Diphtheria: a serious asphyctic disease that reappears occasionally. Description of the disease in Northeastern Italy from the 16th century onwards

Diphtheria is a serious and potentially fatal infection caused by <i>Corynebacterium diphtheriae</i>, which, before the introduction of universal vaccination, was the leading cause of illness and death among children and young adults, but which now causes sporadic but worrying outbreaks worldwide and not only among unvaccinated people. We narrate the first descriptions of the disease until the introduction of seroprophylaxis and vaccination as well as the spread, clinical expression and treatment of diphtheria in Ferrara, and in North-Eastern Upper Adriatic Sea. We also deal with the dramatic resurgence of disease in particular categories of people and in certain countries. The sources consulted were the Academy of Sciences of Ferrara, the Ariostea Municipal Library, periodicals of Trieste and literature books. In the period analyzed (1869-1898), 2794 people died in Ferrara, with a maximum of 44.24 per 10,000 inhabitants in 1883 and a minimum of 0.32 in 1898. Deaths from diphtheria were highly prevalent in the countryside compared to the cities (36% <i>vs</i> 23%, respectively); the female gender was most affected due the prolonged contact with sick people and unhealthy environments. Mortality was very high in those patients aged from 5 to 10 years and from 3 to 5 years, with a much lower percentage in the age groups between 1 to 3 and 10 to 15 years. Cauterization of tonsil plaques, brushing with hydrochloric acid, mucilaginous gargles, cinchona, astringent substances, were among the main remedies proposed by some distinguished academics of the time before the advent of serotherapy. Some authors were the first to describe the effects of post-diphtheria paralysis including phonation disorders. The academic Baldassari connected diphtheria trends to weather variations. In the Eastern Upper Adriatic region, diphtheria was such a threat in the last thirty years of the 19th century that it surpassed cholera and typhus in terms of mortality. The disease was more common in the coastal region than on the mainland. Istria, Koper, Poreč and Pula were the cities with the highest number of cases in 1871 and 1872. The disease hit hard between October 1894 and the first months of 1895. Prophylactic measures to combat the disease included closing schools, isolating the infected patients, and publishing recommendations text on school hygiene Diphtheria, although almost completely eradicated in most industrialized countries thanks to mass vaccination campaigns, remains endemic where inadequate vaccination policies, low socioeconomic status, inaccessibility to public health care, wars, displacement, migratory movements are present.