Chapter 25 Flashcards
The cardiovascular system includes
•Heart
•Blood vessels
•Lymphatics
•Lymph nodes, spleen, “MALT”(mucosa associated lymphoid tissue)
•RBC
•WBC (Macrophage, T, B, NK lymphocytes)
Carries O2, CO2, nutrients, cells, plasma
The blood
Infectious agents in the blood
• Bacteremia– bacteria in the blood
• Viremia - viruses in blood
• Septicemia– growth of bacteria in blood
What happens during septic shock?
1.endotoxin (LPS) release
2.macrophage cytokines
3.low blood pressure (leaky capillaries)
4.high fever
Cardiovascular system defenses
•Defensins
• Neutrophils, antibodies, complement
• Filtering function of Lymph Nodes
• No normal flora
• Transient flora ?
• Infectious agents in blood (makes systemic infection)
Defensive
Antimicrobial proteins in lysosomes of phagocytic cells
Yersinia pestis
Plague (cause of plague)
Borrelia burgdorferi
Lyme Disease
Franscisella tularensis
Tularemia
Gram negative rod that grows in digestive tract of flea (vector)
Yersinia pestis
Reservoir of Yersinia pestis
prairie dogs
Yersinia pestis is endemic above
4,000 ft elevation in Arizona and
around 4 Corners
Reduced Europe’s population by about half; 100 million people (In some towns – 100% mortality)
Black Death
When did the Black Death take place?
1348-1350, some recurrent outbreaks up until 1668
Bubonic plague (historical)
Most common, up to 80% mortality rate in 8 days
Pneumonic plague (historical)
In the lungs, 90-95% mortality rate in 8 days
Septicemic plague (historical)
In the blood, near 100% mortality rate often the first day of symptoms
Bubonic plague (Today)
1-5% mortality (50% untreated)
Pneumonic plague (Today)
5-15% mortality if treated early (almost 100% fatal is not treated)
Septicemic plague (Today)
50% mortality, still no good treatment
Bubonic plague is transmitted by
Flea bite
buboes
Swollen lymph nodes
Enters blood and grows in macrophages in lymph nodes
Y. pestis
Lyme Disease is caused by
Borrelia burgdorferi
Spirochetes
very narrow spiral-shaped bacteria (Borrelia burgdorferi)
Borrelia burgdorferi characteristics
Gram negative, motile
Lyme disease vectors
Tick vector bites infected reservoir (deer, mouse) and becomes infected; transmits disease to humans through bites
Lyme Disease Primary stage
Bulls-eye rash on skin
Lyme disease Secondary stage
Neurological symptoms, cardiac dysfunction
Lyme disease Tertiary stage
Lyme arthritis: Inflammation of large joints (Paraplegia)
Lyme arthritis
Immune system Type III
hypersensitivity to persisting antigen, antigen-antibody complexes, inflammation, tissue damage by neutrophils (Treated with long course
antibiotics)
Francisella tularensis
Cause of Tularemia (Rabbit fever), gram negative cocobacillus
Reservoir of Francisella tularensis
rabbits and small animals
Vector of Francisella tularensis
ticks (Ingestion of contaminated
meat also a cause)
Tularemia Symptoms
• Fever
• Diarrhea
• Pain
• Fatigue
• Difficulty breathing
•Skin ulcer at the site of tick
bite
As little as 10 organisms are
infectious
Tularemia
Viral hemorrhagic Fevers
Yellow Fever, Dengue Fever, Ebola, HIV
Yellow fever
Reservoir: Aedes agypti
Location: Central Africa, S. America
Dengue fever
Reservoir: Aedes agypti
Location: World-wide
Ebola
Reservoir: Tropical Fruit Bat?
Location: Central Africa
Viral Hemorrhagic fevers symptoms
• Capillary fragility and leakage
• Disruption of the blood clotting system
Bleeding, Hemorrhage
• Liver damage, Hepatitis
• High Fatality rate (Up to 90% for Ebola)
Yellow fever causes
Yellow fever virus, Flu-like symptoms, Can be hemorrhagic
Yellow virus worldwide
About 200,000 infected per year (low reporting?) 15% mortality rate
Yellow fever outbreak in USA 1905 along Mississippi River resulted in
20,000 deaths
Dengue fever
Dengue virus, Measles-like symptoms, Plus hemorrhaging if hemorrhagic fever
Dengue fever in Americas 2007 resulted in
About 900,000 cases total, 26,000 were DHF (20% mortality if untreated, 2.5% if treated)
Ebola
Ebola virus (Model for the movie “Outbreak”)
Ebola proposed lifecycle
1.Fruit bats carry virus
2.Drop saliva tainted fruit which is eaten by apes
3.Humans hunt and eat infected apes
4.Get disease
Ebola first found in
1976 (emerging disease)
People who have Ebola die of
hypovolemic shock (Loss of blood volume), 80-90% mortality, few outbreaks keep disease in check
Human immunodeficiency virus (HIV)
-Blood-Borne Viral and STD infection
-Infects helper T lymphocytes (CD4+)
-Acquired immunodeficiency syndrome
-Long (Latent) incubation period
HIV Treatment
Nucleoside analogs (AZT)and protease inhibitors are effective therapies used to treat HIV infections
