scholarly journals EPIDEMIOLOGICAL STUDIES ON RESPIRATORY INFECTIONS OF THE RABBIT

1926 ◽  
Vol 43 (4) ◽  
pp. 555-572 ◽  
Author(s):  
Leslie T. Webster
Keyword(s):  
Respiratory Infections ◽  
Virulent Strain ◽  
Blood Stream ◽  
Epidemiological Studies ◽  
Lobar Pneumonia ◽  
Direct Extension ◽  
Diffuse Form ◽  
Portal Of Entry ◽  
Intranasal Instillation

1. Four general types of spontaneous pneumonia, associated with strains of Bact. lepisepticum similar in biology and virulence, are described: (1) an acute, diffuse form, with subpleural and perivascular orientation of the exudate, (2) lobar, (3) pleuro-, and (4) abscess pneumonia. 2. The acute, diffuse, lobar, and pleuro pneumonias may be induced experimentally by intranasal instillation of a virulent strain of Bact. lepisepticum. 3. These same types occur when the organisms are inoculated intravenously, intratesticularly, and subcutaneously. 4. Intrabronchial insufflation of the organisms brings about infection in less than half of the animals. When effective, a sharply circumscribed, peribronchial lesion is found at the base of the lung, which spreads peripherally by direct extension, and generally by invasion of the blood stream. 5. It is concluded that differences in the types of pneumonia following infection with similar strains of Bact. lepisepticum depend upon the resistance of the animal, and that the usual portal of entry of this organism into the lungs, in cases of acute and lobar pneumonia, is by way of the blood stream.

scholarly journals A Systematic Review and Appraisal of Epidemiological Studies on Household Fuel Use and Its Health Effects Using Demographic and Health Surveys

2021 ◽  
Vol 18 (4) ◽  
pp. 1411
Author(s):  
Daniel B. Odo ◽  
Ian A. Yang ◽  
Luke D. Knibbs
Keyword(s):  
Health Outcomes ◽  
Exposure Assessment ◽  
Health Effects ◽  
Low Birthweight ◽  
Respiratory Infections ◽  
Epidemiological Studies ◽  
The Body ◽  
Demographic And Health Surveys ◽  
Fuel Use ◽  
Cooking Fuel

The domestic combustion of polluting fuels is associated with an estimated 3 million premature deaths each year and contributes to climate change. In many low- and middle-income countries (LMICs), valid and representative estimates of people exposed to household air pollution (HAP) are scarce. The Demographic and Health Survey (DHS) is an important and consistent source of data on household fuel use for cooking and has facilitated studies of health effects. However, the body of research based on DHS data has not been systematically identified, nor its strengths and limitations critically assessed as a whole. We aimed to systematically review epidemiological studies using DHS data that considered cooking fuel type as the main exposure, including the assessment of the extent and key drivers of bias. Following PRISMA guidelines, we searched PubMed, Web of Science, Scopus and the DHS publication portal. We assessed the quality and risk of bias (RoB) of studies using a novel tool. Of 2748 records remaining after removing duplicates, 63 were read in full. A total of 45 out of 63 studies were included in our review, spanning 11 different health outcomes and representing 50 unique analyses. In total, 41 of 45 (91%) studies analysed health outcomes in children <5 years of age, including respiratory infections (n = 17), death (all-cause) (n = 14), low birthweight (n = 5), stunting and anaemia (n = 5). Inconsistencies were observed between studies in how cooking fuels were classified into relatively high- and low-polluting. Overall, 36/50 (80%) studies reported statistically significant adverse associations between polluting fuels and health outcomes. In total, 18/50 (36%) of the analyses were scored as having moderate RoB, while 16/50 (32%) analyses were scored as having serious or critical RoB. Although HAP exposure assessment is not the main focus of the DHS, it is the main, often only, source of information in many LMICs. An appreciable proportion of studies using it to analyse the association between cooking fuel use and health have potential for high RoB, mostly related to confounder control, exposure assessment and misclassification, and outcome ascertainment. Based on our findings, we provide some suggestions for ways in which revising the information collected by the DHS could make it even more amenable to studies of household fuel use and health, and reduce the RoB, without being onerous to collect and analyse.

