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12 bio265 disease of circulatory system instructor dr di bonaventura


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Microbiology with diseases by body system;

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12 bio265 disease of circulatory system instructor dr di bonaventura

  1. 1. Microbial cardiovascular and systemic disease
  2. 2. Cardiovascular system and septicemia  Blood is normally axenic, it contains no microbes  Septicemia refers to microbial infection of the blood which can lead to septic shock  Depending on the type of organism, blood infections are referred to as:  *Bacteremia (bacterial septicemia)  Viremia  Fungemia  Parasitemia Petechiae – sign of bacteremia
  3. 3.  Bacteria can release toxins from a site of infection into the blood causing toxemia  Exotoxins: i.e., neurotoxins (botulism/tetanus)  Endotoxins: lipid A of LPS, which can lead to shock  Severe form of toxemia with septic shock  Streptococcal toxic-shock-like syndrome (TSLS)  Streptococcus pyogenes  From infections of skin/wound  Staphylococcal toxic shock syndrome (TSS)  Staphylococcus aureus  From reproductive tract infections Cardiovascular system and septicemia
  4. 4.  Bacterial septicemia can be associated with  Infections of the skin/wound  Surgical wounds  Urinary tract infections  Infected teeth  Improperly sterilized kidney dialysis machines, ….  Caused by opportunistic or nosocomial bacteria such as  Escherichia coli, Pseudomonas aeruginosa, Neisseria meningitidis, Haemophilus influenzae  Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes Cardiovascular system and septicemia
  5. 5.  Diagnosis of septicemia involves analysis of signs/symptoms  Culturing bacteria from the blood  In occult septicemia the exact bacterial cause is hidden  Treatment involves  Use of antimicrobial drugs  Elimination of the initial site of infection (source of septicemia)  Intravenous fluid replacement/Antibodies against LPS  Toxemia caused by Gram negative bacteria Cardiovascular system and septicemia
  6. 6.  Blood and lymph can carry pathogens throughout the body to cause systemic disease  Bacterial  Tularemia  Plague  Lyme disease  Viral  EBV (Epstein-Barr Virus)  Cytomegalovirus  Protozoan  Toxoplasmosis  Malaria  Chaga’s disease  Helminths  Schistosomiasis Microbial systemic disease
  7. 7. Bacterial systemic diseases - Tularemia  Tularemia is a zoonotic disease caused by Francisella tularensis (Gram- negative coccobacillus)  Virulence (endotoxin and lipid capsule – resists phagocytosis)  Prevalence in animals as intracellular parasite: from mammals (rabbit ), to birds, fish, ticks, flies, mosquitoes, mites  Multiple mode of transmission  bite of a tick  contact with infected animal/animal slaughter  contaminated meat or water  aerosols produced in the laboratory Mortality rate: ~ 5% of untreated patients
  8. 8. Bacterial systemic diseases - Tularemia  Highly virulent organism that causes  Skin lesion (ulcer) and swollen pus-filled lymph nodes near the site of infection, lymphangitis  General symptoms may last for months/years  malaise, fatigue, joint stiffness, myalgia  Diagnosis/treatment  Serological testing  Antimicrobials  Vaccine for people at risk  Possible use of Francisella as bioterrorism weapon – nationally notifiable disease (CDC)
  9. 9. Plague – Yersinia pestis (Enterobacteriaceae)  Bubonic plague - bite of infected flea or direct contact with infected animal  Pneumonic plague - bacilli spread from the blood to the lungs or are inhaled (airborne transmission)  Plague has caused several pandemics Xenopsylla cheopis
  10. 10. Plague – Yersinia pestis Bubo: painfully inflamed lymph node Darkening of dead tissues  Plague has been called the “Black Death”  Bubonic plague is fatal in ~50% of cases if untreated  Pneumonic plague is fatal in ~100% of cases if untreated  Urban living, rodent and flea control, antibacterial drugs have almost eliminated plague  The disease is considered endemic in states like California, Arizona, Nevada  Potential bioterrorism weapon: deadly, progresses rapidly, spread among people
  11. 11. Lyme disease (zoonosis)  Caused by the spirochete Borrelia burgdorferi Gram negative  Bull’s eye rash at the site of infection  Untreated patients can develop severe arthritis
  12. 12. Lyme disease is transmitted by a deer tick (Ixodes)  Deer tick: a 2-years life cycle
  13. 13. Lyme disease  Increase in cases of Lyme disease  Diagnosis: detecting antibodies against Borrelia  Antimicrobial drugs can cure the Lyme disease (first phase)  Treatment of later phases involves anti- inflammatory drugs
  14. 14. Viral systemic diseases – Epstein Barr virus (EBV)  HHV-4  Implicated with several diseases, depending on the “relative vigor” of a host’s cellular immune response
