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Bacterial, Tick-Borne Diseases examples
✓ Lyme Disease
✓ Babesiosis
✓ Rocky Mountain Spotted Fever
viral diseases
✓Infectious mononucleosis
✓ Arboviruses – mosquito
vector
✓ Filoviruses- direct contact
with infected fluids
protozoan infections
malaria
lymph
Plasma that has diffused out of capillaries into
and around tissues
lymph is normally
sterile
WBC in lymph do what
fight foregn pathogens
lymph delivers contaminating microbes to lymph nodes to be
phagocytosed
Blood is normally
axenic (sterile)*
(but recent studies say no and blood microbiome dwells inside blood cells)
venipuncture
different ubes with different anticoagulants for specific tests
anticoagulant of choice
sodium polyanethol sulfonate (SPS- yellow top)
what is done when a microbial infection in blood is suspected
blood culture
Septicemia:
presence of microbial infection on the blood that
causes disease
Bacteremia:
septicemia caused by bacteria
Viremia:
presence of viruses in blood
• Remember that aseptic meningitis refers to viral
Fungemia:
presence of fungi in blood
• Parasitemia:
presence of parasites in blood
toxemia
presence of toxins in the blood
Septic shock:
extremely low blood pressure (hypotension) as a result of inflammation and dilation of blood vessels.High mortality rate
Bacteremia can spread to
joints and bones causing osteomyelitis and to CNS causing meningitis
Lymphangitis:
septicemia spreads to the lymphatic vessels, appearing as a red streak
bacteremia clinical presentation
High fever (over 38°C 99°F)
• Chills, nausea, vomiting, diarrhea,
shortness of breath, and malaise
Bacteremia – Causative Agents
all bacteria can cause bacteremia as long as they can access the bloodstream and survive to multiply
Most septicemia causing bacteria are
opportunistic pathogens
ex Escherichia coli, Pseudomonas aeruginosa, Bacteroides,
Staphylococcus, and Streptococcus
bactericemia caustive agents virulence factors
• Capsule: useful to prevent phagocytosis from WBC circulating in
bloodstream
• Siderophores: certain bacteria require iron for metabolism; therefore
they use molecules that chelate (“trap”) iron from carrier proteins in plasma
• Hemolysins: substances that destroy RBCs
bactericemia pathogenesis
Septicemia usually presents as a result of
direct inoculation of bacteria into blood ex
• Medical procedures
• Catheters, surgery, central venous
line, dialysis
• IV-drug users
• Abrasions
• Result of a secondary infection
who is at higher risk for bactericemia
people with AIDS, cancer, diabetes, malnutrition,
elderly, newborns are all more susceptible
which gram class usually causes severe septicemia
G-
in bacteremia, outer meembrane of dying bacteria releases
Lipid A. causes stronger immune response
exotoxins
produced by gram-positive bacteria only
• Cytotoxins: cell lysing
endotoxins
produced by gram negatvie bacteria
• Lipid A portion of LPS from outer cell membrane
toxic shock syndrome caused by
Staphylococcus aureus and Streptococcus pyogenes
toxic shcok syndrome caused by bacteria secreting
exotoxin: toxic shock syndrome toxin (TSST), a type of superantigen
toxic shock syndrome symtoms
exaggerated immune response
resulting in high fever, vomiting, rash,
and extremely low blood pressure
Staphylococcal Toxic Shock Syndrome
can grow in vagina or wounds
associated with superabsorbent tampons
Bacteremia and Toxemia prevention
taking care of wounds, promptly treat initial
infections, sterilization of surgical equipment
Bacterial Endocarditis
Bacteria infect the endocardium
triggering inflammation,
endocarditis and the formation of
vegetations (masses of platelets
and clotting factors in the
endocardium that bury the bacteria)
Bacterial endocarditis symtpoms
similar to bacteremia signs as well as tachycardia and heart murmurs. complications can lead to strokes are cardiac failure
most common cause of bacterial endocarditis
Viridans alpha streptococci
other things that can bacterial endocarditis
Pseudomonas aeruginosa,
Neisseria meningitidis, Escherichia coli, Salmonella spp.,
Staphylococcus spp., Streptococcus spp.
