Mod 7 Flashcards
Define disease.
Any process or condition that adversely affects the normal functioning of a living thing or parts of a living thing. It is a state of impaired functioning, poor health.
Define infectious disease.
Caused by a pathogen and able to be transmitted from one individual to another.
Define non-infectious disease.
Often known as a disorder; can only be transmitted via genetic inheritance, caused by environmental factors or genetics, with no pathogen involvement.
Define pathogen.
Organisms or biogenic molecules that cause disease, also known as infectious agents.
What is pathogenicity?
The ability of a pathogen to cause disease.
Give examples of living and nonliving pathogens.
Living: bacteria, fungi, parasites, protozoans; Nonliving: viruses, prions.
What is communicable disease?
Diseases that can be transmitted from organism to organism.
What is endemic?
Level of a particular disease is steady.
What is epidemic?
Sudden spike in the prevalence of an infectious disease within the population of a region/community.
What is pandemic?
Sudden spike in a disease across the entire world.
What is epizootic?
Epidemics amongst animals in a particular region.
What are the three requirements for a disease to occur?
There must be a pathogen, a host, and a favorable environment for the pathogen to reproduce.
What is the host in relation to infectious diseases?
An organism susceptible to a disease.
What is interpersonal variation in disease resistance?
A healthy person might resist an infection that is devastating to someone whose immune system works poorly.
What is personal variation in disease resistance?
People under stress may succumb to an infection they might resist at another time.
What does ineffective dose mean?
An ineffective dose is one that is insufficient in quality to cause disease.
What is the effect of pathogens on the host?
Most pathogens stimulate defensive reactions in the host, such as increased white blood cell production, often accompanied by fever and tiredness.
How does the environment affect pathogen transmission?
The nature of the environment affects the likelihood of a pathogen growing and being passed from one host to another.
What is COVID-19 caused by?
COVID-19 is caused by infection with a coronavirus named SARS-CoV-2.
What are the symptoms of COVID-19?
Fever, chills, cough, shortness of breath, fatigue, muscle aches, headache.
How is COVID-19 transmitted?
Spread through direct contact or indirect contact with contaminated objects or surfaces, and can be contagious before symptoms start.
What management strategies were implemented for COVID-19 outbreaks?
Lockdowns, social distancing, quarantine, mandatory testing, and monitoring of cases.
What are some future control measures for outbreaks?
Development of vaccinations.
Define transmission of diseases.
The spread of a pathogen from an infected individual to another susceptible individual.
What is a vector in disease transmission?
Carries a pathogen and transmits it.
What is the chain of infection?
Host susceptible to the disease, pathogen capable of causing the disease, mode of transmission.
What are active and passive carriers of disease?
Humans can act as active or passive carriers of a disease.
What is direct transmission?
Physical contact between the host and the non-infected organism via exposure of infected skin or body secretions.
What is vertical transmission?
From mother to offspring (placenta, vaginal birth, breastfeeding).
What is horizontal transmission?
From one individual to another (not parent and child).
Give examples of direct transmission methods.
Touching, biting, sexual contact, contact with secretions, direct contact with blood or body fluids.
Give examples of indirect transmission methods.
Coughing, touching infected surfaces, contaminated food/water, vectors such as mosquitoes.
What is vector transmission?
A special case of indirect contact where another organism carries the pathogen from one host to another.
What are Koch’s postulates?
The microorganism should be found in all organisms suffering from the disease but not found in healthy organisms; must be isolated and grown in pure culture; must cause the same disease when injected into a healthy organism; must be reisolated and identified.
What did Robert Koch discover?
He discovered that a specific bacterium causes anthrax and developed Koch’s postulates.
What is pasteurization?
The process of heating food to kill pathogens and then letting it cool.
What role does agriculture play in infectious diseases?
It involves the cultivation of crops and rearing of animals for human products.
What is an exotic disease?
Infectious diseases that normally do not occur in the region due to never being present or eradicated.
What is an endemic disease?
Diseases present within a country or region.
What factors contribute to infectious diseases in agriculture?
Host factors, pathogen factors, environmental factors.
What are some causes of infectious disease in plants?