  15. 15. EBV and infectious mononucleosis  EBV is transmitted via saliva, enters the blood and infects B cells, which become enlarged with lobed nuclei  Cytotoxic T cells kill infected B cells  Signs and symptoms: fever, sore throat, fatigue, enlarged lymph nods and spleen  Diagnosis: detecting antibody against EBV  Recover of most patients in few weeks without specific therapy  EBV can become latent in the oropharynx: life long infection which rarely cause disease
  16. 16. Cytomegalovirus (CMV) – Herpes virus  Most people infected with CMV are asymptomatic  CMV remains in a latent state in various cells  Complications in  Immunocompromised patients  May develop pneumonia, blindness,  CMV mononucleosis  Fetuses (may be teratogenic)/newborns  ~7.5% of neonates infected with CMV  Bodily secretions carry CMV (saliva, mucous, milk, urine, feces, semen, vaginal secretions) – it would require a large exchange of secretions
  17. 17. Cytomegalovirus (CMV) – herpes virus  CMV infections is one of the most common infections in humans  Transmission usually occurs via  Sexual intercourse  Prenatal infection  Vaginal birth  Blood transfusion  Organ transplants  Diagnosis/Treatment involve  Owl’s eye appearance of enlarged cells, detection of CMV and antibodies against CMV  Interferons, anti CMV immunoglobulins, fomivirsen against replication of CMV in retinal cells. There is no vaccine against CMV
  18. 18. Protozoan diseases – Toxoplasmosis  Toxoplasma gondii  Nucleated cells of wild and domesticated mammals, birds  Immunocompromised patients can develop the disease  Fever, inflammation of several organs, spastic paralysis, blindness, encephalitis, and death  Transplacental infections – (first-trimester at higher risk) can cause spontaneous abortion, mental retardation, blindness, or microcephaly  Healthy individuals (mostly asymptomatic)  Infection normally resolves without treatment
  19. 19.  Humans become infected when ingesting undercooked contaminated meat  Serological detection and microscopic identification in tissue samples  Treatment with a combination of drugs in AIDS patients, pregnant women, newborns Wash fruits and vegetables, eat well cooked meat!!! Protozoan diseases – Toxoplasmosis  Definitive host
  20. 20. Malaria is transmitted by Anopheles mosquito  Plasmodium species, including P. falciparum (blackwater fever)/P. vivax (chronic malaria)  Malarial paroxysms: cycles of fever-chills correlate with period of erythrocyte lysis  Anemia and jaundice (liver/eyes)
  21. 21. Protozoan diseases - Malaria Ring-stage - trophozoites within red blood cells  Microscopic examination of blood smears allows diagnosis of malaria  Serological tests for specific diagnosis  Treatment and supportive measures  Antimalarial drugs  Anti-fever medication  Blood transfusions  Alternative methods involve  Limiting contact with mosquitos carrying Plasmodium  Malaria vaccines (development and testing in progress)
  22. 22. Protozoan diseases - Malaria  Malaria is endemic throughout the tropics and subtropics, where Anopheles breeds  Mosquito eradication programs eliminated the disease in Countries like US  Over 500 million people are infected  1-3 million people die annually
  23. 23. Chagas’ disease – American trypanosomiasis  Caused by Trypanosoma cruzi  Transmitted with the feces of the bloodsucking “kissing bug”  Major reservoirs: opossum and armadillos though most mammals, including humans, can carry the parasite  ~ 1% of infected humans develop early stages (general symptoms)  Intermediate asymptomatic (chronic) stage for up to ~ 20 years  Heart failure during final symptomatic stage  Clusters of parasites in the heart muscle tissue Trypomastigotes (infective) circulating in the blood are ingested by the kissing bug
  24. 24. Chagas’ disease – American trypanosomiasis  The disease is endemic in Central and South America  Affects 8-15 million people  Thousands die each year, including children  Early stages can be treated but not late stages  No vaccine exists for Chagas’s disease  Prevention involves measures that protect against bugs: mud replaced with concrete/brick, insecticides …..
  25. 25. Schistosomiasis is caused by blood flukes  Genus Schistosoma  The larval stage cercaria burrows into the skin  Feeding on blood, matures, mates, and releases eggs  Eggs lodge in tissues causing damage to several organs
  26. 26.  Treatment/control: drugs that kill the worm in the body, sewage treatment, and snail suppression Egg of Schistosoma mansoni  Diagnosis: identification of eggs - shape of the egg and location of the spines - in stool or urine samples  WHO (World Health Organization) estimates that over 250 million people are infected worldwide – Asia, Africa, South America Schistosomiasis is caused by blood flukes Scarlike tissue surrounds the egg