Midterms Mycovi PDF

SUBCUTANEOUS FUNGI → most are saprobes found in dead decaying vegetation Sporotrichosis and wood → caused by Sporothrix schenckii → MOT: trauma...

SUBCUTANEOUS FUNGI → most are saprobes found in dead decaying vegetation Sporotrichosis and wood → caused by Sporothrix schenckii → MOT: trauma → nodular lesions that suppurate, ulcerate and drain → Fundi capable of producing nodules Ulcerate spread to lymph nodes (more nodules) Secondary bacterial infection TYPES OF SPOROTRCHOSIS Fixed cutaneous sporotrichosis - primary lesions develop at the site of implantation - found: limbs,hand,finger Lymphocutaneous sporotrichosis - Primary lesions KINDS OF INFECTION develop at the site of implantation 1. Phaeohyphomycosis - secondary lesions 2. Mycetoma also appear along 3. Sporotrichosis the lymphangitic 4. Chromobastomycosis channels - No systemic “typically elavated Phaeohyphomycosis symptoms are subcutaneous nodulles” → Causative agents: present ▪ Exophiala Pulmonary Sporotrichosis Symptoms ▪ Phialophora - haematogenous → Cough ▪ Wangiella dissemination → Sputum production ▪ Bipolaris - Symptoms are non- → Fever, weight loss ▪ Exserohilum specific and upper-lobe ▪ Cladophialophora lesions ▪ Phaeoannellomyces Haemoptysis: massive and ▪ Aureobasidium fatal (expectoration of blood) ▪ Cladosporium Lung lesion: gradual ▪ Curvularia progression to death ▪ Alternaria Osteoarticular sporotrichosis → Cystic lesions → cutaneous lesions → Overlying verrucose lesions → stiffness and pain in a large joint Exophiala jeanselmei Wangiella dermatitidis → lesions usually confined to the long bones near affected joints Osteomyelitis: seldom occurs without arthritis Chromoblastomycosis → verrucoid crusted nodules of the skin → painless if without secondary infections → development in tissue dematiaceous (brown- pigmented/copper) → MOT: traumatic implantation of fungal element in skin MYCETOMA → chronic granulomatous infection → swollen tumor-like areas with sinuses for drainage → may be due to several fungi eumycetoma or actinomycetes (actinomycetoma) → notes: a chronic infection of the skin, subcutaneous tissue and sometimes bone characterized by discharging If not treated, will elevate to resemble sinuses filled with organisms. cauliflower (w/ cayenne pepper) → causative agents “Watering can foot” or “Madura ▪ Phialophora verrucosa foot” ▪ Fonsecaea pedrosoi Cause: soil, manure ▪ F. compacta ▪ Cladophialophora carrionii  TYPE OF CONIDIATIONS Cladosporium → chains branch from a conidium → Tree-like appearance Phialophora → with vase base phialide arising from a conidiophore Rhinocladiella → arranged sympodially on short denticles → resembles a body builder → with primary, secondary and tertiary conidia SUBCUATENOUS FUNGI Cladosporium carionii Disease Microscopic morphology Illustration Hyphae: dark septate Chromoblastomycosis Conidia: cladosporium Exophiala jeanselmei Mycetoma Hyphae: septate branched with bends and torturous ends Phaeohyphomycosis Conidia:Annelloconidia - attached to an annellide then to an annellophore - with vermiform granules (black pepper) on direct examination Fonsecaea pedrosoi Chromoblastomycosis Hyphae: Darkbrown septate Phaeohyphomycosis ▪ may have Conidia: all three types secondary infection Phialophora verrucosa Hyphae: dark septate hyphae Chromoblastomycosis Phaehyphomycosis Conidia: Phialophora - with distinct swollen center and collarette  Pseudallescheria boydii → fast grower → perfect fungus (Teleomorph, Anamorph) Eumycotic mycetoma Hyphae: hyaline septate and loosely arranged ◼ with white or light colored granules on Conidia: Lollipop shape or lemon shape drainage annelloconidia on annellides Sporothrix schenckii → other name: “Rose gardener’s disease” contact infection: Sphagnum moss Sporotrichosis Hyphae: hyaline septate Conidia: conidiophores arise at right angles a. darkly pigmented b. hyaline - swell at the distal end which is denticulated - Rosette or daisy-like arrangement of Wangiella dermatitidis Hyphae: septate and branched with Phaeohyphomycosis tortuous twists and turns Conidia: phialophora type with ovoid and unicellular conidia attached to flask shaped phialide and without collarette Xylohypha bantiana Hyphae: septate Cerebral phaeohyphomycosis Conidia: cladosporium type with blastoconidia Conidiophores: with poor posture  SYSTEMATIC FUNGI SYSTEMIC INFECTION: ✓ Route of infection: respiratory tract YEAST: ✓ dimorphism is common to the resembles the figure 8 or hourglass pathogenic types (Blastomyces ▪ Daughter cell is attached by broad necks dermatititdis, Coccidioides immitis, ▪ -Thick refractile walls Histoplasma capsulatum) Blastomyces dermatitidis → dimorphic → airborne routes “only rare infectious” Disease chronic granulomatous and -Blastomycosis suppurative infection of the -Gilchrist’s disease lungs, skin and mucous -Chicago disease membranes MICROSCOPPIC MORPHOLOGY -North American white or beige to brown at first Blastomycosis with a waxy or glabrous texture BLASTOMYCOSIS “skin” some isolates may be fluffy ✓ elevated, macerated, ill-defined, scaly borders, are prickly in the center central ulcer MICROSCOPIC APPEARANCE Hyphae: fine hyaline septate Conidia: - lollipop in appearance, borne directly from the hyphae or on conidiophores - central portion is slightly swollen  Coccidioides immitis MICROSCOPIC MORPHOLOGY Disease: colonies are white and floccose Coccidioidomycosis/ San Joaquin Valley fever at first Posada’s Disease /Erythema multiforme Valley/Dessert Bumps/Erythema nodosum Desert Rheumatism California disease Coccidioidomycosi skin infections are characterized by erythema nodosum and multiforme most virulent human mycosis Mature colonies MICROSCOPIC APPEARANCE ✓ white to gray, but strains with lavender, buff, Hyphae: septate cinnamon, yellow or brown pigment hyaline with varying ✓ Reverse: tan to dark brown or Orange widths Texture:Powdery Spherules (rounded) at BT or at 40C Conidia: arthroconidia (barrel shaped) at 25 – 35C Surface = Partially or completely covered with a cottony aerial mycelium that resembles COBWEB  Histoplasma capsulatum MICROSCOPIC MORPHOLOGY ✓ first isolated from histiocytes (CT macrophage) White, fluffy, Wrinkled, moist, heaped; soft, creamy tan ✓ believed to be encapsulated or pink ✓ stained with Wrights-Giemsa ✓ facultative intracellular fungi- yeast form will grow within leukocytes ✓ can grow intracellularly as small budding yeast in man and in culture media at 37C. ✓ grows as a mold at 25C, producing microconidia Disease: Histoplasmosis or Spelunker’s disease Darling’s disease (pulmonary disease) Paracoccidioides brasiliensis Caver’s disease Disease: Clinical feature: paracoccidiodomycosis Coin lesions, flattened South American Blastomycosis lesions in lungs Lutz-Splendore-Almeida's Disease - lung infection MICROSCOPIC APPEARANCE - asymptomatic and self- limiting MICROSCOPIC APPEARANCE Hyphae: Hyphae: Conidia: not common very fine septate hyaline same with Coccidiodes Macroconidia: sunflower in bloom ▪ large unicellular, Yeast: mariner’s wheel spherical with tuberculate walls Microconidia: borne directly or in short conidiophores Yeast: blastoconidia with narrow necks  YEAST AND YEAST-LIKE ORGANISMS Characteristic Features Importance 1. Normal Flora - skin and mucous membranes - unicellular fungi are disease-causing to man 2. Opportunistic - infections are endogenous - about 30 species Factors for the Severity of Infection Reproduction: budding, by pseudohyphae production Yeasts: 1. How the defenses were weakened perfect fungi ex. Antibiotics Yeastlike: fungi imperfecti (asexual only) 2. How long the condition exists ex. use of catheterization Laboratory Methods Specimen: sputa, skin scrapings, tissue Considerations: 1. Sterile Container 2. Prompt transport to laboratory