Biological Determinants of Health - Session 1 Flashcards
What is an emerging infectious disease?
a previously unrecognized infectious disease
What is a reemerged infectious disease?
IDs that were one under control, but now are not, such as drug resistant and XDR versions of TB, cholera, dengue, etc.
What kind of virus is Zika?
a flavivirus
What family of viruses does Zika come from?
Flaviviridae
What is the vector of the Zika virus?
arthropods, primarily ticks and mosquitos
What are some examples of viruses carried by mosquitos?
Yellow Fever, Dengue, West Nile, Zika
When was Zika first identified in humans, and where?
1952 in many parts of Africa
Where did Zika spread after Africa?
Asia, and then eventually Brazil
When did the outbreak of Zika hit Brazil?
March 2015, declared a PH Emergency on Feb 2016
Why was Zika declared a public health emergency?
An association between Zika, microcephaly, and other neurological disorders
What are two ways Zika can be transmitted?
Through the mosquito vector and from mother to baby during pregnancy
What are the symptoms of Zika?
fever, rash, joint pain, and conjunctivitis
Which mosquito carries and transmits Zika?
Aedes aegypti and Aedes albopictus.
What is one severe side effect of Zika in adults?
Gillian-Barre syndrome, an autoimmune response that attacks the nervous system, causing weakness of muscles and in some cases paralysis
What are some public health interventions for Zika? 5
Travel advisories, protection from mosquitos, reproductive health, screening and monitoring , research
Where did Ebola come from?
A single zoonotic transmission event where a boy was infected from a bat
When did the worst of the Ebola outbreak begin?
December 2013
What’s the viral reservoir of Ebola?
fruit bats
What makes ebola so virulent?
majority of patients are unable to develop sufficient immune responses
What is the mechanism of the ebola virus?
It blocks INF interferon, who’s job is to prevent viral infection and induce other immune cells
What does Ebola infect after interferon?
Macrophages and monocytes, releasing large amounts of cytokines
What is the result of cytokine release in Ebola infection?
Increases permeability of blood vessels, and recruits more macrophages to maximize the number of cells Ebola infects, and then the coagulation cascade is activated
What causes death in Ebola?
hypovolemic shock from massive hemorrhage, or from catastrophe thrombosis, the formation of blood clots
How can Ebola spread?
person to person with direct contact with body fluids of an infected person, including blood, stool, vomit, urine, saliva, semen, and breast milk
Can Ebola be transmitted through fomites?
yes
Can Ebola be transmitted through air?
no
What are some public health interventions for Ebola?
early diagnosis, contact tracing, patient isolation and care, infection control during burial, reduce wildlife to human transmission, reduce human to human transmission, outbreak containment
Related specific microbes to specifc diseases, and the concept of contagiousness
Robert koch
Koch’s postulates
Bacteria has to be present in every case of disease, bacteria must be isolate from host and grown in pure culture, the specific disease has to be reproduced iff a pure culture is inoculated into a healthy susceptible host, bacteria must then be recovered from the experimentally infected
how is the microbiome acquired
originally after birth from the vaginal canal
What relationship does the microbiome have with humans
protective and symbiotic relationship, protection through nutrients, immunity, and barrier/protection
microbes that can cause host damage
pathogens
the ability of a microbe to cause damage
virulence
what are some ways microbes can enter the body to cause an infection?
respiratory tract, gastrointestinal, genitourinary, skin, mucous membranes, bloodstream
How are microbes transmitted to people?
direct contact, indirect contact, soil, water, animal, bugs
Infection that spreads from person to person
communicable disease
Infection that spreads very easily from person to person
contagious disease
an infection by a microbe that results in an expression of illness
symptomatic infection
colonization of the body by a microbe that does not cause symtoms
asymptomatic infection
a usually commensal microbe that can cause infection in someone with a weakened immune respone
opportunistic infection
infection limited to a small area of the body
local infection
infection found throughout the body
systemic infection
infection that develops rapidly and lasts briefly
acute infection
infection that develops slowly and lasts a long time
chronic infection
an inactive infection which can become active and produce symptoms in the future
latent infection
isolated case, a disease that occurs in a single case or scattered cases
sporadic
someone who has the virus but no clinical manifestations of the disease
asymptomatic carrier
disease at a rate that substantially exceeds what is expected based on the norm
epidemic
termination of all transmission of an infection by the extermination of the infectious agent
eradication
the eradication of an infectious agent from a large geographic region
elimination
an epidemic that become worldwide
pandemic
amount of time between infection and symptom onset
incubation period
how is tuberculosis spread?
