The yellow fever of Ireland.

PHYSICIANS practising in Ireland will be surprised to find Ireland listed as a country subject to yellow fever in a comparatively recent publication. Carlos Finlay, ever to be remembered for his work on yellow fever, died in 1915, and in 1955 his medical school, Jefferson Medical College, held a commemorative conference on yellow fever. Doctor Pedro Nogueira (1955) reviewing the history and geography of the disease remarked that "Doctor Graves left a great description of the havoc it played in Dublin in 1826". It is quite true that Graves in the first volume of his Clinical Lectures on the Practice of Medicine described yellow fever in Dublin, but MacArthur (1957; 1959) has emphasised that the yellow fever of Ireland was relapsing fever. According to MacArthur what Graves was describing was louse-borne relapsing fever with jaundice. The epidemic described by Graves occurred at the height of the winter of 1826-27 in December and January. It does not seem likely that any mosquitoes, let alone the usual vectors, would have been available at that time of the year in Dublin to transmit yellow fever, even if there had been a human source of the virus. Further, according to Graves, the deaths he observed amounted to "nearly twenty". This is not the mortality to be expected of epidemic Central American yellow fever. Like many another Nogueira has been misled by the difficulty in nomenclature. There is not one yellow fever but several yellow fevers-classical yellow fever of the Caribbean and Central America (the vomito negro of the Spanish), relapsing fever, viral hepatitis and leptospirosis. All four are micro-organismal. All but leptospirosis can occur in large epidemics, leptospirosis being more restricted in locale and more occasional in time. If this error is not to continue, some synonym in English should be found for the Central American mosquito-transmitted viral disease. It is interesting that Noguchi himself thought he had discovered the cause of classical yellow fever when he discovered a leptospira in a jaundiced patient, another example of confusion of one febrile jaundice with another. It may make little difference if in the military medical appreciations of the powers Ireland is marked as having "yellow fever". It might deter an enemy. It will cause him to dissipate his resources in inoculating his invading troops with yellow fever vaccine. It would be bad, however, for the tourist trade if this false belief persisted. The only communicable "yellow fevers" we see nowadays are viral hepatitis and occasionally leptospirosis. We may safely assume that Central American yellow fever never occurred in Ireland, and happily we can say that relapsing fever has gone too.