Communicable Diseases

12 Key excerpts on "Communicable Diseases"

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  eBook - ePub

  Communicable Diseases

  A Global Perspective

  • Roger Webber(Author)
  • 0(Publication Date)
  • CABI

    (Publisher)

  1 Elements of Communicable Diseases

  1.1 What Are Communicable Diseases?

  A communicable disease is an illness that is transmitted from a person, animal, or inanimate source to another person either directly, with the assistance of an intermediate host or by a vector. Communicable Diseases cover a wider range than the person-to-person transmission of infectious diseases; they include the parasitic diseases, infections transmitted by a vector, the zoonoses and all the transmissible diseases.

  Communicable Diseases present in an epidemic or endemic form. An epidemic is the introduction of a new infection or the presence of an illness in excess of normal expectancy. This can be seasonal, such as with influenza, or when the number of susceptible persons is sufficient for a new epidemic to take place, e.g. measles. Any unknown infection will be epidemic when first introduced. An endemic disease is constantly present in a geographical area or population group, e.g. malaria is found in tropical countries and endemic in the adult population.

  Communicable Diseases are dependent on the person being susceptible to infection, so children meeting an infection for the first time or communities that have been isolated from the infection are more liable to become infected. They are found particularly in conditions that encourage transmission, such as overcrowding or poor hygiene, so are more common in developing countries. They are invariably associated with poverty.

  Epidemic diseases devastate whole populations, as when measles ravaged Fiji in 1875, killing a quarter of the population, both adults and children. Populations then have to start again from the survivors to recover their former strength. These are essentially young and growing populations.

  With endemic diseases it is children that are particularly vulnerable, so there is a high birth rate to compensate. With so many young people in the population, non-Communicable Diseases are uncommon, but as people live longer then they become more frequent. Non-Communicable Diseases such as coronary heart disease (CHD) are the main problem of older aged populations as seen in the Western world.

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  Battling and Managing Disease

  • Britannica Educational Publishing, Kara Rogers(Authors)
  • 2010(Publication Date)
  • Britannica Educational Publishing

    (Publisher)

  EFINING HEALTH AND DISEASE: COMMUNICABLE DISEASE

  C ommunicable disease involves the transmission of a disease-causing agent. This process may entail the transmission of the agent from an environmental source, such as the soil or an animal, to a human, as well as transmission from one person to another. Because of the contagious, or infectious, nature of these conditions, they are frequently described as infectious diseases.

  There are many different agents that can give rise to communicable disease. These include viruses, such as influenza virus and HIV, as well as bacteria, fungi, and protozoans. The human body has several lines of defense against infection, including the skin, which acts as a barrier, and the immune system, which deals with agents once they have entered the body. Defense against infection is sometimes the result of sophisticated mechanisms of resistance employed by cells. Understanding patterns of infection and resistance are fundamental to stopping the spread of infectious agents within communities. When an agent becomes widespread, causing illness in many people within a confined region, it is described as epidemic. When it spreads across countries and becomes a global disease, it is described as pandemic.

  DISEASES OF BIOTIC ORIGIN

  Biotic agents include life-forms that range in size from the smallest virus, measuring approximately 20 nm (0.0000008 inch) in diameter, to tapeworms that achieve lengths of 10 metres (33 feet). These agents are commonly grouped as viruses, rickettsiae, bacteria, fungi, and parasites. The disease that these organisms cause is only incidental to their struggle for survival. Most of these agents do not require a human host for their life cycles. Many survive readily in soil, water, or lower animal species and are harmless to humans. Other living organisms, which require the temperature range of endothermic (warm-blooded) animals, may flourish on the skin or in the secretions of fluids of the mouth or intestinal tract but do not invade tissue or cause disease under normal conditions. Thus there is a distinction to be made between infection and disease.

