Intro to Community Health pt. 3

unique opportunities of communicable diseases (single pathogen)

prevention

eradication

unique challenges of communicable diseases

unpredictable

transmissibility

potential for explosive global impact

eradication not always possible

antibiotic resistance

why is eradication not always possible in communicable diseases?

non-human host, asymptomatic carrier, rapid mutations

why are antibiotics becoming less effective? (antibiotic resistance)

people are overusing them → people use it when they dont reallyyyyyyyyyyyyy need it

eradicated or nearly eradicated communicable diseases

smallpox + polio

re-emerging or emerging communicable diseases

measles

tuberculosis

whooping cough (pertussis)

dengue fever

malaria

cholera

ebola

avian flu

what percent of emerging communicable diseases are zoonotic? (can be transmitted between animals and humans)

75%

why is there an increase in mosquito-borne illnesses?

climate change → increase in mosquitos

epidemiologic triangle

describes what impacts the risk of and response to infection

what are the three pillars of the epidemiologic triangle?

host

environment

agent

host → epidemiologic triangle

organism (usually a human or animal) that the agent can infect

agent → epidemiologic triangle

the cause of the disease → typically a microbe such as a virus, bacterium, parasite, or fungus

environment → epidemiologic triangle

physica, environmental, sociocultural, economic factors that impact spread of disease

host microorganism

humans or animals that have been exposed to or harbor an agent

herd immunity

resistance to the spread of an infectious disease within a population that is based on pre-existing immunity as a result of previous infection or vaccination

T or F: the level required for herd immunity differs per disease

T → depends on how transmissible it is

ex → measles = 95%, covid = 70%

epidemiologic curve

number of cases spike up and then decrease when it becomes under control (think covid) → considerd the pattern of disease

in contrast, sporadic is NOT widespread, and endemic is SUPERRRRRR widespread and always high num cases

social determinants of communicable diseases

trends in child vaccination

in general, most vaccines remain steady

MMR has the greatest controversy

children are vaccinated with hep a the least (46% of children)

trends in adult vaccination

adults have never been great in getting all their vaccines → remain super steady, but not super high → most vaccines are only about 60%

T or F: there is a broad range of kindergartener vaccination rate for MMR (some states super vaxed, some super not) for 2021-2022

T → also caused by differing opinions towards COVID vaccines

T or F: epidemics occur in “pockets”

F → epidemics are wide-spread

T or F: There has been a resurgence of vaccine-preventable disease

T

the continuum of vaccine acceptance

refuse all → refuse but unsure → delay/refuse some → accept but unsure → accept all

T or F: all vaccines have benefits and potential harms

T

examples of harms caused by vaccines

DTP vaccine → linked to seizures and brain damage

Rotavirus vaccine → linked to intussusception (inversion of the bowels)

Oral poliovirus vaccine → linked to paralytic polio

vaccine adverse event reporting system (VAERS)

national “early warning” system co-managed by the CDC and FDA

post-vaccination adverse events, regardless of whether the cause is vaccine-related

“passive reporting system” - accepts reports from anyone

includes minor to major vents

number of reports alone cannot be interpreted as evidence of a casual relationship

around a million reports following COVID-19 vaccination as of December 2024

history of inoculation

2000 BC in china→15th century smallpox → 1721 smallpox → 1796 jenner’s smallpox vaccine → 1885 rabies pasteur → 1940s to 1950s polio vaccine

history of vaccine hesitancy

has been around since the history of vaccines

ex → anti-vacc society in 1902

has gotten worse

what has caused the increase towards vaccine hesitancy?

parents these days havent seen the harmful effects of these diseases since they havent been around for a while → makes it hard for people to understand the importance

T or F: the number of recommended vaccines has increased

T

rising prevalence of autism spectrum disorders

however, more kids are being tested so more kids are being diagnosed

disregards other causes such as dietary choices

people link autism to vaccines because the first signs of autism often occur around the same time as vaccination

myths of covid vaccine

the covid vaccine can affect women’s fertility

researchers rushed the development of the COVID-19 vaccine, so its effectiveness and safety cannot be trusted

getting the COVID vaccine actually gives you COVID

breakthough cases prove that even if i get the vaccine, i might still get COVID, so why bother?