ANALYSIS OF THE REASONS FOR THE REFUSAL OF THE POPULATION FROM VACCINES

Vestnik ◽  
2021 ◽  
pp. 280-284
Author(s):  
Х. Б. Сарсенбай ◽  
А. Н. Турсынханова ◽  
Б. А. Конысов
Keyword(s):  
Preschool Children ◽  
Young Children ◽  
Disease Prevention ◽  
Infectious Diseases ◽  
Respiratory Infections ◽  
Epidemiological Studies ◽  
Recurrent Respiratory Infections ◽  
High Level ◽  
Mandatory Vaccination

Согласно данным ВОЗ, современные эпидемиологические исследования показали, что рецидивирующие респираторные инфекции у детей раннего и дошкольного возраста сохраняются на высоком уровне 10-50% в течение более 40 лет. Конец вакцинации может спровоцировать массовые инфекционные заболевания. Врачи бьют тревогу, что число отказников от обязательной вакцинации растет. Только в каждой поликлинике Алматы 30-40 родителей в год говорят о готовности к профилактике заболеваний. Среди тех, кто категорически отказывается трогать своих детей иголками, - те, кто идет по пути религии. Они считают, что прививка противоречит убеждениям. В последнее время список недовольных групп пополняют и простые жители, которые скептически относятся к квалификации белых. According to WHO, current epidemiological studies have shown that recurrent respiratory infections in young children and preschool children persist at a high level of 10-50% for more than 40 years. The end of vaccination can provoke mass infectious diseases. Doctors are sounding the alarm that the number of refusers from mandatory vaccination is growing. Only in every polyclinic in Almaty, 30-40 parents a year talk about their readiness for disease prevention. Among those who categorically refuse to touch their children with needles are those who follow the path of religion. They believe that vaccination is contrary to their beliefs. Recently, the list of discontented groups has been supplemented by ordinary residents who are skeptical about the qualifications of whites.

scholarly journals EPIDEMIOLOGICAL STUDIES ON RESPIRATORY INFECTIONS OF THE RABBIT

1926 ◽  
Vol 43 (4) ◽  
pp. 573-588 ◽  
Author(s):  
Leslie T. Webster
Keyword(s):  
Respiratory Infections ◽  
Epidemiological Studies ◽  
Previous Exposure

Rabbits with no previous exposure to Bact. lepisepticum were given, intranasally, a known dose of one strain or another of this organism, or of B. bronchisepticus. The results give grounds for the following conclusions.

scholarly journals EPIDEMIOLOGICAL STUDIES ON RESPIRATORY INFECTIONS OF THE RABBIT

1927 ◽  
Vol 45 (3) ◽  
pp. 553-560 ◽  
Author(s):  
David T. Smith
Keyword(s):  
Respiratory Infections ◽  
Epidemiological Studies ◽  
Susceptible Population ◽  
Nasal Passages

These observations have brought out three facts which may be stated briefly as follows. 1. An acute respiratory epidemic was incited by mucoid strains of Bact. lepisepticum of moderate and uniform virulence. 2. The epidemic was brought about not by an alteration in the virulence of the prevailing strains of Bact. lepisepticum but by a sudden distribution of virulent organisms among a susceptible population hitherto unexposed. 3. Individuals in this population showed different degrees of resistance to the infecting bacillus; some died from pneumonia and septicemia, while others localized the infection to the nasal passages. The significance of these facts has been discussed at length elsewhere (4).

scholarly journals Recent Molecular Evolution of Human Metapneumovirus (HMPV): Subdivision of HMPV A2b Strains

2020 ◽  
Vol 8 (9) ◽  
pp. 1280
Author(s):  
Naganori Nao ◽  
Miwako Saikusa ◽  
Ko Sato ◽  
Tsuyoshi Sekizuka ◽  
Shuzo Usuku ◽  
...  
Keyword(s):  
Respiratory Infections ◽  
Epidemiological Studies ◽  
Human Metapneumovirus ◽  
Evolutionary Relationships ◽  
Acute Respiratory Infections ◽  
Evolutionary Analysis ◽  
The Novel ◽  
Genome Wide ◽  
A Genome

Human metapneumovirus (HMPV) is a major etiological agent of acute respiratory infections in humans. HMPV has been circulating worldwide for more than six decades and is currently divided into five agreed-upon subtypes: A1, A2a, A2b, B1, and B2. Recently, the novel HMPV subtypes A2c, A2b1, and A2b2 have been proposed. However, the phylogenetic and evolutionary relationships between these recently proposed HMPV subtypes are unclear. Here, we report a genome-wide phylogenetic and evolutionary analysis of 161 HMPV strains, including unique HMPV subtype A2b strains with a 180- or 111-nucleotide duplication in the G gene (nt-dup). Our data demonstrate that the HMPV A2b subtype contains two distinct subtypes, A2b1 and A2b2, and that the HMPV subtypes A2c and A2b2 may be different names for the same subtype. HMPV A2b strains with a nt-dup also belong to subtype A2b2. Molecular evolutionary analyses indicate that subtypes A2b1 and A2b2 diverged from subtype A2b around a decade after the subtype A2 was divided into the subtypes A2a and A2b. These data support the A2b1 and A2b2 subtypes proposed in 2012 and are essential for the unified classification of HMPV subtype A2 strains, which is important for future HMPV surveillance and epidemiological studies.

