Epidemiology Overview and Terminology

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Questions and Answers

What defines chronic symptoms in medical terms?

Symptoms that tend to recur over a long period. (correct)

Symptoms that have previously resolved and returned.

Symptoms that improve or disappear over time.

Symptoms experienced only sporadically.

Which type of transmission is associated with Hepatitis A?

Airborne transmission.

Contaminated food. (correct)

Blood contact.

Sexual contact.

What is the causative agent of Gas Gangrene?

Clostridium perfringens. (correct)

Escherichia coli.

Clostridium tetani.

Staphylococcus aureus.

Which of the following statements is true about schistosomiasis?

It is commonly transmitted by snails. Signup and view all the answers

Which of the following is a characteristic of relapsing symptoms?

They return after being previously resolved. Signup and view all the answers

What is a major mode of transmission for tuberculosis?

Airborne transmission. Signup and view all the answers

What type of infection is described as sporadic with potential to become endemic?

Worm infection. Signup and view all the answers

Which infectious disease is caused by HIV?

AIDS. Signup and view all the answers

Which type of epidemic results from exposure to a single contaminated source?

Common-source Epidemic Signup and view all the answers

What mechanism helps a population resist the spread of infectious organisms?

Herd Immunity Signup and view all the answers

What describes a healthy carrier?

An individual who carries the pathogen but shows no symptoms Signup and view all the answers

What type of carrier is characterized by having an overt clinical case of a disease?

Active Carrier Signup and view all the answers

Which of the following best explains antigenic drift?

Small, gradual changes in a pathogen's antigens Signup and view all the answers

What is an example of airborne transmission?

Pathogens suspended in air traveling more than a meter Signup and view all the answers

What distinguishes a chronic carrier from other types of carriers?

Holds the pathogen for months or years Signup and view all the answers

What is the primary role of a clinical microbiology laboratory in disease causation?

Isolation and identification of pathogens Signup and view all the answers

Which of the following diseases caused by mosquitoes can lead to hemorrhagic symptoms?

Dengue fever Signup and view all the answers

Which of the following characteristics distinguishes communicable diseases from non-communicable diseases?

Communicable diseases are caused by pathogenic microbes. Signup and view all the answers

What type of transmission is associated with Ebola virus disease?

Contact transmission Signup and view all the answers

What type of transmission involves direct physical interaction between an infected person and a host?

Contact Transmission Signup and view all the answers

What is the definitive mode of transmission for Meningococcemia?

Airborne transmission Signup and view all the answers

Which of the following correctly describes passive escape of pathogens?

Excretion in various bodily fluids Signup and view all the answers

Which symptom is commonly associated with both AH1N1 and Bird flu infections?

Respiratory infections Signup and view all the answers

How are diseases classified in terms of their duration?

Communicable diseases are acute. Signup and view all the answers

What distinguishes pathognomonic signs from diagnostic signs?

They indicate a specific cause with high certainty. Signup and view all the answers

Which one of the following diseases is NOT caused by mosquito bites?

Plague Signup and view all the answers

What term describes microorganisms adhering to dust particles?

Dust Particles Signup and view all the answers

What type of epidemic does Anthrax represent?

Common source epidemic Signup and view all the answers

Which vehicle transmission example describes a single vehicle spreading a pathogen to multiple hosts?

Common Vehicle Transmission Signup and view all the answers

Which of the following statements best describes symptoms?

Subjective experiences reported by patients. Signup and view all the answers

What does disease susceptibility depend on?

The host's defense mechanisms and pathogen's pathogenicity Signup and view all the answers

Which of the following is not categorized as a type of disease sign?

Symptomatic Signup and view all the answers

What defines a pandemic?

Long-term increase in frequency in a large, usually worldwide, population. Signup and view all the answers

Which term describes a disease that occurs occasionally at irregular intervals?

Sporadic Disease Signup and view all the answers

What is morbidity rate?

Number of new cases in a specific time per unit of population. Signup and view all the answers

What characterizes an outbreak?

An epidemic-like increase occurring in a very limited segment of the population. Signup and view all the answers

Which of the following best describes zoonosis?

Diseases of animals that can be transmitted to humans. Signup and view all the answers

What type of disease is characterized by a gradual increase in frequency above the endemic level?

Hyper Endemic Signup and view all the answers

Which of the following accurately describes 'Symptoms' in disease surveillance?

Subjective changes experienced by the patient. Signup and view all the answers

What is the incubation period?

A period after the pathogen enters the body with no symptoms. Signup and view all the answers

What is the primary function of Lactobacillus acidophilus in the female genital tract?

To maintain an acidic pH in the vagina and cervix Signup and view all the answers

What distinguishes an opportunistic pathogen from a primary pathogen?

Opportunistic pathogens are part of the normal microbiota but can cause disease under certain conditions Signup and view all the answers

Which of the following best describes the term 'commensal' in relation to normal microbiota?

The parasite gains from the host without harming it Signup and view all the answers

What role do microbes in the large intestine play in relation to pathogenic microbes?

They compete with pathogenic microbes and release inhibitory substances Signup and view all the answers

What is the primary characteristic of an ectoparasite?

It lives on the surface of the host Signup and view all the answers

What does 'virulence' refer to in terms of a pathogenic organism?

The degree of pathogenicity of an organism Signup and view all the answers

How can stress impact the microbial community in the colon?

It can disturb the self-regulating nature of the community Signup and view all the answers

Which of the following best describes a final host in the context of parasitology?

The host where the parasite reaches sexual maturity or reproduces Signup and view all the answers

What defines the term 'infectious disease'?

A change from a state of health due to a parasitic infection Signup and view all the answers

Which host type is essential for the initial development of a parasite?

