INFECTIOUS DISEASES Categories of INFECTIOUS AGENTS • Prions • *Viruses • Bacteriophages, Plasmids, Transposons • *Bacteria • Chlamidiae, Rickettsiae, Mycoplasmas • *Fungi: Yeasts, Hyphae • Parasites: Protozoa, Worms, Arthropods.
Download ReportTranscript INFECTIOUS DISEASES Categories of INFECTIOUS AGENTS • Prions • *Viruses • Bacteriophages, Plasmids, Transposons • *Bacteria • Chlamidiae, Rickettsiae, Mycoplasmas • *Fungi: Yeasts, Hyphae • Parasites: Protozoa, Worms, Arthropods.
INFECTIOUS DISEASES Categories of INFECTIOUS AGENTS • Prions • *Viruses • Bacteriophages, Plasmids, Transposons • *Bacteria • Chlamidiae, Rickettsiae, Mycoplasmas • *Fungi: Yeasts, Hyphae • Parasites: Protozoa, Worms, Arthropods Classes of Human Pathogens and Their Habitats Taxonomic Size Site of Propagation Sample Species Disease Viruses 20–300 nm Obligate intracellular Poliovirus Poliomyelitis Chlamydiae 200–1000 nm Obligate intracellular Chlamydia trachomatis Trachoma, urethritis Rickettsiae 300–1200 nm Obligate intracellular Rickettsia prowazekii Typhus fever Mycoplasmas 125–350 nm Extracellular Mycoplasma pneumoniae Atypical pneumonia Bacteria 0.8–15 µm Cutaneous Staphylococcus aureus Wound Mucosal Vibrio cholerae Cholera Extracellular Streptococcus pneumoniae Pneumonia Facultative intracellular Mycobacterium tuberculosis Tuberculosis Cutaneous Trichophyton sp. Tinea pedis (athlete's foot) Mucosal Candida albicans Thrush Extracellular Sporothrix schenckii Sporotrichosis Facultative intracellular Histoplasma capsulatum Histoplasmosis Mucosal Giardia lamblia Giardiasis Extracellular Trypanosoma gambiense Sleeping sickness Facultative intracellular Trypanosoma cruzi Chagas disease Obligate intracellular Leishmania donovani Kala-azar Mucosal Enterobius vermicularis Enterobiasis Extracellular Wuchereria bancrofti Filariasis Intracellular Trichinella spiralis Trichinosis Fungi Protozoa Helminths 2–200 µm 1–50 µm 3 mm–10 m PRIONS, “BSE” (Cows), “CJD”, Kuru (Humans) NON-Nucleic Acid PrP = Prion Protein Diagnostic Test : NL-COW MAD-COW http://www.youtube.com/watch?v=w5aAPEYIL9A Bovine Spongiform Encephalitis, Creutsfeldt-Jakob Disease VIRUSES • Less than ½ micron, usually MUCH less • DNA/RNA “CORE” (genome) • Protein “CAPSID” (protein –NA “coat”) • Sometimes a lipid “ENVELOPE” • Limited number of genes coding for all other structures • NO consistent naming system Respiratory Adenovirus Adenoviridae DS DNA Upper and lower respiratory tract infections, conjunctivitis, diarrhea Rhinovirus Picornaviridae SS RNA Upper respiratory tract infection Coxsackievirus Picornaviridae SS RNA Pleurodynia, herpangina, handfoot-and-mouth disease Coronavirus Coronaviridae SS RNA SARS, URIs Influenza viruses A, B Orthomyxoviridae SS RNA Paramyxoviridae SS RNA Respiratory syncytial virus Influenza Bronchiolitis, pneumonia Digestive Mumps virus Paramyxoviridae SS RNA Mumps, pancreatitis, orchitis Rotavirus Reoviridae DS RNA Childhood diarrhea Norwalk agent Caliciviridae SS RNA Gastroenteritis Hepatitis A virus Picornaviridae SS RNA Acute viral hepatitis Hepatitis B virus Hepadnaviridae DS DNA Acute or chronic hepatitis Hepatitis D virus Viroid-like SS RNA Hepatitis C virus Flaviviridae SS RNA With HBV, acute or chronic hepatitis Acute or chronic