who is at highest rsik for bacterial endocarditis
Patients with tooth lesions or wounds, IV-drug users, artificial
heart valve recipients
Borrelia burgorferi – Lyme disease phases
bulls eye rash
neurological symptoms
severe arthritis
lyme disease signs and stages
1. Erythema migrans
2. Early disseminated stage
• Multiple erythemas
• Arthritis
• Musculoskeletal pain
• Meningitis
• Lymphocytoma
• Carditis
3. Late disseminated stage
• Acodermatitis
• Arthritis
• Neurological symptoms
4. Post-treatment Lyme disease
syndrome
Babesia spp caused by
B. microti (a parasite! not a bacterium). spread throgh ticks
Babesiosis signs
General malaise, fever,
headaches, chills, sweating,
fatigue, and weakness
(nonsynchronous)
• Hemolytic anemia
• Renal failure
• Hepatosplenomegaly
Rocky Mountain Spotted Fever (RMSF) caused by
Rickettsia rickettsii (spread by ticks)
Rocky Mountain Spotted Fever (RMSF)
Headache, vomiting, and muscle pain
• Rash consisting of small, flat, pink/red, non-
itchy spots that spread from the wrists,
arms, and ankles inward to the torso
rocky mountain spotted fever pathophysiology
infects endothelial cells
rocky mountain spotted fever complications
If untreated, may cause blood vessel damage impacting circulation to the arms and legs
• May require limb amputation
• Vessel damage in 5% of cases causes fatal organ or brain
bleeding
• Untreated cases can be fatal within 8 days
viral diseases of cardiovascular system
• Infectious mononucleosis (EBV)
• Arboviruses
• Yellow fever
• Dengue
• Filoviruses
• Ebola
• Marburg
Infectious Mononucleosis causitive agent
epstein barr virus
Infectious Mononucleosis transmission
person-to-person or sharing of fomites (glasses) or via inhalation of respiratory droplets containing the virus
• “Kissing disease”
infectious mononucleosis pathogenesis
infects epithelial cells of throat and salivary glands, enters the blood where it infects B lymphocytes. becomes latent. infects and replicates in oropharyngeal epithelium, tonsils and salvary glands.
infectious mononucleosis signs
Lymphadenitis (especially lymph nodes of the neck)
• Extreme fatigue, nausea, loss of
appetite, headache, and sore throat
• May lead to chronic tiredness
many hosts of mononuelcosis are
asymptomatic
Arboviruses 2 types
yellow fever and degnue fever
yellow fever symotoms
Acute: headache, fever, and muscle pain 3-5 days
• Severe disease (15%): high fever, severe nausea, violent-black
vomit. Liver damage, internal bleeding, delirium, coma, and death
arborvirus pathogenesis
Viruses infect and replicate in the liver and spleen, leading to
viremia
• Cytokine release incites systemic inflammatory response
• Causes leaky capillaries, decreased blood pressure, may lead to
shock and organ failure
yellow fever transmission
Jungle: Transmits primarily between monkeys via mosquitoes in jungle areas
• Intermediate: In areas with both villages and jungle, mosquitoes infect both humans and monkeys
• Urban: Human-to-human transmission via mosquitoes
dengue fever is common or uncommon
Most common arboviral disease in humans. can be asymptomaitc
dengue fever 1st stage
febrile phase - Fever, vomiting, rash, and
body aches
dengue fever 2nd stage
critical stage
• Extreme abdominal pain, persistent vomiting, and dehydration
• Hemorrhagic features may develop
• Bleeding from the nose or mouth, petechiae, and leaky capillaries
• May lead to decrease in blood volume, shock, organ failure, and death
• For both – Monkeys/humans are initially infected and then pass the virus via mosquito vector
arborviruses transmission
Monkeys/humans are initially infected and then pass the virus via
mosquito vector
filoviruses examples
Marburg and Ebola viruses
filoviruses transmission
Transmission is person-to-person,
Ebola – ingestion of bush meat,
Marburg – inhalation of bat droppings
how does filovirus replicate
Virus replicate in monocytes,
macrophages, and dendritic cells
filoviruses can cause
severe hemmoragic fever
Extensive tissue necrosis of liver, spleen, lymph nodes, and lungs
Hemorrhage causes edema and hypovolemic shock
malaria caused by
protozoan
species of plasmodium that cause malaria
P. falciparum (*most deadly)
• P. vivax (*most prevalent)
• P. malariae
• P. ovale
• <P.knowlesi – emerging parasite>
definitive host of malaria is
where sexual reproduction takes place
malaria signs
Causes cycles of fevers, headaches, delirium, body aches (due to rupture of RBCs & release of toxins)
• Death from loss of RBCs, complications from blood clots
plasmodium depends on what to complete its life cycle
Anopheles mosquito and humans