Intermediate host Signup and view all the answers

Study Notes

Epidemiology

The science that evaluates the occurrence, determinants, distribution, and control of health and disease in a defined human population.
Epidemiologist: one who practices epidemiology.
Health: a state of physical and mental well-being, not merely the absence of disease.
Disease: an impairment of an organism which hinders vital function.

Epidemiological Terminology

Sporadic Disease: occurs occasionally at irregular intervals in a human population.
Endemic Disease: maintains a relatively low level frequency at a moderately regular interval. (Examples: flue, dengue, malaria, sore eyes, tigdas)
Hyper Endemic: gradual increase in frequency above the endemic level, but not to the epidemic level.
Epidemic: sudden increase in frequency above endemic level.
Index Case: the first case in an epidemic (first person infected).
Outbreak: epidemic-like increase in frequency, but in a very limited (focal) segment of the population.
Pandemic: long-term increase in frequency in a large (usually worldwide) population (Examples: COVID 19, monkeypox, HIV).
Enzootic: moderate prevalence in animals.
Epizootic: sudden outbreak of disease in animals.
Zoonosis: diseases of animals that can be transmitted to humans (e.g., rabies).

Frequency Rates

Morbidity Rate: number of new cases in a specific time per unit of population (newly infected).
Prevalence Rate: number of individuals infected at any one time per unit of population (all infected).
Mortality Rate: number of individuals who died during a time period.

Disease Surveillance

Signs: objective changes in the body (e.g., fever, rash).
Symptoms: subjective changes experienced by the patient (e.g., pain, appetite).
Syndrome: set of signs and symptoms characteristic of a disease.

Patterns of Disease

Incubation Period: the period after pathogen enters the body with no signs or symptoms.
Prodromal Period: onset of signs and symptoms that are not clear enough for diagnostic.
Period of Illness: the disease is most severe.
Period of Decline (Convalescence): signs and symptoms begin to disappear.

Epidemic Recognition

Common-source Epidemic: a sharp rise to peak and then rapid but not pronounced decline in cases, resulting from exposure of all infected individuals to a single common source (e.g., food or water contamination).
Propagated Epidemic: gradual increase and decrease in cases. An infected individual infects others until many are infected.
Herd Immunity: resistance of a population to infection due to the immunity of a large percentage of the population (achieved by vaccination, quarantine, avoiding contact).
Antigenic Shift: change in the antigenic (protein) character of the pathogen.

Infectious Disease Cycle

Disease Cause: the clinical microbiology laboratory plays a role in identifying the infectious agent.
Disease Source or Reservoir: location where organisms immediately transmit to the host, or where organisms normally found in the environment.
Disease Carrier: infected individual who may be a potential source of pathogen.

Disease Transmission

Airborne Transmission: pathogen suspended in air.
Contact Transmission: direct or indirect person-to-person touching or physical interaction.
Vehicle Transmission: transmission when inanimate materials or objects are involved.
Vector-borne Transmission: when a living intermediary carries the pathogen.

Types of Signs

Diagnostic Signs: help a doctor diagnose a medical problem.
Pathognomonic Signs: similar to diagnostic but with greater certainty.
Prognostic Signs: help predict a patient's health outcome.
Anamnestic Signs: indicator of a past medical condition.

Types of Symptoms

Chronic Symptoms: tend to recur over a long period.
Relapsing Symptoms: previously resolved symptoms that return.
Remitting Symptoms: improve or disappear.

Common Infectious Diseases

Various diseases (e.g., worm infections, diarrheal diseases, schistosomiasis, spongiform encephalopathy, hepatitis infections, tetanus, gas gangrene, leprosy, poliomyelitis, AIDS, chickenpox, influenza, measles, mumps, diphtheria, pertussis, pneumonia, tuberculosis, leptospirosis, rabies, sore eyes, skin infections, mosquito-borne infections (e.g., Dengue, Zika, and Malaria), flea/tick-borne infections (e.g., Plague), AH1N1, bird flu, anthrax, and meningoccoccemia) are listed.

Communicable vs. Non-Communicable Diseases

Duration: communicable diseases are acute (short-term), while non-communicable are chronic (long-term).
Seasonality: communicable diseases are often seasonal.
Cause: communicable are caused by pathogenic microbes, while non-communicable are caused by other factors.
Inheritance: non-communicable diseases can be inherited.
Spread: communicable diseases can spread, while non-communicable do not (e.g., diabetes, cancer).
Signs/Symptoms: communicable are often quickly obvious, while non-communicable may not be.
Observed: communicable are often less severe while non-communicable often more serious and long term.
Diagnosis: communicable diseases have more straightforward diagnosis compared to non-communicable.

Normal Microbiota

Endosymbiosis: inside the body.
Ectosymbiosis: outside the body.
Lists the microbes found on the skin, nose, oropharynx (throat), respiratory tract, mouth, eyes, ears, stomach, small intestine, and large intestine/colon.

Further Topics (from pages 14-17):

Relationship of Microbiota to the Host: mutualism, commensalism, pathogenicity, opportunism, role of microbes.
Parasitology and Infectious Diseases: parasitism, host-parasite interaction (ectoparasites/endoparasites).
Pathogenesis of Viral Diseases:
- host entry
- contact and susceptible cells
Pathogenesis of Bacterial Diseases:
- reservoir maintenance
- host transportation
Transformative Viruses: transforming host cells into cancer cells
Various other detailed microbiology concepts are discussed; these notes provide a general overview.

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Description

Test your knowledge on the fundamentals of epidemiology, including the concepts of health, disease, and various types of epidemiological terms such as endemic, epidemic, and sporadic diseases. This quiz is designed to help you understand the key terms and principles essential for studying the distribution and determinants of health in populations.