a microchip, with the backing of Bill Gates, is being implanted with the vaccine

results of vaccine conspiracy beliefs and covid 19 vaccine study

43% of parents endorsed at least one conspiracy belief

parents who were hesitant about vaccines were less likely to vaccinate their own kids

Why is vaccine hesitancy increasing?

trust in science down

trust in government and public authorities down (73% complete trust in 1958 to 19% trust in 2015)

“vaccine altruism” → grounded in social responsibility and the concept of herd immunity → belief that everyone should be vaccinated to protect those with a weaker immune system

trust in each other down (mistrust in neighbors has gone up)

“infodemic” → lots of info out there

WHO Top threat to global health

vaccine hesitancy sits in the top 10 (#8)

misinformation

no intent to deceive, just inaccurate

ex → click baiting, satire/parody, newspaper hoax

disinformation

specific intent to deceive

ex → manipulated (deepfakes, falsified photos, counterfeit websites), taken out of context, purey fictional (biased claims)

why do we believe things that aren’t true? → why does mis/disinformation circulate so easily?

affect heuristic → relying on emotions, rather than concrete information (heart over brain) (shortcut)

bandwagon effect → adopting certain behaviors or beliefs because many other people do the same

confirmation bias → tendency to notice, focus on, and give greater credence to evidence that fits with our existing beliefs

commitment bias → tendency to remain committed to our past behaviors, particularly those exhibited publicly, even if they do not have desirable outcomes

framing effect → equivalent info can be more or less attractive depending on what features are highligthed (20% fat vs 80% fat-free)

interventions to combat mis/disinformation

innoculation (prebunking) → pre-emptively warn people to look for potential for being misled and train them to identify the techniques used to mislead or misinform

debunking → lead with the facts (make them simple and sticky using expert sources)

fact checking → improve media literacy-encourage verification of info + provide authoritive context alongside search results or online posts about dubious claims

accuracy nudges → think critically about message before sharing it

tagging/warnings → ex, “this page has repeatedly shared false info”

interventions to combat misinfo that are not effective

shaming or mocking → can deepen mistrust and entrench beliefs

censorship alone → may limit spread but can fuel conspiracy theories about suppression →overloading w facts

excessive detail → cognitive overload can lead to confusion or disengagement

impact of interventions for vaccination (biggest impact to smallest impact)

policy changes → clinical interventions → individual/health education

what types of interventions are generally considered to be most effective in increasing vaccination?

policy

epidemiologic transition

the shift in disease patterns and causes of death within a population over time, typically moving from a focus on infectious and parasitic diseases to a focus on chronic, non-communicable diseases

endemic

a disease that is regularly occurring within an area or community

epidemic

the rapid sprread of disease to a large number of hosts in a given population within a short period of time

pandemic

an epidemic that occurs worldwide or over a very wide area, crossing international boundaries and usually affecting a large number of people

T or F: exemptions permitted for state childcare and school immunization requirements differ per state

T → ex, only medical exemptions are permitted, medical and religious, medical and personal belief, medical and religiousand personal belief

Why is vaccination so important for population health?

they protect individuals and communities, reduce healthcare costs, and contribute to herd immunity

what are the Sustainable Development Goals (SDGs)

A set of UN goals to end proverty, protect the planet, and promote prosperity by 2030

replaced the MDGS that were in place form 2000-2015

main goal = “universal and equitable access to safe and affordable drinking water”

what is safely managed water?

drinking water from an improved water source which is located on premises, available when needed and free from fecal and priority contamination

safe water is water that is safe to drink in the users’ cup

NOT JUST HEALTH, safety, dignitiy

under-five mortality worldwide

the under-five mortality rate has fallen by more than half since 1990

12.6 mil in 1990, 5.6 mil in 2016

causes of death for children less than five, ranked most prevalent to least

neonatal causes, pneumonia, other/misc, diarrheal diseases, congenital/birth, injuries, malaria, menigitis, AIDS, measles

why do children die of diarrhea

youngest children → immature immune system, less physiologic reserve (skinny babies have no protection when they lose weight from diarrhea)

multiple physiologic insults → malnutrition, frequent infections

feces contaminated environment → water, food, environment

limited access to effective clinical care

organisms that cause diarrhea

bacteria → chlorine inactivates, ~1 micron (filterable), cholera, typhoid

protozoa → (Oo)Cyst chlorine resistant, 3-10 microns (filterable), cryptosporidiosis, giardiasis

viruses → chlorine inactivates, <1 micron (not filterable), rotavirus, norovirus

The incidence of ______ fell steeply during the early part of the 20th century after the introduction of filtration (1906) and chlorination (1913)

typhoid fever

advantages of WASH infastructure

provision of reliable, quality water

disease reduction

increase quality - better hygeine

what does a WASH infastructure require?

