Two items appear below:
1    The Ten plagues of Egypt
2    For a Smoother Life Use Oil


(Investigator 78, 2001 May)



The Ten Plagues of Egypt as described in the Bible would have killed about 20% of Egypt's 3,000,000 people.

In 1996 two American researchers explained the Plagues as natural events occurring in a falling domino effect. Their work was publicised on a website – Plaguescape – and in a TV documentary The Ten Plagues of Egypt.

Dr John S Marr is former chief epidemiologist for the New York City Department of Health. Curtis D Malloy, also an epidemiologist, has a degree in Medical Research.

They treated the Plagues as an epidemiological puzzle with rational causes. Scientific disciplines consulted included marine biology, entomology, epidemiology, herpetology (frogs), infectious diseases, tropical medicine, animal virology, theology, Egyptology.

Ancient Egypt was a hierarchical society based on agriculture dependent on the River Nile. Its main city was Memphis south of present-day Cairo.

The Israelite slaves – if the Bible is correct about Israelites building cities in Egypt – lived in Goshen, the Nile Delta, 100km north of major Egyptian settlements.

Bible chronology puts Moses and the Plagues in the 15th century BC. In Exodus Chapter 4 God told Moses to command Pharoah of Egypt to: "Let my people go." Pharoah remained stubborn and so the Plagues struck–one after another.



The First Plague turned the Nile River red but left groundwater unaffected:

…all the water that was in the Nile turned to blood. And the fish in the Nile died; and the Nile became foul…
And all the Egyptians dug water round about the Nile for water to drink, for they could not drink the water of the Nile. (Exodus 7:20-24)
Algal blooms, toxic to fish, are known in seawater. They release red pigment causing "red tides" and kill fish in millions. According to the TV program, no red-tide algae that would survive in fresh water were known until 1996. This is not strictly accurate:
Freshwaters also sometimes produce red blooms of dinoflagellates, and in the Lago ti Tovel in the Trentino region of Italy these are sufficiently striking to provide a tourist attraction. (Fogg 1975 p. 108)
Another example of freshwater red tides is Lake Ikeda south of Kagoshima on Kyushu.

In 1996 a new environmental disaster struck rivers in North Carolina, USA. A billion fish died – their flesh covered in deep sores. The fish were bulldozed from beaches. Dr JoAnn Burkholder, Professor of Aquatic Botany and Marine Sciences at the North Carolina State University, identified the cause – Pfiesteria piscidia a dinoflagellate.

Dinoflagellates belong to the Kingdom of Protista defined as: "eukaryotic organisms that are not plants, animals or fungi." The Protista include over 10,000 species of algae. Algae in turn include dinoflaggelates – single-celled organisms propelled by whipping movements of one or two threadlike flagella. Dinoflaggelates include plant-like groups that photosynthesize and animal-like groups whose nutrition is "heterotrophic". Pfiesteria are heterotrophic.

When in bloom Pfiesteria secrete neurotoxins. Five water-soluble and lipid-soluble toxins that enter the water, stun fish, and dissolve their flesh have been identified. Clams, oysters and mussels survive but concentrate the toxins and may kill humans if eaten.

Pfiesteria could have caused the first Plague. Blood leaking from dying fish and red pigment released by some strains of the algae could have turned the Nile red.

Pfiesteria can also hurt humans via air-borne toxins. Laboratory workers experienced kidney and liver problems, joint and muscle aches and severe head-aches. In New Scientist Burkholder said:

I lost eight days of my life. It's like the tape was erased… I doubled over, had severe stomach pains, muscle cramping and asthma-like symptoms when the drugging effect wore off… I'm on antibiotics 200 days a year… I've been told that three of the five people badly hurt have had sporadic but serious multiple-sclerosis-like symptoms. (Pain, 2000)
Dinoflagellates mainly occur in tropical waters. Therefore, if they explain Plague One it suggests a period of prolonged warm weather in Egypt.


