Chapter 23: Microbial Diseases of the Cardiovascular and Lymphatic Systems

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Chapter 23 Microbial Diseases of the
Cardiovascular and Lymphatic Systems
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Cardiovascular Lymphatic Systems

• Plasma leaves blood to become interstitial fluid
• Lymph capillaries Transport interstitial fluid
  to blood
• Lymph nodes contain
• Fixed macrophages
• B cells
• T cells

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Lymphatic System

• The system also includes all the structures
  dedicated to the circulation and production of
  lymphocytes, which includes the spleen, thymus,
  bone marrow
• it is responsible for the removal of interstitial
  fluid from tissues
• Transports pathogen to lymph nodes for antibody
  macrophages to digest
• The digested pathogen then goes to the spleen to
  be removed from the body

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Cardiovascular Lymphatic Systems
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Sepsis and Septic Shock

• Septicemia
• Persistent pathogens or their toxins in blood
• Sepsis
• Systemic inflammatory response
• Severe sepsis
• Sepsis decreased blood pressure
• Septic shock
• Sepsis uncontrollable decreased blood pressure

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Sepsis and Septic Shock

• Lymphangitis
• Inflamed lymph vessels accompanying septicemia
  and septic shock

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Gram-Negative Sepsis

• Endotoxin shock
• Endotoxins cause blood pressure to decrease
• Antibiotics can worsen condition by killing
  bacteria and the release of more endotoxin.
• Possible treatment
• Human activated protein C, an anticoagulant

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Gram-Positive Sepsis

• Nosocomial infectionsMost common
• Start as infection in another body area
• Staphylococcus aureus
• Streptococcus pyogenes
• Group B streptococcus, S. agalactiae
• Enterococcus faecium and E. faecalis

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Puerperal Sepsis

• Childbirth fever
• Streptococcus pyogenes
• Transmitted to mother during childbirth by
  attending physicians and midwives

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Diseases in FocusInfections from Human
Reservoirs

• A 27-year-old woman had a fever and cough for 5
  days. Despite aggressive treatment with fluids
  and massive doses of antibiotics, she died 5
  hours later. Catalase-negative, gram-positive
  cocci were isolated from her blood.
• What infections could cause these symptoms?

Streptococcus pyogenes
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Bacterial Infections of the Heart

• Endocarditis
• Inflammation of the endocardium
• Subacute bacterial endocarditis
• Alpha-hemolytic streptococci from mouth
• Acute bacterial endocarditis
• Staphylococcus aureus from mouth
• Pericarditis
• Streptococci

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Rheumatic Fever

• Inflammation of heart valves
• Autoimmune complication of Streptococcus pyogenes
  infections

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Tularemia

• Francisella tularensis
• Gram-negative rod
• Zoonosis
• Transmitted from rabbits and deer by deer flies
• Bacteria reproduce in phagocytes

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Brucellosis (Undulant Fever)

• Brucella spp.
• Gram-negative rods that grow in phagocytes
• B. abortus (elk, bison, cows)
• B. suis (swine)
• B. melitensis (goats, sheep, camels)
• Undulating fever spikes to 40C each evening
• Transmitted via milk from infected animals or
  contact with infected animals

High incidence in persons living in the Middle
East Mediterranean Areas
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Clinical Focus A Sick Child

• A child underwent excisional biopsy of the left
  axillary lymph node when intermittent fever and
  enlarged lymph node persisted for 49 days. The
  excised tissue was cultured a Gram stain of the
  bacteria that grew is shown.

Clinical Focus, p. 644
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Clinical Focus A Sick Child

• What is the cause of the infection?

