9:3 שמות
הִנֵּ֨ה יַד־ה׳ הוֹיָ֗ה בְּמִקְנְךָ֙ אֲשֶׁ֣ר בַּשָּׂדֶ֔ה בַּסּוּסִ֤ים בַּֽחֲמֹרִים֙ בַּגְּמַלִּ֔ים בַּבָּקָ֖ר וּבַצֹּ֑אן דֶּ֖בֶר כָּבֵ֥ד מְאֹֽד׃
Behold, the hand of the Lord is upon thy cattle which is in the field, upon the horses, upon the asses, upon the camels, upon the oxen, and upon the sheep: there shall be a very grievous plague.
Scientific Explanations of the Ten Plagues
There is a fascinating explanation on this pasuk from Rabbi Yehuda Ayyash (1688–1760) who lived in Algiers, and served as rabbi of the city. He eventually made his way to Jerusalem although his lengthy work, Vezot Leyehuda was published in Sulzbach, Germany in 1776. It included a commentary on the Pesach Haggadah, in which Rabbi Ayyash asked why, when God threatened Pharaoh with the plague of pestilence [dever] the Torah used the specific words found in our parsha: “ . . . the hand of the Lord will strike cattle which is in the field” (Exodus 9:3). It would surely have been obvious that cattle, which generally spend time outside in fields, would be smitten with the plague there, in those same fields.
To explain why this location—the fields—was specifically mentioned, Rabbi Ayyash reminded his readers of the etiology of plagues, or what today we might call their scientific explanations. They were believed to have been caused by foul air, or miasmas, which poisoned those who breathed it. Therefore, when a plague struck, it was best to flee to a place where the air was clean of these poisonous vapors, and this often meant leaving the confines of one’s home and living in open fields.
Yehudah Ayyash, Vezot L’Yehudah. Sulzbach 1776. 58a column II.
It was important to note that in a pandemic [magefah] most of the sickness is caused by poisonous air and foul smells. Therefore, many people flee to the fields and orchards and meadows, open spaces where there is no foul air, but instead the air is pure and clean and sweet . . . And it is here that the Egyptians were forced to acknowledge the hand of God and his providence, because they realized that these deaths were not natural . . . for they occurred in the fields and not inside, which is the opposite of what usually happens. This is the hand of God and there is none like Him.
This account was published some two centuries before a rational etiology of the Ten Plagues became a topic of scientific interest. and it demonstrated that even traditional Jews turned to the scientific theories of their time as a starting point for understanding the significance of biblical miracles. Although Rabbi Ayyash understood the plague of pestilence as a supernatural event and a reversal of the natural order, it could only be understood as such using the widely accepted theory of miasmas to explain how it miraculously everted the natural order.
Academic scholars generally do not view the Bible as the word of God given at Sinai. Instead, it is a collection written and edited over hundreds of years, starting around the tenth century B.C.E. and ending sometime in the fifth. What natural events, these scholars have asked, might explain the Ten Plagues? Over the last sixty years there have been a number of different theories, each describing a scenario in which one plague causes the next, and each has a rational explanation. As we discuss some of the purported scientific explanations for the miraculous Ten Plagues, it is worth remembering it was not just academic scholars, historians, and scientists who used the best contemporary theories to make sense of the biblical account of the plagues. Deeply religious Jewish thinkers like Rabbi Ayyash did the same long before.
It begins with Silt, and ends with ANTHRAX
Writing in 1957, Greta Hort suggested the plagues began with silt that was washed into the Nile from one of its flooded tributaries. The river was overrun, with bacteria which caused the fish to die. As a result, “the frogs would have to leave their normal biotope and seek refuge on dry land.” However, the frogs themselves died from anthrax, one of those bacteria that bloomed in the Nile. The plague of “lice” was actually a mosquito infestation, and the fourth plague, a swarming of fleas, “is the sudden mass multiplication of some insect or other and its just as sudden disappearance, as it is known to everyone who has lived for any length of time in tropical or subtropical regions.” The decimation of the cattle was caused by their ingesting fodder contaminated with the same anthrax that killed off the frogs. When the anthrax bacillus later infected the Egyptians, it caused the skin pustules described in the sixth plague. Hort’s series of unfortunate events stops at this plague; she postulated that the last four plagues were not interconnected.