droplet nuclei expelled when person with infectious B coughs, sneezes, speaks, or sings
can transmission how TB happen from someone with a latent infection?
no
what determines a TB infection?
infectiousness, environment, duration or exposure, and virulence
how many of those with TB infection get active disease?
5%
How many of those with latent infection will go on to become actively infected?
5%
Why screen for Tb?
find people with latent Tb who would benefit from treatment
derived from substances that are made by microorganisms and kill or inhibit other microorganisms
antibiotics
what structures do antibiotics target?
structures unique to bacterial structures, including cell wall, ribosomes, etc
4 mechanisms of bacterial resistance
destroy the antibiotic, modify the antibiotic, pump out antibiotic, mutate the target sructure
MRSA
methicillin resistant staph auras - usually harmless but can become infectious if enters a break in the skin
a version of MRSA that can be transmitted outside of the hospital, and is associated with severe infctions, though it is less resistant to antibiotics
Community acquired MRSA
What is MRSA’s virulence dependent on?
virulence factors that both enhance its ability to attach and incite host cells and inhibit the immune systemm
How is antibiotic resistance transferred from one bacteria to another
horizontal gene transfer through transformation
What is the range of the Aedes mosquito?
Tropical areas
isolated infections - occur in a single or scattered case
sporadic
examples of a sporadic infection
pneumococcal pneumonia
refers to the constant underlying presence of a disease in an area
endemic
an example of an endemic disease
malaria
a disease that appears above the normal levels, and substantially exceeds those levels
epidemic
What’s an example of an epidemic disease?
smallpox
When an epidemic goes global
pandemic
What’s an example of a pandemic?
H1N1
Why has there been a measles outbreak in the US?
families delay or don’t vaccinate their kids
When did Measles get reintroduced in the US?
late 2014 early 2015 outbreak in Disney
What are some reasons parents choose not to vaccinate?
complacency, internet, preservatives, autism, concerns of overwhelming the immune system
the public health concept that if large enough members are vaccinated, a measure of protection is given to the sensitive population by blocking widespread infection
heard immunity
What reasons do some children need to remain unvaccinated even though they are highly susceptible to measles?
Immunocompromised, or too young to receive the vaccine
What virus does measles come from?
Rubeola
Symptoms of measles
fever, runny nose, cough, red eyes, sore throat, followed by a rash
Why is measles so contagious?
virus is viable in the air for 2 hours, long latency period, sickness lasts a week
How is measles treated?
supportive care, and vitamin A suplemnets, rehydration, and antibiotics for eye and ear infections, as well as to prevent against pneumonia
What are the two parts of the immune system
innate and acquired
The primitive, non-specific, but fast acting part of the immune system
innate
the part that is more specific to particular organisms, involves antibodies, and is slower to act in the immune system
adaptive/acquired immune system
What are the two main cell classes in the adaptive immune system?
T and B cells which respond to specific threat
A group of signaling proteins that are released by a cell infected with a virus that signals for response of neighboring cells to stem the infection
INFs or interferons
Respond to viral infections - in B cells, they secrete antibodies that neutralize the bacteria or virus, and the other is a cell-mediated response where the T cells kill the virus-infected cells
Lymptocytes
How does the immunity response change as the infection progresses?
Initial immune response is the innate immunity (IgM), and then the acquired immunity comes later and lasts longer (IgG)
How can we acquire immunity to some diseases?
memory B cells are immediately activated upon a secondary exposure
Which cells are the basis for vaccines?
memory B
Why do we need the innate immunity?
it takes time for the required immune response to build up - in the mean time we need a fast-acting response
What are the two arms of the adaptive immune system?
B (humoral) and T (cellular) cells
What do B-cells do?