Francisella tularensis
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Anthrax

• Bacillus anthracis
• Gram-positive, endospore-forming aerobic rod
• Found in soil
• Cattle sheep routinely vaccinated
• Treated with ciprofloxacin or doxycycline

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Anthrax

• Cutaneous anthrax
• Endospores enter through minor cut
• Most common naturally occuring infection of
  Anthrx
• 20 mortality

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Anthrax

• Gastrointestinal anthrax
• Ingestion of undercooked, contaminated food
• 50 mortality
• Inhalational (pulmonary) anthrax
• Inhalation of endospores
• 100 mortality

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Biological Weapons

• 1346 Plague-ridden bodies used by Tartar army
  against Kaffa
• 1937 Plague-carrying flea bombs used in the
  Sino-Japanese War
• 1979 Explosion of B. anthracis weapons plant in
  the Soviet Union
• 1984 S. enterica used against the people of The
  Dalles
• 1996 S. dysenteriae used to contaminate food
• 2001 B. anthracis distributed in the United
  States

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Biological Weapons
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Gangrene

• Ischemia Loss of blood supply to tissue
• Necrosis Death of tissue
• Gangrene Death of soft tissue
• Gas gangrene
• Clostridium perfringens, gram-positive,
  endospore-forming anaerobic rod, grows in
  necrotic tissue
• Treatment includes surgical removal of necrotic
  tissue and/or use of hyperbaric chamber

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Systemic Diseases Caused by Bites Scratches

• Pasteurella multocida
• Clostridium
• Bacteroides
• Fusobacterium
• Bartonella henselae Cat-scratch disease

Symptoms pustule at site of scratch or bite,
swollen lymph nodes, Fever, headache, loss of
appetite
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Cat-Scratch Disease
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Diseases in Focus Infections Transmitted by
Soil or Water

• A 65-year-old man with poor circulation in his
  legs developed an infection following injury to a
  toe. Dead tissue further reduced circulation,
  requiring amputation of two toes.
• What infection could cause these symptoms?

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Infections from Animal Reservoirs

• A 10-year-old girl was admitted to a local
  hospital after having fever (40C) for 12 days
  and back pain for 8 days. Bacteria could not be
  cultured from tissues. She had a recent history
  of dog and cat scratches. She recovered without
  treatment.
• What infections could cause these symptoms?

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Plague

• Causative agent Yersinia pestis, gram-negative
  rod
• Reservoir Rats, ground squirrels, and prairie
  dogs
• Vector Xenopsylla cheopis
• (flea)
• Bubonic plague Bacterial growth in blood and
  lymph
• Septicemia plague Septic shock
• Pneumonic plague Bacteria in the lungs

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A Case of Bubonic Plague
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U.S. Distribution of Plague, 19702004
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Relapsing Fever

• Causative Agent Borrelia spp., spirochete
• Reservoir Rodents
• Vector Ticks
• Successive
• relapses are
• less severe

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Lyme Disease

• Causative agent Borrelia burgdorferi
• Reservoir Deer, field mice
• Vector Ixodes Ticks
• First symptom Bull's-eye rash
• Second phase Irregular heartbeat, encephalitis
• Third phase Arthritis

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Lyme Disease in the U.S., 2005
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Lyme Disease
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Rocky Mountain Spotted Fever

• Ricketsia rickettsii
• Gram negative coccobacillus
• Obligate intracellular parasites
• symptoms fever, nausea, vomiting, severe
  headache, muscle pain, lack of appetite
• Rash 2-5 days after fever onset
• R. rickettsii infects the cells lining blood
  vessels

Vector-Dermacentor Ticks Reservior-small mammals
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Typhus

• Endemic murine typhus
• Rickettsia typhi
• Gram negative coccobacillus
• Obligate intracellular parasites
• In endothelial cells of the vascular
• System (usually less severe)
• Arthropod vectors

• Epidemic typhus
• Causative agent Rickettsia prowazekii
• Reservoir Rodents
• Vector Pediculus humanus corporis
• Transmitted when louse feces are rubbed into bite
  wound

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Ehrlichiosis and Anaplasmosis

