10:832:240 Chapter Notes - Chapter 12: Bloodborne, Isoniazid, Vector Control
Chapter #12: Communicable Diseases
I. Overview
• What are the determinants of selected communicable diseases?
• What are the key concepts concerning prevention, transmission, and treatment?
• What are the costs and consequences of communicable diseases?
• What are examples of successful interventions?
• What are the key challenges to future efforts?
II. The Importance of Communicable Diseases
• Cause 31% of deaths and 40% of DALYs in low- and middle-income countries.
• Disproportionately affect the poor.
• Enormous economic consequences.
• Relevance to MDGs.
• Much of the burden of communicable diseases is avoidable, many can be prevented or treated.
III. Key Terms, Definitions, and Concepts
• Communicable Disease-Transmission- Animal-animal, animal-human, or human-human.
• Communicable disease synonymous with infectious disease.
• Includes infectious and parasitic diseases.
• Case- An individual with a particular disease.
• Case Fatality Rate- The proportion of persons with a particular condition (cases) who die from
that condition.
• Control (Disease Control)- Reducing the incidence and prevalence of a disease to an
acceptable level.
• Elimination (of Disease)- Reducing the incidence of a disease in a specific area to zero.
• Emerging Infectious Disease- A newly discovered disease.
• Eradication (of Disease)- Termination of all cases of a disease and its transmission globally.
• Parasite- An organism that lives in or on another organism and takes its nourishment from that
organism.
• Reemerging Infectious Disease- An existing disease that has increased in incidence, spread to
new place, or has taken on new forms.
• Transmission paths for communicable diseases:
• Foodborne: Salmonella, E. coli.
• Waterborne: Cholera, rotavirus.
• Sexual or Bloodborne: Hepatitis, HIV.
• Vector-borne: Malaria, onchocerciasis.
• Inhalation: Tuberculosis, influenza, meningitis.
• Nontraumatic Contact: Anthrax.
• Traumatic Contact: Rabies.
• Different control measures:
• Vaccination.
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• Mass chemotherapy.
• Vector control.
• Improved water, sanitation, hygiene.
• Improved care seeking, disease recognition.
• Case management (treatment) and improved caregiving.
• Case surveillance, reporting, and containment.
• Behavioral change.
IV. The Burden of Communicable Diseases
V. The Costs and Consequences of Communicable Diseases
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• Constrain health and development of children, affecting schooling and adult productivity.
• Strong stigma and discrimination associated with HIV, TB, and others such as leprosy.
• Limit productivity and income of adult workers.
• Costs of treatment burden families.
• High rates of communicable diseases reduce investment in a country’s development.
VI. The Leading Burdens of Communicable Diseases
• The Burden of Emerging and Reemerging Infectious Diseases:
• Examples of emerging infectious diseases:
• SARS, China (2002).
• MERS, Arabian Peninsula (2012).
• Examples of reemerging infectious diseases:
• Cholera, Peru (1997).
• Ebola, West Africa (2014).
• Truly global threats and “a perpetual challenge.”
• Zoonoses (infection spread from animals to humans) cause of about 60%.
• Key factors include microbial adaptation and change, climate, changing ecosystems,
international travel and commerce, and war.
• 578 outbreaks in 132 countries from 1998–2001.
• Antimicrobial Resistance:
• Resistant forms of disease can emerge or reemerge when bacteria, parasites, and viruses are
altered through mutation, natural selection, or the exchange of genetic material among
strains and species.
• Examples of drug resistance:
• HIV, any first-line drug.
• MRSA, beta-lactams.
• In 2013, about 480,000 people globally developed multidrug-resistant TB.
• There is resistance to all malaria drugs.
• Factors contributing to development of drug resistance include increasing use of drugs,
poor prescribing and dispensing practices, inappropriate use, failure of patients to take
correct dosages, and counterfeit drugs.
• The Consequences of Emerging and Reemerging Infectious Diseases:
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