Plants are commonly attacked by pathogens, and if conditions are not optimal, pathogens can enter easily.
What abiotic factors can affect plant disease?
Temperature, light, chemical agents, water quality, nutrient availability.
What effects do plant diseases have on agriculture?
Reduced yields, loss of trading opportunities, economic loss for farmers.
Give an example of a plant disease and its effects.
Panama disease caused by Fusarium Oxysporum results in yellowing and wilting of leaves, damaging the plant.
What types of pathogens impact agricultural animals?
Bacteria and viruses impact agricultural animals, similar to human diseases.
What are the control methods for exotic animal diseases?
Control methods include vaccination programs, rapid quarantine, and culling infected animals.
Give an example of an animal disease and its effects.
Bird Flu, which can cross-infect humans with a high fatality rate.
What are some other causes/effects of infectious diseases?
Changing land use can spread diseases; pesticide resistance increases disease transmission risk; loss of genetic diversity increases susceptibility to disease.
What adaptations must a pathogen have to cause disease?
Pathogens must enter the host, multiply in tissues, resist host defenses, and damage the host.
What transmission methods do bacteria use?
Transmission may occur through close contact or indirectly through contaminated objects.
What adaptations do bacteria have for entry and transmission?
Many have pili and fimbria for adhesion, produce proteins to be engulfed, and toxins to fight off immune cells.
What transmission methods do fungi use?
Occurs through close contact or contaminated objects; fungi form spores for survival.
What adaptations do fungi have for entry and transmission?
Molecules in the cell wall help fungi adhere to host cells and they can survive without a host.
What transmission methods do protozoans use?
Uses insect vectors for entry; transmission occurs via bites or contaminated water.
What adaptations do protozoans have for entry and transmission?
Creates a lipid membrane for protection and enters privileged sites to overwhelm the immune system.
What transmission methods do macroparasites use?
Transmission occurs directly or through ingestion of eggs; ectoparasites require close contact.
What adaptations do macroparasites have for entry and transmission?
Secrete immunomodulatory proteins and can change host behavior for transmission.
What transmission methods do viruses use?
Enveloped viruses enter via endocytosis, non-enveloped attach to host cells to replicate.
What adaptations do viruses have for entry and transmission?
Can change antigens, spread through various vectors, and impact host behavior to induce coughing/sneezing.
What are prions and how can they be contracted?
Prions alter normal proteins upon contact; can be contracted via ingestion, surgery, transplants, or inheritance.
What adaptations do prions have for entry and transmission?
Able to travel through nerves, may piggyback on other proteins.
What are antigen-presenting cells (APCs)?
Cells that display antigens bound by MHC and present them to T-cells.
What is the plant’s response to pathogens?
Plants use physical barriers like bark and waxy cuticles and produce toxic compounds when pathogens breach these barriers.
What are Passive Defence Mechanisms?
They are barriers that exist before pathogen contact, requiring no energy from the plant to function.
What are Active Defence Mechanisms?
Targeted responses activated after pathogen recognition, involving chemical barriers that activate when passive barriers are breached.
What do physical barriers do?
They prevent movement or contact with pathogens.
What do chemical barriers do?
They interfere with microbes by breaking them down or inactivating them.
What is the 1st Line of Defence?
Passive barriers that physically and chemically prevent pathogen entry.
Give examples of physical barriers in plants.
Cell walls containing lignin and cellulose, waxy epidermal cuticles, bark, and stomata (which can close).
Give examples of chemical barriers in plants.
Antifungal and antimicrobial compounds, enzymes that break down pathogen toxins, saponins, and defensins.
What is the 2nd Line of Defence in plants?
The innate immune response, including PAMPs and other chemical responses activated by pathogen recognition.
What are Pathogen-Associated-Molecular-Patterns (PAMPs)?
Chemical receptors on plants that detect the presence of a pathogen and activate the next stage of defence.
What happens when a pathogen is detected?
The plant thickens cell walls, closes stomata, cuts off infected cells, and sends chemical signals to trigger defences in unaffected cells.
What is Gene for Gene Resistance?
Resistance genes in some plants produce proteins that disable specific pathogens in response to entry.
What is Basal Resistance?
