Minarcik robbins 2013_ch8-infectious
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Transcript of Minarcik robbins 2013_ch8-infectious
INFECTIOUSINFECTIOUS
DISEASESDISEASES
AAA
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 SizeSite of
Propagation Sample Species DiseaseViruses 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
Fungi 2–200 µm Cutaneous Trichophyton sp. Tinea pedis (athlete's foot)
Mucosal Candida albicans Thrush
Extracellular Sporothrix schenckii Sporotrichosis
Facultative intracellular Histoplasma capsulatum Histoplasmosis
Protozoa 1–50 µm Mucosal Giardia lamblia Giardiasis
Extracellular Trypanosoma gambiense Sleeping sickness
Facultative intracellular Trypanosoma cruzi Chagas disease
Obligate intracellular Leishmania donovani Kala-azar
Helminths 3 mm–10 m Mucosal Enterobius vermicularis Enterobiasis
Extracellular Wuchereria bancrofti Filariasis
Intracellular Trichinella spiralis Trichinosis
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
RespiratoryAdenovirus 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, hand-foot-and-mouth disease
Coronavirus Coronaviridae SS RNA SARS, URIs
Influenza viruses A, B
Orthomyxoviridae SS RNA Influenza
Respiratory syncytial virus
Paramyxoviridae SS RNA Bronchiolitis, pneumonia
DigestiveMumps 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 With HBV, acute or chronic hepatitis
Hepatitis C virus Flaviviridae SS RNA Acute or chronic hepatitis
Hepatitis E virus Norwalk-like SS RNA Enterically transmitted hepatitis
Systemic with Skin EruptionsMeasles virus ParamyxoviridaeSS
RNA Measles (rubeola)Rubella virus Togaviridae SS
RNA German measles (rubella)Parvovirus Parvoviridae SS
DNA Erythema infectiosum, aplastic anemia
Vaccinia virus Poxviridae DS DNA 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 DisordersCytomegalovirus Herpesviridae DS DNA Cytomegalic inclusion disease
Epstein-Barr virus Herpesviridae DS DNA Infectious mononucleosis
HTLV-I Retroviridae SS RNA Adult T-cell leukemia; tropical spastic paraparesis
HIV-1 and HIV-2 Retroviridae SS RNA AIDS
Arboviral and Hemorrhagic FeversDengue virus 1–4 Togaviridae SS RNA Dengue, hemorrhagic fever
Yellow fever virus Togaviridae SS RNA Yellow fever
Regional hemorrhagic fever viruses
Filoviridae SS RNA Ebola disease
Hantavirus SS RNA Korean pneumonia
Warty GrowthsPapillomavirus Papovaviridae DS DNA Condyloma; cervical carcinoma,
squamous proliferations in general
Central Nervous SystemPoliovirus Picornaviridae SS
RNAPoliomyelitis
JC virus Papovaviridae DS DNA
Progressive Multifocal Leukoencephalopathy (opportunistic)
Arboviral encephalitis viruses
Togaviridae SS RNA
Eastern, Western, Venezuelan, St. Louis
BACTERIOPHAGESPLASMIDS
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 Frequent Disease Presentations
Infections by pyogenic cocci
Staphylococcus aureus, S.
epidermidis*Abscess, cellulitis, pneumonia, septicemia
Streptococcus pyogenes, β-hemolytic
Upper respiratory tract infection, erysipelas, scarlet fever, septicemia
Streptococcus pneumoniae (pneumoccoccus)
Lobar pneumonia, meningitis
Neisseria meningitidis (meningococcus)
Cerebrospinal meningitis
Neisseria gonorrhoeae (gonococcus)
Gonorrhea
Gram-negative infections, common
Escherichia coli 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
Haemophilus influenzae Meningitis, upper and lower respiratory tract infections
Bordetella pertussis Whooping cough
Corynebacterium diphtheriae Diphtheria
Enteropathic infections
Enteropathogenic E. coli Invasive or noninvasive gastroenterocolitis, some with septicemia
Shigella spp.