Or maybe mold
More recently, other microbes responsible for the plagues have been suggested. Perhaps it was not anthrax, but by a tiny single-celled protozoon which goes by the scientific name of Trypanosoma evans and causes disease in cattle, or the rove beetle, which produces a blister-inducing toxin. Perhaps molds played a part. They would have grown quickly in the wet and humid conditions of Egypt’s grain stores, where they released dangerous mycotoxins. In biblical times (and long beyond), firstborn sons were always treated more favorably. Maybe, “during the famine that must have followed the previous plagues, any little food that might have remained inside the houses would have been given to the firstborn. Such food would have been moldy and toxic in view of the rain, hail, and darkness.” In the mold theory, the victims of the tenth plague were killed by the very prejudices of a society that had favored them.
Or the weather
Another telling lays the blame not only on bacteria or molds but on something with which we are all too familiar—climate change, or more specifically, an “unseasonable and progressive climate warming along the eastern Mediterranean coast where Israelites worked in forced labor.” It all began with a change in the weather over the eastern Pacific Ocean, which today we call the El Niño effect. This in turn heated the Mediterranean and the atmosphere over Africa. The Nile waters warmed to a critical temperature, which allowed a massive red algae to bloom. This was described as the plague of blood. The river then became uncomfortably warm for the frogs, who fled to dry land, where they later died and spread disease. The third plague, lice, was caused by a rise in the population of small insects that enjoyed the unusual wet and humid conditions. Then came the larger fleas and biting flies of the fourth plague “having hatched in soil heavily polluted with animal urine and feces.” The fifth plague that killed Egypt’s livestock was due to infections like the Rift Valley Fever Virus and West Nile Virus, both having been spread by mosquitos enjoying the unusually warm and moist climate. Other fly larvae burrowed into the skin and were responsible for the boils inflicted on the Egyptians and described in the sixth plague. The last four plagues were also consequences of the El Niño effect. As the warm moist seas air collided with the cooler inland air, violent storms with hailstones resulted. These same storms and high winds then carried huge swarms of locusts into Egypt; as they subsided, a dense fog settled, caused by the sudden condensation of moisture. This was described in the Torah as the penultimate plague of darkness. Once again, these conditions were perfect for the mosquitos, which this time spread viral diseases into the Egyptian human rather than the animal population. Older Egyptians would have been immune, having already been infected in previous years but the younger population, which of course included the firstborn, were not so lucky. In this, the final plague, they died in large numbers.
Or Volcanoes
There is another natural explanation for the biblical plagues in Egypt. Volcanos. This was first suggested in 1940 by a father-son pair of British archeologists who theorized that a volcanic eruption along the rift valley in central Africa led to a series of ecological changes, which resulted in the plagues. The theory was criticized soon after its publication not because of its vulcanology but rather its geography: a volcanic eruption in central Africa would send lava south rather than north toward the Nile. This problem was addressed in 1964 when a German researcher suggested a new volcanic site. Around 1600 B.C.E. there had been a massive eruption that destroyed the Aegean island of Thera. It was this eruption, and not one in central Africa, that was the proximate cause of the ensuing plagues. The Aegean eruption was also offered as an explanation of the plagues in a recent book by Barbara Sivertsen. It was too far away, she notes, to have been seen in the Egyptian delta, though perhaps the people there “noticed a clattering or shattering of some of their pottery as a wave of air seemed to rush past.”The tsunami that followed the eruption flooded the Delta and contaminated the normal supplies of drinking water. Iron dust from the volcanic eruption settled in the water and was taken up by iron- eating bacteria, which in turn excreted large amounts of organic nitrogen. This nitrogen stimulates the “massive growth of toxic dinoflagellates and results in a red tide two or three months after the original dustfall.”It was this chain of events that turned the water red. Sivertsen further suggested that an echo of the plague of Blood might be found in an Egyptian text known as the Admonitions of Ipuwer: “Lo, the river is blood. As one drinks of it one shrinks from people and thirsts for water.”