Plague Two was "frogs":

…the Nile shall swarm with frogs which shall come up…into the houses of your servants and of your people, and into your ovens and your kneading bowls; the frogs shall come up on you and on your people and on all your servants. (Exodus 8:3-4)
Marr and Malloy consulted Dr. Richard Wassersug an authority on amphibians at the Department of Anatomy and Neurobiology at Dalhousie University, Halifax, Canada.

The word translated "frogs" includes toads. The genus Bufo is widespread. In some species individuals produce large clutches – thousands – of eggs.

With no fish to feed on the eggs, toads by billions would hatch and then abandon the toxic river. Many would have headed for warmth and light – hence houses and ovens.

The toads came "upon the land of Egypt." (Exodus 8:5) This does not mean they crossed the Sahara Desert. Most Egyptians lived in the cultivated areas within several kilometres of the Nile River. The toads, therefore, did not travel far.

Away from their normal river habitat the toads then died:

And they gathered them together in heaps, and the land stank. (Exodus 8:14)
The decline in toads would release insect populations from constraints.


Plague Three:
…there came gnats on man and beast; all the dust of the earth became gnats throughout all the land of Egypt. (Exodus 8:17)
Gnats – other translations say "lice” – do not thrive in Egypt. Also no lice are known that attack both "man and beast”. Classification of insects started long after Moses. The Hebrew word for gnats or lice could therefore refer to any of numerous insect species.

By considering the Ten Plagues as a related whole, and by seeking a cause for Plague Five that killed livestock, the "gnats" of Plague Three are identified as the genus Culicoides – comprising over 1500 species of midge. Culicoides not only account for Plague Three but some species also spread a virus that explains Plague Five. (See below)

Some Culicoides species go from animal to animal and some bite humans too causing severe itch (e.g. Australians know about "sandflies”). Their flight, however, is limited to about 50 metres. The Israelites in Goshen being about 100km from major Egyptian population centres may have been less affected.

Many Culicoides thrive around stagnant water with decaying vegetation and animal matter. Larvae feeding on this would produce plague numbers of adults.

Pharoah's magicians copied – doubtless in a minor way – the first two plagues but not the third.  (7:22; 8:7; 8:18)  Perhaps they could not design an impressive conjuring trick using the tiny midge!


The first three plagues hit both Egyptians and Israelites. Not so the fourth:

I will send swarms of flies on you and your servants and your people, and into your houses; and the houses of the Egyptians shall be filled with swarms of flies, and also the ground on which they stand. But on that day I will set apart the land of Goshen, where my people dwell, so that no swarms of flies shall be there… (Exodus 8:21-22
Here Marr and Molloy assume the "flies" bit or stung people. This is unstated but perhaps implied since: "…in all the land of Egypt the land was ruined by reason of the flies."

Dr Andrew Spielman of Harvard helped Marr and Malloy eliminated as possibilities:

The Stable Fly however fits. In an area of introduced cattle and horses, stable flies might explode in number. They lay up to 500 eggs – more than any other fly – and deliver painful bites!

So if we assume biting insects – the Stable Fly fits. Its flying range is one kilometre. It also spreads a disease that would account for Plague Six – see below.


Plague Five affected hoofed animals and camels:

…the hand of the Lord will fall with a very severe plague upon your cattle which are in the field, the horses, the asses, the camels, the herds, and the flocks. But the Lord will make a distinction between the cattle of Israel, so that nothing shall die of all that belongs to the people of Israel. And the Lord set a time, saying, "Tomorrow the Lord will do this thing in the land." And on the morrow the lord did this thing; all the cattle of the Egyptians died, but of the cattle of the people of Israel not one died. (Exodus 9:4-6)
Plum Island off the coast of Connecticut used to be the storage facility of Earth's deadliest diseases being studied by the US Army. Today it's a facility of the US Department of Agriculture and is called the USDA Animal Research Center.