Sudden Infant Death Syndrome (SIDS) in Denmark: Evaluation of the Increasing Incidence of Registered SIDS in the Period 1972 to 1983 and Results of a Prospective Study in 1987 through 1988

PEDIATRICS ◽  
1992 ◽  
Vol 89 (5) ◽  
pp. 855-859
Author(s):  
Karin Helweg-Larsen ◽  
Lisbeth B. Knudsen ◽  
Markil Gregersen ◽  
Jørn Simonsen
Keyword(s):  
Sudden Infant Death Syndrome ◽  
Infant Death ◽  
Respiratory Infections ◽  
Sudden Infant Death ◽  
Epidemiological Studies ◽  
Sudden Infant ◽  
Unexpected Death ◽  
National Board ◽  
Infant Deaths ◽  
Live Births

To investigate a reported increase, from 0.4 to 1.3 per thousand live births, in the Danish incidence of sudden infant death syndrome (SIDS), a retrospective analysis of SIDS in Denmark from 1972 to 1983 was carried out. Based on data registered with the National Board of Health, a notable regional difference in SIDS rate between the western and eastern parts of Denmark was found. This difference did not correlate with the overall postneonatal mortality by region. Danish law requires medicolegal investigation in all cases of sudden unexpected death. Medicolegal autopsies are performed only in the three forensic institutes which cover all of Denmark. Despite the law and a uniform organization of the forensic medical services, differing application of postmortem examinations and individual interpretation of the history and autopsy in cases of sudden infant death existed. Differences in reporting of respiratory infections, suffocation, and cardiac malformation were found to contribute to the increase and to regional disparities in SIDS incidence. The three Danish forensic institutes examined all cases of sudden infant deaths in Denmark 1987 and 1988. These cases were classified as explained cause of death, pure SIDS, and atypical SIDS; atypical cases were evaluated by consensus. The SIDS incidence (the number of classic SIDS and atypical SIDS per thousand live births) was 1.9 in 1987 and 1.3 in 1988, and it was identical in the eastern and western part of Denmark; however, a higher incidence both of overall postneonatal and SIDS mortality was found in the middle region of Denmark. The analysis stresses the importance of high autopsy rate and expert investigation in all cases of infant death in order to obtain reliable data for epidemiological studies. A prospective joint study of all postneonatal infant deaths in Finland, Iceland, Norway, Sweden, and Denmark will be carried out to analyze the reliability and the possible cause of reported differences in SIDS incidence in the five Nordic countries.

scholarly journals EXPERIMENTAL CONGENITAL TOXOPLASMOSIS

1950 ◽  
Vol 92 (5) ◽  
pp. 403-416 ◽  
Author(s):  
David Cowen ◽  
Abner Wolf
Keyword(s):  
Congenital Toxoplasmosis ◽  
Blood Stream ◽  
Vaginal Wall ◽  
Essential Factor ◽  
Vaginal Route ◽  
Normal Test ◽  
Pregnant Mice ◽  
Placental Blood ◽  
Portal Of Entry ◽  
Syncytial Trophoblast

Pregnant mice infected with Toxoplasma by the vaginal route have been found to transmit toxoplasmosis to the placentas and fetuses in utero. The microorganism entered the blood stream of the mother from primary foci of infection in the vaginal wall and produced disseminated lesions in the labyrinth of the allantoic placenta at the same time as other peripheral maternal tissues were involved. Placental lesions were observed in mice infected with Toxoplasma by vagina between the 3rd and the 9th day of pregnancy. They consisted of microscopic foci of degeneration, without inflammation, in the syncytial trophoblast, and parasites undergoing multiplication were readily identified in them. Here Toxoplasma gained access to the fetal circulation. Following the vaginal instillation of Toxoplasma on the 8th day of pregnancy, subinoculation of test animals revealed the parasites in the maternal peripheral and placental blood on the 13th day and later, while the first histopathologic changes in the placenta were found on the 17th day. Toxoplasma could be demonstrated in suspensions of fetal tissues on and after the 17th day by the injection of normal test animals. However, no lesions of toxoplasmosis, or Toxoplasma, were found in histologic sections of fetuses 11 to 21 days old removed at autopsy from vaginally infected mothers. It is concluded that before birth the parasites were confined to the fetal blood. The experiments provide the first direct histological demonstration of placental toxoplasmosis. The possible bearing of the experimental disease on human placental and fetal toxoplasmosis is briefly considered. It is probable that a maternal parasitemia during the latter part of pregnancy, whatever the portal of entry may be, is an essential factor in the pathogenesis of human congenital toxoplasmosis and that this occurs shortly after exposure to Toxoplasma rather than in a later chronic stage of the infection. The suggestion is offered that some instances of spontaneous abortion or fetal death in man, as in the mouse, may be due to inapparent toxoplasmosis.

