Slide 1Structure of the Cardiovascular SystemStructure of the Cardiovascular SystemLyme Disease – Pathogen and Virulence FactorsLyme Disease - PathogenesisLyme Disease - PathogenesisLyme Disease - PathogenesisLyme Disease – Signs and SymptomsLyme Disease – Signs and SymptomsLyme Disease – Signs and SymptomsLyme Disease – EpidemiologyLyme Disease – DiagnosisLyme Disease – TreatmentLyme Disease – PreventionInfectious Mononucleosis – Pathogen and Virulence FactorsInfectious Mononucleosis - PathogenesisInfectious Mononucleosis – Signs and SymptomsInfectious Mononucleosis - EpidemiologyInfectious Mononucleosis - DiagnosisInfectious Mononucleosis - TreatmentInfectious Mononucleosis - PreventionMalaria – Pathogens and Virulence FactorsMalaria – Pathogens and Virulence FactorsMalaria – Pathogens and Virulence FactorsMalaria – Pathogens and Virulence FactorsMalaria – Pathogens and Virulence FactorsMalaria – Pathogens and Virulence FactorsMalaria – PathogenesisMalaria – PathogenesisMalaria – Signs and SymptomsMalaria – EpidemiologyMalaria – EpidemiologyMalaria – DiagnosisMalaria – TreatmentMalaria – TreatmentMalaria – PreventionM I C R O B I O L O G YWITH DISEASES BY BODY SYSTEM SECOND EDITIONChapter 21Microbial Cardiovascular and Systemic DiseasesTHIRDStructure of the Cardiovascular System•Composed of three parts–Heart–Blood–Blood vessels•Blood composition–Serum – liquid part of blood–Formed elements – erythrocytes, leukocytes, platelets•Capillaries carry blood to the surrounding tissues and also leak fluid that is picked up by the lymphatic vesselsStructure of the Cardiovascular System•Defenses that Protect the Cardiovascular System–Closed system–Mechanical defenses•Normal Microbiota of the Cardiovascular System–Blood normally does not contain microbes–Breaks in skin or mucous membranes provide entry route–Blood and lymph may spread microbes throughout bodyLyme Disease – Pathogen and Virulence Factors•Borrelia burgdorferi–Gram-negative spirochete that has endoflagella within the periplasmic space–Burrows into tissues•Linear chromosome•Lacks iron-containing enzymes and molecules•Changes outer surface proteins (OSPs)–Antigenic variation–OSPs trigger an imbalance in the immune system•Releases endotoxin when it diesLyme Disease - Pathogenesis•Small mammals, including mice and squirrels, are the reservoirs (zoonosis)•Hard ticks of the genus Ixodes are the vectors (biological vectors)–Deer ticks in northeastern and north-central U.S.–Western black-legged tick in the Pacific coastal U.S.•Nymphs and adults primarily responsible for transmission into large animal hostsLyme Disease - Pathogenesis•Spring – eggs hatch into larvae•Fall – larvae feed and may become infected•Nymphs dormant until spring•Nymphs feed a second time during spring and summer–May become infected or may infect host via saliva–Ticks must remain on a host for 36-48 hours•Fall – nymphs molt into adults–Females require blood meal before laying eggs–Infect large animal hostsLyme Disease - Pathogenesis•Organisms move from the site of infection through the blood and lymph•Can accumulate in joints and can subsequently trigger arthritis•Organisms have affinity for endothelial cells lining blood vessels–Trigger inflammation (skin, nervous system, muscle, tendons, and connective tissue)•Can go dormant in the body for lengthy periods of timeLyme Disease – Signs and Symptoms•Mimics many other diseases and is highly variable in its presentation•Vast array of signs and symptoms because the organism can infect several parts of the body at the same time•Typically has three phases in untreated patientsLyme Disease – Signs and Symptoms•Phase 1•Expanding red rash resembling bull’s eye at site of infection–Within 3-30 days of infection and lasts 2-4 weeks–70-80% of patients develop•Malaise, headaches, dizziness, stiff neck, severe fatigue, fever, chills, muscle and joint pain, and swollen lymph nodesLyme Disease – Signs and Symptoms•Phase 2 –Only seen in 10% of cases–Neurological symptoms (meningitis, encephalitis, and peripheral nerve neuropathy) and cardiac dysfunction•Phase 3 – Severe arthritis that can last for years–Seen in 80% of cases–Deposition of antigen-antibody complexes in joints resulting in joint pain and swelling•Rarely if ever fatalLyme Disease – Epidemiology•Discovered in 1975•Disease was present in U.S. decades before its discovery•One of the more reported vector-borne disease in U.S.•Increased incidence in last 20-30 years–Humans moving into woodland areas–Deer population protected; even encouraged to feed in suburban yards•Cases are concentrated in the Northeast and upper MidwestLyme Disease – Diagnosis•Based on the signs and symptoms of the disease•Diagnosis can be confirmed by detecting organisms in blood•Diagnosis confirmed by detecting antibodies against the bacterium in the bloodLyme Disease – Treatment•Antimicrobial drugs such as doxycycline or a penicillin can cure if disease is in first phase–Prolonged treatment with larges doses may be required (14-21 days)•Treatment of later phases is difficult because symptoms are often caused by the immune systemLyme Disease – Prevention•Prevent contact with ticks particularly in the summer when nymphs are feeding•Wear long-sleeved shirts and long, tight-fitting pants and tuck pants cuffs into socks•Repellents using DEET (N,N-diethyl-m-toluamide)•Examine body for ticks or bites•Remove attached ticks using forceps•Vaccine was available until March 2002–Not widely used–Produced symptoms of Lyme disease in some patientsInfectious Mononucleosis – Pathogen and Virulence Factors •Human herpes virus 4 (HHV-4; also known as Epstein-Barr virus (EBV)) is the causative agent–Enveloped, ds DNA virus–Can become latent within cells, resulting in lifelong infection–Causes infected B lymphocytes to become immortal which then are one source of cancers•EBV may play a role in chronic fatigue syndrome, Hodgkin’s lymphoma, and oral hairy leukoplakiaInfectious Mononucleosis - Pathogenesis•EBV is transmitted through saliva (direct or indirect contact)–Kissing (“kissing disease”), coughing, sneezing, sharing drinking glass or eating utensils–Humans are only known reservoir•Infects epithelial cells of the pharynx and parotid salivary