Viral Infections of CNS-Zoonotic / Vector Borne and Bact. Infect of Circulatory.

Question 1

What is the natural host of WEE and EEE?

Answer 1

Birds

Host Horses and humans

Question 2

What is the natural host of the VEE?

Answer 2

House mice

Host: Horses and Humans

Question 3

What is the natural host of St Louis, West Nile?

Answer 3

Bird

Host: Humans

Question 4

What are the only ways that West Nile has been transmited from human to human?

Answer 4

Breast Feeding

Organ Transplantation

Question 5

Most West Nile cases are mild and asymptomatic however, 20% will develop into an illness known as?

Answer 5

West Nile Fever appearing as a sudden onset of febrile flu-like illness.
1 in 150 will result in a severe neurological disease primarily in the ELDERLY.

Question 6

What infection should be highly suspect in individuals >50 years old with encephalitis or meningitis in the summer/fall months?

Answer 6

West Nile or other arboviral diseases.

Question 7

What specific breed of mosquito transfers St. Louis to patients?
What is the incubation for St. Louis Encephalitis?

Answer 7

The Culex mosquito working through birds and horses.

Incubation time is 5-15 days.

Question 8

Which arbovirus causes a greater illness in children than in adults?

Answer 8

Western Equine Encephalitis Virus EEE typically seen in June or July.

Question 9

The LACROSSE (California) Encephalitis Virus is carried mostly by what vector?

Answer 9

This disease is mostly carried by chipmunks and squirrels.

Question 10

What is the general treatment plan for an individual who has come in contact with Rabies? (Think Scared of water/ stimulus)

Answer 10

Administer vaccine and prohylatic immunoglobulin immediately.

Follow up with additional five vaccinations over a 28 day period on days 3, 7, 14, and 28.

Question 11

The presence of Negri Bodies post mortem would be indicitive of what sort of infection?

Answer 11

This would prove prior Rabies infection.

Question 12

Humans become infected with this disease after inhalation of infectious aerosolized particles of rodent (Mus musculus) urine, feces, or saliva.

Can this disease be transfered from person to person?

Answer 12

Lymphocytic choriomeningitis virus (LCMV)

Only vertical transfer from mother to fetus has been recorded.

Question 13

What is unique about the sickness that follows an infection with Lymphocytic choriomeningitis virus (LCMV)?

Answer 13

Typically follows a bi-phasic febrile illness with the first week having fever and the second phase of the disease characterized by meningitis or encephalitis.

Question 14

What did Stanley Prusiner discover?

What did Carlton Gajdusek discover?

Answer 14

Stanley Prusiner discovered that prions were caused by proteins.

Carlton Gajdusek discovered that Kuru was transmitted through ingestion of contaminated meat.

Question 15

What are the naturistic characterstics of Prions?

Answer 15

Prions lack detectable nucleic acids and are composed of:
Protease
Heat/chemically resistant hydrophobic glycoprotein (PRP)
The normal PRP is composed of alpha helices, once changed the PRPsc contains multiple beta pleated sheets.

Question 16

What percentage of prions are said to be inherited vs naturally sporadically being induced?

Answer 16

15-20% of prions are said to be inherited with the remaining arising from sporadic mutation.

Question 17

In order for Systemic Inflammatory Response Syndrome to be present, what characteristics must be met?

Answer 17

At least two or more of the following:
Fever > or Hypothermia 20 breaths per min
Tachycardia HR >90
Abnormal WBC count >12000 or below 4000 (Leukopenia)

Question 18

What exactly is Sepsis?

Answer 18

Sepsis is SIRS with suspected microbial etiology!

Keep in mind BACTEREMIA IS NOT REQUIRED FOR SEPSIS TO OCCUR.

Question 19

What constitutes Severe Sepsis?

Septic Shock?

Answer 19

Severe sepsis occurs following one or more signs of organ dysfunction.

Septic shock is the case in which there is severe sepsis along with hypotension.