The director Dr Roger Breeze, an animal virologist, eliminated various diseases Exodus 9:4-6 could not refer to:

African horse sickness is a virus that infects horses, mules and asses but not ruminants like cattle and camels that Exodus specifically mentions. Up to 95% of infected horses die and 50% of mules. The virus grows in cells lining the blood vessels throughout the body. Infected cells deteriorate and fluid and blood flood the lungs. The animals drown in their own fluids. It can happen quickly – animals that look healthy can be dead two hours later. African horse sickness is endemic to central/tropical Africa with occasional outbreaks in North Africa, Spain and Western Asia.

A related virus called Blue-tongue affects ruminants such as cattle, sheep and goats. It attacks small blood vessels and hinders blood flow.

 Both viruses – African horse sickness and Blue-tongue – occurring together fit Plague Five.

Both viruses are spread by the same insect carrier, a midge called Culicoides. The midge can multiply explosively during prolonged wet weather. Humans are bitten but do not get the diseases – although repeated bites cause large itchy spots.


Plague Six was:
…boils breaking out in sores on man and beast throughout the land of Egypt. (Exodus 9:9)
Both humans and beasts were infected – ruling out bubonic plague, herpes and small pox. Leishmania tropica causes skin lesions resembling boils, occurs around the Mediterranean and its vector or carrier occurs in Egypt. However, L. tropica does not infect hoofed animals.

Dr Malloy came up with an obscure bacterial infection called Glanders. Glanders infects horses, sheep and pigs, as well as humans. It causes boils and could be carried by Stable Fly – see Plague Four.

Glanders makes lymph nodes swell and suppurate and causes chronic, progressive conditions that often lead to death.

Most Egyptians would now have been too sick to work. Also Plagues One and Five reduced fish and animals. Hunger would have stalked the land.


Plague Seven made food even scarcer:

…there was hail, and fire flashing continually in the midst of the hail, very heavy hail, such as had never been in all the land of Egypt since it became a nation

The hail struck down everything that was in the field throughout all the land of Egypt, both man and beast; and the hail struck down every plant of the field, and shattered every tree of the field. Only in the land of Goshen, where the people of Israel were, there was no hail. (Exodus 9:24-25)

"All the cattle of Egypt had died" in Plague Five. Yet "beasts" were struck by hail in Plague Seven. The "beasts" struck by hail must have been different animals to those that died in Plague 5. Alternatively the Egyptians may have obtained new cattle after Plague 5 from the Israelis.

A hailstorm in Israel and Jordan in October 1997 injured 60 people. In Jordan the hail was a metre deep. I possess Israeli postcards showing Jerusalem and Bethlehem in thick snow. Egypt is further south and hail would be rarer but possible.

The hail was the worst "since it [Egypt] became a nation" – hence the sort of storm that occurs once in thousands of years.

The hail ruined the flax and barley but spared the wheat and spelt. (9:31) Why? Because "the barley was in the ear and the flax was in bud." The hail must have struck at the barley harvest time – February. Wheat and spelt, however, were harvested in March/April. The next plague, however, took care of that.


Plague One – dinoflagellates turning the water red – suggests prolonged warm weather. Plague Seven was the opposite extreme – the worst of hailstorms. It seems that the Ten Plagues occurred at a period of climatic instability. This may be relevant for Plague 8 – locusts – because climate is a factor in the stability or otherwise of insect populations. (Sugihara, 1995)

Plague Eight – the greatest locust plague ever – would have devastated what meagre food supplies were left:

And the locusts came up over all the land of Egypt, and settled on the whole country of Egypt, such a dense swarm of locusts as had never been before, nor ever shall be again. For they covered the face of the whole land, so that the land was darkened, and they ate all the plants in the land and all the fruit of the trees which the hail had left; not a green thing remained, neither tree nor plant of the field, through all the land of Egypt. (Exodus 10:14-15)
Locust plagues of great size are rare:
In 1968, one of the most terrible plagues in recorded history struck the ancient kingdoms of Egypt, the Sudan, Ethiopia, Somaliland, and Eritrea. Five Sudanese provinces with a total of more than 200,000 square acres were infested with giant swarms of hopping, flying, chirping insects… Poor farmers watched helplessly as the sky turned black with clouds of flying locust. Literally millions of the hungry pests settled down on fields and trees, devouring everything in sight… (Cornell, 1972)
Egypt's people, already weak from lack of protein and disease, now faced starvation! They would have hastily competed with the locusts and picked whatever crops they could and stored them underground. Locust faeces and dead locusts would have contaminated such stores. And this storage, according to Marr and Malloy, prepared Plague Ten. How?

