing the livestock – is combined with the biological attack of the sixth plague the possibility arises that the fifth plague was caused by anthrax infection of the livestock. Such anthrax outbreaks among wild as well as domesticated animals are well know also today both in the Middle East and elsewhere.2,4 Recurrent outbreaks of anthrax infection among wild bison in Canada were suggested to be caused by contamination from carcasses and from inhalation of aerosolized spores during wallowing or ingestion during grazing.6 It was also found that burning anthrax infected carcasses did not eliminate all of the anthrax spores, and even the smoke and steam above burning carcasses could possibly contain viable spores.2 If the anthrax infested carcasses of the livestock of the Egyptians to some extent were burned on open fires or in furnaces, incomplete destruction may have left intact anthrax spores in the remains or the ‘soot’ of the furnace. Such a source may well have resulted in larger particle sizes than the 1‐5 micrometers which is necessary for efficient inhalation but which could still cause coetaneous anthrax. As it is unlikely that Moses used modern personal protective equipment the reason why the anthrax containing soot did not affect Moses and Aaron and hit the Israelites as hard as the Egyptians may possibly be found in previously acquired immunity. This might be the case if the Israelites or at least Moses and Aaron had been exposed to B. anthracis previously either in low but still immunogenic concentrations insufficient to cause disease or if they had recovered from previous coetaneous anthrax illness. Such exposure is known to occur among people coming into contact with anthrax infected animals or environmental contamination.7 It has been suggested that anthrax infections were well known to the Israelites and that figs were used as a remedy against coetaneous infections.8 Selective immunological protection would of course also be possible for other microorganisms though not for any hypothetical chemical agent. In any case, from the description in Exodus it can be assumed that Moses had the wind in his back when he scattered the fine dust in the air and that this anthrax laden aerosol cloud drifted towards the Egyptians away from the Israelites thus by itself explaining why none of the Israelites ‐ except Moses and Aaron ‐ were exposed and became ill.
That the sixth plague of Exodus was a biological attack with anthrax spores, the first recorded in history, is not incompatible with current knowledge but is still a hypothesis. It is impossible to prove but may possibly be substantiated or not by further study of ancient scripture. However, whether or not Bacillus anthracis was the cause or some other agent was used, the account of the sixth plague, of Moses and the Egyptians, shows that biological warfare in the service of God resulting in mass destruction is not a modern invention by islamic radicals or immoral Cold War fanatics. Modern efforts to curtail the savagery of warfare through conventions and bans against weapons of mass destruction – and similar attempts of containment in the Middle Ages through development of Just War principles – happens on a background where weapons of mass destruction in Jewish‐Christian biblical tradition is placed by God himself in our hands to serve a higher goal. Religiously motivated terrorists, e.g. Al Qaida, may therefore have an ancient precedent for religiously justified mass destruction.
2 Robertson AG, Robertson LJ: “From asps to allegations: biological warfare in history.” Milit Med 1995; 160: 369‐73.
3 Hugh‐Jones ME, de Vos V: “Anthrax and wildlife.” Rev Sci Tech Off Int Epiz 2002; 21: 359‐83.
4 Inglesby TV, et al.: “Anthrax as a biological weapon”. In Bioterrorism: guidelines for medical and public health management, pp 63‐97. Edited by Henderson DA, Inglesby TV, O’Toole T. American Medical Association, 2002.
5 Titball RW, Turnbull PC, Hutson RA: “The monitoring and detection of Bacillus anthracis in the environment”. Soc Appl Bacteriol Symp Ser 1991; 20: 9S‐18S.
6 Dragon DC, Rennie RP, Elkin BT: “Detection of anthrax spores in endemic regions of northern Canada.”J Appl Microbiol 2001; 91: 435‐41.
7 Mwenye KS, Siziya S, Peterson D: “Factors associated with human anthrax outbreak in the Chikupo and Ngandu villages of Murewa district in Mashonaland East Province, Zimbabwe.” Cent Afr J Med 1996; 42: 312‐5.
8 Ben‐Noun LL: “Figs – the earliest known ancient drug for coetaneous anthrax”. Ann Pharmacother 2003; 37: 297‐300.