Question 20

What is Refractory Septic shock?

Multiorgan Failure?

Answer 20

Septic shock that lasts for longer than 1 hour and does not respond to fluid and pharmacologic treatment.

Multiorgan failure is characterized by dysfunction of greater than 1 organ along with disseminated intravascular coagulation (DIC). High fatality rate.

Question 21

Classic septic shock is characterized by what?

What would be considered a non classical septic shock?

Answer 21

Classic septic shock is induced by Gram-negative bacteria in the bloodstream that produce endotoxin (LPS) and cause sepsis via Lipid A.

Non classically would be Gram positive bacteria causing septic shock by peptidoglycan or exotoxins (TSST-1 by Staph)

Polysaccharides of C. albicans
Techoic acid of Staph
Capsule of S. pneumoniae

Question 22

How does LPS/Endotoxin cause inflammation?

Answer 22

Binds CD14 and TLR4 on phagocytes/ antigen presenting cells activating the immune system:
TNF
IL-1
IL-6
= Septic Shock

Question 23

How does LTA cause inflammation?

Answer 23

LTA binds TLR2 causing the release of septic shock cytokines:
TNF
IL-1
IL-6

Question 24

What sort of infections are characteristic of Coagulase negative Staphyloccocci species?

Answer 24

These guys like to form biofilms and are seen in catheters and shunts.
Think:
Staph epidermidis: Implants/ Device Failure
Staph Saprophyticus: UTI / Novobiocin Resistant.

Question 25

What are characteristics of Toxic shock syndrome caused by Streptococcal agents?
What toxins are specific to this?
How is it different from Staph caused TSS?

Answer 25

Soft tissue inflammation at site of entry.
Most display bacteremia (in contrast to staph) with NECROTIZING FASCITIS.

Toxins: SpeA and SpeC pyogenic exotoxins.

Question 26

Describe Streptococcal pyrogenic exotoxins (A,B,C)

Answer 26

These are superantigens that stimulate T cells by bindin MHC II in Vb region of TCR.

The activated T cells then release toxic shock cytokines.

Question 27

How is Sepsis typically treated?

Answer 27

Hypotension: IV
Hypoxia: Ventilator
DIC: Transfusion of fresh frozen plasma and platelets or heparin.
Bacterial infection: Antibiotics.

Question 28

What characteristics does Acute endocarditis display and what agent is the most common cause?

Answer 28

A high fever
Rapid damage to cardiac structures with death occurring within weeks.
Most commonly caused by S. aureus

Question 29

What characteristics does subacute endocarditis display and what agent is the most common cause?

Answer 29

Typically low grade fever with night sweats and weight loss. Progresses to death over weeks to months.

Most typically caused by Viridians strep and in some cases coagulase negative staph.

Question 30

Red Linear streaks in the nail bed and retinal hemorrhages are signs of what sort of infection?

Answer 30

These are clinical features of endocarditis.

Question 31

Compare and contrast Janeway lesions to Osler nodes

Answer 31

Janeway lesions are painless lesions found on the palms and soles of feet following endocarditis.

Osler nodes are painful subcutaneous nodules typically found on the pads of the digits following endocarditis.

Question 32

S. Veridians is a common causer of subacute endocarditis. What characteristics does this microbe have?

Answer 32

Strep Viridians is characterized as being alpha hemolytic (or gamma hemolytic) within normal oral flora.

Treated with penicillin and vancomycin for resistant strains.

Question 33

What are the two major predisposing causes of infective endocarditis?

Answer 33

Susceptible cardiovascular substrate: Prosthetic valves

Source of bacteremia: IV injection of drug users.

Question 34

How is endocarditis treated?

Compare this to sepsis treatment.

Answer 34

It is treated using Agressive antimicrobial therapy and prolonged antimicrobial therapy.

Sepsis can be treated in multiple ways depending on the systems being infected. (I.E. Ventilation etc.)