In Cleveland, 33 babies in four years got a rare lung disease. Dr Eduado Montano of the Atlanta Centre for Disease Control identified a toxic black mould or fungus found in water-saturated wood. All the homes of the infected babies had water damage in the basement and the presence of a black slimy mould.

The black mould Stachybotris atra releases "mycotoxins" – chemicals carried on fungal spores and which can be inhaled. Under exact conditions they reach dangerous levels with lethal results such as capillary breakdown and bleeding in the lungs.

S. atra grows on cellulose – including grains and cereals. If it grew on the damp, hail-surviving, contaminated Egyptian grain it would be dangerous!


Plague Nine was darkness so dense that people stayed indoors:

…there was thick darkness in all the land of Egypt three days; they did not see one another, nor did any rise from his place for three days; but all the people of Israel had light where they dwelt. (Exodus 10:22)
Darkness lasting "three days" means it wasn't an eclipse. Desert sand storms called "Casheen" can cause darkness for days and literally bury houses, monuments and agricultural land.

Layers of dust warming the food stored in humid, underground pits would help make it mouldy.

The Israelites, however, had light – the sandstorm evidently did not reach to Goshen.


Plague Ten was the death of all the first-born:

At midnight the Lord smote all the first-born in the land of Egypt, from the first-born of Pharaoh who sat on the throne to the first-born of the captive who was in the dungeon, and all the first-born of the cattle. (Exodus 12:29)
Imagine crops wet from hail, contaminated with locust faeces, stored underground and warmed without ventilation under layers of sand.

Moulds that grow on food would have proliferated. Some moulds (such as S. atra) produce potent "mycotoxins" that can kill humans and animals.

The Egyptians already malnourished and sick and kept indoors for three days by the sandstorm would then probably have raided the granaries.

The people who entered the granaries first and/or ate first would be the dominant and socially powerful. These would have inhaled airborne mycotoxins released by the fungi or been poisoned directly by eating. S. atra can kill within hours by internal bleeding into lungs and intestines. After the surface layers of food were used the layers below would be less lethal. Consumption of beer made from tainted grain could also have killed selectively – high-status people would drink first or, if supplies were short, be the only ones to drink.

Similarly with the animals: Either the dominant animals would have been selectively fed to save them or the dominant animals would eat first of their own accord.

The deaths of the first-born and dominant of humans and animals would have had no obvious cause – except as an act of God!

Mycotoxins alone, however, would not have killed every first-born while sparing everyone else. At best there would be a higher proportion of first-born killed than of other groups – a big enough difference so it would seem as if only the first-born died. If the Bible literally means that every first-born, and only the first-born, died then the natural explanation by itself is inadequate – we need the supernatural.


Moses turned 80 prior to the Ten Plagues. (Exodus 7:7) After the Plagues the Israelites lived in the desert for 40 years. (Exodus 16:5) Moses died at 120. (Deuteronomy 34:7)

The Plagues fit into this time frame if Moses turned 80 just before they started and if he died shortly before turning 121. This would allow almost one year for the Plagues. [The 40 years in the desert were exactly 40 years – See Exodus 12:1-6; 16:1; Deuteronomy 1:3; 32:48-50; 34:8]

Plague One (Nile River to Blood) lasted seven days (7:25) after which Moses went to Pharoah and Plague Two (Frogs) started. If algal blooms caused Plague One the most likely time would be when the Nile was at its lowest, most sluggish, phase – in June or early July. Prior to the Aswan Dam the Nile water level used to start rising in July and reach its peak in October. Moses announced Plagues One, Four and Seven when Pharoah went to the Nile presumably for his morning bath. This suggests that the increased water flow of July had cleaned away the first plague – so Plague Four (Stable Fly) would have struck after that.

