Common colds on Tristan da Cunha

Abstract

Eight epidemics of respiratory disease have been observed among islanders of Tristan da Cunha. They seem to be initiated by the arrival of ships and transmission seemed to occur as a result of close human contact but could not always be traced. Islanders suffered from less colds than those in less isolated communities.

A mathematical model of common-cold epidemics on Tristan da Cunha

“…3 to arise from two independent epidemics involving different viral agents. It may be noted in this respect that both epidemics were associated with the arrival at Tristan da Cunha of two ships and that contact with infected passengers has been identified as the origin of commoncold epidemics on the island (Shibli et al 1971). In the case of the May 1967 outbreak one ship arrived 2 days before the first notified infection and another ship arrived 1 week later; in February 1968 two ships arrived at the island on the day preceding the first notification of infection.…”

“…The occurrence of common-cold epidemics among the islanders of Tristan da Cunha has already been discussed in a previous paper (Shibli, Gooch, Lewis & Tyrrell, 1971). For the purpose of that study daily records of the development of upper respiratory infection were kept by individuals involved in each of the seven outbreaks that affected the community between 1964 and 1968.…”

“…Firstly, the moderate size and free social mixing of the community (Shibli et al 1971) suggests that topographical or sociological groupings may not significantly affect the progress of the epidemic; and secondly, the isolation of the community rules out the effects of emigration and immigration. The Tristanian community would in fact seem to approach very closely the ideal homogeneous and closed society whose theoretical consideration has provided a basis for epidemic theory since its inception.…”

An epidemic of influenza on Tristan da Cunha

“…The isolated population has for many years been subject to epidemics of common colds which follow the arrival of supply ships from Cape Town (Woolley, 1946; Shibli, Gooch, Lewis & Tyrrell, 1971). It is many years since an epidemic of influenza-like illness occurred there, but one occurred in the winter of 1971 and is reported here because of some unusual features.…”

The Transmission of Colds and Coughs

“…The viruses presumably infected all the susceptibles of the small community, of rather over 200 individuals, and then died out. There was some clinical evidence that successive epidemics were due to different agents [12]. The inhabitants themselves were not particularly resistant to infection; indeed, when they were evacuated to the outside world they suffered severely from respiratory infections, and some of the viruses involved were documented [ 13], In these studies the illnesses spread quite slowly through families and the community.…”