Vibrio cholerae
Campylobacter fetus, C. jejuni
Yersinia enterocolitica
Salmonella spp. (1000 strains)
Salmonella typhi Typhoid fever
Clostridial infections 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 Bubonic plagueFrancisella tularensis Tularemia
Brucella melitensis, B. suis, B. abortus
Brucellosis (undulant fever)
Burkholderia mallei, B. pseudomallei
Glanders, melioidosis
Leptospira spp. (many groups)
Leptospirosis, Weil disease
Borrelia recurrentis Relapsing feverBorrelia burgdorferi Lyme borreliosisBartonella henselae Cat-scratch disease; bacillary
angiomatosisSpirillum minus, Streptobacillus moniliformis
Rat-bite fever
Human treponemal infections
Treponema pallidum Venereal, endemic syphilis (bejel)
Treponema pertenue Yaws (frambesia)
Treponema carateum (T. herrejoni)
Pinta (carate, mal pinto)
Mycobacterial infections
Mycobacterium tuberculosis, M. bovis (Koch bacillus)
Tuberculosis
M. leprae (Hansen bacillus)
Leprosy
M. kansasii, M. Avium (Complex), M. intracellulare
Atypical mycobacterial infections
M. ulcerans Buruli ulcerActinomycetaceae Nocardia asteroides Nocardiosis
Actinomyces israelii Actinomycosis
ChlamydiaeRickettsiae
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
• PLASMODIUM (MALARIA)
• LEISHMANIA• ENTAMOEBA • TRYPANOSOMA• TOXOPLASMA• GIARDIA
SINGLE CELL
INTESTINAL or BLOOD
Species Order Form, Size DiseaseLuminal or Epithelial
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
BloodstreamPlasmodium species Hemosporidia Trophozoites, schizonts,
gametes (all small and inside red cells)
Malaria
Babesia microti, B. bovis Hemosporidia Trophozoites inside red cells Babesiosis
Trypanosoma species Hemoflagellates Trypomastigote 14–33 µm African sleeping sickness
IntracellularTrypanosoma 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 Tachyzoite 4–6 µm (cyst larger) Toxoplasmosis
HELMINTHS (ROUND[nematode]), FLAT[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
In small intestine TWICE
ARTHROPODS:INSECTS: = 6 legs
• LICE
• BEDBUGS
• FLEAS
ARACHNIDS: = 8 legs• MITES (chiggers)
• TICKS
• SPIDERS
CLASS INSECTA, 6 legs
C
R
A
B
L
O
U
S
E
L
O
U
S
E
BEDBUG
FLEA
CLASS ARACHNIDA, 8 legs
TICK ADULT MITE LARVAL MITE
BLACK
WIDOW BROWN
<--RECLUSE
SCABIES
BARRIERS• ALL ANATOMIC MUCOSAL
POSSIBILITIES–SKIN
–GI
–RESPIRATORY
–UROGENITAL
SPREAD• DIRECT EXTENSION
• LYMPHATICS
• BLOOD
• NERVE
SAME AS TUMOR?
RELEASE(TRANSMISSION)
• SKIN SHEDDING
• COUGHING/SNEEZING
• URINE
• FECES
• BLOOD
• VECTORS, e.g., insects, “zoonosis”
• “STDs” (Sexually Transmitted Diseases)
I=V/R
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
INFECTIONSof 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
ABSCESSABSCESS
CHRONIC “MONONUCLEAR” CHRONIC “MONONUCLEAR” INFLAMMATIONINFLAMMATION
GRANULOMA
FIBROSIS
H & E PRUSSIAN BLUE
H
E
M
O
S
I
D
E
R
I
N
CalcificationCalcification
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 A, B, C
• “TRANSFORMING” (Epstein-Barr
EBV, Human Papilloma, HPV)
BACTERIAL•Gram+•Gram-• MYCO-bacteria• SPIROCHETES• ANAEROBIC• “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
CMV (HHV-5) pneumonia
BASOPHILIC
CONGENITAL
IMMUNOSUPPRESSED
VZ Virus
VIRAL• CHRONIC (HEPATITIS), Hep. A, B, C
–A, Mildest, most universal
–B, Most dangerous in the acute phase, but most are SUB-clinical
–C, Most common cause of persistent transaminitis
–D, E…
NORMALNORMAL LIVER
ACUTE VIRAL HEPATITIS
VIRAL“TRANSFORMING”
Epstein-Barr, EBV, lymphoma (Burkitts), nasopharyngeal
Human Papilloma, HPV, cervical cancer (squamous cell), types 16 and 18 are always at the top of the list!
MONONUCLEOSIS, caused by EBV
PHARYNX
NODES
SPLEEN
LIVER
HETEROPHILE
“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
• Bordetella pertussis
• Pseudomonas aeruginosa
• Klebsiela/Aerobacter
• Yersinia pestis (plague)
• Hemophilus ducreyi (chancroid)
•E. COLI
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)
• 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
• 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” non-keratinized squamous mucosa, aren’t they?
• Immunocompromised, e.g., HIV, Diabetes
Budding Yeasts and “PSEUDO” hyphae
Budding cryptococcal yeasts, India ink prep, CSF
CRYPTOCOCCUSNEOFORMANS
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
GAMETOCYTESAre COMMONAnd SAUSAGEshaped
SCHUFFNER‘S
DOTS
Affected RBC’s are NOT enlargedNO SCHUFFNER’s DOTS
SCHUFFNER‘S
DOTS
“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