Plague Nine (Darkness) lasted three days. (Exodus 10:22) Plague Five (Death of Livestock) occurred one day after its announcement. (Exodus 9:5) The delay between announcement and occurrence of Plague Ten was two weeks. (Exodus 12:1-13) Also, from Plague Seven (the February Hailstorm) to Plague Ten – on the 14th of the Jewish month of Nisan corresponding to March/April – would be about six weeks. (Exodus 12)

Locusts change from the solitary phase, when they behave like harmless grasshoppers, to the migratory, destructive phase under ecological factors that include ground moisture and humidity. Subject to how long the change takes (I could not find this out) the Hail Plague may have prepared the conditions for Plague Eight (Locusts).

If Moses returned to Goshen after each plague we'd have to count his travel time. But it's not certain he did this. We read of Moses "rising up early in the morning and waiting for Pharoah" (8:20) but are not told of travel distances. Moses announced plagues One, Four and Seven when Pharoah went to the Nile. (7:15; 8:20; 9:13) The other announcements were probably in Pharoah's palace since Moses went "in" and "out" – 8:12; 9:1; 10:1, 3, 6, 8, 11, 16, 18.

By my analysis the Ten Plagues struck between June and April – a nine or ten month period.


The Ten Plagues, by the Marr/Malloy explanation, were a rare sequence of natural events. Yet, Moses' appearances before Pharoah were perfectly orchestrated with the Plagues. It's like those movie scenes where someone about to be executed knows a solar eclipse is about to occur and wins his release by pretending to magically darken the sun!

The Ten Plagues therefore – if the scientific explanation moves us to accept the story – imply a behind-the-scenes-intelligence informed enough to direct Moses to act in perfect synchronicity with nature to achieve political and religious goals.


Alward, Joseph Francis 1998 The Murrain and Hail Plagues, Internet, October 27, 1998.
Cornell, J C  1972 Strange Sudden & Unexpected!, Scholastic Book Services; Australia. p. 87
Fogg, G E 1975 Algal Cultures and Phytoplankton Ecology, University of Wisconsin Press; USA p. 108.
Imms, A D 1967 Outlines of Entomology, Chapman & Hall, London.
Marr, J S and Malloy, C D Plaguescape (Internet Website)
Matthews, R  Science explains the wrath of God, Ottawa Citizen, August 19, 1998.
Pain, S  Scary monsters super creeps, New Scientist, June 3, 2000, pp. 43-45.
Sugihara, G  From out of the blue, Nature, Volume 378, December 7, 1995, pp. 559-560.
The Bible Revised Standard Version, 1952, Wm. Collins Sons & Co. Ltd., for The British Foreign Bible Society, Great Britain.
The Ten Plagues of Egypt. TV documentary on SBS, Australia, November 27th, 1999.


Frank Russo

(Investigator 93, 2003 November)

Although Anonymous did a good rendition of the Biblical Plagues of Egypt (Investigator 2001 May) I'm sure he would appreciate some slight elaboration.

To the ancient Jews olive oil represented 'the Spirit of God'! They were obsessed with oiling their skin.

This may be an additional explanation why the insects, during the plagues of Egypt, went for the Egyptians and not the Jews! I mean what would a blood-sucking insect prefer –  a good feed of whole-blood from Egyptian skin or bland olive-oil from Israelite skin?

In Australia, too, outdoor workers bothered by sandflies and lacking insect repellent sometimes apply vegetable oils for protection.

Oiling the skin also dispensed with the body-odour that characterizes our existence today! The ancient Israelites therefore needed to wash their clothes only infrequently.

The Israelites were instructed to oil most items in the Tabernacle such as leather scrolls. This would act to preserve them. Oiling may also explain why during the 40 years in the wilderness many things did not wear out.

For more of my research and insight, go to my website:

The Bible explained scientifically on this website: