Infectious Disease -- Bacterial IV - Rickettsial and Zoonotic Diseases Flashcards
Three Intracellular Vector-Bourne Diseases (with vector)
Epidemic typhus (lice)
Rocky Mountain Spotted Fever (ticks)
Erlichiosis (ticks)
Three extracellular vector bourne diseases (with vector)
Lyme Disease (ticks) Relapsing Fever (lice or ticks) Plague (fleas)
What are Rickettsia bacteria
Small, G- obligate intracellular bacteria
How are rickettsia transmitted
Arthropod (ticks, mites, fleas, or lice) bites or excreta
What do eschars typically look like?
Dark, Swollen, Crusted lesions that ma appear at inoculation site
How do you diagnose a rickettsial infection
Immunostaining of organisms
Antirickettsial serology (Convalesence)
Exposure to Vector
What cell type does rickettsia mainly multiply in?
Small vessel endothelia
There they cause vascular leakage issues in rickettsial diseases
Difference between mechanism of typhus and spotted fever group rickettsia
Typhus - Lyse endothelial cells
Spotted Fever – Spread Cell to Cell
Rickettsia exotoxins and endotoxins?
None
How does Rickettsia fuck up so many blood vessels
- Small vessel damage from thrombosis and hemorrhage
- NK cells make g-INF
- CD8 T Cells mediate immune responses responsible to most damage
Often seen pathological staining of Rickettsia
- Perivascular cuffing (infection of endo cells with perivascular lymphocytic intermediate.)
- Mostly lymphocytes, few neutrophils (approx 1 week)
Average Rickettsia clinical features
Fever, Rash, CNS symptoms, Gangrene
Severe Rickettsial clinical features
Hypovolemic Shock, DIC, Pulmonary Edema
Treatment for Rickettsia?
Doxycycline
What should be in the DDx of a Rickettsia patient
Rickettsia Meningococcemia Rubeola Rubella Erlichiosis
Organism for Epidemic Typhus
R. prowazekii
Method of Epidemic Typhus Transmission
Head lice mediates human to human transmission
Manifestations of Epidemic Typhus
Centrifugal Rash –> CNS involvement
High Fever
Chills, Cough, Rash, Muscle Pain, Light Sensitivity
Untreated mortality Epidemic Typhus
10-60%
Clinical Findings in Severe cases of epidemic typhus
Gangrene – tis of fingers, nose, earlobes, scrotum, penis, and vulva
Morphology seen in Epidemic Typhus
Cuff of mononuclear inflammatory cells around vessels
Ecchymotic hemorrhages of organs
Microthrombi
No necrosis of vessels
Organism for Rocky Mountain Spotted Fever
R. rickettsi
Method of Rocky Mountain Spotted Fever transmission
American Dog Tick/Rocky Mountain Wood Tick
Incubation period for Rocky Mountain Spotted Fever?
7 days
Symptoms of Rocky Mountain Spotted Fever
Fever, Nausea, Vomiting, Headache, Muscle Pain
High Fever 2-3 weeks
Rash appears by day 6 (Lymphocytes attack vessels)
Describe the rash in Rocky Mountain Spotted Fever
Hemorrhagic rash extends over entire body, including palms and soles. Typically spreads from periphery inward.
Rarely, an eschar
Morphology seen in Rocky Mountain Spotted Fever
Perivascular Mononuclear Infiltrate Necrosis, Fibrin Extravasation Thrombosis of small blood vessels/arterioles Foci of necrotic skin Microinfarts in brain
Major Cause of Death in Rocky Mountain Spotted Fever
Noncardiogenic Pulmonary Edema
What kind of fluid is found in the pulmonary edema of Rocky Mountain Spotted Fever patients
Exudative
There are lymphocytes in the fluid
Where in the country does Rocky Mountain Spotted Fever tend to happen?
East Coast, South, Oklahoma/Arkansasish area
Potential Rocky Mountain Spotted Fever patient shows up in the cold of winter. They probably really have…
Meningitis
What is scrub typhus?