hepatitis Hepatitis E virus Norwalk-like SS RNA Enterically transmitted hepatitis Systemic with Skin Eruptions Measles virus Paramyxoviridae SS RNA Measles (rubeola) Rubella virus Togaviridae SS RNA German measles (rubella) Parvovirus Parvoviridae SS DNA Vaccinia virus Poxviridae DS DNA Erythema infectiosum, aplastic anemia Smallpox vaccine Varicella-zoster virus Herpesviridae DS DNA Chickenpox, shingles Herpes simplex virus 1 Herpesviridae DS DNA "Cold sore" Herpes simplex virus 2 Herpesviridae DS DNA Genital herpes Systemic with Hematopoietic Disorders Cytomegalovirus Herpesviridae DS DNA Cytomegalic inclusion disease Epstein-Barr virus Herpesviridae DS DNA Infectious mononucleosis HTLV-I Retroviridae HIV-1 and HIV-2 Retroviridae Dengue virus 1–4 Yellow fever virus SS RNA Adult T-cell leukemia; tropical spastic paraparesis SS RNA AIDS Arboviral and Hemorrhagic Fevers Togaviridae SS RNA Dengue, hemorrhagic fever Togaviridae SS RNA Regional hemorrhagic Filoviridae SS RNA fever viruses Hantavirus SS RNA Yellow fever Ebola, disease Korean, pneumonia Warty Growths Papillomavirus Papovaviridae DS DNA Condyloma; cervical carcinoma, squamous proliferations in general Central Nervous System Poliovirus Picornaviridae SS RNA Poliomyelitis JC virus Papovaviridae DS DNA Progressive Multifocal Leukoencephalopathy (opportunistic) Arboviral encephalitis viruses Togaviridae SS RNA Eastern, Western, Venezuelan, St. Louis BACTERIOPHAGES PLASMIDS TRANSPOSONS • INFECT BACTERIA, but may make a bacteria more difficult to treat because it may increase its “virulence” or its susceptibility to antibiotics BACTERIA • GRAM staining with CRYSTAL VIOLET – POSITIVE: THICK wall, ONE phospholipid layer – NEGATIVE: THIN wall, TWO phospholipid layers • SHAPE – COCCI (balls) – BACILLI (rods) • OXYGEN requirements – AEROBIC (NEED O2) – ANAEROBIC (do NOT NEED O2) – “FACULTATIVE” AEROBIC, makes ATP if O2 is present. Species Infections by pyogenic cocci Gram-negative infections, common Staphylococcus aureus, S. Frequent Disease Presentations Abscess, cellulitis, pneumonia, septicemia * epidermidis Streptococcus pyogenes, βhemolytic Upper respiratory tract infection, erysipelas, scarlet fever, septicemia Streptococcus pneumoniae (pneumoccoccus) Neisseria meningitidis (meningococcus) Neisseria gonorrhoeae (gonococcus) * Escherichia coli Lobar pneumonia, meningitis Cerebrospinal meningitis Gonorrhea Urinary tract infection, wound infection, abscess, pneumonia, septicemia, endotoxemia, endocarditis Klebsiella pneumoniae “ * Enterobacter (Aerobacter) “ aerogenes * Proteus spp. (P. mirabilis, P. “ morgagni) * Serratia marcescens “ * Pseudomonas spp. (P. “ aeruginosa) Bacteroides spp. (B. fragilis) Anaerobic infection Legionella spp. (L. pneumophila) Legionnaires disease * Contagious childhood bacterial diseases Enteropathic infections Haemophilus influenzae Meningitis, upper and lower respiratory tract infections Bordetella pertussis Whooping cough Corynebacterium diphtheriae Diphtheria Enteropathogenic E. coli Invasive or noninvasive gastroenterocolitis, some with septicemia Shigella spp. Vibrio cholerae Campylobacter fetus, C. jejuni Yersinia enterocolitica Salmonella spp. (1000 strains) Clostridial infections Salmonella typhi Typhoid fever