An unsuccessful plant defence response that involves shutting gaps between cells to limit pathogen spread.
What is the Hypersensitive Response?
Activated if basal resistance fails, producing oxidative agents that trap pathogens inside host cells, leading to apoptosis.
What is the Systemic Acquired Response?
A non-specific, whole-plant response after localized pathogen exposure that prepares other tissues for potential pathogens.
Describe the interaction between Eucalyptus trees and water mould.
Water moulds damage Eucalyptus roots, but marri gum trees show resistance through increased lignin development.
What does Myrtle Rust cause in Eucalyptus?
Deformed leaves, defoliation, reduced fertility, stunted growth, and plant death, primarily affecting new growth.
How does the fungal pathogen penetrate plant tissue?
It forms haustoria that extract nutrients, and the plant responds by killing surrounding cells to cut off the fungus’s nutrient supply.
What is Banana Bunch Disease?
It prevents fruit production and causes yellowing and stunted leaf growth, transmitted via infected aphids.
What is the 1st Line of Defence in humans?
Non-specific physical and chemical barriers that protect against pathogen entry.
Give examples of physical barriers in humans.
Skin, mucous membranes, cilia, vomiting, and diarrhea.
Give examples of chemical barriers in humans.
Stomach acid, alkaline intestines, microbiome, and body secretions like urine and saliva.
What happens if the 1st Line of Defence fails in humans?
The innate immune response takes over, which is non-specific and not improved with re-exposure.
What is an Antigen?
Molecules that the host recognizes as foreign, triggering an immune response.
What are Exogenous and Endogenous antigens?
Exogenous are found on invading pathogens; endogenous are produced by pathogens within the host.
What is an Antibody?
A protein produced by the immune system that attacks specific antigens and forms antigen-antibody complexes.
What is Phagocytosis?
The process by which white blood cells engulf and destroy pathogen microbes.
What is the role of Neutrophils?
They are the first responders to acute inflammation.
What is the role of Macrophages?
They act as antigen-presenting cells (APCs) and are involved in chronic inflammation.
What is the Inflammatory Response?
It is triggered by tissue injury, causing increased blood flow, swelling, and attracting white blood cells.
What are Mast cells?
Cells that release histamines during the inflammatory response.
What do lysosomes do in the innate immune response?
They directly attack bacterial antigens by breaking down their cell walls.
What are Natural Killer Cells?
Specialized white blood cells that recognize and signal infected body cells to stop replicating.
What is the role of the lymphatic system?
It filters and returns intercellular fluid to the blood and traps antigens for lymphocytes to bind.
What is the Complement System?
A group of proteins that assists in destroying extracellular pathogens and stimulating phagocyte activity.
What is the 3rd Line of Defence in the immune response?
The adaptive immune response that targets specific pathogens and improves upon re-exposure.
What is the role of T cells?
They recognize specific antigens and activate immune responses against pathogens inside cells.
What do Helper T cells do?
Activate other T cells and stimulate phagocytes via cytokines.
What are Memory T cells?
T cells that remain after exposure to an antigen for a more effective secondary response.
What is Cell Mediated Immunity?
A response involving Helper T cells activating Killer T cells to target and kill infected cells.
How do Killer T cells destroy infected cells?
They release perforin to create pores in the cell membrane, allowing granzymes to enter and induce apoptosis.
What is the function of B cells?
They produce antibodies specific to antigens and can present these antigens to Helper T cells.
What happens when B cells are activated?
They clone themselves and form plasma cells that produce antibodies against the specific antigen.
What is Antibody Mediated (Humoral) Immunity?
The response that targets extracellular pathogens using antibodies produced by plasma cells.
What is Opsonisation?
The process of tagging foreign pathogens for elimination by phagocytes.
What is Immunological Memory?
Memory B and T lymphocytes persist after an infection, enabling a faster and larger response upon reinfection.
What is the Primary Response?
The initial response of the adaptive immune system when exposed to a pathogen, requiring time to develop.
What is the Secondary Response?
A faster and more robust response to the same pathogen upon subsequent exposure due to memory cells.
Define incidence.
Incidence is a measure of how many NEW cases of a disease are occurring over a given time.