Caused by Orientia tsutsugamushi
Endemic in Far East
Like Typhus, but transmitted by mites
Transitory Rash, Prominent Lymphadenopathy
Ehrlichiosis is caused by what organisms…
E. chaffeensis
Anaplasma phagocytophilum
Difference between clinical appearance of an Ehrlichiosis patient and a Rocky Mountain Spotted Fever
No Eschar
Rash Rare/Less Prominent
Ehrlichiosis is an infection of…
Neutrophils or Monocytes
Classic pathologic findings in Ehrlichiosis
Cytoplasmic Inclusions (Morulae)
Shaped like mulberries
These are masses of bacteria
Ehrlichiosis is transmitted by…
Ticks
Organism behind Lyme Disease…
Borrelia burgdorferi
Spirochetes in Lyme Disease are transmitted by…
Tick Bites Primarily – White tail deer tick
Also Lice
How does Borrelia avoid host antibodies
Shifting antigenic markers
Where does Lyme Disease happen
Wisconsin and the NE US
So what is Lyme Disease anyway?
A multisystem chronic inflammatory disorder
Local lesion progresses to bacteremia and chronic lesions in distant organs.
Much of the pathology of Lyme Disease is caused by…
Immune response against the organism
- Triggered by LPS binding macrophage TLR2
How to prevent Lyme disease.
OspA vaccine commercially available for high risk groups
Vector Avoidance
How to treat Lyme Disease?
Doxycycline
What is specific to Lyme Disease – Primary Disease?
Erythema chronicum migrans
Skin, Rash shows vasodilation with dense perivascular inflammatory infiltrates of mononuclear leukocytes
Fever
Things specific to secondary disease?
Dissemination of spirochetes
Joint Disease, Muscle Pain, Cardiac Arrhythmias, Meningitis, CN Involvement
Things specific to tertiary Lyme Disease?
CNA, Cardiac, and Skeletal involvement
Timeline for Secondary and Tertiary Lyme Disease
Secondary - Months
Tertiary - Years
Pathology of Lyme Disease
Focal Necrosis, Hemorrhages, and DIC
Skin rash – vasodilation w/ dense perivascular inflam. infiltrates (lymphocytes)
Two diseases known for lymphoplasmacytic Cell infiltrate
Lyme Disease and Syphillis
Lyme Disease arthritis looks an awful lot like….
Why
Rheumatoid Arthritis
Synovial hyperplasia, lymphocytes+plasma cells
Proliferative arteritis
Relapsing fever is caused by what organism
Borrelia recurrentis
Relapsing fever is transmitted by what organisms
Human Lice
Rodent Ticks
Symptoms of Relapsing fever?
1-2 week latent period
Shaking chills, Fever, Headache, and Fatigue
Successive Attacks
Successive attacks of Relapsing fever result from…
Ability of the organism to express new surface antigens
Forces the body to make new antibodies every time
What makes Relapsing fever fatal?
Hepatosplenomegaly
Generic shit about Yersnia pestis
G- Bacillus
Yersnia pestis method of transmission
Arthropod Bite (Flea bite from a rodent)
Pathology of Yersnia pestis
Rapid proliferation within lymphoid tissues Injection of YOPs Necrosis of Tissues and BVs Swelling of Lymphoid Tissue Leukocytosis/Septicemia/DIC
What are YOPs?
Yersnia Outer Proteins
Inactivating molecules that regulate actin polymerization
Inhibits secretion of inflammatory cytokines
What are the swollen lymphoid tissues of Yersnia pestis called?
Buboes
Cause of death in Yersnia pestis?
Septicemia/DIC
Four types of Yersnia pestis disease
Minor Plague
Bubonic Plague
Pneumonic Plague
Septicemia
Symptoms of Minor Plague Yersnia pestis
Lymphadenopathy
Constitutional Symptoms
Symptom of Bubonic Plague Yersnia pestis
Prominent lymphadenopathy (buboes)
Symptoms of Pneumonic Plague Yersnia pestis
Hemorrhagic, Necrotizing Pneumonia
Primary or Secondary to bubonic infections
Most common form of Yersnia pestis
Bubonic Plague
Treatment for Yersnia pestis
Doxycycline
Mortality of Yersnia pestis untreated
50-90%
Two diseases especially associated with border waters
Lyme Disease
Giardia