Microscopic Examination 1. Wet Mount 2. Gram’s Stain - dark blue-black Culture Media 1. Modified SDA 2. BAP 3. SABHI 4. CMT – Cornmeal-Tween 80, enhances chlamydospores Macroscopic Features - white or cream - resembles coagulase negative Staphylococcus YEAST-LIKE FUNGI → they grow partly as yeast and partly as elongated cells resembling hyphae. The latter forms a pseudomycelium. Microscopic Features 1. Hyphae 2. Pseudohyphae - no septa - with constriction where daughter cell is attached 3. Blastoconidia YEAST → unicellular round/oval like fungi reproduction by budding YEAST LIKE FUNGUS → fungus that reproduction by budding, but bud fails to separate from paraent cell and ultimately form a structure that looks like a chain of elongated cell → they form pseudohyphae Differences Between Germ Tube and Pseudohyphae 1. Germ tubes have parallel walls Cryptococcus neoformans 2. Pseudohyphae have constrictions ▪ occur in approx. 15% of AIDS patients and other cases of immunosuppression ▪ fungi grow as large, encapsulated, budding yeast cell ▪ pread via the inhalation of Pigeon droppings DISEASE Cryptococcosis Turolosis European Blastomycosis Fungal Meningitis Microscopic Features: C. neoformans ▪ thin walled globose or Candida albicans oval shaped ▪ a dimorphic fungi; normal microbiota in the vagina, GIT, ▪ w/o hyphae nor Respiratory tract, mouth pseudohyphae ▪ formerly known as Monilia albicans ▪ encapsulated DISEASE Candida/ Moniliasis ▪ detected by latex a. oral candidiasis/ Trush agglutination ▪ seen as small, white- flesh film covering the tongue and the mouth ▪ infection of the mucous membrane ▪ common among newborns and infants ▪ an infection will occur because the growth of C. albicans will not be inhibited by other LABORATORY DIAGNOSIS microorganisms direct examination India Ink Preparation b. Paronychia ▪ C. neoformans appear as ▪ for rapid I.D.; most ▪ infection surrounding spherical, single/multiple widely used technique the nails budding yeast cells, thick ▪ appears as a yeast cell walled, 2-15 μ in surrounded by a diameter refractile polysaccharide gelatinous capsule c. Balanitis and vaginitis ▪ due to lowered pH (oral contraceptives, diabetes, pregnancy and antibiotic therapy) ▪ strawberry lesion ▪ curdlike yellow white Geotrichum candidum liquid discharge usually isolated from dairy products, vegetables and fruits DISEASE Geotrichosis Doderlein’s bacilli ▪ initial characteristics: -responsible for the acidic pH white to cream, yeast in the vagina (pH 4.5) like, some isolates are white powdery molds d. Disseminated infections Microscopic Features of Geotrichum candidum - pulmonary diseases, ▪ arthroconidia: resembles endocarditis a “hockey stick” MICROSCOPIC FEATURES: C. albicans ▪ no blastoconidia nor - presence of pseudohyphae blastoconidia on ▪ with true hyphae pseudohyphae - chlamydospores are thick walled Pneumocyctis carinii OTHER YEASTS Was first classified as a protozoan Risk factors: malnutrition; HIV-infection Saccharomyces cerevisiae Clinical diseases Pneumonia (most common)- lung ▪ single celled fungus infection common to AIDS microorganism patients ▪ involved in the Microscopic Features of P. carinii production of many - cyst - trophozoite fermented beverages (amoeboid in shape) Toluidine Blue Cyst:reddish-blue, purple against blue background Torulopsis glabrata/ Candida glabrata ▪ causes life-threatening bloodstream infections ▪ strictly haploid and normally grows only in the yeast form  OPPORTUNISTIC FUNGI OPPORTUNISTIC FUNGI DISEASE CAUSED → usually a Hospital Acquired Infection Phaeohyphomycosis Hyalohyphomycosis Conidiogenous cells where conidia arises Phialide ▪ determinate ▪ stops elongating when 1st conidium appears Annellides ▪ indeterminate ▪ continues to grow even when 1st chronic infectious conidium appears condition caused by infection cause by nonp- dematiaceous fungi pigmented fungi