Define prevalence.
Prevalence is a measure of the proportion of the population that HAVE the disease over a certain time period.
Give an example of incidence and prevalence for a disease.
Incidence: 500 cases of Covid a day; Prevalence: 10,000 cases present in NSW.
What is an outbreak?
An outbreak is when a specific disease suddenly starts to have an increased incidence.
List some laws and legislation for disease control.
Improve access to vaccinations, facilitate screening and education, support access to treatment, and authorize public health authorities to limit contact.
What is immunization?
Immunization is a successful and cost-effective public health strategy that saves millions of lives each year.
What local factors affect monitoring and control of infectious diseases?
Sanitation, overcrowding, poor communication networks, agricultural practices, local or spiritual beliefs.
Give an example of a local factor affecting influenza spread.
Influenza occurs in local environments like schools and hospitals, leading to higher incidences due to widespread exposure.
What are regional factors affecting disease transmission?
Geographical factors, temperature, and precipitation can influence disease transmission in a specific area or region.
Give an example of a regional factor affecting influenza.
Transmission of influenza can occur through airplanes, transporting both infected and non-infected individuals across regions.
What are global factors related to infectious disease?
Increased movement of people, migration, effective communication, and global trends in medicine.
Give an example of a global factor affecting influenza.
Influenza can spread to different countries via airplanes, especially when infected people travel internationally.
Define virulence.
Virulence refers to the ability of a pathogen to cause damage to a host.
What factors relate to the pathogen’s ability to infect?
Virulence, transmission methods, incubation period, evolution, and neutralization.
What host factors can affect disease susceptibility?
Concurrent illness, general health, and the use of pharmaceuticals like immunosuppressants.
What environmental factors influence the spread of diseases?
Environmental conditions, natural disasters, and reservoirs that may expose populations to unknown pathogens.
What social factors affect health practices?
Societal beliefs, affordability and accessibility, war, isolated societies, and travel.
List some measures for limiting the spread of diseases.
Availability of healthcare, social distancing, covering mouth/nose, washing hands, surveillance of strains, and quarantine.
Define active immunity.
Active immunity involves your body developing an immune response to a pathogen by exposing it to recognizable antigens.
What is naturally induced active immunity?
Naturally induced active immunity occurs when the body undergoes the immune response and suffers symptoms of the disease to develop immunity.
What is artificially induced active immunity?
Artificially induced active immunity is achieved through vaccines, which cause the production of memory cells without the body experiencing disease symptoms.
How do vaccines work?
Vaccines are harmless to the body and contain antigens that trigger an immune response, producing memory cells specific to that antigen.
What is passive immunity?
Passive immunity is provided when a person is given antibodies to a disease rather than producing them through their own immune system.
What is the advantage of passive immunity?
The advantage of passive immunity is that protection is immediate, whereas active immunity takes time to develop.
How long does passive immunity last?
Passive immunity lasts only a few weeks or months, while active immunity is long-lasting.
Define herd immunity.
Herd immunity occurs when a large portion of a community (generally 70%) becomes immune to a disease, reducing the likelihood of disease spread.
How can herd immunity be achieved?
Herd immunity can be achieved through widespread infection or widespread vaccination.
Who benefits from herd immunity?
Herd immunity helps protect vulnerable individuals who cannot get vaccinated, such as children, the immunocompromised, and the elderly.
What are public health campaigns?
Public health campaigns are government regulations aimed at reducing the spread of disease based on epidemiological and scientific studies.
What are public health programs?
Public health programs involve efforts to communicate information about specific diseases to raise awareness and advise affected individuals.
Give examples of government regulations in public health.
Regulations include guidelines for food handling, sterilization in healthcare, garbage disposal, treatment of drinking water, and disease reporting.
What types of public immunization programs exist?
Public immunization programs exist for diphtheria, tetanus, whooping cough, measles, mumps, rubella, and human papillomavirus.
What are pesticides?
Pesticides are chemicals used to kill pests, including pathogens and their vectors, reducing disease occurrence.
What is the purpose of insecticides, fungicides, and herbicides?
Insecticides kill insects, fungicides kill fungal pathogens, and herbicides kill weeds.