political stability

large investment of public dollars

terrain conducive

population density

population stability → slums, emergencies

land tenur → slums, emergencies

→ may be challenges in lower class countries

What are the benefits of WASH infastructure in low-resourced settings

Reliable, quality water

Reduction of infectious illnesses

improved hygiene

T or F: Humanitarian emergences are crises that threaten the health, safety, or well-being of large groups of people due to conflict, disaster, or disease

T

humanitarian emergencies

disasters caused by natural hazards → earthquales, eruptions, landslides, tsunamies, floods, drought. increasing unplanned settlements and climate change

outbreaks/epide,ics → disease → cholera, ebola, zika, COVID, mpox. increasing particularly animal → human spillover (zoonotic)

complex emergencies → conflict increasing

populations → refugees, IDPs, entrapped

each major categories of humanitarian emergencies are experiencing an increasing trend

T or F: IDs increase after flooding and displacement

T

syria water supply in conflict

pre-conflict syria = high access to safe drinking water and sanitation, not much of the population under extreme poverty. they achieved universal primary education

when conflict began in march 2011, 13.6 million needed assistance, 6.3 million internally displaced, 69% under the poverty line, 1.9 million needed shelter, 67% had no consistent water access

In southern syria in 2016+2017, what were the main sources of water?

trucked water (77% and 83%)

network (22% and 15%)

trucked water increasing, network water decreasing

where to intervene in low income countries → WASH

support private sector → get chlorine in trucks, cash to vulnerable populations

support infastructure → pay operators, rebuild/repair/maintain, get chlorine in system

household water treatment → tablets for when the above don’t work

risk management approach in low income countries → WASH

entry points, cash

WASH

safe drinking water, sanitation, hygiene

crucual to human health and well-being

environmental hygiene

aspects of the human health and disease that are determined by factors in the environment

also refers to the theory and practice of assessing and controlling factors in the environment that can potentially affect health

refugee

people who have fled war, violence, conflict, or persecution and have crossed an international border to find safety in another country

internally displaced people

persons or gorups of persons who have been forced or obliged to flee or leave their homes or places of habitual residence, in particular as a result of or in order to avoid the effects of armed conflict, situations of generalized violence, violations of human rights, or natural disasters

remain within the country’s borders

entrapped people

individuals who are unable to leave an area due to conflict, violence, natural disaster, or other crisis

spillover

when viruses move from one species to another

What is an examlpe of a success in terms of kenya’s sanitation?

the sanitation chain →

moving beyond latrines to collection → treatment → reuse

sanergy (in slums)

sanitation chain

waste is transported and removed from sanitation facilities

treated

and reused

hygiene kits

pre-packaged collections of items designed to promote and support hygiene practices, especially in emergency or disaster situations

a collection of items designed to prevent the spread of germs

chlorination tablets

solid forms of chlorine used to disinfect water in the process of water purification

they dissolve slowly, releasing chlorine that kills bacteria, algae, and other microorganisms

rapid response timing

the time taken from the initiation of a rapid response call to when a trained team arrives at the patient's bedside to assess and treat a deteriorating patient

What groups experience a disproportionate burden when there is inadequate WASH infastructure? Why are they particularly vulnerable?

marginalized inhabitants of border areas, such as the MEXICO-US border crossing, low income populations, communities of color, women, children, older adults, those with disabilities

They are particularly vulnerable due to limited access to resources, pre-existing health conditions, and social determinants

What are the four main categories of WASH interventions? What are the main interventions for water treatment? Sanitation? Hygiene?

water safety and supply, sanitation, hygiene, behavior change

water safety → source-based water treatment, household water treatment, improved water storage, improving water supply infastructure

sanitation → improved sanitation facilities, community-driven sanitation, solid waste management, wastewater management

hygiene → handwashing with soap, hygiene kit distribution, hygiene education

What are the main mechanisms by which WASH interventions operate to reduce disease?

improve water quality, provide sanitation facilities, promote handwashing → block fecal-oral transmission pathway, reduce environmental contamination, improve immune function, community empowerment

What are the challenges to doing “robust” research on WASH interventions in humanitarian responses and complex emergencies?