The contamination of the water left it uninhabitable, and the amphibians were forced to leave, which resulted in the plague of frogs. The third plague, lice, was actually a dust storm in which fine volcanic ash reached the Delta.
Over the centuries, as the story was remembered and misremembered, the dust from the sky became lice from the ground. “The first light ashfall was not dense enough to produce darkness,” Sivertsen explained. “It was only dense enough to be perceived as dust— an acid-bearing dust, irritating the skin of man and beast, like gnats or lice or mosquitos biting. In time, the modifier “like” would be dropped from the oral tradition . . . and the dust was transformed into small biting insects.” The same oral tradition might have embellished the small insects and turned them into the large flying insects of the fourth plague. That, or the insects swarmed and invaded Egyptian homes as the ash “blocked their tra- cheal tubes and hindered their ability to fly.” This falling ash killed the livestock that could not be sheltered indoors and caused the blisters, described in the fifth and sixth plagues. This would explain the biblical connection between hot soot and the plague of blisters and boils: “Then God said to Moses and Aaron, ‘Take handfuls of soot from a furnace and have Moses toss it into the air in the presence of Pharaoh. It will become fine dust over the whole land of Egypt, and festering boils will break out on men and animals throughout the land.’” The seventh plague of hail was an aggregation of cyclonic storms and ash from the eruption. The next plague, locusts, had nothing to do with volcanos, but was an ordinary perhaps even expected occurrence in the Egyptian Delta. It was remembered as an especially severe outbreak and was incorporated into exodus story. The ninth plague of darkness is readily explained by the huge clouds of volcanic ash, but rather disappointingly Sivertsen stops here. She makes no attempt to explain the etiology of the final plague, the death of the firstborn: “ . . . from the firstborn son of Pharaoh, who sits on the throne, to the firstborn of the slave girl, who is at her hand mill, and all the firstborn of the cattle as well.”
“שָׁ֭לַח מֹשֶׁ֣ה עַבְדּ֑וֹ אַ֝הֲרֹ֗ן אֲשֶׁ֣ר בָּחַר־בּֽוֹ׃
שָֽׂמוּ־בָ֭ם דִּבְרֵ֣י אֹתוֹתָ֑יו וּ֝מֹפְתִ֗ים בְּאֶ֣רֶץ חָֽם׃
שָׁ֣לַֽח חֹ֭שֶׁךְ וַיַּחְשִׁ֑ךְ וְלֹֽא־מָ֝ר֗וּ אֶת־[דְּבָרֽוֹ] (דבריו)׃
הָפַ֣ךְ אֶת־מֵימֵיהֶ֣ם לְדָ֑ם וַ֝יָּ֗מֶת אֶת־דְּגָתָֽם׃
He sent Moshe his servant; and Aharon whom he had chosen. They performed his signs among them, and wonders in the land of Ḥam. He sent darkness, and made it dark, and they did not rebel against his word. He turned their water into blood, and slew their fish.
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How many plagues were there, really?
Despite the importance of the plagues to the Exodus story, nowhere in the Bible are they listed as being “ten.” When they are mentioned in the book of Psalms, which they are, twice, they are reduced to only seven in number. In Psalm 78, no mention is made of lice and darkness; in Psalm 105 darkness is mentioned as the first plague, not the ninth. This suggests that there had been different traditions about both the number and the nature of the plagues, which were later unified in the account found in Exodus. In light of these different accounts, it is difficult to give credence to any of the differing attempts to explain the natural causes and order of the Ten Plagues, no matter how imaginative they are.
Regardless of which of these highly conjectural explanations might be correct, the Bible would have described the plagues in terms that would resonate with those who first read it. Those for whom the story was first written would have recognized many features of the plagues described in the book of Exodus. They would have nodded their heads at the accounts of lice infestations, skin boils, and sudden deaths, for they were also features of their own lived experience. The Ten Plagues included both natural disasters and epidemics, which, just as they do today, claimed lives in a capricious and random way. The formation of the Children of Israel took place in a crucible of disease.
Excerpted from The Eleventh Plague; Jews and Pandemics from the Bible to COVID-19 (Oxford University Press 2023).