For the most part, they make antibodies that bind to the pathogen and flag the pathogen for destruction by the macrophages
What are the 4 steps of phagocytosis?
chemoattraction, adherence, ingestion, destruction
How do vaccines work?
expose individuals to a weakened or killed pathogen so an immune response is created, so that if an actual exposure occurs, the immune system readily response to the exposure
Vaccine type that contains a weakened version of the living virus - effective, but immunoupressed can’t get them
live, attenuated vaccines
What type of vaccine is MMR?
live, attenuated
What type of vaccine is varicella?
live, attenuated
What type of vaccine is oral polio?
live, attenuate
An killed virus is used in the vaccine - usually you need more than one dose to produce and maintain immunity
inactivated vaccines
What is the inactivated polio vaccine’s vaccine type?
innactivated
What type of vaccine is whole pertussis?
inactivated
Vaccine that only has parts of the virus or bacteria and not the entire organism - has fewest number of side effects
subunit
What kind of vaccine is cellular pertussis?
subunit vaccine
Vaccine that contains weakened toxins so the body can fight off the natural toxin?
toxoid vaccine
What type of vaccine is DTap?
toxoid - contains diphtheria and tetanus toxoids
Vaccine that fight bacteria with sugar like coating?
conjugate
What type of vaccine is Haemophilus influenza type B?
conjugate
recombine pathogens so that it appears to be the dangerous pathogen, but acts like a more benign pathogen
recombinant vector vaccine
Name two examples of passive immunity
antibodies passed from mother to baby through placenta or breastmilk, or antibodies to a particular antigen injected after a known or suspected infection (rabies)
Non-living particles that contain a nucleic acid, coat protein, and a lipid envelop in some cases - cannot live outside of a host cell
Viruses
explain how DNA viruses replicate
uses the host cell machinery to synthesize viral DNA. the viral DNA enters the nucleus to make RNA to code for viral proteins, then this is packaged for spread to other cells
explain how +ssRNA viruses replicate
have genomes that ae like mRNA, that can used directly to make viral proteins
how are retroviruses different?
they are a +ssRNA that brings in reverse DNA Pol to convert their RNA into DNA, and they inset into the the host genome
Why is it harder for us to get immune to the common cold, rhinovirus?
It;s a non enveloped virus with over 100 serotypes, so each cold is a new virus
How does the immune system respond to virus?
initial immune response includes fever, resulting from mast cells and macrophages, which helps fight infection by slowing the rate of viral reproduction
What are some ways to reduce the spread of viruses?
cover mouth or nose when sneezing or coughing, wash hands, avoid contact with other’s bodily fluids
What type of virus is the influenza?
-ssRNA virus in the family orthomyxoviridae
How many single strand RNA segments does the influenza virus have?
8
What are the two major glycoproteins on the surface of influenza a?
hemagglutinin and nauraminidase
involves different strains of viruses combining to make a new virus to create a very sudden, large change that can lead to a pandemic
antigenic shift
strains defined by tiny differences between subtypes
Antigenic drift
How does antigenic drift occur?
occurs through mutations that arise since RNA viruses can’t fix their mutations
Which strain of influenza causes disease in humans?
A
How many subtypes of hemagglutinin in influenza are there?
15
How mnay subtypes of hemaglutinin in influenze are there?
9
What are the two most common subtypes of influenza A?
H1N1 and H3N2
How do we know what influenza vaccine to make?
We monitor and predict which strain of flu will show up and make vaccines accordingly
How does untreated HIV lead to AIDS?
it slowly destroys the immune system and CD4+ T helper cells, meaning the immune system is severely weakened and can’t fight off normally harmless organisms (opportunistic infections)
What cells does HIV infect and wipe out?