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  The Law and Regulation of Public Health

  Global Perspectives on Hong Kong

  • Eric C. Ip(Author)
  • 2023(Publication Date)
  • Routledge

    (Publisher)

  5 Communicable Diseases

  DOI: 10.4324/9781003044741-5

  5.1 Introduction

  The human immune system is ‘a fearsome fighting machine’ deploying two modes of operation: a rapid-response, albeit generic mode, and a highly specific, albeit slower-evolving killer force that recognises the attacker—a ‘pathogen’1 —and can pre-emptively counterattack the latter if it infects again.2 Communicable Diseases are illnesses, the causes of which can be transmitted by persons, animals, or inanimate objects to other inanimate objects, animals, or persons, either directly or indirectly.3 Over 200 new infectious diseases4 have broken out in the human population in the past three decades, including several coronavirus epidemics since 2000.5 Many Communicable Diseases transmit between humans via air-borne agents, such as influenza.6 Others transmit via casual contact, like chicken pox; from mother to child, like HIV/AIDS; in bodily fluids, like transfused blood with gonorrhoea; on such living vectors as animals, insects, and plants, like rabies, Lyme disease, and Valley Fever, respectively.7 Certain infectious agents—anthrax, botulism, plague, smallpox, and tularaemia—have become bioterrorist weapons.8 Urbanised, high-density living worsens communities’ vulnerability to Communicable Diseases.9 Governments across the globe reckon on pathogens becoming not merely public health threats, but national security threats, too, and have expanded their powers to control Communicable Diseases accordingly.10

  1 ‘Pathogen’ is an English word with roots in Greek meaning ‘disease’ and ‘to cause to be’. See K Harper, ‘Deep History and Disease: Germs and Humanity’s Rise to Planetary Dominance’ in J Thomas (ed), Altered Earth: Getting the Anthropocene Right

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  Health, Disease and Society

  A Critical Medical Geography

  • Kelvyn Jones, Graham Moon(Authors)
  • 2022(Publication Date)
  • Routledge

    (Publisher)

  CHAPTER 4 Communicable Diseases

  Introduction

  This chapter is concerned with diseases that are capable of being transmitted from someone who is infected (the host) to someone who has not yet had the disease (the susceptible); they are variously known as contagious, infectious and Communicable Diseases. In the industrialised countries, despite the recent threat of AIDS, they are generally of low importance; even in childhood, Communicable Diseases are a minor cause of suffering and morbidity and now cause less than 5 per cent of all childhood deaths in Britain. Historically, they have been of much greater importance; only forty years ago tuberculosis was the disease of civilisation, and in the economically backward countries they remain the major killers today. Communicable Diseases are given a separate chapter here because of this worldwide importance (two-thirds of all human illness is attributed to such causes), and because their fundamentally different disease processes, when compared to chronic and degenerative diseases, require different modes of analysis. The discussion begins with a brief introduction to the biology of the diseases and then the different research traditions of ‘disease ecology’ and ‘diffusion’ studies are outlined and illustrated. As the discussion proceeds we move away from the biomedical model towards a social, and arguably deeper, understanding of Communicable Diseases.

  The biology of infectious diseases

  Communicable Diseases have a bewildering diversity and it is wise at the outset to offer a classification. It is possible to produce a classification on a number of criteria (for example, portal of entry and exit of infectious agent) but a classification based on the various types of organisms and their differing means of transmission is most appropriate for our purposes.

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  Diseases and Disorders

  • (Author)
  • 2014(Publication Date)
  • Research World

    (Publisher)