Clostridium tetani Tetanus (lockjaw) Clostridium botulinum Botulism (paralytic food poisoning) Clostridium perfringens, C. septicum Gas gangrene, necrotizing cellulitis * Clostridium difficile Pseudomembranous colitis Zoonotic bacterial infections Bacillus anthracis Anthrax (malignant pustule) Listeria monocytogenes Listeria meningitis, listeriosis Yersinia pestis Francisella tularensis Bubonic plague Tularemia Brucella melitensis, B. suis, B. abortus Burkholderia mallei, B. pseudomallei Leptospira spp. (many groups) Borrelia recurrentis Borrelia burgdorferi Bartonella henselae Brucellosis (undulant fever) Spirillum minus, Streptobacillus moniliformis Glanders, melioidosis Leptospirosis, Weil disease Relapsing fever Lyme borreliosis Cat-scratch disease; bacillary angiomatosis Rat-bite fever Human treponemal Treponema pallidum infections Treponema pertenue Venereal, endemic syphilis (bejel) Yaws (frambesia) Treponema carateum (T. Pinta (carate, mal pinto) herrejoni) Mycobacterial infections Mycobacterium tuberculosis, M. bovis (Koch bacillus) Tuberculosis M. leprae (Hansen bacillus) M. kansasii, M. Avium (Complex), M. intracellulare M. ulcerans Nocardia asteroides Leprosy Actinomyces israelii Actinomycosis * * Actinomycetaceae * Atypical mycobacterial infections Buruli ulcer Nocardiosis Chlamydiae Rickettsiae Mycoplasmas • Like Bacteria, but….. –NO cell wall (mycoplasma [MANY pneumonias]) –NO ATP (chlamydia [STD, worldwide blindness]) –NO life outside a cell (obligate intracellular, rickettsiae [RMSF]) FUNGI • YEASTS, HYPHAE • CANDIDA, by far, the MOST PREVALENT ONE • DERMATOPHYTES(superficial), (“tinea”), i.e., epidermophyton, trichophyton, microsporum • DEEP FUNGI (GRANULOMAS) – HISTOPLASMOSIS – BLASTOMYCOSIS – COCCIDIOMYCOSIS YEASTS, HYPHAE PARASITES • PROTOZOA • “META”-ZOA (HELMINTHS) • “ECTO”-PARASITES, i.e., ARTHROPODS PROTOZOA SINGLE CELL INTESTINAL or BLOOD • PLASMODIUM (MALARIA) • LEISHMANIA • ENTAMOEBA • TRYPANOSOMA • TOXOPLASMA • GIARDIA Species Order Form, Size Luminal or Epithelial Disease Entamoeba histolytica Amebae Trophozoite 15–20 µm Amebic dysentery; liver abscess Balantidium coli Ciliates Trophozoite 50–100 µm Colitis Naegleria fowleri Ameboflagellates Trophozoite 10–20 µm Meningoencephalitis Acanthamoeba sp. Ameboflagellates Trophozoite 15–30 µm Meningoencephalitis or ophthalmitis Giardia lamblia Mastigophora Trophozoite 11–18 µm Diarrheal disease, malabsorption Isospora belli Coccidia Oocyst 10–20 µm Chronic enterocolitis or malabsorption or both Cryptosporidium sp. Coccidia Oocyst 5–6 µm Trichomonas vaginalis Mastigophora Trophozoite 10–30 µm Urethritis, vaginitis Bloodstream Plasmodium species Hemosporidia Babesia microti, B. bovis Hemosporidia Trypanosoma species Trophozoites, schizonts, Malaria gametes (all small and inside red cells) Trophozoites inside red cells Hemoflagellates Trypomastigote 14–33 µm Babesiosis African sleeping sickness Intracellular Trypanosoma cruzi Hemoflagellates Trypomastigote 20 µm Chagas disease Leishmania donovani Hemoflagellates Amastigote 2 µm Kala-azar Leishmania species Hemoflagellates Amastigote 2 µm Cutaneous and mucocutaneous leishmaniasis Toxoplasma gondii Coccidia Toxoplasmosis Tachyzoite 4–6 µm (cyst larger) HELMINTHS (ROUND[nematode]), TAPE[cestode]) • Roundworms, Tapeworms • Complex Life Cycles: sexual, asexual • ROUNDWORMS (nematodes): ASCARIS, TOXOCARA (VLM), STRONGYLOIDES, ENTEROBIUS • TAPE(FLAT)WORMS (cestodes): TAENIA (solium vs. saginata), DIPHYLLOBOTHRIUM, HYMENOLEPSIS Ascaris life cycle ARTHROPODS: INSECTS: • LICE • BEDBUGS • FLEAS ARACHNIDS: • MITES • TICKS • SPIDERS CLASS INSECTA, C L L R O O U U S S E E A B BEDBUG FLEA 6 legs CLASS ARACHNIDA, TICK BLACK WIDOW LARVAL MITE 8 legs ADULT MITE BROWN <--RECLUSE S C A B I E S BARRIERS • ALL ANATOMIC MUCOSAL POSSIBILITIES –SKIN –GI –RESPIRATORY –UROGENITAL SPREAD SAME AS TUMOR? • DIRECT EXTENSION • LYMPHATICS • BLOOD • NERVE RELEASE (TRANSMISSION) • • • • • • SKIN SHEDDING COUGHING/SNEEZING URINE FECES BLOOD VECTORS, e.g., insects, “zoonosis” • “STDs” (Sexually Transmitted Diseases) INFECTIVITY, GENERAL • AGENT HOST CELL • AGENT TOXINS NECROSIS • AGENTHOST CELLULAR REACTIONDAMAGE/DEATH INFECTIVITY, VIRAL • ATTACHMENT • ENTRY • TRANSCRIPTION (forw./rev.) • TRANSLATION – INCLUSIONS – REDUCED HOST CELL FUNCTION – CELL INJURY, LYSIS, DEATH – LATENCY – NEOPLASM?, aka, “transforming” INFECTIVITY, BACTERIAL • ADHERENCE • ENTRY • TOXINS –ENDO, Gram - , bacterial components, LPS –EXO, Gram -/+, secreted proteins IMMUNE EVASION • INACCESSIBILITY to host defense (Mr. Myagi, “no be there”) • VARYING (mutating) antigens • SHEDDING antigens, like jet or sub tactics • RESISTING INNATE (NATURAL) immunity • IMPAIRING T-CELLS INFECTIONS of IMMUNOSUPPRESSED HOSTS • Protozoal/Helminthic: Cryptosporidium, PCP (Pneumocystis Carinii [Jirovecii] Pneumonia), Toxoplasmosis • Fungal: Candida, and the usual 3 • Bacterial: TB, Nocardia, Salmonella • Viral: CMV, HSV, VZ DIAGNOSTIC TECHNIQUES • DIRECT PATHOGEN IMAGING, gross/micro • GRAM STAIN • “SPECIAL” (NOT H&E) STAINS, e.g., PAS • AGAR, e.g., CULTURES • TISSUE CULTURE, CPE (CytoPathological Effect) • ANTIBODIES (SEROLOGY) • PCR, POLYMERASE CHAIN REACTION, e.g., viral “LOAD” amazingly specific and sensitive. WHY? CELLULAR HOST RESPONSES • SUPPURATIVE (NEUTROPHILS, PMNs) (cultures may be positive) • MONO-NUCLEAR, i.e., Lymphocytes, Macrophages (i.e., Monocytes), GRANULOMAS • FIBROSIS • HEMOSIDERIN • CALCIFICATION ACUTE APPENDICITIS ABSCESS CHRONIC “MONONUCLEAR” INFLAMMATION GRANULOMA FIBROSIS H E M O S I D E R I H&E N PRUSSIAN BLUE Calcification The 4 Biggies •VIRAL •BACTERIAL •FUNGAL •PARASITIC VIRAL • TRANSIENT, ACUTE, e.g. Measles, Mumps, Polio, West Nile • CHRONIC LATENT (HERPES FAMILY), HSV, CMV, VZ • CHRONIC (HEPATITIS), Hep. B, C • “TRANSFORMING” (Epstein-Barr EBV, Human Papilloma, HPV) BACTERIAL •Gram+ •Gram•NON-GRAM MYCO-bacteria (AFB, aka, “Z-N”) SPIROCHETES, “darkfield” ANAEROBIC, vs. aerobic “OBLIGATE” INTRACELLULAR FUNGAL • YEASTS –CANDIDA –CRYPTOCOCCOSIS • MOLDS (HYPHAL) –ASPERGILLIS –MUCORMYCOSIS (ZYGOMYCOSIS) PARASITES •PROTOZOA (GI, BLOOD) •METAZOA (WORMS) VIRAL • TRANSIENT, ACUTE –Measles: Skin, URI, Lung, GI, Cornea, Brain –Mumps: Parotitis, Orchitis, Pancreas, CNS –Polio: Myelitis (Anterior horn motor neurons) –West Nile (arbo-): Meningoencephalitis VIRAL • CHRONIC LATENT (HERPES FAMILY), HSV, CMV, VZ –Herpes Simplex Virus –CytoMegalo Virus –Varicella-Zoster Virus (DRG) HSV CONGENITAL IMMUNOSUPPRESSED BASOPHILIC CMV (HHV-5) pneumonia