scholarly journals STUDIES ON NATURAL IMMUNITY TO PNEUMOCOCCUS TYPE III

1936 ◽  
Vol 64 (2) ◽  
pp. 307-330 ◽  
Author(s):  
John F. Enders ◽  
Morris F. Shaffer ◽  
Chao-Jen Wu
Keyword(s):  
Virulent Strain ◽  
Blood Stream ◽  
The State ◽  
The Body ◽  
Polymorphonuclear Leucocytes ◽  
Natural Immunity ◽  
Phagocytic Cells ◽  
Fixed Tissue ◽  
Type Iii ◽  
Pneumococcus Type

Among the experimental findings reported in this paper to which we wish to give particular emphasis are the following: 1. The results which follow the intravenous injection into rabbits of two strains of Pneumococcus Type III of different degrees of virulence vary with the state of the capsule. Thus when this structure is completely developed both remain in the blood. A culture of either strain begins to become susceptible to the blood-clearing mechanism contemporaneously with the onset of capsular degeneration and the initiation of other concomitant changes at the surface of the organism (cf Paper II), which occur much earlier with the less virulent strain. 2. When, in either case, removal from the blood stream occurs, this is effected by the phagocytic cells of the body. There is no suggestion that a new or unknown mechanism is involved. The greatest share of the burden is borne by the fixed phagocytic cells of the liver and spleen, and to a less extent by those of the lung and bone marrow. Nevertheless, it has been demonstrated that the polymorphonuclear leucocytes may also participate. 3. Phagocytosis by the leucocytes of the normal animal either in intro or in vivo has been observed only at such a time as the capsule has become impaired. Ingestion of the organisms by the fixed tissue cells appears also to be effective only under the same condition and is accordingly observed with much younger cultures of the less virulent strain. 4. Following their removal from the blood and their accumulation within the fixed phagocytes of the organs, destruction of most of the cocci proceeds within 2 to 4 hours. Both strains are destroyed provided they are in the state favorable to phagocytic attack. 5. Evidence has been presented which indicates that just as in vitro, so in a local area of inflammation within the body, aging with attendant capsular loss and increasing susceptibility to phagocytosis may take place. 6. With organisms from either strain a variable period of lag follows their injection into the blood stream, even when they are introduced in a state of active multiplication and complete encapsulation. 7. Differences in virulence for rabbits of two strains of Pneumococcus Type III do not imply that this animal possesses a defensive mechanism which is absent in other species, since it has been possible to demonstrate similar differences when the organisms are injected intravenously into mice. This fact indicates that the factors determining the degree of virulence of these strains are to be sought in the organisms themselves, rather than in the kind of host.

The CepIR quorum-sensing system contributes to the virulence of Burkholderia cenocepacia respiratory infections

Microbiology ◽  
2003 ◽  
Vol 149 (12) ◽  
pp. 3649-3658 ◽  
Author(s):  
P. A. Sokol ◽  
U. Sajjan ◽  
M. B. Visser ◽  
S. Gingues ◽  
J. Forstner ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Parent Strain ◽  
Respiratory Infections ◽  
Virulent Strain ◽  
Interleukin 1 ◽  
Homoserine Lactone ◽  
Burkholderia Cenocepacia ◽  
Sensing System ◽  
Quorum Sensing System ◽  
The Difference