Poroconidia arises from pores of the hyphae which usually involve he skin and subcutaneous tissue GROUPING OF OPPORTUNISTIC FUNGI ▪ Glabrous/ velvety A. DEMATIACEOUS ▪ Dark brown to black septate hyphae ▪ Asexual reproduction Disease MICROSCOPIC APPEARANCE Hyphae Conidiosphore Conidia Poroconidia Alternaria Phaeohyphomycosis ▪ Club shaped ▪ Sinusitis ▪ Arrange ▪ Asthma acropetally ▪ Osteomyelitis ▪ Young cell at ▪ Eye and ear tip w/ infection transverse and longitudinal septa Bipolaris ▪ Respiratory ▪ Geniculate ▪ Sympodial and infection (bent knee) indeterminate ▪ Meningistis ▪ multicellular ▪ Osteomyelitis ▪ Pea-pod shaped Curvularia ▪ Allergies ▪ dematiaceous ▪ w/ transverse ▪ Onychomycosis septate w/ thin septum shaped ▪ endocarditis wall like ellipse ▪ geniculate ▪ 3-5 cells “crescent roll” Drechslera ▪ Mycotic ▪ Single, ▪ sympodial keratitis branched and intedeterminate ▪ Allergies geniculate ▪ Acropetally arranged ▪ 4 cells ▪ Thick walled Epicoccum ▪ Skin allergies ▪ Intertwine and ▪ short ▪ globose to branched subglobose together Fusarium ▪ Keratitis ▪ No ▪ w/ “foot cell” ▪ fusarium borne ▪ Onychomycosis conidiosphore ▪ fusarium shape directly on the ▪ Fungamia macroconidia: hyphae banana shape microconidia: balls Helminthsporium ▪ Endocarditis ▪ determinate, ▪ slightly curved ▪ keratitis straight w/ tapering end Nigrospora ▪ keratitis ▪ dark and oval ▪ attached to conidiophore at its side B. HYALINE SEPTATE GROUP 1. Aspergillus Group ▪ Causes Aspergillus ▪ Conidiophores terminate in a swollen vesicle ▪ Uniseriate: produces one series of structure between vesicle and conidium ▪ Biseriate: forms two series of intermediate structures disease Culture media Czapek’s agar Macroscopic Microscopic Features features hyphae conidiophore vesicles Phialocondia Aspergillus ▪ Colonization SDA, modified w/ ▪ flat Broad, Smooth Flask Round and fumigatus ▪ Allergy SDA w/ magnesium white branches walled, light shape, echinulate ▪ Disseminated chloramphenicol and ferrous colonies at 450 green or uniseriate infection or gentamicin sulfate w/ ▪ 3-6 days brown w/ flaskshaped Looks like ▪ toxicity sucrose and foot cell phialides child who potassium stuck his salts to Each finger in live enhance phialide socket pigmentation contains ▪ grows at chain of 500 C conidia Aspergillus flavus Due to toxin Grows at 370C 2-6 days on Broad, Thick-walled, Large and Unicellular production modified SDA w/ foot coarsely globose and globose cell roughedened biseariate Yellow-yellow green pigment Aspergillus niger ▪ Otomycosis Grows at 25- 2-6 days on Similar Same w/ A. Spherical, Produced ▪ Aspergilloma 340C modified SDA to others fumigatus, biseriate, basipetally ▪ Nasal sinus longest jet-black infection Flat and Newest white with Phialides conidium is jet-black are flask- at the base conidia shaped Think Resembles a echinulate sprinkled walls and pepper jet-black Aspergillus terreus ▪ Invasive 25-300C 5-10 days Same with A. flavus Dome disseminated modified SDA shaped, aspergillosis biseriate meningitis Heavy ▪ Osteomyelitis sporulation Smallest ▪ endocarditis aspergilli  FUNGUS CONIDIOPHORE LENGTH CONIDIOPHORE SHAPE VESICLE PHIALIDE A. fumigatus 150-300 Smooth Flask shaped Uniseriate A. flavus ≤ 850 Roughened Globose Both A. niger ≤3mm Broad, brown Spherical Biseriate A. terreus 100-250 Smooth Dome shaped Biseriate 2. PENICILLUS GROUP ▪ Conidiophores branching into a penicillus ▪ Brush like arrangement due to branching of conidiopore Disease Macroscopic MICROSCOPIC FEATURES features Hyphae Conidiophores Phialoconidia Annelophores Annellides Anneloconidia Penicillium Secondary Usually 4 Thin Erect, Basipetal infections days (except penicillus w/ growth penicillium White secondary marneffei,2 reverse phialide weeks Paecilomyces Contaminant, 4-5 days Hyaline Erect w/ Produced at pulmonary septate irregular the tips infections Flat and branching w/ floccose metillae and phialides Different colors but Phialides have not blue- long tapering green necks Scopulariopsis Contaminant, 2-4 days broad Short septate Cylindrical Besipetal onychomycosis or flask growth, Velvety to Cant be shaped pyriform powdery distinguished (pear-shaped) from hyphae resembles w/ nipple like penicillium projections HYALINE SEPTATE GROUP WITH CONIDIA CLUSTERS Disease Macroscopic features MICROSCOPIC FEATURES Hyphae Phialophores Phialocondia Acremonium Contaminant Waxy, velvety w/ pink Delicate and thin Slender, upright or at Unicellular, egg reverse intertwining ropes right angle shaped in clusters Long and tapering t the tip Trichoderma Contaminant, 4-5 days covering te Thin Short and rerect, Subglobose to hyalohyphomycosis plate with flat white branching at right elliptical in clusters growth angle Swells at the center and tapers at the tip Gliocladium Non-pathogenic Fusarium HYALINE SEPTATE GROUP WITH CONIDIA BORNE SINGLY Chrysosporium Adiaspiromycosis 6 days, floccose and With spiral vegetive Similar to hyphae One celled, clavate (enlargement of flat structures with numerous conidia in tissue w/out arthroconidia replication) Hyalohyphomycosis Sepedonium Non-pathogenic  C. ZYGOMYECETES/ HYALINE ASEPTATE GROUP Zygomycetes/Aseptate ▪ Cottony ▪ Fast growers ▪ Sexual/asexual (sporongiosphore) ▪ Few or no septum Diseases: MACROSCOPIC MICROSCOPIC FEATURES Columella FEATURES - domelike structure at distal end that Zygomycoses, 2- 4days Hyphae: aseptate extends and support the sporangium mucormycoses- by inhalation of spores, w/ abundant Hyaline: Apophysis introduction by intertwining aerial Wider than most fungi, ribbon- -swelling of sporangiophore at the juncture trauma, ingestion hyphae like w/columella May cause occlusion cotton candy-like Reproductive structure: Collarette of blood vessels due Asexual: -ring of fragments of sporangium attached to the fungi’s rapid Sporangiospore,chlamydoconidia to the sporangiophore at the base of growth columella Sexual: Zygospore Rhizoids -resemble tree roots -for anchorage ▪ Nodal Rhizoid -sporangiophore develops at the opposite side of hyphae ▪ Internodal Rhizoid -sporangiophores develop between groups of rhizoids ▪ Rudimentary Rhizoid -primitive or poorly developed MICROSPIC FEATURES Hyphae Sporangiophore Columellae Sporangium Rhizoid Absidia Thin walled 2-5 internodal goup Conde shaped with a pointed Pyriform, becomes Rudimentary apex brown or gray with age Branching at right Apophysis remains angles when sporangium Resembles a hershey’s kiss ruptures with collarette Mucor Thick walled Long and straight, Varying shapes globose none with collarette Rhizomucor Widest hyphae Arise globose Round and black Primitive among others irregularly,internodal with collarette Without apophysis Rhizopus Thin walled Light brown,long and Hemishpherical w/ a flattened With varying size and Well developed “salt and pepper straight base with flattened base colony surface” Nodal When mature, it bends resembling an up side down With apophysis umbrella Syncephalastrum Not as wide as other Arise sympodially Merosporangium: Rudimentary zygpmyctes long and erect Resembles tubes or *resembles a fingers that radiare from test tube which Branches at right the arount the vesicles contains a stack angles Branches are shot of marbles and curved enlarges inside to a swollen vesicle  Fungus Columella Sporangiophore Rhizoid Others Absidia Hershey’s Internodal Rudimentary Arched stolon Mucor Variable Solitary None No apophysis Rhizomucor Globose Internodal Rudimentary Wide hyphae Rhizopus Hemispherical Nodal Well developed Columella collapses Syncephalastrum Round vesicles Straight, branching Rudimentary Merosporangia Virology THE YEAR 3700 BC - Is the bioscience for the study of viral nature - Hieroglyph from Memphis, 3700 BC (capital and the relationship between viruses and ancient Egypt) →1st written record