VZ virus HHV3 VIRAL • CHRONIC (HEPATITIS), Hep. A, B, C –A, Mildest, most universal, chiefly acute –B, Most dangerous in the acute phase, but most are SUB-clinical –C, Most common cause of persistent transaminitis, more apt to go chronic –D, E… NORMAL LIVER ACUTE VIRAL HEPATITIS VIRAL “TRANSFORMING” Epstein-Barr, EBV (HHV4), lymphoma (Burkitts), nasopharyngeal Human Papilloma, HPV, cervical cancer (squamous cell), types 16 and 18 are always at the top of the list! PHARYNX NODES SPLEEN LIVER HETEROPHILE MONONUCLEOSIS, caused by EBV “MALIGNANT” cells on PAP smear, caused by HPV BACTERIAL •Gram+ (Staph, Strep) •Gram- (rods) • • • • MYCO-bacteria (TB) SPIROCHETES (SYPHILIS) ANAEROBIC (ABSCESSES) “OBLIGATE” INTRACELLULAR BACTERIAL • Gram+ cocci (Staph, Strep) SKIN RESPIRATORY TRACT S T A P H STREP: SKIN RESPIRATORY ERISIPELAS GRAM POSITIVE RODS • DIPTHERIA • LISTERIA • ANTHRAX------ • NOCARDIA • CLOSTRIDIUM GRAM NEGATIVE COCCI •Neisseria –GONORRHEA –MENINGITIS GRAM NEGATIVE RODS • E. COLI • • • • • Bordetella pertussis Pseudomonas aeruginosa Klebsiela/Aerobacter Yersinia pestis (plague) Hemophilus ducreyi (chancroid) MYCOBACTERIA (acid fast) •Tuberculosis • “Atypical” mycobacteria, the most important of which is MAC (Mycobacterium Avium Complex, in HIV patients) • Leprosy MORE ACID-FAST BACILLI, AFB (MAC) SPIROCHETES •SYPHILIS (Treponema pallidum), 1,2,3 • RELAPSING FEVER (Borrelia sp., via lice and ticks) • LYME DISEASE (Borrelia burgdorferi, via deer ticks) SYPHILIS • PRIMARY (CHANCRE) • SECONDARY (MANY skin manifestations) • TERTIARY (GUMMAS, CNS, BONE) • CONGENITAL ANAEROBES • Clostridium (Gram + bacillus) –Cause of many/most cases of “gas” gangrene “OBLIGATE” intracellular bacteria • Chlamydia trachomatis – Conjunctivitis – LGV (LymphoGranuloma Venerium) – Urethritis, salpingitis (parallels GC) • Rickettsia (Rocky Mountain Spotted Fever, Typhus) • Mycoplasma (very common cause of community acquired pneumonias) RMSF FUNGAL • YEASTS –CANDIDA –CRYPTOCOCCOSIS • MOLDS (HYPHAL) –ASPERGILLIS –MUCORMYCOSIS (ZYGOMYCOSIS) Candida albicans • Oral • Vaginal • Esophageal • All of the above are “moist” nonkeratinized squamous mucosa, aren’t they? • Immunocompromised, e.g., HIV, Diabetes Budding Yeasts and “PSEUDO” hyphae CRYPTOCOCCUS NEOFORMANS Budding cryptococcal yeasts, India ink prep, CSF MOLDS • Aspergillus • Zygomycosis (Mucormycosis) DERMATOPHYTES (“TINEAS”) (superficial fungi) •EPIDERMOPHYTON •MICROSPORUM •TRICHOPHYTON SIGNIFICANT FUNGI (deep) • HISTOPLASMOSIS, tiny granules within macrophages, ~3μ • BLASTOMYCOSIS, ~20μ • COCCIDIOMYCOSIS, ~50μ PROTOZOA • MALARIA (Plasmodium sp., of which falciparum is the most serius) • Babesiosis, transmitted by deer tick, • Leishmaniasis • Trypanosomiasis (sleeping sickness) • Chagas disease (also a trypanosome) • Entamoeba histolytica GAMETOCYTES Are COMMON And SAUSAGE shaped S C H U F F N E R ‘S D O T S Affected RBC’s are NOT enlarged NO SCHUFFNER’s DOTS S C H U F F N E R ‘ S D O T S “comets” TRYPANOSOMIASIS METAZOA (ROUNDworms/FLATworms) • Strongyloides (microscopic roundworm) • Tapeworms (Beef, Pork, flatworm) • Trichinosis (larva in skeletal muscle) • Schistosomiasis (bladder cancer) • Filariasis (elephantiasis) • VERY OFTEN, COMPLEX LIFE CYCLES Ascaris life cycle