Vaccine and zoonotic diseases

How was smallpox caused?

By a virus transmitted in contaminated droplets of body fluids or in contaminated clothes and bedding

Smallpox mortality rate

20-30% in Eruope/Asia/Africa

Who was smallpox more lethal to?

Indigenous Americans

Smallpox and the indigenous population

95% of them died from smallpox between the 16th and 17th centruy

When was smallpox introduced in America?

In 1520

How was smallpox introduced in America?

By a Spanish ship that landed in Cuba carrying an infected African slave

The progression of smallpox

It takes 4-6 weeks to recover if the patient survived

Late 70’s smallpox

Dr. Edward Jenner observed that dairy maids did not get smallpox

Dairy maids exposed to cowpox

We protected from smallpox

The hypothesis Dr. Edward Jenner tested

He scratched the pus from cowpox lesions into the skin of a non-infected person

Exposure to cowpox

Results in protection from smallpox

Smallpox and cowpox protein coats

They are very similar

One of the first ever vaccines

The smallpox vaccine

When did Edward Jenner publish his findings?

1798

Smallpox vaccine

Injection of a live vaccinia virus for cowpox that is related to smallpox, it is not dangerous

Antibodies produced during cowpox infection (harmless)

Provide protection against the deadly smallpox virus

World Health Organization

Began a vaccination campaign against smallpox in the 1960’s

Countries with active cases of smallpox

Diminished through the 60’s-70’s from vaccinations

When smallpox was eradicated in the wild

1977

Risk of reaction to the vaccine

In minimal

Risk of death from the vaccine

Zero

People vaccinated against smallpox

None, except military personnel

Where is smallpox kept alive in labs

The U.S, Russian, etc.

Why is smallpox kept alive in labs?

To make a biological weapon

Vaccines

Expose a human to a protein that is associated with a disease causing microbe

The vaccine microbe

Could be a dead microbe, live but weakened, altered toxin, or the mRNA that codes for a protein associated with the microbe

Immune system response

Makes antibodies and memory cells for that specific protein and disease

Skin

Provides first line defense

Inflammation and fever

Makes condition bad for the microbe

Microphages

Circulate the body either alert helper T cells, or could defeat the microbe

What do vaccines trigger?

Adaptive immune system just like an invading microbe

Helper T cells

Coordinates response of T and killer T cells

B cells

Makes antibodies that target the antigen of the microbe

Killer T cells

Destroys the entire cell infected with the microbe

Memory cells

Leftover B and T cells that result in immunity

More antibodies are produced after initial exposure to a vaccine

The subsequent increased level of antibodies after a booster shot

What is in a booster shot?

An increase in memory B and T cells

Receiving numerous vaccines and boosters

Children and Adults

Reduction in pertussis vaccine

Led to a sharp increase in cases of whooping cough

Vaccinations go rebounded

Whooping cough became low again

When should vaccines continue?

When the disease is completely eradicated

Childhood vaccines

Save lives and money

What do booster shots increase?

Antibodies and memory cells

What is polio caused by?

A virus that in some people attack the nervous system and prevents nerve impulses being sent to the muscles by motor neurons

The body without nerve impulses

Muscles weaken and a person could becomes crippled or die

Paralysis of Polio

<1% of cases

How many people suffer Polio symptoms

4-5% of people

How is the Polio virus spread?

Feces, nasal, and orally

How does Polio infect people?

Through the mouth and multiplies in the digestive tract

Peak Polio epidemic

1952

Salk vaccine

1955

Sabin vaccine

1961

What is the Salk vaccine made of?

“Killed” Polio vaccine

How does the Salk vaccine work?

It protects against Polio but the person can still spread it

What is the Sabin vaccine made of?

Live but weakened Polio vaccine

How does the Sabin vaccine work?

It protects against Polio and against spreading it

Rare instances of Sabin Polio vaccine

A person could get Polio from the vaccine

Salk and Sabin reward

Received the Presidential Medal of Freedom for their role in developing a Polio vaccine

The only protection of Polio

Vaccines, there is no cure

Consistent world-wide vaccination for Polio

Could one day be eradicated like smallpox

Poliovirus cases declined

More than 99.9% worldwide

Which countries still have polio?

Afghanistan and Pakistan

What is measles caused by?A

A virus that leads to a reash

Measles in extremely contaigous

90% of those exposed to measles will get the disease themselves unless they have been vaccinated

Measles in small children

Can be serious or even fatal

How many people were infected each year with measles prior to the MMR vaccine

3 million people

After the MMR vaccine, how have measles cases been reduced

By 99%

Measles deaths prevented during 2000-2019

25.5 million deaths prevented

Why do some parents think the MMR vaccine causes cancer?

At the same time a child receives the MMR vaccine, autism symptoms appear

What news platform pushed pseudoscience about Autism?

The Lancet

Who pushed pseudoscience about Autism?

Andrew Wakefield

What happened to Andrew Wakefield?

He lost his medical credentials and had to retract his paper.

MMR and Autism

There is no connection between MMR and Autism

What does Measles erase?

Previous immunity, making future infections of other diseases more likely

Children unvaccinated to the MMR vaccine

Health risk from getting MMR is much greater

Coronavirus name

SARS CoV-2

What does the covid19 virus look like?

It looks like there are spike proteins.

What do the spikes proteins on covid19 virus do?

They help the virus penetrate cells in its host

How do mRNA vaccines work

mRNA from vaccine is translated to make the “spike protein”. The body identifies and defeats the protein. It destroys the spike proteins rendering the virus much less harmful

Once the body learned how to defeat spike proteins

It has memory cells that provide immunity against exposer to covid19 virus

What do harmless spike proteins teach your body?

It teaches the body how to destroy the spike protein in the covid19 virus

Without the spike protein in covid19 virus

Covid19 has difficulty penetrating and infecting cells

Zoonotic disease

Diseases that can spread between humans and othe ranimals

Examples of zoonotic diseases

Viruses, bacteria, parasites, or fungi

The worse diseases for humans began as…

Zoonotic diseases

Direct contact

Contacting blood, saliva, feces, or other bodily fluids of animals

Indirect contact

Contacting areas an infected animal has been and contaminated

Vector borne

Bitten by an infected animal

Food borne

Eating uncooked, contaminated animal products

Water borne

Drinking water contaminated with waste from an infected animal

Common zoonotic diseases

Plague, West Nile, Lyme Disease, Rabies, HIV, Covid-19, Smallpox

Future zoonotic pandemic

Avian influenza (Bird Flu), Swine Flu, Ebola, SARS

What is rabies caused by?

A virus transmitted in the saliva

Where do humans most likely get rabies from?

Dogs

How do rabies infect people?

It travels in neurons to the brain and causes death

How do doctors treat rabies?

By giving antibodies for rabies to build up the immune system against the virus

Diseases with the arrival or Europeans

Native American populations were decimated

Why did Europeans have greater resilience to disease?

Centuries of contact with zoonotic diseases

Where did HIV originate?

In Africa

Zoonotic SIV

Simian immunodeficiency virus.