Download Public Health & Microbiology

MLAB 2434- Microbiology
Keri Brophy-Martinez
Public Health & The Microbiology Lab
Epidemiology
• Study of the occurrence, distribution, and
causes of disease and injury
• Purposes
– Study the course or history of disease
– Determine the frequency of disease
– Identify patterns of disease occurrence
– Identify risk factors for potential causes of disease
– Evaluate the effectiveness of preventative
measures
General Concepts of Public Health
• Laboratory
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Identify isolates
Specimen contamination rates
Number of isolates per site
Number of isolates per hospital unit
• Improvements to care
– Reduce cost associated with contaminated specimen
– Educate professionals in specimen collection and
specimen quality
General Concepts in Public Health
• Prevalence of bacterial isolates
– Influence the initial antibiotic choices and
empirical therapy
– Prevent the buildup of antibiotic resistance
• Especially in specific units or facilities
Definitions
• Carrier
– Person or animal who harbors and spreads
microorganisms that cause disease
– Person DOES NOT become ill
– Example: Typhoid Mary
– http://www.pbs.org/wgbh/nova/typhoid/mary.html
– http://www.pbs.org/wgbh/nova/body/diseasedetective.html
Definitions
• Reservoir
– Source of infection
– Site where the pathogen can multiply or survive
until its transferred to the host
– Can be living organisms, nonliving organisms, or
materials
– Examples: people, animals, environmental
elements
Definitions
• Endemic
– Organism or disease is constantly present in a
population
– Examples: Cholera in third world countries
• Epidemic
– Disease affects a significantly large number of people
at the same time in a geographic area
– Examples: West nile virus in 2002 in the U.S
• Pandemic
– Worldwide epidemic
– Example: Swine flu
Definitions
• Incidence Rate
– Number of times a new event occurs in a given period
– Usually given as cases per 1000 or 100,000 population
• Incubation Period
– Time between exposure to a pathogen and the onset
of symptoms
• Index case
– First case of a disease which serves as source of
infection
Epidemiologic Curves
Epidemiologic Curves (Cont’d)
Definitions
• Morbidity Rate
– Rate at which an illness occurs
• Mortality Rate
– Number of deaths caused by a disease in a population
• Surveillance
– Collection of data pertaining to disease occurrence
• Morbidity and Mortality Weekly Report
– Generated by the CDC
– http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6016a5.htm?s_ci
d=mm6016a5_w
Surveillance & Reporting
• Certain diseases are required by law to be
reported to public health authorities
– http://www.dshs.state.tx.us/idcu/investigation/for
ms/101A.pdf
– Diseases that have significant effect on the
population or have potential for grave
consequences
– Centers for Disease Control (CDC)
– World Health Organization (WHO)
References
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Engelkirk, P., & Duben-Engelkirk, J. (2008). Laboratory Diagnosis of Infectious Diseases: Essentials of
Diagnostic Microbiology . Baltimore, MD: Lippincott Williams and Wilkins.
http://www.cdc.gov/mmwr/about.html
http://www.pbs.org/wgbh/nova/body/disease-detective.html
http://www.kintera.org/atf/cf/%7B2DB64348-B833-4322-837C8DD9E6DF15EE%7D/Brochure_EpidemiologyFAQ.pdf
http://www.dshs.state.tx.us/idcu/investigation/forms/101A.pdf
Mahon, C. R., Lehman, D. C., & Manuselis, G. (2011). Textbook of Diagnostic Microbiology (4th ed.).
Maryland Heights, MO: Saunders.