Chapter 27 Systemic Infections 2004 Wadsworth Thomson Learning

Chapter 27 Systemic Infections © 2004 Wadsworth – Thomson Learning

Organs of the Cardiovascular and Lymphatic Systems Figure 27. 1 © 2004 Wadsworth – Thomson Learning

Infections of the Heart • Carditis – inflammation of heart tissue – endocarditis--epithelial and connective (valves) • subacute bacterial endocarditis ( -hemolytic strep) • acute bacteria endocarditis (S. aureus and S. pyogenes) © 2004 Wadsworth – Thomson Learning

Infections of the Heart – Myocarditis • cardiac muscles • Viral myocarditis – coxsackievirus • American Trypanosomiasis (Chagas’ disease) • Trypanosoma cruzi – animal and insect hosts – Pericarditis • • membrane surrounding heart usually viral Streptococcus spp. Staphylococcus spp. © 2004 Wadsworth – Thomson Learning

Systemic Bacterial Infections • Plague – Yersinia pestis – bubonic • bubos--inflamed lymph nodes – septicemic plague • • bloodborne tissue necrosis skin blackened Black death – pneumonic plague • lung infection © 2004 Wadsworth – Thomson Learning

Systemic Bacterial Infections • Tularemia – Francisella tularensis • vector: deer fly in SW/wood tick NW and Midwest • direct contact: ingest/handle, rabbits • highly virulent • ulceroglandular tularemia – small sore at entrance – swelling in surrounding lymph node – multiply in phagocytes • symptoms – high fever, chills, headache, possibly pneumonia © 2004 Wadsworth – Thomson Learning

Systemic Bacterial Infections • Brucellosis – several Brucella species • domestic animals • Pasteurization • symptoms: – undulating fever – disoriented © 2004 Wadsworth – Thomson Learning

Systemic Bacterial Infections • Lymes Disease – – – Borrelia burgdorferi Spirochete tick born: Ixodes species animal reservoir 1975 Lyme, Connecticut • cluster of pediatric arthritis – three phases • bulls eye rash--75% of cases • headache, stiff neck, muscle aches, fatigue • eventually arthritis © 2004 Wadsworth – Thomson Learning

Systemic Bacterial Infections • Relapsing Fever – Borrelia spp. – Symptoms • sudden onset of fever, slowly subsides • week later, symptoms reappear – Antigenic variation • type-specific antibodies during fever • bacteria are cleared • alter surface antigens and reappear – Epidemic relapsing fever – Endemic relapsing fever © 2004 Wadsworth – Thomson Learning

Systemic Bacterial Infections • Anthrax – Bacillus anthracis • spore former • three exotoxins – symptoms – domestic and wild animals – humans • cutaneous anthrax • respiratory anthrax • gastrointestinal anthrax Figure 27. 6 © 2004 Wadsworth – Thomson Learning

Systemic Bacterial Infections • Cat Scratch Disease – Bartonella bonselae – symptoms • swollen lymph gland – arm or groin • healing scratch marks on same limb © 2004 Wadsworth – Thomson Learning

Systemic Bacterial Infections • Typhus – epidemic typhus • Rickettsia prowazekii – vector: lice from human to human/crowded conditions – murine typhus • Rickettsia typhi – vector: flea from mouse/rat, endemic – scrub typhus • Rickettsi tsutsugamushi • Asia and SW pacific – WWII and Vietnam War © 2004 Wadsworth – Thomson Learning

Systemic Bacterial Infections • Rocky Mountain Spotted Fever – Rickettsia rickettsii – wood tick – dog tick – Lone Star tick – symptoms • spotty rash • abnormal clotting Incidence of cases within the U. S. Figure 27. 7 © 2004 Wadsworth – Thomson Learning

Systemic Viral Infections • Yellow fever – RNA flavivirus – mosquito Aedes aegypti – symptoms • most--mild fever, headache, weakness • 20%--sever fever, chills, headache, jaundice – reservoir • monkeys – prevention • vaccine © 2004 Wadsworth – Thomson Learning

