BYUI Bio 221 Griffith/ Final

What is the Etiology of Herpes Simplex?

1) HSV1 (Herpes Simplex 1)

2) HSV2 (Herpes Simplex 2)

What is the attachment for Herpes Simplex?

Virus binds to SKIN & NERVE CELLS

Portal of Entry for Herpes Simplex

Skin Penetration

How does Herpes Simplex Evade the Immune System?

Intracellular Parasite (in nerve cells)

Herpes Simples means of Destruction?

Destroys epidermis & mucous membrane

Mode of Transportation for Herpes Simplex

Direct Contact

Herpes Simplex Reservoir

Human; Trigeminal Nerve Ganglion

Herpes Simplex Signs & Symptoms

90% of infections subclinical (asymptomatic)

Lesions in oral mucous membranes (cold sore)

Prophylaxis for Herpes Simplex

Acyclovir-Antiviral Agent (during a flare)

Secondary Infections from Herpes Simplex

Herpes Encephalitis

-chances of survival less than 50% w/o tx

-Tx with high-dose Acylovir

What is the etiology of Measles (Rebeola)?

Morbillivirus

-Single-stranded RNA

What is Measles aka/

Rebeola

What is the attachment for Measles/rebeola?

Hemagglutinin Spikes

-Bind to CD150 which is a Glycoprotein on most cells

Portal of Entry for Measles/Rebeola?

Respiratory Mucous Membrane

How does Measles/Rebeola evade the Immune System?

Immunosuppression

-Hemagglutinin & fusion proteins bind to lymphocytes= Interrupt IL-2 Cell Signalling and TH proliferation

=Immunosuppression lasts for two years

What is the means of destruction of Measles/Rebeola?

1) High Fever

2) Maculopapular Rash

What is the cause of the maculopapular rash?

Immune T-Cells target infected endothelial cells of small blood vessels

What is a complication that arises from measles in individuals that are T-Cell deficient?

No Maculopapular Rash

-They will have uncontrolled disease which will result in their death

In measles, what is all of the damage (and potential death) actually caused by?

Immune system overreaction. Not the disease itself.

What are 4 Hallmark Symptoms of Measles/Rebeola?

1) High Fever

2) Sore Throat

3) Koplik Spots (white spots in mouth)

4) Maculopapular Rash on palms and soles

What is the prophylaxis for Measles/Rebeola?

MMR Vaccine & Herd Immunity

What are Secondary Infections associated with Measles/Rebeola?

1) Middle Ear Infections

2) Pneaumonia

3) Encephalitis

4) Subacute Sclerosing Panencephalitis

What is Subacute Sclerosing Panencephalitis?

-History of measles before the age of 2

-Gradual progressive psychoneurological deterioration: Personality changes, seizures, myoclonus, ataxia, photosensitivity, spasticity, & coma

=No cure. Often fatal

What is the etiology of Tetanus?

Tetanospasmin Neurotoxin

What is Tetanospasmin Neurotoxin?

A-B Exotoxin

What is the attachment of Tetanus?

B chain binds to Disialogangliosides on neuron membrane

What is the Portal of Entry for Tetanus?

Parenteral Route- Obligate Anaerobe Microbe

-wound must be deep enough for anaerobic conditions

-Puncture wounds especially good for Tetanus

How does Tetanus evade the immune system?

Toxin required to cause disease is so small that it does not elicit an immune response

How is Destruction carried out with Tetanus?

A-Chain stops neurons from releasing GABA (inhibitory neurotransmitter)

=results in dangerous overactivity of muscles

=hypercontracted muscles

What is the Mode of Transmission for Tetanus?

Indirect Contact- through Fomite

-through break in skin and contact with soil, dust, or manure

NOT RUST

What is the reservoir for Tetanus?

Soil contaminated with animal fecal waste

What are the signs and symptoms of Tetanus?

Tetany- Spastic paralysis

-Jaw muscles affected early = LOCK JAW

Death results from respiratory failure

=Can't exhale-can't relax diaghram

=die with full lungs

Are there any Prophylaxis for Tetanus?

DTP/DTAP Vaccination

-These vaccines wear off:

96% of 6 year olds have immunity

30% of 70 year olds have immunity

TIG- Tetanus/ImmunoGlobulin (Temporary Immunity)

Is there any history associated with Tetanus?

Civil War - 100,000's ended up with Tetanus because aseptic technique NOT practiced

What are exotoxins?

Most powerful biological agents known

-Tetanospasmin Neurotoxin is A-B Exotoxin

What is the etiology for Botulism?

