**8. The Smallpox epidemic in St Kilda<sup>7</sup>**

Smallpox outbreaks were common on the Scottish Islands in the eighteenth and nineteenth centuries. All the islands had a similar hostile climate, and varying degrees of isolation and malnutrition. Ten outbreaks occurred on the Shetland Islands between 1700 and 1830. The 1740 diary of Thomas Gifford of Busta, from Greig's *Annals of a Shetland parish*,7 recorded that two of his daughters became unwell and bed-bound, developed a rash five days later and died a further eight and nine days respectively after that. Some of Gifford's 11 other children developed a rash but all survived, thus illustrating the typical features of smallpox:

Limited Bio-Diversity and Other Defects of

*mankind'.* 

smallpox.

time;

than smallpox;

**9. The boat cough11**

chickenpox than smallpox;

the Immune System in the Inhabitants of the Islands of St Kilda, Scotland 235

*'I am patriot enough to take pains to bring this useful invention into fashion in England, and I should not fail to write to some of our doctors very particularly about it if I knew any one of them that I thought had virtue enough to destroy such a considerable branch of their revenue for the good of* 

Montagu has an extraordinary coincidental connection with St Kilda. Her sister, Lady Frances Pierrepont, married John Erskine, the 22nd Earl of Mar, a Jacobite general in the 1715 battle of Sherriffmuir. John's brother, Lord Grange married Rachel Chiesley, who soon, perhaps correctly, suspected her husband's infidelity and Jacobite loyalties. Grange imprisoned her, initially on the Monarch Islands, west of North Uist in the Outer Hebrides, and then on St Kilda from 1734 to 1742, where she became the celebrated Lady Grange of St. Kilda. Had Chiesley heard of vaccination from Lady Montagu, her brother-in-law's sister-inlaw, and arrived seven years earlier, she may have prevented the epidemic if indeed it was

William Heberden differentiated chickenpox from smallpox in 1767; hence 'smallpox'

Limited biodiversity may well have reduced the population's resistance to this infection, which could equally have been chicken pox. The 1727 epidemic has always been labelled

The similar exanthemas of smallpox and chickenpox were not distinguished at that

The epidemic spread widely and rapidly among the inhabitants, more like chickenpox

The epidemic caused a higher death rate among adults than children – again, more like

 Chickenpox probably had a high mortality in the 'virgin soil' of the Americas, in a nonimmune society, with limited genetic biodiversity of the HLA system, though there are

 The viability of the smallpox virus is inversely related to its infectivity. Smallpox is only highly contagious in the aerosolised form. Smallpox virions have a low survival rate

Another well documented infection peculiar to the inhabitants of St Kilda was called by the

Martin during his visit to the island in 1697, did record details of this boat cough. He wrote: *'They [the islanders] contract a cough as often as any strangers land and stay among them, and it* 

*continues for some eight or ten days; they say the very infants on the breast are affected by it.8* The Reverend Macaulay arrived in St Kilda in 1758, and related his experience as follows: *'When I landed, all the inhabitants, except two women in child-bed enjoyed perfect health.... On the third day after I landed, some of the inhabitants discovered evident symptoms of a violent cold, such as hoarseness, coughing, discharging of phlegm, etc. and in eight days, they were all infected with this* 

*un-common disease, attended in some with severe head-aches and feverish disorders'*.5

smallpox; however the following points suggest the alternative of chickenpox:

no data on the comparative mortality of smallpox and chickenpox;

and smallpox scabs an even lower infectivity in fomites.

native Gaelic speakers '*cnatan-nagall'* or the strangers' cough. 10

epidemics prior to that date cannot be accepted as indisputable.

No clinical features of the 1727 St Kilda epidemic are available;


In contrast to such episodes, in 1727 an outbreak of possible smallpox on St Kilda killed nearly the entire population. Ninety-four deaths in a population of 132 were recorded, leaving four adult and twenty-six children as the survivors.

Neil MacKenzie, minister on St Kilda from 1829 to 1843, writing a hundred years later stated *'Death after death followed. At last there were scarcely sufficient to bury the dead… There were 94 deaths… those who had been left on Stac an Armin returned mostly to empty houses'.* 

Fig. 14. Stac an Armin

A small party of three men and eight boys were marooned on Stac an Armin, a 196-metre high sea stack, where they had been taken to collect birds and birds eggs, but also survived through an Atlantic winter till rescued on 13 May 1728 in a little known epic tale of endurance in adversity. A small bothy gave limited shelter, and the group lived off the stack's fresh water supply, birds and their eggs and fish caught with a bent nail, though they were noted to have lost weight. They patched their clothes as well as possible with birds' skins. Although the greater resources of Boreray Island were 100 yards away, the vertical rock face prevented ascent from the water.

A decade earlier Lady Mary Wortley Montagu, wife of the ambassador to Turkey discovered there the procedure of variolation, or intradermal inoculation of smallpox scabs. This caused a moderate infection with a mortality rate of 0.5–2%, compared with a death rate of 10% from the actual disease, She variolated her own children, and though sceptical of physicians there, hoped to introduce the process into England, writing

*'I am patriot enough to take pains to bring this useful invention into fashion in England, and I should not fail to write to some of our doctors very particularly about it if I knew any one of them that I thought had virtue enough to destroy such a considerable branch of their revenue for the good of mankind'.* 

Montagu has an extraordinary coincidental connection with St Kilda. Her sister, Lady Frances Pierrepont, married John Erskine, the 22nd Earl of Mar, a Jacobite general in the 1715 battle of Sherriffmuir. John's brother, Lord Grange married Rachel Chiesley, who soon, perhaps correctly, suspected her husband's infidelity and Jacobite loyalties. Grange imprisoned her, initially on the Monarch Islands, west of North Uist in the Outer Hebrides, and then on St Kilda from 1734 to 1742, where she became the celebrated Lady Grange of St. Kilda. Had Chiesley heard of vaccination from Lady Montagu, her brother-in-law's sister-inlaw, and arrived seven years earlier, she may have prevented the epidemic if indeed it was smallpox.

William Heberden differentiated chickenpox from smallpox in 1767; hence 'smallpox' epidemics prior to that date cannot be accepted as indisputable.

Limited biodiversity may well have reduced the population's resistance to this infection, which could equally have been chicken pox. The 1727 epidemic has always been labelled smallpox; however the following points suggest the alternative of chickenpox:

