Problem Set 5 Flashcards
How is health viewed from an evolutionary perspective?
From an evolutionary perspective, health is often considered in terms of how well individuals can survive and reproduce in their environments. Evolutionary medicine examines how evolutionary processes, such as natural selection and adaptation, shape human health and disease susceptibility.
What are the advantages that an evolutionary approach can provide for epidemiology?
An evolutionary approach can provide insights into the origins and adaptations of pathogens, helping to understand their behavior and transmission dynamics. It can also inform the development of vaccines and treatments by considering how pathogens evolve resistance. Additionally, it can help identify risk factors for diseases based on evolutionary history, leading to more effective public health strategies.
What are the differences between incidence and prevalence? How are these rates used to assess the impact that a pathogen has on a population?
Incidence refers to the number of new cases of a disease that occur in a specific population during a defined time period. It reflects the risk of contracting the disease.
Prevalence refers to the total number of cases (both new and existing) of a disease in a population at a specific point in time. It indicates how widespread the disease is. These rates help assess the impact of a pathogen by providing insights into the disease’s spread and burden on the population.
What are the most common study designs in epidemiology?
Common study designs in epidemiology include:
Cohort studies: Follow a group over time to see who develops the disease.
Case-control studies: Compare individuals with the disease (cases) to those without (controls) to identify risk factors.
Cross-sectional studies: Assess the prevalence of disease and associated factors at a single point in time.
Randomized controlled trials (RCTs): Test the effectiveness of interventions by randomly assigning participants to treatment or control groups.
What are the advantages and disadvantages of prospective and retrospective studies?
Prospective studies:
Advantages: Can establish a timeline of events, reduce recall bias, and allow for the collection of data on exposures before disease onset.
Disadvantages: Time-consuming and often more expensive.
Retrospective studies:
Advantages: Generally quicker and less expensive, as they use existing data.
Disadvantages: Prone to recall bias and may have incomplete data.
What is transmissibility?
Transmissibility refers to the ability of a pathogen to spread from one host to another. It is often quantified by the basic reproduction number (R0), which indicates the average number of secondary infections produced by one infected individual in a fully susceptible population.
What are the main forms of transmission of infectious disease?
The main forms of transmission include:
Direct transmission: Person-to-person contact (e.g., respiratory droplets).
Indirect transmission: Through vectors (e.g., mosquitoes), fomites (contaminated surfaces), or airborne particles.
Vertical transmission: From mother to child during pregnancy, childbirth, or breastfeeding.
Explain the relevance of the overlap between the incubation period (asymptomatic period) and the infectious period.
The overlap between the incubation period and the infectious period is crucial because it determines when an infected individual can spread the disease to others. If a pathogen is transmissible during the incubation period, it can lead to outbreaks before symptoms appear, complicating control measures.
What is virulence? What is the relevance of virulence in terms of biological fitness?
Virulence refers to the degree of harm a pathogen causes to its host. It is relevant to biological fitness because a pathogen that is too virulent may kill its host too quickly, reducing its chances of transmission. Conversely, a balance between virulence and transmissibility can enhance a pathogen’s spread.
Why is it important to understand the life history of a parasite when developing appropriate preventive strategies and treatments for disease?
Understanding a parasite’s life history helps identify critical stages in its lifecycle that can be targeted for intervention. This knowledge can inform the timing of treatments, the development of vaccines, and strategies to interrupt transmission.
How can a parasite influence its host’s behaviour for its own benefit?
Parasites can manipulate host behavior to enhance their own transmission. For example, some parasites may alter host feeding or mating behaviors to increase the likelihood of being transmitted to new hosts.
How can we influence parasite life history to improve public health?
Public health strategies can influence parasite life history by targeting specific stages of the parasite’s lifecycle, implementing vaccination programs, improving sanitation, and using vector control measures. Understanding the ecological and evolutionary dynamics of parasites can lead to more effective interventions.
