MLAB 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 – 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 – – detective.html detective.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 – d=mm6016a5_w d=mm6016a5_w

Surveillance & Reporting Certain diseases are required by law to be reported to public health authorities – ms/101A.pdf 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 Engelkirk, P., & Duben-Engelkirk, J. (2008). Laboratory Diagnosis of Infectious Diseases: Essentials of Diagnostic Microbiology. Baltimore, MD: Lippincott Williams and Wilkins DD9E6DF15EE%7D/Brochure_EpidemiologyFAQ.pdf 8DD9E6DF15EE%7D/Brochure_EpidemiologyFAQ.pdf Mahon, C. R., Lehman, D. C., & Manuselis, G. (2011). Textbook of Diagnostic Microbiology (4th ed.). Maryland Heights, MO: Saunders.