Plague occurred frequently in Egypt during the years b.c., and was also fairly common in Pal., esp. in Philistia, along the seacoast. Terrible outbreaks also occurred in Asia and Europe. In the 14th cent., plague, called Black Death, swept across Europe and killed an estimated 25,000,000 people, or one-fourth of the entire population. Even as late as 1907, 1,316,892 persons were reported from world-wide sources as having died from plague.
In the years before modern medicine, there was no known cure for plague. People did learn, however, that if rodents were drastically controlled, and fleas were discouraged by cleanliness, the spread of plague could be slowed down. Today there are medicines that usually cure the infected person if given promptly after symptoms first appear. Furthermore, vaccines are effective.
In Leviticus 13 and 14 (KJV) the word plague is used loosely for almost any kind of skin rash. It was the duty of the priests to determine whether the condition was relatively harmless, or required isolation.
The ten plagues in Egypt did not include plague as a disease entity. Attempts have been made to show that these plagues were really accentuated but otherwise normal phenomena to the Egyptians. Thus the bloody Nile is said to have received its appearance from an exceptionally large content of red clay silt, and that the three days of total darkness were only blinding dust storms. It is more reasonable to accept the record of the visitations as just plain miracles.
The horrible plagues experienced by the Hebrews during their Sinai Desert journey (Num 14:37; 16:47; 25:9) could well have been plague in its true medical sense.
When the Ark was returned from Ashdod and other Philistine cities, after the inhabitants had suffered many deaths, probably due to plague, gold mice and tumors were presented to the Hebrews (1 Sam 5). The Heb. word for mice and rats is considered to be the same, and the tumors could well have been representative of the enlarged glands, or buboes, observed in plague.
Note that in Mark 3:10 (KJV) plague is used as a synonym for diseases.
International Standard Bible Encyclopedia (1915)
This word which occurs more than 120 times is applied, like pestilence, to such sudden outbursts of disease as are regarded in the light of divine visitations. It is used in the description of leprosy about 60 times in Le 13 and 14, as well as in De 24:8. In the poetical, prophetic and eschatological books it occurs about 20 times in the general sense of a punitive disaster. The Gospel references (Mr 3:10; 5:29,34; Lu 7:21) use the word as a synonym for disease.
The specific disease now named "plague" has been from the earliest historic times a frequent visitant to Palestine and Egypt. Indeed in the Southeast between Gaza and Bubastis it has occurred so frequently that it may almost be regarded as endemic. The suddenness of its attack, the shortness of its incubation period and the rapidity of its course give it the characters which of old have been associated with manifestations of divine anger. In the early days of an epidemic it is no infrequent occurrence that 60 per cent of those attacked die within three days. I have seen a case in which death took place ten hours after the first symptoms. In the filthy and insanitary houses of eastern towns, the disease spreads rapidly. In a recent epidemic in one village of 534 inhabitants 311 died within 21 days, and I once crossed the track of a party of pilgrims to Mecca of whom two-thirds died of plague on the road. Even with modern sanitary activity, it is very difficult to root it out, as our recent experiences in Hong Kong and India have shown.
A later epidemic, which was probably of bubonic plague, was that which avenged the capture of the ark (1Sa 5:6). We read of the tumors which were probably the glandular enlargements characteristic of this disease; also that at the time there was a plague of rats (1Sa 6:5)--"mice," in our version, but the word is also used as the name of the rat. The cattle seem to have carried the plague to Beth-shemesh, as has been observed in more than one place in China (1Sa 6:19). Concerning the three days’ pestilence that followed David’s census (2Sa 24:15; 1Ch 21:12), see Josephus, Ant, VII, xiii, 3. The destruction of the army of Sennacherib may have been a sudden outbreak of plague (2Ki 19:35; Isa 37:36). It is perhaps worthy of note that in Herodotus’ account of the destruction of this army (ii.141) he refers to the incursion of swarms of mice.
One of the latest prophetic mentions of plague is Ho 13:14, where the plague (debher, Septuagint dike) of death and the destruction (qaTabh, Septuagint kentron) of the grave are mentioned. From this passage Paul quotes his apostrophe at the end of 1Co 15:55, but the apostle correlates the sting (kentron) with death, and changes the dike into nikos.