II. A clinical and parasitological survey of the Tristan da Cunha islanders

Of the 268 islanders, who were transferred to Britain following the eruption of the volcano, 259 were surveyed during the 4-week period between December, 1961, and January, 1962. History and a full examination including the routine testing of the urine were recorded for each individual at the time. The findings from the survey and also the subsequent investigations carried out in the light of this survey are reported. Though none of them mentioned diarrhoea as a complaint, this as a symptom was complained of by about half the islanders during the summer months on the island. The results of stool examination in 259 persons showing a high degree of parasitic infection are reported in detail. No correlation between the findings of asthma in 48.5 per cent. of the Tristanians and the worm infection was found. The examination also revealed that 16 of the islanders had posterior segment lesions in the eye. Retinitis pigmentosa was present in four and choroido-retinitis in 12. While looking for the cause of the choroido-retinitis, it was found that the Sabin-Feldman dye-test carried out on 147 sera showed a high prevalence (78.9 per cent.) of toxoplasma infection among the islanders.