of virus hosts infection VIRUSES - Depicts a temple priest (Ruma) showing - Smallest infectious agents (20nm200 nm) typical clinical signs of paralytic poliomyelitis - May contain either a DNA or RNA (single or → infection disease cause by polio virus double-stranded) - The Pharaoh Siptah rules Egypt from 1200- 1193 BC when suddenly at the age of about 20 years old - The mummy shows that his left leg was withered and his foot was rigidly extended like a horse’s hood signs of classic paralytic poliomyelitis - Ramesses V’s preserved mummy shows that he died of smallpox at about the age of 35 in MARTINUS BEIJERINCK 1143 BC - Coined the term virus - The pustular lesions on the face of the - Coined “contagium vivum fluidum (soluble mummy are very similar to those of more living germ) recent patients FREDERICK TWORT - Early 20th century covered that bacteria could Thackery_ Variolation be attack by viruses as well - Using a scab from a healed small pox sore to create powder FELIX d’Herelle - Thackery exposes the villagers to the virus by - Named it bacteriophage blowing the powder in their noses - Provide invaluable opportunities to study - Variolation-rudimentary form of vaccination, various replications at 8th times prior to it exposes individual to virus so that they can the development of cell culture come down with mild case of small pox to inn - Only way to study viruses is by infecting whole order to develop immunity organisms THE YEAR 1520 SMALLPOX - Had reached Europe from the East in 710 AD - Was transferred by America by HERNANDO CORTEZ - 3 million 500 hundred thousand died in the next 2 year and effectively the end of aspect empire  THE YEAR 1796 THE YEAR 1939 - On 14th May 1796 Edward Jenner is introduce - EMORY ELLIS (1906)-and MAX DELBRUCK the small vaccine (1st successful vaccine to be - Established the concept of the “one-step virus develop) growth cycle” essential to understanding of - James, who had never had small pox, virus replication developed a small lesion at the site of - This work laid the basis for the understanding vaccination which healed in 2 weeks. On 1st of virus replication July 1796, Jenner challenged the boy by THE YEAR 1941 deliberately inoculating him with material from a real case of small pox GEORGE HIRST THE YEAR 1892 - Demonstrated that influenza virus agglutinates ed blood cells Dmitri Iwanowski Baruch Blumberg - Russion botanist - February 12th extracts from disease tobacco - Discovered hepatitis B virus (HBV). (Noble plants can transmit disease to other plants Prize, 1976) after passage through ceramic filter fine - Considered by some to be the first vaccine enough to retain the smallest known bacteria against cancer because of the strong association of hepatitis B with liver cancer NOTABLE PERSONS AND THEIR CONTRIBUTION TO VIROLOGY Howard Temin and David Baltimore (1934-1994) Walter Reed (1851-1902) - Independently discovered reverse transcriptase in retroviruses. (Noble Prize, - 1900, demonstrated that yellow fever was 1975) caused by a virus, spread by mosquitoes THE YEAR 1983 Karl Landsteiner and Erwin Popper (1868-1943) LUC MONTAIGNER AND ROBERT GALLO - Proved that poliomyelitis was caused by a virus - Discovered human immunodeficiency virus (HIV) as the causative agent of AIDS Wendell Stanley (1887-1955) THE YEAR 1999 - Crytallizes tobacco mosaic virus (TMV) and shows that it remains infectious (Nobel Prize, - Nucleotide sequence of the largest virus 1946) genome yet known completed: Paramecium - First step towards describing the molecular bursaria Chlorella virus 1 structure of any viruses THE YEAR 2001 Max Teiler (1899-1972) - The complete nucleotide sequence of the - Was the first to propagate yellow fever virus human genome is published in chick embryos - About 11% of the human genome- retrovirus- - Successfully produced an attenuated vaccine- like retrotransposons: “transposable