The cepIR genes encode an N-acyl homoserine lactone (AHL)-dependent quorum-sensing system consisting of an AHL synthase that directs the synthesis of N-octanoyl-l-homoserine lactone (ohl) and n-hexanoyl-l-homoserine lactone and a transcriptional regulator. The virulence of cepIR mutants was examined in two animal models. Rats were infected with agar beads containing Burkholderia cenocepacia K56-2, K56-I2 (cepI : : Tpr) or K56-R2 (cepR : : Tn5-OT182). At 10 days post-infection, the extent of lung histopathological changes was significantly lower in lungs infected with K56-I2 or K56-R2 compared to the parent strain. Intranasal infections were performed in Cftr (−/−) mice and their wild-type siblings. K56-2 was more virulent in both groups of mice. K56-I2 was the least virulent strain and was not invasive in the Cftr (−/−) mice. OHL was readily detected in lung homogenates from Cftr (−/−) mice infected with K56-2 but was only detected at levels slightly above background in a few mice infected with K56-I2. Lung homogenates from mice infected with K56-2 had significantly higher levels of the inflammatory mediators murine macrophage inflammatory protein-2, KC/N51, interleukin-1β and interleukin-6 than those from K56-I2-infected animals. These studies indicate that a functional CepIR quorum-sensing system contributes to the severity of B. cenocepacia infections. A zinc metalloprotease gene (zmpA) was shown to be regulated by CepR and may be one of the factors that accounts for the difference in virulence between the cepI mutant and the parent strain.

scholarly journals STUDIES ON THE MECHANISM OF RECOVERY IN PNEUMOCOCCAL PNEUMONIA

1941 ◽  
Vol 73 (2) ◽  
pp. 201-222 ◽  
Author(s):  
W. Barry Wood
Keyword(s):  
Main Bronchus ◽  
Left Lung ◽  
Blood Stream ◽  
Pulmonary Lesion ◽  
Type I ◽  
Polymorphonuclear Leucocytes ◽  
Lobar Pneumonia ◽  
White Rats ◽  
Edema Fluid ◽  
Phagocytic Reaction

A uniformly fatal lobar pneumonia was produced in white rats by inoculation of the left main bronchus with virulent Type I pneumococci suspended in mucin. All of the animals succumbed in less than 5 days, half of them dying within 48 hours. In only 5 of 40 rats was the lesion confined to the left lung, and all but one developed pleurisy, pericarditis, or both. All had bacteriemia at the time of death. The pathogenesis of the pulmonary lesion was studied by examining the lungs of 35 rats killed at various intervals following inoculation. The pneumonic process spread rapidly until most of the left lung was involved in 36 hours. Frequent blood cultures showed invasion of the blood stream in a few rats at 6 hours and in over 90 per cent at the end of the first day. The first signs of pleurisy usually appeared at 18 hours. Microscopic examination of the actively spreading lesion revealed three characteristic zones: (1) an outer "edema zone" in which the alveoli contained many pneumococci floating freely in edema fluid, (2) a middle zone where both leucocytes and organisms were present, many of the latter being phagocytized, and (3) an inner zone of advanced consolidation in which the alveoli contained many leucocytes but no organisms and where there were already local areas of early resolution. Study of numerous lesions, at intervals of from 12 to 36 hours after inoculation, indicated that the pneumococci spread into normal alveoli principally by way of the infected edema fluid in the outer zone. Pneumococcus-laden edema fluid in large bronchi and in alveoli beneath the pleura suggested the mode of spread of the infection to other lobes and possibly to the pleural cavity. No adequate explanation could be found for the presence of active phagocytosis in the lungs of animals with bacteriemia and presumably without circulating antibodies, but this conspicuous phagocytic reaction was obviously responsible for the clearing of the central part of the spreading lesion. The action of type specific antibody upon the pulmonary lesion of experimental lobar pneumonia was studied in rats similarly infected but treated with antipneumococcal serum. When injected intravenously in a single dose within 18 hours after inoculation the antiserum was found to protect all of the rats against the otherwise fatal pneumonia. It stopped the spread of the pneumonic lesion, cleared the blood stream of organisms, and prevented the extension of early pleurisy. The antibody caused agglutination and capsular swelling of the pneumococci in the lung, particularly in the edema zone at the margin of the lesion where they were most numerous. Apparently immobilized by agglutination the organisms were overtaken by leucocytes and destroyed by phagocytosis. The phagocytic reaction was greatly accelerated by the specific opsonins of the antiserum, and the pneumococci were destroyed by polymorphonuclear leucocytes before many macrophages appeared in the alveolar exudate. Within a week after treatment resolution of the pulmonary lesion was well in progress. Both horse and rabbit antibody were shown to penetrate the lung, and immune bodies were demonstrated in the alveoli within 10 minutes after the start of treatment. The relation of the observed phenomena to the curative action of anti-pneumococcal serum has been briefly discussed, and it is pointed out that the principal effect of antiserum is to cause immobilization of the pneumococci in the advancing edema zone. Experiments to be reported in a later publication have shown that sulfapyridine exerts a similar effect through a different mechanism.

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