Today’s Plan:

 Cardiovascular and Lymphatic diseases
 Respiratory diseases?
 
Practice Test
•

What is lysozyme?

•a. an enzyme secreted by sweat glands on the skin that destroys the cell walls of certain bacteria
•b. the fermentation product that gives yogurt its characteristic "tang"
•c. the enzyme that is involved in transporting glucose into a bacterial cell
•d. a selective ingredient in mannitol salt agar plates
 
•All of the following provide your skin protection against potential pathogenic bacteria EXCEPT:
•a. hair follicles
•b. high salt
•c. low moisture
•d. low pH
 
•The causative agent of meningitis is:
•a. a bacterium
•b. a virus
•c. a fungus
•d. all the above
•
 
•Which of the following statements is false regarding pathogenic strains of Staphylococcus aureus?
•a. associated with toxic shock syndrome
•b. commonly coagulase positive
•c. Associated with nosocomial infections
•d. is catalase negative
 
•Which statement is false about Streptococccus pyogenes?
•a. it is beta hemolytic
•b. it is catalase negative
•c. it is only known to cause strep throat
•d. it is synonymous with group A streptococci
 
CMU STUDENT DIAGNOSED WITH BACTERIAL MENINGITIS
 

MOUNT PLEASANT - A Central Michigan University student has been diagnosed with a form of bacterial meningitis. Staff from University Health Services, working in conjunction with the Central Michigan District Health Department, are notifying people who have been in close contact with the infected individual.

 

The student, a resident of CMU's Woldt Hall, was diagnosed over the weekend at the student's home residence in southeast Michigan and is currently hospitalized there. CMU health officials were contacted about the diagnosis Monday (April 21) morning.

 

Meningitis is an inflammation of the membranes that cover the brain and spinal cord. The bacteria are spread through direct contact with respiratory secretions when people cough, sneeze, kiss or share saliva, or share drinking glasses or cigarettes.

 

"People who have not had direct contact with infected individuals should not be overly concerned about contracting meningitis," said Sarah Campbell, director of University Health Services. "It is less contagious than colds and the flu. Individuals of any age can carry the germ without becoming ill, but only rarely do the bacteria overcome the body's immune system and cause meningitis.

 

"We have contacted the student's roommates and are attempting to contact other individuals who may have had long face-to-face contact with the infected student to be treated with an antibiotic," said Campbell. "Individuals who do not need to be treated include casual acquaintances, such as those who attended the same classes or live in the same residence hall."

 

High fever, headache and stiff neck are common symptoms of meningitis. Individuals who develop symptoms should see their physician or contact CMU Health Services immediately.

 

Precautions include frequent and careful hand washing, not sharing a drinking glass or cigarette, and avoiding contact with respiratory secretions of other people.

 

Additional information is available at University Health Services at (989) 774-5693. Information also can be found at the Web site: www.healthservices.cmich.edu.

 
Unit 4. Survey - Role of Microbes in Health and Disease
 
A. Environmental Microbiology
B. Medical Microbiology
1. Epidemiology
2. Significant/Interesting Human Diseases
a. Skin
 Staph and Strep
Streptococcus pyogenes
Group A Strep
Invasive - flesh-eating strep
Staphylococcus aureus
Toxic Shock Syndrome, sty
MRSA
b. Nervous system
 Meningitis
c. Cardiovascular and lymphatic system
 Hemorrhagic fevers
 Lyme disease
The plague
 

Cardiovascular system

Rapidly distributes
Pathogens
Left untreated multiple
organs affected
 
Sepsis or Septicemia
Uncontrolled reproduction
of microbes in the blood
 

Cardiovascular - lymphatic system

•Permeability of lymph system make it more likely to pick up microorganism
•Then destroyed by lymphocytes in nodes

 

Emerging Infectious Disease (EID) New or changing disease with increasing prevalence
Ebola Outbreak
What did we learn?
•Precautions should be in place for EID’s.
•Had they been in place before the Ebola outbreak, many lives would have been saved.
•Luckily Ebola is not easily transmitted
•317 people infected and 255 died.
 
Filoviridae - Marburg, Ebola
 

Small RNA viruses

Zoonotic Reservoir of infection are chimps/monkeys
Infectious via aerosols
Widespread vascular damage
 

Hemorrhagic fever

Incubation - 4-16 days
Early - Flu-like symptoms (malaria)

Later - Nausea, abdominal pain, vomiting, diarrhea

5-7 days - Hemorrhaging
7-16 days - Death
 

Victims bleed to death out of every orifice

Treatment - none
Prevention - stay away
 

Lyme Disease

Why the increase?  Increasing deer population
Borrelia burgdorferi (Bacterium that causes the disease)
Most common tickborne disease in US
Transmitted to humans by infected deer tick
Natural host (Zoonotic reservoir)- deer and field mice
Tick is the insect vector
Bull’s Eye Rash
50-70% of the cases
•Disease progression
–7-10 days post bite - typical lesion, flu
–Weeks to months - arthritis, heart inflammation, neurological problems
–Years later - brain degeneration
•Early diagnosis and antibiotic therapy is key to limiting damage
Prevention
Highest transmission from May - July
Light colored pants, tucked into socks
Insecticide
Examine for ticks, remove promptly
A CMU graduate student recently discovered he has
contracted Lyme’s disease
 

 

Bubonic Plague 14th century

•Disease of the rats” as people observed dead rats just before the outbreaks
•Only recently dead rats were dangerous leading to the conclusion that fleas were the vector
•Pestilence- Yersinia pestis
•Yersin-Scientist who discovered transmission route using Koch’s postulates in 1894
•
 

Black Death- Dark purple color of victims

 
Bubo- lymph node symptomatic swelling
•About 1/3 of Europe’s
Population was wiped out.
•25 million people died
•Death for entire villages
•People would run from their own families
 

Cultural Changes

•Doctors would not treat patients
•Lawyers would not write wills
•Laws and governments collapsed
•Worker shortage
•People lost faith in the church
 

Respiratory Diseases

•    Upper Respiratory
–Ear, nose, and throat
•
•    Lower Respiratory
–Voice box, trachea, lungs
–
•

Pharyngitis- “Sore throat”

•Inflammation of mucous membrane
•Only 5-10% are strep
•Most are viral
•Rhinovirus and adenovirus which cause the common cold
 

Common Cold

•Rhinovirus cause 50%
•Build immunity over time but so many varieties a vaccine is difficult
•Up to 70% of the population will carry these adenovirus and rhinovirus and be asymptomatic Endemic disease = always in the population
•Having antibodies to a virus does not mean immunity to the disease