Communicable Disease Epidemiology Flashcards
Anesthesiologist; disputed the miasmic theory of disease
John Snow
an empirical study in which the experimental conditions (i.e., which units receive which treatment) are determined by nature or by other factors out of the control of the experimenters and yet the treatment assignment process is arguably exogenous or “as-if random.” Broad Street Pump intervention
Natural experiment
True or False. Farr disputed Snow.
True
“bad air theory”
Miasmic Theory
Causative agent of plague
Yersinia pestis
Vector responsible for The Black Death
Rats. Ships travelled bringing food and produce infested by rats
of people; and year of the Great Plague
450M down to 350M-375M by the year 1400
Enumerate the plagues
The Great Plagues of Seville, London, Vienna, Marseille. Italian Plague; Great Plague of 1738, Russian Plague of 1770-1772
Ships arriving at Venice were required to sit at anchor for 40 days before landing
Quarantine (from Italian quaranta giorni)
Established the Bureau of Quarantine
Public Health Services Act of 1944
Reports underestimate the true burden of disease
The Iceberg Concept of Infection
Attempted to document the natural history of syphilis
Tuskgee Trial
Causal links of NCDs
Underlying factors, Behavorial risk factors, metabolic/physiological factors
Number 1 Global Cause of Death in 2006
Heart Disease
phase of development witnessed by a sudden and stark increase in population growth rates brought about by medical innovation in disease or sickness therapy and treatment, followed by a re-leveling of population growth from subsequent declines in fertility rates
Epidemiological Transition
Posited the replacement of infectious diseases by chronic diseases over time due to expanded public health and sanitation
Abdel Omran
No. 1 re-emerging and re surging communicable disease in the world
Dengue Fever
Where mortality is high and fluctuating, precluding sustained population growth, with low and variable life expectancy, vacillating between 20 and 40 years.
Age of Pestilence and Famine
Where mortality progressively declines, with the rate of decline accelerating as epidemic peaks decrease in frequency. Average life expectancy increases steadily from about 30 to 50 years. Population growth is sustained and begins to be exponential.
The Age of Receding Pandemics
empirical cross-sectional relationship between life expectancy and real per capita income
Preston Curve
Upward shift in the x.s. graph of expectancy and real per capita income
Technology applies equally to all
Increase in the first derivative or slope of x.s. graph of expectancy and real per capita income
Favors the rich countries
Decrease in the first derivative or slope of x.s. graph of expectancy and real per capita income
Favors poor countries
Preston Attributes
Education, Better Technology, Vaccinations, Improved provision of public health services, oral rehydration therapy, better nutrition
True or False. Africa will still be the number 1 country in terms of number of cases of HIV
False. China and India will by the principle of economies of scale.
Addressing mere symptoms or manifestations of disease, rather than the underlying pathogenesis e.g. organ transplantation
Half-way technology
Dialysis, respiratory
Non-technology
True or False. Young adults were most susceptible during the 1918 Spanish Influenza
True
Elements of the epidemiological triad
Host, Agent, Environment
True or False. Epid triad may apply for NCDs
True.
Entry and devpt or mult. of an infectious agent in the body of man or animals
Infection
Gradients of infection
Colonization, subclinical, latent, manifest or clinical
Presence of an ID agent on a bodyu surface or in clothes, beddings, toys, surgical instruments or dressing or other articles or substances including water and food
Contamination
lodogement, development and reproduction of arthropods on the surface of the body or in the clothing, e.g. lice, itch mite. invasion of the gut by parasitic worms e.g. STH
Infestation
transmitted through contact. name and give examples.
Contagious disease. scabies and STDs
True or False. Incidence is usually more relevant for a communicable disease
True. Prevalence is of little interest. Remember, P=ID, but D is short usually for CDs.
natural habitat of the infectious agent
Reservoir
Always, Sometimes, Never. An epidemic is 10% more than the usual.
Sometimes. One case of smallpox or polio may be considered an epidemic already.
Constant presence of a disease or ID agent within a given geographic area of population group
Endemic
Disease is constantly present at high incidence and/or prevalence rate and affects all age groups equally.
Hyperendemic
Age groups are not affected equally and children are more vulnerable and taper off in adult stage showing evidence of disease.
