Just what was English sweating sickness?

Were you among the four million who watched the first episode of Wolf Hall, BBC Two’s adaptation of Hilary Mantel’s historical novels centred on Thomas Cromwell? If not, look away now to avoid SPOILERS. If so, you will have seen Cromwell’s wife and their two daughters dying suddenly of sweating sickness.

The earliest references to this highly virulent disease (also known as English sweat, or in Latin sudor anglicus) are connected with Henry Tudor’s return from France in 1485 to seize the English throne as Henry VII. The disease may possibly have been brought across the Channel by his army, although there are no prior records of it on the continent.

After victory over Richard III at the Battle of Bosworth Field, Henry and his forces entered London. Shortly afterwards, an epidemic of the disease broke out, killing several thousand people before fading away after a couple of months.

A further outbreak occurred in Ireland in 1492, but nothing more was recorded in England until 1502, when the disease is thought to have been responsible for the death of the young Arthur, Prince of Wales, paving the way for his younger brother to succeed their father as Henry VIII.

Increasingly severe epidemics occurred in 1507, 1517 and 1527. The last of these began in London, where it became so widespread that Henry VIII took his court away from the capital. This was also the epidemic that killed Cromwell’s wife (although his daughters actually died later, and possibly from other causes). After spreading rapidly through England, apart from the far north, the disease suddenly appeared in Hamburg. From there it swept through eastern Europe, with high mortality rates. Wherever it emerged, outbreaks tended to last for only a week or two. It died away by the end of 1528.

So what was sweating sickness? Our knowledge of it is mainly derived from an account of England’s final epidemic, in 1551. In a book published the following year, an eminent physician, John Caius, recorded that the disease began suddenly with a sense of apprehension, followed by violent cold shivers, giddiness, headache, exhaustion and severe pains in the neck, shoulders and limbs. After sometimes as little as half an hour, profuse sweating broke out suddenly, accompanied by a sense of heat, headache, delirium, rapid pulse and intense thirst. In the final stage, sufferers experienced a “marvellous heavinesse, and a desire to sleape”. After 24 hours they were either dead or clearly recovering.

As was recognised at the time, the disease’s characteristic sweating and its rapid course distinguish it from the epidemic infections that had preceded it, such as plague. Modern-day suggestions for possible causes include relapsing fever, hantavirus infection and anthrax. However, none of these fully shares the symptoms described by Caius.

Since sweating sickness tended to occur only in random years, and mainly in summer, it may have been conveyed by a vector susceptible to climate change. One candidate would be a mosquito-borne viral disease similar to dengue fever, although dengue itself — as we all know from the current problems in West Africa — usually lasts for more than 24 hours and tends to be accompanied by a rash, which Caius does not mention.

Medical researchers are still searching old documents for clues, but we may never learn the cause of sweating sickness.