A-B Exotoxin

What are the 3 Types of Exotoxins for Botulism?

1) Type A Toxin- Most virulent & heat resistant

2) Type B Toxin- Prominent in Europe

3) Type E Toxin- Found in river sediment (in Alaska)

What is the Attachment for Botulism?

Toxin binds to nerves

Do Bacteria and endospores colonize in Adults for Botulism?

No. The Low pH in stomach acid makes it inhospitable for vegetation

Do Bacteria and endospores colonize in infants for Botulism?

Yes. Infants have a higher pH that can allow for bacteria and endospore colonization

=this is why NO honey for infants. Honey has botulism endospores.

What is the Portal of Entry for Botulism?

Toxins from vegetative cells cross mucus membrane

How does Botulism evade the immune system?

Small amount of toxin required to cause disease is so tiny that no immune response is elicited.

How is destruction enacted by Botulism?

Toxins act at muscle nerve junction and block release of acetylcholine (Ach)

=Result is FLACCID PARALYSIS of muscles

What does Ach do in relation to Botulism?

it is the neurotransmitter that cause muscles to contract

=cannot breathe in (opposite of GABA and tetanus)

=Respiratory muscles become affected

What is the mode of transmission for Botulism?

Vehicle Transmission - Food

Reservoir for Botulism?

Soil

Fresh water sediments

Home-canned food

Signs and Symptoms of Botulism?

Dizziness

Slurred Speech

Double Vision

Death Results from Respiratory failure

*Constipation in infant botulism

What is the incubation period for Botulism?

12-36 hours

What is the prophylaxis for Botulism?

Proper care of food

Pasteurization will NOT kill endospores in baby food

What history is associated with Botulism?

NYC Epidemic tied to Blood Sausage

SIDS- thought to be associated with this.

-Autopsy found that 80% of babies that died from SIDS actually died from botulism

True or False: There is a link between SIDS and Botulism?

True. Study found 80% of babies that died from SIDS actually died from botulism.

How many strains are there of the Common Cold?

Over 200 types of viruses cause the cold

What are the three main types the cause the Common Cold?

1) Rhinovirus (50%)

2) Coronaviruses (15%)

3) Various other agents (35%)

What is the attachment of the Common Cold?

Viral receptors bind to surface receptors on host cells

What is the Portal of Entry for the Common Cold?

Mucus Membrane

How does the Common Cold Evade the Immune System?

Intracellular Pathogen

-Cell Mediated Immune Response kicks in and clears out in a week and a half

What is the means of Destruction for the Common Cold?

Lysis of epithelial cells in upper respiratory tract

What is the Mode of Transmission for the Common Cold?

Direct Contact- Respiratory Secretions

-Infections may occur any time of year, BUT peaks are seen in fall and early winter (seasonal)

What is the reservoir for the Common Cold?

Human

What are the Signs and Symptoms of the Common Cold?

Incubation Period= 3-7 days

Acute Symptoms= 3-7 days

-Sneezing

-Excessive nasal secretion

-Congestion

What is the Prophylaxis against the Common Cold?

Anti-histamine to control symptoms

IgA antibodies to a particular serotype (Nasal mist)

Zinc

What secondary infections are associated with the Common Cold?

Sinus Infections

Otitis Media

What is the protein structure of Influenza?

Single-Stranded RNA Virus

What is the etiology of Influenza?

Influenza A, Influenza B, Influenza C

-A most lethal to humans

-B & C endemic to humans and usually mild

What is the attachment of Influenza?

Hemagglutinin on viral envelope attaches to Sialic acid surface receptors on respiratory cells (humans) and intestinal cells (birds)

What are the 2 main antigenic determinants of Influenza?

Which is THE main one?

1) Hemagglutinin (Main antigenic determinant)

-What the "H" stands for in "H1N1"

-What we use to make the vaccine from

-Attaches to sialic acid on our body cells

2) Neuramidase (The "N" in H1N1)

-Tears down and dissolves the sialic acid to allow virus to not get tangles

-Allows influenza to escape host cell

What is the portal of entry for Influenza?

Respiratory- mucus membrane

How does influenza evade the immune system?

Intercellular Pathogen

1) NS1 blocks production of Interferon

(Antiviral Cytokine)

2) Antigenic Drift or Shift

-Influenza is constantly mutating

Drift=small changes; Shift=Large changes

Antigenic Drift in Influenza?

From year to year its proteins change amino acids to create modified strains requiring new vaccines

Antigenic Shift in Influenza?

Every 20 to 30 years, Influenza A will change drastically enough to jump species

How is Antigenic Shift accomplished in Influenza?