Give an example of a pesticide and its effect on disease transmission.
DDT controlled the spread of malaria by killing mosquitoes, which are vectors for the disease.
Why has the use of DDT been banned in many countries?
The effectiveness of DDT decreased due to mosquito resistance, and its harmful environmental effects led to its ban.
What is genetic engineering?
Genetic engineering involves altering the genetic makeup of organisms to produce disease-resistant plants and animals and control disease spread.
How can genetic engineering help in public health?
It can create vaccines for large populations, produce pesticides, and alter vectors like mosquitoes to prevent disease transmission.
What are OX513A mosquitoes?
OX513A mosquitoes are genetically engineered to prevent the transmission of diseases like Zika, Malaria, and Dengue Virus by inserting new genes into their eggs.
What do the new genes in OX513A mosquitoes do?
The new genes inserted into OX513A mosquitoes are lethality and fluorescent genes, making them disease-resistant and considered friendly to the environment.
Define Active Immunity.
Active immunity involves your body developing an immune response to a pathogen by exposing it to recognizable antigens.
What is naturally induced active immunity?
Naturally induced active immunity occurs when the body has to undergo the immune response and suffer the symptoms of the disease to develop immunity to it.
What is artificially induced active immunity?
Artificially induced active immunity is achieved through the use of vaccines, which cause the production of memory cells without the body experiencing the symptoms of the disease.
What are vaccines?
Vaccines are harmless substances that contain antigens, causing the body to undergo an immune response and produce memory cells specific to that antigen.
What is passive immunity?
Passive immunity is provided when a person is given antibodies to a disease rather than producing them through their own immune system.
What is the main advantage of passive immunity?
The main advantage of passive immunity is that protection is immediate, while active immunity takes time to develop.
What is Herd Immunity?
Herd immunity occurs when a large portion (generally 70%) of a community becomes immune to a disease, making the spread unlikely and protecting the whole community.
How can herd immunity be achieved?
Herd immunity can be achieved through widespread infection or widespread vaccination.
What are Public Health Campaigns?
Public health campaigns are government regulations aimed at reducing the spread of disease based on epidemiological studies.
What is the role of pesticides?
Pesticides are chemicals used to kill pests, including pathogens and vectors, reducing disease occurrence by controlling the spread.
What are antibiotics?
Antibiotics are substances capable of destroying or inhibiting the growth of bacteria, derived from microorganisms or synthetically produced.
What are the two types of antibiotics?
Bacteriocidal antibiotics kill bacteria, while bacteriostatic antibiotics inhibit bacterial growth.
What is antibiotic sensitivity testing?
Antibiotic sensitivity testing involves placing antibiotics in a petri dish with bacteria to observe if there is a zone of inhibition indicating effectiveness.
What is the primary goal of environmental management during an epidemic?
The primary goal of environmental management during an epidemic is to reduce the pool of available pathogens.
What is the incubation period of Ebola virus disease?
The incubation period for Ebola virus disease is between 2-21 days.
What are some symptoms of active tuberculosis?
Symptoms of active tuberculosis include chronic cough, coughing up blood, chest pain, weakness, weight loss, chills, fever, and night sweats.
How is tuberculosis primarily spread?
Tuberculosis is primarily spread through the air when an infected individual coughs or sneezes and another person inhales the droplets.
What are the first lines of defense against Mycobacterium tuberculosis?
The first lines of defense include airway epithelial cells, mucociliary escalator, phagocytes (neutrophils, monocytes, dendritic cells), and macrophages.
What are cytokines?
Cytokines are signaling molecules that mediate and regulate immunity and inflammation.
What is leukocytosis?
Leukocytosis is an elevated white blood cell count due to the immune response to chronic infection.
Define accuracy in scientific measurement.
Accuracy is the extent to which a measured value agrees with its true value (reference value).
Define precision in scientific measurement.
Precision is the extent to which multiple measurements made under identical or similar conditions agree with each other.
What does reliability refer to in scientific studies?
Reliability refers to the extent to which the findings of repeated experiments agree with each other.
What is validity in the context of scientific experiments?
Validity is the extent to which an experiment addresses the question under investigation.
