Cardiovascular and Lymphatic systems

• Plasma leaves blood to become interstitial fluid
• Lymph capillaries: Transport interstitial fluid to blood
• Lymph nodes contain cells of the immune system
• Diseases in this chapter represent organisms that invade and/or replicate within bloodstream and/or lymphatic system

Sepsis

• Systemic inflammatory response from bacteria in blood
• Gram negative- endotoxin
• Gram positive- exotoxins

Severe sepsis

•  Sepsis + decreased blood pressure

Septic Shock

• Sepsis + uncontrollable decreased blood pressure

Lymphangitis

• Inflamed lymph vessels

Endocardium

• inner lining of heart

Endocarditis

• Inflammation of the endocardium

Bacterial endocarditis

• Alpha-hemolytic streptococci from mouth
• Staphylococcus aureus from mouth
• Individuals with valve problems may need prophylactic antibiotics for dental work

Rheumatic Fever

• Autoimmune complication of Streptococcus pyogenes infections
• Arthritis and fever; leads to inflammation of heart valves
• Misdirected immune attack against streptococcal M protein damages valves

Tularemia

• Francisella tularensis
• Gram-negative rod
• Zoonosis
• Transmitted to humans from rabbits and deer by deer flies (“rabbit fever”)
• Skin ulcer; swollen lymph nodes
• Bacteria reproduce  in phagocytes

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 in evening
• Transmitted via milk from infected animals or contact with infected animals

Anthrax

• Bacillus anthracis
• Gram-positive, endospore-forming aerobic rod
• Found in soil
• Cattle routinely vaccinated
• Treated with antibiotics (Cipro)

Cutaneous anthrax

• Endospores enter through minor cut
• 20% mortality

Gastrointestinal antrax

• Ingestion of undercooked, contaminated food
• 50% mortality

Inhalation (pulmonary) anthrax

• Inhalation of endospores
• 100% mortality

Ischemia

• Loss of blood supply to tissue

Necrosis

• Death of tissue

Gangrene

• Death of soft tissue

Gas Gangrene

• Clostridium perfringens and other clostridia, gram-positive, endospore-forming anaerobic rod, grows in necrotic tissue
• Treatment includes surgical removal of necrotic tissue

Systemic diseases caused by bites & scratches

• Bartonella henselae: Cat-scratch disease
• More common in US than Lyme disease
• From cat bite or scratch
• Organism replicates in the digestive system of cat fleas
• Initially, papule at infection site, then lymph node swelling

Plague

• Causative agent: Yersinia pestis, gram-negative rod
• Reservoir: Rats, ground squirrels, and prairie dogs
• Vector: rat fleas
• Bubonic plague:
• Most common form
• Bacterial growth in blood and lymph
• Buboes- swollen lymph nodes
• Pneumonic plague: Bacteria in the lungs
• “Black Death” destroyed 30% population in Europe in 14th century

Lyme Disease

• Most common tick-borne disease in US
• Cluster of cases in Lyme, CT in 1975 originally diagnoses at rheumatoid arthritis
• Causative agent: Borrelia burgdorferi
• Reservoir: Deer
• Vector: Ticks
• First symptom: Bull's-eye rash
• Second phase: Irregular heartbeat, encephalitis
• Third phase: Arthritis

Rocky Mountain spotted fever

• Caused by Rickettsia rickettsii
• Reservoir and vector: ticks
• Measles-like rash, except that the rash also appears on palms and soles

Infectious Mononucleosis

• Epstein-Barr virus (HHV–4)
• Childhood infections are asymptomatic
• Adolescents and adults “mono”
• Fever, swollen lymph nodes in neck, fatigue
• Transmitted via saliva
• Associated Burkitt’s Lymphoma- cancer in immunosuppressed individuals and in malaria and AIDS patients
• Most common childhood cancer in Africa
• Suspected in MS, Hodgkin’s disease

Cytomegalovirus Infections

• Cytomegalovirus (HHV-5)
• Infected cells swell (cyto-, mega-)
• Latent in white blood cells
• May be asymptomatic or mild
• Serious opportunistic infection for immunocompromised (HIV)
• Transmitted via saliva, sexually, by blood, or by transplanted tissue

Viral Hemorrhagic Fevers

• Fever, chills, headache, nausea, vomiting, jaundice
• Endemic is Central America, S. America, Central Africa, Caribbean
• Yellow fever: Arbovirus: Skin: Monkeys: mosquito
• Dengue: Arbovirus: Skin: Humans: mosquito

Viral Hemorrhagic Fevers

• Marburg, Ebola, Lassa
• Africa
• High fever, vomiting blood, profuse bleeding internally and externally (nose, eyes)
• Death within days
• Filovirus, arenavirus: mucous membranes: fruit bats other mammals: contact with blood

Viral Hemorrhagic Fevers

• Hantavirus
• 1993- increase rain, crops flourished
• Deer mouse population boomed
• 27 dies in southwest US from inhalation of virus from droppings
• Hantavirus pulmonary syndrome: buynavirus: respiratory tract: field mice: inhalation

Chagas' Disease

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

Toxoplasmosis

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

Malaria

• Four major forms:
• Plasmodium vivax
• P. ovale
• P. malariae
• P. falciparum- most dangerous
• Chills, cyclical fever, vomiting
• Vector : Anopheles mosquito
• Definitive host: Anopheles mosquito
• Treatment
• Chloroquine
• Control
• Bed nets

Leishmaniasis

• Three major forms transmitted by sandflies
• Visceral Leishmaniasis
• Leishmania donovani
• Affects internal organs
• Cutaneous Leishmaniasis
• L. tropica
• Affects skin
• Mucocutaneous Leishmaniasis
• L. braziliensis
• Disfiguring disease

Schistosomiasis

• Caused by small fluke (Schistosoma)
• Tissue damage (granulomas) in response to eggs lodging in tissues
• Cause permanent and destructive damage to different organs
• bladder, liver, lungs, brain