Caused by REASSORTMENT OF RNP'S

(Ribonucleic Proteins)-segments of RNA

-segments of RNA can "spill out" into cytoplasm. if you get two different viruses, 1 from humans, and 1 from birds and put in same cell then replicate=new hybrids

What is antigenic shift caused by?

Reassortment of RNP's

What causes destruction in Influenza?

Tissue Destruction

-Replicates in alveolar epithelial cells=leads to rupture of walls of alveoli and bronchioles

=Inflammation of Respiratory System leading to AARDS

What is the mode of transmission for Influenza?

Aerosol Droplets-usually emitted w/in 6ft

When is flu season in the northern latitudes?

November to March

What is the reservoir for Influenza?

Animal= Ducks, Geese, Swine

Signs and symptoms of Influenza?

Fever (usually high)

Headache

Muscle Aches

Chills

Extreme Fatigue

Dry Cough

Runny Nose (more common in children)

GI Symptoms (N/V/D- more common in kids)

What is the prophylaxis against Influenza?

Annual Flu Vaccine

History associated with Influenza?

2009- H1N1 Swin Flu Pandemic (Started in CA)

1918- Spanish Flu Pandemic

What is the nucleic acid for Covid 19?

Single-Stranded, Positive, RNA

What is the etiology for Covid 19?

SARS-CoV-2

(Severe Acute Respiratory Syndrome Coronavirus-2)

What is the attachment for Covid 19?

Spike Proteins on virus attach to ACE2 receptors

Where do we have ACE2 Receptors? What do they do?

Found on the tongue, throat, deep in lungs, and in intestinal tract

=Regulate B/P

=Down-Regulate Immune Response

*Can't turn down the immune response if they are all bound up and we will end up with high B/P as well.

Explain why some of the early symptoms of Covid19 are no taste, smell and diarrhea.

ACE2 receptors are on tongue, throat, and in intestinal tract

What is the portal of entry for Covid 19?

Mucus Membrane of Respiratory Tract (#1)

Mucus Membrane of Intestinal Tract

How does Covid19 evade the immune system?

Intercellular Parasite- but doesn't really evade.

-it is an overreaction to the virus by immune system that leads to the most severe cases

How does destruction occur with Covid 19?

Destruction of Pneumocytes that make up alveoli sacs

Severe Cases- exaggerated immune response leads to increased lung inflammation

=Response is a Cytokine Storm

What is the mode of transmission of Covid 19?

1) Contact Droplet Transmission (main)

(Coughing, Talking, Breathing)

2) Indirect Contact with Fomites

3) Direct Contact

Possible but Unproven:

Vehicle Air Transmission

Fecal/Oral Route

What is the reservoir for Covid 19?

1) Bats--2) Civet Cats--3) Humans

main----intermediate----US

How long is the incubation period for Covid 19?

5 Days (Average)

What are some signs/symptoms of Covid 19? What are not S/S?

1) Cough

2) Fever

3) Difficulty Breathing

4) Extreme Tiredness

5) Diarrhea

6) Blood Clots

7) AARDS (Serious cases: 8-9 days after onset)

*Sneezing & Runny Nose are NOT Symptoms

What is a possible emergency treatment for Covid 19?

Remdesivir. Antiviral Drug authorized by FDA for ER use

-Reduce death by 62%

What are some prophylaxis for Covid 19?

Support immune system with sleep, exercise, nutrition, WASH HANDS, practice social distancing.

-Flatten the Curve

What does it mean to "Flatten the Curve" in relation to Covid 19?

Slow down transmission rate so as not to overrun the hospital system.

-give time for vaccine development

Secondary infection associated with Covid 19?

Fungal Infections - AARDS leads to low O2 levels

=immune response depends on high O2 levels

=fungus like Candida Alibcans grow in low O2 environments

=30% of covid deaths are from fungal infections

*Fungal infections can lead to sepsis quickly

History associated with Covid 19?

-No other peace-time event has killed more people in the last 100 years.

-US has become the epi-center of pandemic

Nucleic Acid for Polio

Small RNA

Etiology for Poliomyelitis (aka Polio)

Picorna Virus

What is the attachment method for Polio?

2 Receptor Locations

1) Epithelial Cells of Mucus Membrane

2) Motor Neurons (PVR)

(Polio Virus Receptors-dictate what tissues can be infected and infiltrated)

Where are the most common places for polio to attach?

Throat and small intestine

=not a serious disease in these locations

Lymph nodes & into blood (Viremia)

=This can indicate a serious disease if the virus migrates further to the CNS as it has a high affinity for motor neurons