CD4+ T helper cells
What does the CD4+ cell do?
regulates the immune response to an infection
What are the modes of transmission of HIV?
sexual contact or blood exposure or milk exposure to someone infected with HIV
What are some ways that transmission can be prevented?
prevent MTC transmission through c-sections and by not breastfeeding, use antiretrovirals to reduce viral blood load to undetectable, postexposure prophylaxis, pre-exposure prophylaxis
Why did stress evolve?
mechanism to react rapidly to danger - fight or flight
Where does the stress response begin?
amygdala - emotion processing part of the brain
Where does the amygdala send the stress signal?
the hypothalamus, which is the comment center
the autonomic system we can’t consciously control
sympathetic nervous system
What does the hypothalamus active?
sympathetic nervous system
What does the HPA axis release during a stress response??
cortisol - keeps the body on high alert
What does cortisol do?
increases glucose in bloodstream, and update in nervous system, raises BP, surpasses immune, digestive, reproductive, and growth systems
homeostasis, or maintaining stability through change
allostasis
the wear and tea that the body experiences due to repeated cycles of allostasis turning on or shutting off cortisol responses
allostatic load
how many pairs of chromosomes do we have?
23
Griffith experiment
transforming factor which turned nonvirulent strains virulent in the presence of heat killed virulent strains
Hershey Chase experiment
used bacteriophages and labeled phosphorous and suffer to discover that DNA was the genetic material
heritable modifiactions that change gene expression but do not change the sequence
epigenetics
what are three epigenetic systems
DNA methylation, histone modication, and non-coding RNA
a disease of high blood glucose levels
diabetes mellitus
occurs when individuals make little or no insulin, the hormone that control blood glucose levels
Type 1 diabetes
occurs in individuals who make insufficient insulin or whose cells resist insulin
Type 2 diabetes
a group of risk factors that include, Type 2 diabetes, high blood pressure, excess abdominal fat, and high cholesterol that in combination increase the risk of heart disease and stroke
metabolic syndrome
lowers blood glucose levels, secreted from beta cells from the pancreas
insulin
raises blood glucose levels, is secreted from the alpha cells from the pancreas
glucagon
the form of diabetes that is an autoimmune response
type 1
why does insulin not necessarily work for Type 2 diabetes?
cells lose their ability to respond to insulin
how does insulin work?
insulin increases glucose uptake by getting more GLUT transporters to the cells membrane when blood glucose levels are high
what does hyperglycemia result in?
microvascular disease, and microvascular complications
why is diabetes a public health concern?
85% of diabetics have type 2, more common as we age, and increasing in every country, including low and middle income
What are the primary risk factors for diabetes?
physical inactivity, cigarette smoking, alcohol, obesity
what are the two basic types of malnutrition?
protein-energy and micronutrient
the lack of enough proteins and carbs that defines hunger
protein-energy malnutrition
insufficient vitamins and minerals
micronutrient deficiency
results from a severe and often sudden lack of food, or disease. results in a child actually digesting their own muscle for energy
wasting
a child who is too small for their age because they have not developed properly
stunting
What are some reasons there is still food scarcity?
nature, war, poverty trap, agricultural infrastructure, over-exploitation, and distribution of local resources
characterized by protein deficiency, generalized by bloating and edema
Kwashiokor
characterized by extreme wasting from not getting enough calorie intake
marasmus
What is the relationship between malnutrition and disease?
malnutrition exacerbates other disease
primary source of energy
carbs
how are carbs broken down?
polysaccharides into oligosaccharides, then disaccharides, then smile sugars, glucose, galactose, and fructose
where does glucose go when we eat it?
pancreas B cells, which release insulin
What are the 3 simple sugars we can use?
glucose, galactose, and fructose
What are some issues with fructose?
less sweet, so we use more, but no insulin responses, so our appetite is not surpassed, and fructose can only be taken up in the liver, excess fructose is concerted into triglycerides in the liver (converted to fat)
elements we need for metabolic processes
minerals
the most common and widespread nutritional disorder - causes anemia because this mineral is needed in hemmaglutin
ion
mineral responsible for maintaining a strong immune system and promoting good health, as well as growth and develop,eat
zinc
what is the role of fat in the diet?
most energetic food - stored and then broken down slowly
suppress autoimmune response, lower LDL and CVD
essential fatty acids
mineral used in the thymus to produce t3 and t4 hormones the control body’s metabolism and prevents in utero complications
iodine
important in preventing blindness, anemia, and infections
vitamin a
involved in carbon metabolism, and dan synthesis, and especially important when fetus is rapidly growing - low amounts associated with spina bifida
folate
how was the green revolution affected hunger?
more people can be fed using oderninzed farming and GMA crops