  ________________________ WORLD TECHNOLOGIES ________________________ Chapter- 2 Infectious Disease Infectious disease A false-colored electron micrograph shows a malaria sporozoite migrating through the midgut epithelia. ICD-10 A00.-B99. ICD-9 001-139 MeSH D003141 ________________________ WORLD TECHNOLOGIES ________________________ Infectious diseases , also known as Communicable Diseases , or transmissible diseases comprise clinically evident illness (i.e., characteristic medical signs and/or symptoms of disease) resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism. In certain cases, infectious diseases may be asymtomatic for much or all of their course. Infectious pathogens include some viruses, bacteria, fungi, protozoa, multicellular parasites, and aberrant proteins known as prions. These pathogens are the cause of disease epidemics, in the sense that without the pathogen, no infectious epidemic occurs. Transmission of pathogen can occur in various ways including physical contact, contaminated food, body fluids, objects, airborne inhalation, or through vector organisms. Infectious diseases that are especially infective are sometimes called contagious and can be easily transmitted by contact with an ill person or their secretions. Infectious diseases with more specialized routes of infection, such as vector transmission, sexual transmission, are usually not regarded as contagious so do not require medical quarantine of victims. The term infectivity describes the ability of an organism to enter, survive and multiply in the host, while the infectiousness of a disease indicates the comparative ease with which the disease is transmitted to other hosts. An infection is not synonymous with an infectious disease, as some infections do not cause illness in a host. Classification Among the almost infinite varieties of microorganisms, relatively few cause disease in otherwise healthy individuals.

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  Encyclopedia of Syndromes, Diseases and Disorders

  • (Author)
  • 2014(Publication Date)
  • College Publishing House

    (Publisher)

  ________________________ WORLD TECHNOLOGIES ________________________ Chapter 8 Infectious Disease Infectious disease A false-colored electron micrograph shows a malaria sporozoite migrating through the midgut epithelia. ICD-10 A00.-B99. ICD-9 001-139 MeSH D003141 Infectious diseases , also known as Communicable Diseases , or transmissible diseases comprise clinically evident illness (i.e., characteristic medical signs and/or symptoms of disease) resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism. In certain cases, infectious diseases may be asymtomatic for much or all of their course. Infectious pathogens include some viruses, bacteria, fungi, protozoa, multicellular parasites, and aberrant proteins known as prions. These pathogens are the cause of disease epidemics, in the sense that without the pathogen, no infectious epidemic occurs. ________________________ WORLD TECHNOLOGIES ________________________ Transmission of pathogen can occur in various ways including physical contact, conta-minated food, body fluids, objects, airborne inhalation, or through vector organisms. Infectious diseases that are especially infective are sometimes called contagious and can be easily transmitted by contact with an ill person or their secretions. Infectious diseases with more specialized routes of infection, such as vector transmission, sexual trans-mission, are usually not regarded as contagious so do not require medical quarantine of victims. The term infectivity describes the ability of an organism to enter, survive and multiply in the host, while the infectiousness of a disease indicates the comparative ease with which the disease is transmitted to other hosts. An infection is not synonymous with an infectious disease, as some infections do not cause illness in a host. Classification Among the almost infinite varieties of microorganisms, relatively few cause disease in otherwise healthy individuals.

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  Biology Trending

  A Contemporary Issues Approach

  • Eli Minkoff, Jennifer K. Hood-DeGrenier(Authors)
  • 2023(Publication Date)
  • CRC Press

    (Publisher)

  Communicable Diseases Prevention and Control: New, Emerging and Re-emerging Infectious Diseases (WHA48.13). This resolution ushered in a new era of public health measures designed to increase disease surveillance (the detection of disease patterns in populations) and improve control programs. Applied research is leading to more effective and low-cost ways to prevent the spread of disease. These efforts have been aided by computer databases and the sharing of such databases by governments and nongovernmental organizations around the world. The infrastructure for local health care providers to report disease cases to centralized public health systems has become better. In addition, geographical information system (GIS) computer software has allowed those data to be instantaneously mapped so disease trends can be spotted quickly.

  In the remainder of this chapter, we will examine various infectious organisms that can spread through human populations and cause disease. We will also examine some of the factors that change the balance between pathogens and their hosts. Before we do so, we discuss the threat from pathogens that can be introduced into the human environment intentionally.