Holoendemic. A disease for which a high prevalent level of infection begins early in life and affects most or all of the child population, leading to a state of equilibrium, such that the adult population shows evidence of the disease much less frequently than do the children.
True or False. Rabies is an example of a holoendemic disease.
False. Malaria is.
An epidemic affecting a large prop of the popln occuring over a wide geographic area such as a section of a nation, entire nations or continents
Pandemic
Cases are few and are separated widely in time and place they show no or little connection with each other nor a recognizable common source of infection
Sporadic Disease
Always, Sometimes, Never. Sporadic cases of polio may be a starting point of an epidemic.
Sometimes. Only when there are favorable conditions. :))
Give examples of organisms that take the opportunity to infect when the host defense is low.
TB, Pneumocystis jirovecii, Herpes simplex, cytomegalovirus
True or False. When one case resurfaces, there is no more eradication.
True. It’s an all-or-none phenomenon. e.g. smallpox
Eradication of a disease from a large geographic area
Elimination. Such as in polio, measles and diphtheria
Proportion of non-immune exposed individuals who become clinically ill.
Attack rate
First case.
Index case.
Transmission of disease from vertebrate animal to man
Zoonosis
Outbreak of disease in an animal population
Epizootic e.g. rift valley fever
Endemic occurring in animals
Enzotic e.g. bovine TB
Potential for an ID to spread
Reproductive rate of isolation
Name the factors for the spread of ID
Probability of transmission between infected and susceptible; frequence of population contact; duration of infection; virulence of organism, population immune proportion
Vaccinate a minimum number of people confers immunity to the population
Herd Immunity
Source/Reservoir–>Modes of transmission–>Susceptible host
Chain of Infection
Types of reservoir
Human, animal, non-living
Classification of cases are?
Latent, Subclinical, clinical (mild/severe-typical/atypical)
Three elements to be a carrier
presence in the body of the disease agent. absence of recognizable Sx, shedding of disease agent
Examples of diseases found in non-living reservoirs
Tetanus, anthrax, and cocciodiomycosis
Direct modes of transmission and give examples for each
Direct contact (scabies), Droplet infection (TB), Contact with soil (e.g. STH), Incubation with skin or mucosa (HIV?), trans-placental (vertical transmission) (Hepa and HIV as well)
Four stages of successful parasitism
Portal of entry; site of selection inside the body; portal of exit; survival in external evt.
Degree of pathogenicity; disease evoking power; Overt Infection/Case load; may be equal to CFR
Virulence
True or False. CFR lowering means that there are more effective treatments for a disease.
False. It it possible that the number of cases detected just dropped di ba? :)) Pwede pa ngang negative ang mangyari
Gap between the onset of primary and secondary cases
Serial interval
Length of time a person can transmit disease
Infectious (communicable) period
time from exposure to devpt of disease (onset of first Sx)
Incubation period
Period between exposure and the onset of infectiousness
Latent Period/Generation Time (Epi Book)
True or False. Incubation period is longer than latent period.
False. The two may vary.
The Big Three
AIDS, TB and malaria
Emerging and re-emerging
Dengue, AH1N1, Corona
NTDs
Leprosy, rabies, Lepto, Schisto, STH, Lymph. filariasis
Celebrity poster boy of AIDS
Rock Hudson
We educated a lot of people today.
Michael Johnson to Dennis Rodman
Cause of Manuel Quezon’s death
TB
True or False. The lifetime risk of developing TB is 60% in PPD+ and HIV+
True. Duh.
Four Stages of HIV Infection
Primary HIV Infection, Asymptomatic, Symptomatic, AIDS
<500 cells/mm3 CD4 count. What is this level and what is its significance.
TB Death Zone. Give ARTs at this level because RCTs have shown dramatic better prognosis.
convergence of two or more diseases that act synergistically to magnify the burden of disease
Syndemic
Mortality continues to decline and eventually approaches stability at a relatively low level.
Age of Degenerative or Man-made Disease
Period of SARS, H1N1, Cancers,
Age of Delayed Degenerative and Re-emerging Infections
No. 1 Disease by 2030
Unipolar depressive disorders
Stages in the Natural History of Disease
Susceptibility; Subclinical; Clinical; Recovery, Death or Disability
Inanimate object that is laden with disease causing agents
Fomite
