Etiology Of Infectious Diseases Research Articles

Entre les miasmes et les germes: L'impact de la bacteriologie sur la pratique medicale en territoire Canadien 1870-1930

This article analyzes some aspects concerning the introduction of bacteriological theory and practice into Canadian territory from 1870 to 1930. The author begins by presenting the principal explanatory models characterizing the transition period from pre-bacteriological discourse- referring to infectious diseases and surgical infections- to new bacteriological paradigms. He goes on to analyze the different ways in which the germ theory and then bacteriology spread into Canadian territory. The transition periods, where old and new coexisted, reveal a kind of syncretism by physicians in relation to both aetiology of infectious diseases and surgical procedures. The author then shows that there were two distinct phases in the overall context of the history of antiseptic surgery from 1868 to 1890. He demonstrates that the use of antiseptics did not necessarily mean either adherence to Pasteur's postulates on fermentation or strict observance of Listerian methods. Finally, the article expounds on the role played by European institutions in importing bacteriological knowledge and institutionalizing this new discipline in Canadian territory.

Use of isogenic mutants to study bacterial virulence factors

The development of molecular techniques in genetic analysis of bacteria has enabled detailed dissection of complex problems in microbiology. Among these is bacterial pathogenesis. However, use of the new tools must still be coupled with adherence to rules of genetic analysis so that appropriate conclusions may be derived from experimentation. Just as Koch's postulates are used in defining bacterial etiology of infectious disease, a molecular version of Koch's postulates is applied to determining if particular attributes or functions of bacteria contribute to virulence. The molecular version of Koch's postulates states than an epidemiological association exists between presence of a trait and virulence, that a specific mutation be constructed to inhibit the function resulting in decrease in virulence, and finally that the mutation be complemented in trans with only the wild-type allele of the mutated gene provided on a recombinant plasmid. The molecular genetic analysis of the virulence plasmid of Salmonella typhimurium over the past decade serves as an example of the application of these rules to a complex problem in bacterial pathogenesis. This discussion of molecular Koch's postulates and analysis of the S. typhimurium virulence plasmid are aimed at aiding in the design of a complete and thorough genetic approach to the study of bacterial virulence.

Parasites and the germ theory of disease.

{ ( T*-HERE HAS ARISEN, NOTED DR. AUGUST HIRSCH * (1885, vol. 2, 279) in his Handbook of Geographical and Historical Pathology, prospect of adding to this department of pathology. The department to which he referred was that of and what was to be added to it, he thought, were Such diseases, he estimated, may well be of parasitic nature, or that there occur in them organisms of the lowest rank of organic development-the micrococci and bacilli. Hirsch, like many others at that time, stood on the brink of accepting a generalized parasitic theory of disease. In this article I will examine the history of parasitology in the nineteenth and early twentieth century, and suggest ways in which models drawn from the study of parasitic organisms may have influenced debates over the etiology of infectious diseases. I shall argue that a generalized parasitic theory of disease only appeared very briefly, if at all, at the end of the nineteenth century. Both before and after this short period, those who studied parasites seemed to have little to offer those concerned with infectious diseases; parasites made minimal contributions to the modern germ theory of disease. The professional study of parasitic organisms long predated the era of Pasteur and Koch; it began essentially in Germany at the beginning of the nineteenth century. In 1810, for example, Carl Rudolphi, who began his career at the University of Greifswald in Sweden after

Hepatosplenic Schistosomiasis in Pregnancy: Report of a Case and Review of the Literature

We present a report of a pregnancy complicated by chronic schistosomiasis. A.H. is a 22 year old G1 Filipina, referred at 34 weeks gestational age for evaluation of hypersplenism and progressive thrombocytopenia. Physical exam was remarkable for hepatosplenomegaly. Laboratory evaluation of hepatic, renal, hematologic, autoimmune, or infectious disease etiology or abnormality was negative. Ultrasound revealed a normal fetus, an enlarged spleen, dilated splenic and hepatic vasculature and an enlarged liver with periportal fibrosis. Abdominal computed tomography revealed subcapsular calcifications, dilated ducts, and periportal fibrosis. Esophagogastrojejeunoscopy showed no varices. The presumptive diagnosis of hypersplenism secondary to chronic hepatosplenic schistosomiasis was made. Based on pathophysiology and literature review conservative management was elected. Liver functions, clotting functions, and platelet counts were monitored closely. Intense antepartum fetal monitoring was performed. Platelet counts remained between 30 and 40K. The patient went into labor at 38 3/7 weeks and delivered a 3148 g female Apgars 8/9 by spontaneous vaginal delivery. Evaluation of the placenta was negative for ova. By 2 weeks postpartum platelet counts had increased to the 60-70 k range, and a rectal biopsy, positive for S. japonicum ova was performed. Treatment with three doses of Praziquantel 20 mg/kg q8h was completed prior to her return to the Philippines.