  16.1.4 Intentional transmission turns disease into bioterrorism

  In 2001, the world learned what can happen if a person decides to spread a disease intentionally. On a small scale, a deranged individual who knows they have an infectious disease may deliberately expose others in the hope of making them suffer. But the incident that began in October, 2001 was different from this. Someone prepared large quantities of a bacteria called Bacillus anthracis and distributed it widely through the U.S. postal system, spreading the disease anthrax to a total of 22 people and causing 5 deaths and great economic and social disruption. Intentional transmission to large numbers of people for the purpose of spreading disease or suffering is called bioterrorism

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  Donaldsons' Essential Public Health

  • Liam J. Donaldson, Paul Rutter(Authors)
  • 2017(Publication Date)
  • CRC Press

    (Publisher)

  3 Communicable Diseases INTRODUCTION

  Ask a group of people in a high-income country today what disease they most fear, and they are likely to say cancer, dementia or perhaps stroke. They are unlikely to name an infection. This is a very modern phenomenon. From the dawn of human existence until the twentieth century, infectious disease was what people rightly feared.

  Schoolchildren learn about the Black Death (plague) that swept across medieval England killing millions of people. This terrifying disease is thought to have cut the global population from 450 million to 375 million. Historical accounts of the Great War often cover what followed it – an influenza virus that spread globally in 1918–19. The Spanish flu infected 20% of the world’s population and killed 40 million to 50 million people (more than died during the war itself). The threat of death from consumption (tuberculosis) was never far from mind throughout the nineteenth century and well into the twentieth. As recently as the 1980s, polio paralyzed a quarter of a million children every year worldwide.

  Down the centuries, public health interventions have improved human health in many ways, but two stand out: sanitation and vaccination. In comparison with modern medical technologies, each is remarkably simple. Yet, each has been highly effective in reducing the harm that communicable disease brings to the human population, and each is more cost-effective than any other health intervention. Many would add a third to the list, although its impact is more curative than preventive: the advent of antibiotics, from the time of the Second World War.

  In 1901, Communicable Diseases in England killed 369 people in every 100,000. By 2000, that figure was 2 per 100,000. The Global Burden of Disease study has estimated that, in 1990, 47% of all ill health globally (measured in disability-adjusted life years) was caused by communicable disease. By 2010, this had been reduced to 35%. Over the same period, the under-five mortality rate fell by 70% – again, mostly because of reductions in communicable disease.

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  Encyclopedia of Infectious Diseases

  Modern Methodologies

  • Michel Tibayrenc(Author)
  • 2007(Publication Date)
  • Wiley-Liss

    (Publisher)

  Local communities, and thus pathogens within them, are ultimately dependent upon a balance between the rates of migration and extinction throughout ecological times.This necessitates a consideration of balance in nature as a starting point of discussion on infec- tious disease dynamics in space and time (Fig. 33.5). As illustrated in Figure 33.5, the conventional statical view of health is now replaced by a more complex, dynamic three- piece puzzle in which the component parts, that is, the host, the agent and the environment, abiotic or biotic, strongly interact with each other and where multiway interactions, feedbacks and loops may intervene in disease behavior in time and space. As such infectious diseases cannot be viewed as a separate, independent entity apart from the whole ecosys- tem–the conventional downstream approach to health–but rather, need to be considered as a piece of a more complicat- ed puzzle in which all components are extensively interde- pendent on each other; in other words, any effect on one sub- set may potentially lead to consequences for the others [97]. Because of the reality of this diversity of interactions and other linkages between the agent, the host and the environ- ment, health problems, at least when it concerns communica- ble diseases, have much to do with complexity, rather than 574 ◆ ENCYCLOPEDIA OF INFECTIOUS DISEASES: MODERN METHODOLOGIES being simple cause-and-effect relationships. One pertinent example of such complexity is the demonstration of how the interplay between environmental forces and ecological responses may mould the population dynamics of disease. A cogent illustration is that of the cholera epidemic resurgence in certain populations, which clearly shows the existence of cyclic fluctuations in disease case numbers (Fig. 33.6).

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  Global Health

  • Brian Nicholson, Judy McKimm, Ann K Allen, Brian Nicholson, Judy McKimm, Ann K Allen, Author(Authors)
  • 2015(Publication Date)
  • SAGE Publications Ltd

    (Publisher)

  9 Communicable Diseases

  Colin S. Brown

  and William Newsholme

  Chapter overview

  After reading this chapter you will be able to:

  • describe the burden of infectious diseases
  • explain how disease burden is used and the limitations of data
  • describe programmes for control of Communicable Diseases.