Conducting robust research on WASH interventions in humanitarian responses and complex emergencies faces significant challenges, including limited funding, resource constraints, political obstacles, and the need for strong collaboration between stakeholders

What are the barriers to identifying and implementing effective evidence-based interventions during a humanitarian response?

time constraints, resource limitations, lack of relevance to humanitarian practice, and challenges in adapting evidence-based practices to specific contexts.

How do issues like political instability, terrain, population density, and funding impact the ability to build WASH infastructure?

Political instability can lead to corruption and diverted funding, while difficult terrain increases construction costs and logistics. High population density, particularly in informal settlements, strains resources and makes infrastructure expansion difficult. Insufficient funding hinders the planning, implementation, and maintenance of WASH projects

T or F: Residents still have not recieved their money after the Flint water crisis settlement

T

When did we first know lead was a problem?

200 BC → evidence of lead posioning from ceramics

1796 → ben franklin wrote abt it

1950s → herb needleman → associated with figuring out long-term negative effects

T or F: there is no safe level of lead

T

T or F: Lead is everywhere throughout the US in the water

T

impact of lead on health

young children - intellectual disability, underperforming at school, behavioral issues

in adults → ischaemic heart disease, stroke

pregnant women → affects the development of the fetus

short-term consequences of lead

immediate neurotoxic effects of lead poisioning → irritability, loss of appetite, weight loss, sluggishness and fatigue, pica, seizures

legionnaires disease

long-term consequences of lead

decreased intelligence (small change in mean IQ = shift in entire population’s IQ distribution)

behavioral issues

speech impairment

hearing loss

reduced sperm count and abnormal sperm

miscarriage, stillbirth or premature birth in pregnant women

hematologic, cardiovascular, etc

widespread lead exposure in Flint (2009-2016)

spike in blood levels of children in flint → represents an epidemologic curve

cost of lead poisioning in the US

economic cost in the US → 50.9 billion dollars

cost of detoxifying entire nation = 1 trillion

costs include → health care cost, lost productivity, special education

for $1 invested in lead paint hazard control results in net savings of $181-$269 billion

biggest lead producers in the US (prior to 1978)

paint manufacturers, petrolieum industry, batteries, plumbing and construction, mining and smeltering

When did the issue in Flint start?

Flint changes the water supply from the municipal water supply from Lake Huron to the Flint River → associated with corroded pipes

When did Flint change the water source back to Lake Huron?

October 2015 (despite initial switch and problems occuring in early 2014)

What happens when Flint switches its water source from Lake Huron to the Flint River?

2014 → legionnaires disease spikes

June = residents raise concerns

october = GM stops using water from flint

january 2015 = flint declares a state of emergency

feb = city announces high lead levels in water

october = flint switches back to the Detroit water system

jan 2016 = governor rick snyder declares a state of emergency, president obama declares a federal state of emergency

april = crimincal charges against government officials

june = the CDC rereport confirming a link between blood lead levels in children

june 2017 = michigan attorney general drops charges against several officials, stating a need for more thorough investigation

2018 = michigan neds the free bottled water program, stating that water quality has improved

2019 = former governor rick snyder and other officials face new charges, including willful neglect of duty

2020 = michigan attorney general announces a settlement with a $600 million fund for water crisis victims + the settlement is approved by a federal judge

2021 = charges against former governor rick snyder are dropped

2024 = payments not yet distributed

how to prevent lead posioning

elminiate exposure (banned in 1978)

#1 exposure in housing built before 1978

primary prevention → individual level → lead posioning

use a home testing kit

hire a risk assessor to check your home

wash your hands frequently

take a daily supplement of iron and calcium

mop and vacuum frequently

surveillance

research

recommendations

secondary prevention → individual level screening → lead posioning

blood test for elevated BLL (current)

X-ray fluorescence (cumulative)

blood film examination (changes in red blood cells)

tertiary prevention → individual level chelating therapy → lead posioning

chelation therapy (if BLL is >45 ug/dL) →

less value in chronic cases below this value

chelating agents actively bind to lead

oral or intravenous

administration

forms a non-toxic compound excreted in urine