Parasites and the Germ Theory of Disease

Particular options for framing disease are not equally available to would-be framers. The history of parasitology in the nineteenth and early twentieth centuries suggests ways in which models drawn from the study of parasitic organisms might have influenced debates over the etiology of infectious diseases and led to a unified theory if parasitology had not been segregated intellectually. Intellectual and institutional history thus determined that the study of parasites would offer little to the modern germ theory of disease by making its models unavailable to physicians and biologists seeking to understand particular ills.

Influence of Amperozide on Disease Occurrence in a Pig Fattening Unit

The social and physical environments of animals and man have long been implicated in the etiology of infectious diseases. However, controlled experiments on adverse social and environmental stimuli and animal health are meagre (Kelley 1980). Recently the term psychoimmunology was coined to reflect the growing interest in the relationship between stress, reduced immune function and illness. For more than a decade it has been known that prolonged secretion of stress hormones, particularly corticosteroids, contributes to regression of the lymphoid tissues (Selye 1974, Freeman 1975). Now it has been shown more specifically, that the level of secretory immunoglobulin A is reduced in periods of high stress and that the activity of lymphocytes and natural killer cells are significantly reduced after intense stress periods (Wood 1985). Although the relationship between stress and immunity thus seems to be clear, studies linking those to disease are still a rarity.

Perinatal lamb mortality in the central sierra of Peru

Perinatal lamb mortality is one of the major factors in impairment of productivity on sheep raising enterprises around the world. In this study, perinatal mortality on one of the largest sheep raising enterprises in Peru was measured over a 10-year period. Between 1971 and 1980, a total of 603 694 lamb births was recorded. Mortality during the first 3 days of life was 36.94/1000 births and for the period from 4 to 30 days mortality was 5.87/1000. Non-infectious conditions predominated as causes of mortality. The weak lamb syndrome, accidents, injuries and starvation were the leading causes of mortality. Diseases of infectious etiology were second in importance, but may have been under-reported. Variation in mortality between years, did not appear to affect the patterns of mortality by cause. Approximately 86% of mortality occurred in the first 3 days of life. During this period, nutritional, environmental and management factors resulting in weak lambs and starvation accounted for approximately a third of total mortality. Infections (22%), accidents (22%), and stillbirths (16%) followed in order of importance. During the remainder of the first month of life, deaths from infections predominated, accounting for 60% of mortality from 4 to 30 days.

Viral Diseases of the Chest

Newer techniques promise to give us a better understanding of the etiology of infectious diseases of the chest and with such knowledge, developments in prevention and therapy can be anticipated.

The immunology of the human mycoses.

The immunological aspect of medical mycology has tended to lag behind similar aspects of other fields. It appears, however, that immunologic proc­ esses in the fungus-infected host are essentially similar to those which occur in bacterial, viral, and other diseases of infectious etiology. The procedures and techniques for measuring immunologic reactions are, therefore, similar to those which have been established for the infectious diseases in general. Possibly because of the somewhat more highly differentiated structure of the fungi, the preparation of antigens for immunologic studies requires certain modifications. Except for this difference no really specialized knowledge ap­ pears to be necessary in the performance of immunologic tests. As in other infectious diseases, immunologic data are of diagnostic and prognostic consequence only when interpreted in the light of the limitations of the commonly used tests. In some instances negative results, such as negative tests for cutaneous sensitivity, are of greater significance in exclud­ ing a particular diagnosis than are positive tests in establishing it, as exempli­ fied by the tu berculin test and, similarly, by the coccidioidin test for coccidi­ oidomycosis. Immunologic studies, however, constitute an important part of the clinical evaluation in respect to diagnosis, prognosis, and management of many of the systemic mycoses. The systemic mycoses are insidiously developing, chronic, and often fatal diseases. They tend to simulate tuberculosis. Consequently, there are many pathologic and immunologic analogies between the mycoses and chronic bacterial diseases. The pathogenic fungi may, on the one hand, be characterized as being more allergenic than bacteria, in the sense that cutaneous sensitivity is practically a constant feature of the human mycoses. On the other hand, they may be said to be less antigenic than many bacterial pathogens in that concentrations of circulating antibodies, expressed as antibody titers, are generally low. For example, although a positive complement-fixation test with undiluted serum or serum diluted 1 : 2 might be skeptically regarded in other infections, such low titers may assume diagnostic significance in the human mycoses, as is the case in blastomycosis ( 1 ) . The reasons for this mea­ ger antigenicity are not well known. It is possible that the slow progression

Tuberculosis allergy

The doctrine of allergy in general and tuberculosis in particular appeared during the heyday of bacteriology and immunology. This was the time when in the etiology of infectious diseases the causative agent was attributed to an exceptional value, while the state of the microorganism was interested mainly in terms of its immuno-biological properties.