Systemic Viral Infections • Dengue fever – RNA flavivirus – mosquito Aedes aegypti – symptoms • high fever and headaches • rash and pain in the limbs – breakbone fever • apparent recovery--return of fever • supportive care – dengue hemorrhagic fever • children--bleeding and shock © 2004 Wadsworth – Thomson Learning

Systemic Viral Infections • Infectious mononucleosis – Epstein-Barr virus (herpesvirus) • age 15 -25, 90% adults seropositive – Pathogenesis • replication in URT • infection of B lymphocytes – virus-induced proliferation of B cells – T cell suppression response to turn off B cells » immune battling itself – Symptoms • sore throat, low-grade fever, enlarged lymph nodes • general fatigue/ 2 -3 weeks/even month – Cancers associated with EBV • Nasopharyngeal carcinoma, Burkitt’s lymphoma © 2004 Wadsworth – Thomson Learning

Systemic Viral Infections • Acquired immunodeficiency syndrome – Human immunodeficiency virus (HIV) – Virus binds receptor on CD 4+ TH cells Figure 27. 11 © 2004 Wadsworth – Thomson Learning

Systemic Viral Infections • HIV/AIDS – Transmission • sexual transmission • exposure to contaminated blood • mother to fetus – Treatment • HAART (highly active antiretroviral therapy) – long term survival – costly © 2004 Wadsworth – Thomson Learning

Systemic Viral Infections • HIV infection – Acute phase • first weeks • viral replication • killing TH cells – Chronic phase • peripheral blood viral load decreases • TH continues Figure 27. 10 decreasing • normal: 800 /mm 3 • AIDS: 200/ mm 3 © 2004 Wadsworth – Thomson Learning

Systemic Viral Infection • Ebola hemorrhagic fever – filovirus--threadlike morphology – Pathogenesis: • spread in blood and fluids • throughout blood, replication in many organs • focal necrosis: liver, lymphatic, kidneys, gonads • central lesions • bleeding: mucosa, abdomen, peridcardium vagina • shock, fever, delirium acute respiratory disorder – Potential vaccine (DNA and vector) © 2004 Wadsworth – Thomson Learning

Systemic Protozoal Infection • Malaria – 100 million cases/year (1 million die) – tropical and subtropical – Plasmodium species (4 species) • different disease pathogenesis • Vector: Anopheles mosquito © 2004 Wadsworth – Thomson Learning

Systemic Protozoal Infection • Plasmodium Life cycle – mosquito infects sporozoites into blood – sporozoites reproduce asexually in liver – Merozoites enter red blood cells--asexual reproduce • some return to liver • some develop into male and female gametocytes Figure 27. 13 – mosquito feeds and takes in gametocytes – sexual reproduction in mosquito © 2004 Wadsworth – Thomson Learning

Systemic Protozoal Infection • Malaria – Symptoms: • 2 weeks after infection • chills, fever, headaches, muscle ache • cycles with destruction of red cells--release of merozoites – Prevention • early attempts--control mosquito • drug therapy not as effective • vaccine: research and testing – multiple stages of protozoa – slow and weak immunity © 2004 Wadsworth – Thomson Learning

Systemic Protozoal Infection • Toxoplasmosis – Toxoplasma gondii – zoonosis • eating meat with cysts – heating kills cysts • Babisiosis – Babesia spp – zoonosis • tick vector © 2004 Wadsworth – Thomson Learning

Systemic Helminthic Infections • Schistosomiasis – – Schistosoma japonicum blood flukes (flatworm) complex life cycle infection • lasts for decades • human proteins on surface • many worms in blood • granulomas Figure 27. 16 © 2004 Wadsworth – Thomson Learning

Systemic Helminthic Infections • Filariasis – nematodes • • Wuchereria bancrofti and Brugia malayi transmitted by mosquitoes adult worm grows in lymph node elephantiasis – swelling of limb or scrotum – worms block lymphatic circulation © 2004 Wadsworth – Thomson Learning