A Prehistory of the Diathesis-Stress Model: Predisposing and Exciting Causes of Insanity in the 19th Century.

Histories of the diathesis-stress model trace its origins to the 1950s. However, of 26 psychiatric texts published between 1800 and 1910, 17 noted that causes of insanity could be usefully divided into those that predispose to illness and those that excite onset. In this "predisposition-excitation framework" (PEF) for the etiology of insanity, hereditary or constitutional factors were critical predisposing causes, but education, occupation, sex, and marital status were typically included as well. Psychological traumas were key exciting causes, but so were somatic diseases, pregnancy, and substance abuse. The PEF was often used to explain the diversity of individual responses to adversity. While single dramatic events often excited onset, daily repetition of lesser shocks could also bring on insanity. Matching could occur between predisposing and exciting causes in individuals who had "special susceptibilities." Predispositions could lead to "affects, passions, and perverse manner of life," which became exciting causes. Authors emphasized that it was easier to prevent exposures to exciting causes than to reverse predispositions. A thought experiment of an individual "transplanted early into new and different social conditions" anticipated models of primary prevention. Ratings of predisposing and exciting causes were mandated in the United Kingdom from 1878 to 1887 and at several U.S. psychiatric hospitals in the early 20th century. The PEF was far more stable over place and time in the 19th century than any psychiatric nosologic system. Contrary to the doctrinaire schools of psychoanalytic and biological psychiatry that dominated much of 20th-century psychiatry, the PEF proposed a flexible, developmental, and pluralistic view of etiologic pathways to psychiatric illness.

Quantifying the consequences of measles-induced immune modulation for whooping cough epidemiology.

Measles, an acute viral disease, continues to be an important cause of childhood mortality worldwide. Infection with the measles virus is thought to be associated with a transient but profound period of immune suppression. Recently, it has been claimed that measles-induced immune manipulation lasts for about 30 months and results in increased susceptibility to other co-circulating infectious diseases and more severe disease outcomes upon infection. We tested this hypothesis using model-based inference applied to parallel historical records of measles and whooping cough mortality and morbidity. Specifically, we used maximum likelihood to fit a mechanistic transmission model to incidence data from three different eras, spanning mortality records from 1904 to 1912 and 1922 to 1932 and morbidity records from 1946 to 1956. Our aim was to quantify the timing, severity and pathogenesis impacts of measles-induced immune modulation and their consequences for whooping cough epidemiology across a temporal gradient of measles transmission. We identified an increase in susceptibility to whooping cough following recent measles infection by approximately 85-, 10- and 36-fold for the three eras, respectively, although the duration of this effect was variable. Overall, while the immune impacts of measles may be strong and clearly evident at the individual level, their epidemiological signature in these data appears both modest and inconsistent. This article is part of the theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes'. This issue is linked with the subsequent theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control'.

Existential vulnerability: toward a psychopathology of limit situations.

Jaspers' concept of limit situations seems particularly appropriate not only to elucidate outstanding existential situations in general, but also basic preconditions for the occurrence of mental disorders. For this purpose, the concept is first explained in Jaspers' sense and then related to an 'existential vulnerability' of mentally ill persons that makes them experience even inconspicuous events as distressing limit situations. In such situations, an otherwise hidden fundamental condition of existence becomes manifest for them, e.g. the fragility of one's own body, the inevitability of freedom, or the finiteness of life. This fundamental condition is found unbearable and, as a reaction, gives rise to mental illness. This concept of existential vulnerability is illustrated by some psychopathological examples.

Use of vaccination against foot and mouth disease in zoo animals, endangered species and exceptionally valuable animals.

A historical review of foot and mouth disease (FMD) in non-domestic species is given and the use of FMD vaccines to protect those species is described. Several non-domestic species are susceptible to FMD. Legislation in many countries, based on the definition of FMD-free status as determined by the Office International des Epizooties (OIE: World organisation for animal health), forms an important barrier against the use of vaccines. National authorities may even feel obliged to slaughter animals of threatened species protected by international agreements during an outbreak of FMD to preserve their FMD-free status. The importance of international breeding programmes for endangered species is forcing the international community to reconsider the role that vaccination against FMD should play in animal health prevention programmes of captive populations. Much research is still required in regard to vaccine types and diagnostic procedures. Species-specific differences in susceptibility to FMD make this a challenging research topic for zoological institutions.

The origins and precolonial epidemiology of tuberculosis in the Americas: can we figure them out?

Paleologic evidence of tuberculosis in the precolonial Americas is reviewed to cast light on its origins and subsequent epidemiology. The genus Mycobacterium is an ancient one, and M. tuberculosis may have differentiated 20,400 to 15,300 years ago. The Americas were peopled by migrants from Asia in two major migrations, one occurring more than 20,000 years ago and the other 12,000 to 11,000 years ago. Tuberculosis reached the Americas with these migrants, persisting at a low level of endemnicity in small, dispersed population groups. Beginning about 1500 years ago, an epidemic of tuberculosis began, probably in the Andean region of South America. It did not reach or subsided in time to leave highly susceptible indigenous American populations at the time of European colonization.

Child survival: physical vulnerability and resilience in adversity in the European past and the contemporary Third World.

Infant and child physical vulnerability is demonstrated by the extremely high mortality levels in these age groups in the pre-modern West and parts of the contemporary Third World. Some children, such as females or later additions to the family, are subject to disproportionately high mortality risk. In spite of the age-old vulnerability of young children, disproportionate gains have been made in reducing their mortality in modern times. This has been a product of social and individual change, government intervention and biomedical research. These advances exhibit during crises greater resilience to reversal than might be anticipated. Rarely do infant and child mortality levels return more than a fraction of the way to the original levels. The explanation is irreversible changes to individuals and society and the persistence of health knowledge even when health facilities are paralysed.