The Forthcoming Congress of Hygiene and Demography

FROM a circular just received, we learn that satisfactory progress has been made with the arrangements for the eighth International Congress of Hygiene and Demography, to be held at Budapest, from September 1 to 9. The work of the Congress will be carried out in two divisions, relating respectively to hygiene and demography. Hygiene comprises nineteen, and demography seven, sections. In Section I. of the former division (the etiology of infectious diseases, or bacteriology), notices of thirty papers had been received up to March 31; in Section II. (the prophylaxis of epidemics), thirty-six papers are at present announced; in Section III. (the hygiene of the Tropics), twelve papers; in Section IV. (the hygiene of trades and agriculture), twenty-nine papers; in Section V. (the hygiene of children), twenty-eight papers; in Section VI. (the hygiene of schools), thirty-nine papers. Thirty-six papers have been notified in Section VII. (articles of food); thirty-eight in Section VIII. (the hygiene of towns); eleven in Section IX. (the hygiene of public buildings); nine in Section X. (the hygiene of dwellings); seventeen in Section XI. (the hygiene of communications, that is, of railroads and navigation), and twenty-four in Section XII. (military hygiene). Fourteen papers are promised on the saving of life (Section XIII.), thirty-three on State hygiene (Section XIV.), six on the hygiene of sport (Section XV.), twenty on the hygiene of baths (Section XVI.), thirty-eight on veterinary matters (Section XVII.), seventeen on pharmacology (Section XVIII.), and eleven on general sanitarian affairs (Section XIX.).

XI. Studies on some new micro-organisms obtained from air

In some papers on the micro-organisms present in air, previously communicated to the Royal Society by one of us, the relative abundance of microbes in the air of different places has been called attention to and the methods of experiment fully described. As these investigations were carried out with the aid of solid nourishing media, we were able to obtain a collection of pure cultivations of a number of micro-organisms derived directly from the air. It appeared to us, therefore, desirable to utilise the opportunity which these experiments furnished for minutely characterising some of the principal forms which are thus obtainable from the atmosphere. There are many reasons which render it of importance that the task in question should be undertaken. Thus, in the methods of cultivation employed by bacteriologists, the experimenter may at any moment be brought face to face with organisms from the air which have accidentally contaminated his cultivations, and it is obvious, therefore, that an intimate acquaintance with the various forms which may thus invade culture-media must be both of interest and importance to all practically engaged in experiments on micro-organisms. It is not unnatural that the brilliant discoveries in connection with the etiology of infectious diseases should have absorbed the lion’s share of the attention of investigators in the field of bacteriology, and that the non-pathogenic organisms should have come to be regarded as comparatively uninteresting by the side of their more formidable brethren. It must, however, be remembered that the functions of the non-pathogenic organisms in the economy of nature are as yet but very imperfectly understood, and that as far as these functions have been investigated they do not yield in point of importance to those of the most virulent pathogenic forms.

III. Experimental contribution to the etiology of infectious diseases with special reference to the doctrine of contagium vivum

The present communication has for its object to bring before the Royal Society the results of an experimental inquiry into the etiology of an infectious disease of the pig, known as Hog Plague, Mai Rouge, Red Soldier, Malignant Erysipelas, or also Typhoid Fever of the Pig. There are English and continental writers who describe the disease as Anthrax or Splenic Fever of the Pig. I shall show, however, conclusively, in my Report to the Medical Officer of the Local Government Board, that it is neither typhoid fever nor anthrax, but is an infectious disease of its own kind, which I propose to call “Infectious Pneumo-Enteritis of the Pig” ( Pneumo-enteritis contagiosa ). Like other infectious diseases, the “Pneumo-Enteritis” possesses an incubation period, followed by constitutional disturbance and certain anatomical changes. These latter are invariably affections of the lung, of the intestine, and of the lymphatic glands, not only of those of the organs of respiration and alimentation, but also those of the inguinal and lumbar regions. In the lung the changes are those known to pathologists as lobular pneumonia. In the alimentary canal the mucous membrane of the large intestine is chiefly affected, being the seat of smaller or larger ulcerations. There is generally also inflammation of the serous membranes, especially the peritoneum, leading to an exudation of lymph into the serous cavity. The skin is occasionally affected with greater or smaller red patches.

Experimental Contribution to the Etiology of Infectious Diseases with special reference to the Doctrine of Contagium Vivum

ABSTRACT The present communication has for its object to bring before the Royal Society the results of an experimental inquiry 1 into the etiology of an infectious disease of the pig, known as Hog Plague, Mai Rouge, Red Soldier, Malignant Erysipelas, or also Typhoid Fever of the Pig. Their are English and continental writers who describe the disease as Anthrax or Splenic Fever of the Pig. I shall show, however, conclusively in my Report to the Medical Officer of the Local Government Board, that it is neither typhoid fever nor anthrax, but is an infectious disease of its own kind, which I propose to call “ Infectious Pneumo-Enteritis of the Pig” (Pneumo-enteritis contagiosa).