  Introduction

  Though there are various ways in which to measure disease burden, no matter what metric is used, Communicable Diseases continue to wreak havoc on the young and working-age populations in LMICs. Furthermore, Communicable Diseases disproportionately affect the poor.

  Measures of disease burden

  Disability-adjusted life years (DALYs) is a widely used metric to describe disease burden. Infectious diseases account for a significant proportion of DALYs. The Global Burden of Disease Report suggested that lower respiratory tract infections, diarrhoeal illnesses, human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS), malaria and tuberculosis (TB) accounted for approximately one fifth of global morbidity in 2004 (Murray et al., 2012). Updates in 2010 revised these estimates downwards (see Table 9.1

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  The Social Ecology of Infectious Diseases

  • Kenneth H. Mayer, H.F. Pizer(Authors)
  • 2011(Publication Date)
  • Academic Press

    (Publisher)

  But AIDS is only one of multiple microbial threats, and other human activities can cause devastating infectious epidemics. The goal of this text is to analyze the wide range of activities and behaviors that influence the evolu-tion and dissemination of infectious disease epidemics. They include the migra-tion of people and the transport of goods; the production and distribution of food; human-influenced changes in demography and the environment; advances in medical technologies; and patterns of governance, conflict, natural disaster and the dislocation of populations. Taken together, we believe these diverse activities are essential determinants of the prevalence and incidence of the current array of infectious diseases that continue to be major causes of morbidity and mortality across the planet. In the electronic media era, on almost any given day, it seems the news is highlighting a new infectious disease pathogen as the next great threat to human-ity. In 2003 it was SARS. In 2006 it was avian influenza. Before that there were Legionnaires’ disease and Toxic Shock Syndrome, and earlier tuberculosis was (as coined by Rene and Jean Dubos) known as “the white plague” (Dubos and Dubos, 1952). While the battle between humans and constantly evolving microbes is continuous, it would be wrong to be unduly pessimistic about the future. The microbes adapt to their hosts and humans respond. Each year, more people have access to modern medicines. Health programs expand to more com-munities, and more young professionals are trained in clinical care and public health. In response to the AIDS epidemic, the international health workforce is expanding and improving at an unprecedented pace. While more always needs to be done, there now is a historic commitment to improving health, especially in the developing world.

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  Human Biology

  A Text Book of Human Anatomy, Physiology and Hygiene

  • C. J. Wallis(Author)
  • 2014(Publication Date)
  • Butterworth-Heinemann

    (Publisher)

  METHODS OF INFECTION There are various ways in which pathogens are able to enter the body and so cause disease, by physical contact and human carriers, in food and water, through wounds, by insect bites, from MICRO-ORGANISMS AND INFECTIOUS DISEASES 335 dust and dirt and by infected droplets in the air. Animals, too, are often carriers of diseases to man. Personal Contact Some diseases, particularly venereal diseases and skin diseases are contracted by actual physical contact or by contact with some article with which contact has been made by an infected person. Examples of the latter are spoons and forks, glasses, crockery (especially if it is cracked), towels, bedding, clothing and toilet seats. The importance of hand-washing after going to the toilet cannot be over emphasised. Venereal diseases have been dealt with at length at the end of Chapter XVII and this should be studied by all readers. Anyone who has been in company with an infected person may also contract some diseases and he or she is referred to as a contact. Human Carriers Human carriers are people who harbour pathogens from contact with a disease or from previously suffering from it themselves, without actually suffering from it at the time and who can therefore infect others. They are usually perfectly innocent of their danger to the community and are difficult to trace. Typhoid fever, diphtheria, smallpox and cholera are examples of diseases which can be trans-mitted in this way. Food Infected particles of dust may settle on food or in milk. Food may be contaminated by flies or it may be touched by people with dirty hands or hands contaminated after defaecation or micturition because of failure to wash after performing these processes. Water Infection by water may be through contamination at source, by sewage or by workers who are carriers.

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