• Human monocytotropic ehrlichiosis (HME)
• Causative agent Ehrlichia chaffeensis
• Gram-negative, obligately intracellular (in
  white blood cells)
• Reservoir White-tailed deer
• Vector Lone star tick
• Human granulocytic anaplasmosis (HGA)
• Causative agent Anaplasma phagocytophilum
• Reservoir Deer
• Vector Ixodes Ticks
• Symptoms flu-like fever headache
• Diagnoses by indirect FA test

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Mononucleosis

• Cause Epstein-Barr virus (HHV4)
• spread through contact with saliva, mucus from
  the nose and throat, and sometimes tears
  (nicknamed the kissing disease)
• Symptoms high fever, a severe sore throat,
  swollen glands and tonsils, and weakness and
  fatigue (may cause spleen swelling)
• start 4 to 6 weeks after exposure

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Burkitts Lymphoma

• CauseEpstein-Barr virus (HHV4) Plasmodium
  infection
• Nasopharyngeal carcinoma
• Cancer in immunosuppressed individuals and in
  malaria and AIDS patients

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Cytomegalovirus Infections

• Cytomegalovirus CMV -(HHV-5)
• Infected cells swell (cyto-, mega-)
• Latent in white blood cells
• May be asymptomatic or mild
• Transmitted across the placenta may cause mental
  retardation
• Transmitted sexually, by blood, or by
  transplanted tissue

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Typical U.S. Prevalence of Antibodies
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Viral Hemorrhagic Fevers

• Symptoms of Yellow fever fever, headache,
  jaundice, vomiting, red face, heart dysfunction,
  bleeding, coma, muscle aches, low urine output
• Symptoms of Dengue fever, severe muscle and
  joint pain, and a rash.
• Found in Africa, S. C. America, SE Asia,
  Carribean

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Viral Hemorrhagic Fevers

• Marburg, Ebola, Lassa,Argentine and Bolivian
  hemorrhagic fevers, Whitewater Arroyo

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Marburg

• 1967, outbreak in Marburg Frankfort
• 37 people infected had been exposed to African
  green monkeys
• the monkeys had been imported from Uganda for
  research to prepare polio vaccine
• incubation period of 5-10 days
• Often fatal

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Ebola

• Severe, often-fatal disease in humans and
  nonhuman primates
• First seen in 1976 in Zaire (now D. Republic of
  Congo)
• Spread by direct contact with infected source
• Symptoms fever, headache, joint and muscle
  aches, stomach pain, red eyes, possible external
  bleeding

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Viral Hemorrhagic Fevers
1993 Famous Hanta virus OutBreak in Navajo
Village in New Mexico/Arizona area
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Ebola Hemorrhagic Virus
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Chagas Disease

• Also called American trypanosomiasis
• Causative agent Trypanosoma cruzi
• Reservoir Rodents, opossums, armadillos
• Vector Reduviid bug

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Toxoplasmosis

• Caused by Toxoplasma gondii
• Transmission
• Ingesting undercooked meat
• Contact with cat feces
• Congenital infection
• Stillbirth
• Neurological damage

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Malaria

• Four major forms
• Plasmodium vivax
• P. ovale
• P. malariae
• P. falciparum
• Vector Anopheles mosquito
• Definitive host Anopheles mosquito
• Symptoms chills, fever, (from parasite
  hemolysis) headache, convulsions, jaundice, coma
• gt1 million die each year

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Malaria
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Malaria in the United States
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Malaria
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Malaria

• Prophylaxis
• Chloroquine
• Malarone atovaquone and proguanil,
• Mefloquine
• Treatment
• Artemisinin artesunate and artemether
• Control
• Bed nets

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Cutaneous Leishmaniasis
Symptoms papule, enlarged lymph nodes.
Microscopic examination of the papule reveals
nucleated cells in white blood cells.
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Leishmaniasis
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Schistosomiasis

• Most symptoms are caused by tissue damage
  (granulomas) in response to eggs lodging in
  tissues

• Parasite of wild birds
• Cercariae penetrate the skin
• Intermediate host is the snail

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Types of Schistosomiasis
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