elements the 17D strain in which transposition involves a process of reverse transcription with an RNA Friedrich Loeffler and Paul Frosch (1898) intermediate similar to that of a retrovirus - Observed the causative agent of foot and mouth disease to be similar to the observations of Iwanowski and Beijernick  VIRUSES VIRUS CLASSIFICATION ✓ Very small, acellular infectious agents 1. According to Type of Genetic Material Virions complete virus particle DNA-double stranded (ds): RNA- ss: segmented or non- 10 to 300 nm in diameter segmented Can infect virtually all organisms ▪ linear or circular ▪ ss: polarity+(sense) or Viroid ▪ Single stranded (ss) : polarity - (non-sense) ▪ with circular RNA molecules linear or circular ▪ ds: linear (only ▪ without capsid and envelope reovirus family) Virusoids ▪ viroid-like particles ▪ passengers in virus capsids 2. According to Shape of Capsid Prions ▪ believed to consist of a single type of protein molecule without Helical Polyhedral Nucleic Acid content ▪ mostly spherical in ▪ DNA or RNA viruses shape, RNA viruses ▪ example: Icosahedral SPECIFIC PROPERTIES OF VIRUSES only (20 sides) ▪ Possess either DNA or RNA. ▪ Unable to replicate (multiply) on their own. 3. Number of Capsomeres ▪ Do not divide by binary fission, mitosis, or meiosis. ▪ Lack genes and enzymes necessary for energy production. 4. Size of Capsomeres ▪ Depend on ribosomes, enzymes, and metabolites of the host cell for protein and nucleic acid production. 5. Presence or Absence of Envelope Genome ▪ nucleic acid ▪ Single-stranded genomes Icosahedral may be of positive (i.e.mRNA) or negative (i.e. anti-mRNA) ▪ Adeno-associated Virus (AAV) polarity. ▪ Adenovirus ▪ B19 ▪ Coxsackievirus - A ▪ Coxsackievirus - B ▪ Cytomegalovirus (CMV) ▪ Eastern Equine Encephalitis Capsid ▪ a coat of protein arranged in ▪ Virus (EEEV) one of several possible ▪ Echovirus morphologies, encloses the ▪ Epstein-Barr Virus (EBV) genome. ▪ Hepatitis A Virus (HAV) ▪ Hepatitis B Virus (HBV) a. Icosahedral ▪ Hepatitis C Virus (HCV) - cubical with 20 flat sides ▪ Hepatitis Delta Virus (HDV) ▪ Hepatitis E Virus (HEV) b. Helical - spiral ▪ Herpes Simplex Virus 1 (HHV1) Capsomere ▪ sub-unit of capsid ▪ Herpes Simplex Virus 2 (HHV2) ▪ Human Immunodeficiency Virus (HIV) ▪ Human T-lymphotrophic Virus (HTLV) Envelope ▪ a lipid -containing membrane ▪ Norwalk Virus that surrounds some viral ▪ Papilloma Virus (HPV) particles ▪ Polio virus ▪ Rhinovirus ▪ Rubella Virus Nucleocapsid(Naked Virus) = Enveloped Virus =Nucleocapsid+ ▪ Saint Louis DNA or RNA +Structural proteins Viral specific glycoproteins and ▪ Encephalitis Virus +Enzymes &Nucleic Host Membrane ▪ Varicella-Zoster Virus (HHV3) acid binding proteins ▪ Western Equine Encephalitis Virus (WEEV) ▪ Yellow Fever Virus HELICAL ▪ California Encephalitis Virus ▪ Coronavirus ▪ Hantavirus ▪ Influenza Virus (Flu Virus) ▪ Measles Virus (Rubeola) ▪ Mumps Virus ▪ Parainfluenza Virus Spikes ▪ glycoprotein that functions as ▪ Rabies Virus attachment or as an enzyme ▪ Respiratory Syncytial Virus(RSV)  MULTIPLICATION OF VIRUSES AFTER INFECTION ▪ fever ▪ inflammatory processes (edema, leucocyte accumulation, local hyperthermia, reduced oxygen tension and altered cell metabolism ▪ interferon I. activate an RNA endonuclease causing mRNA degradation or II. cause phosphorylation of eIF2, essentially turning off cellular protein synthesis SPECIFIC HOST DEFENSES ANTIVIRAL ANTIBODY ▪ prevent adsorption to target cells and cytotoxic T-lymphocytes, which recognize virally-infected cells and destroy them, reducing viral production. DNA VIRUSES 2) HBcAg 3) HBeAg 1) Adenoviridae Human Adenovirus PATHOGENESIS: ▪ over 80 species with about 40 are pathogenic to man Virus enters hepatocytes via blood ▪ non-enveloped, 70-90 nm in size Immune response (cytotoxic T cell) to viral antigens expressed ▪ Linear ds DNA genome with core on hepatocyte cell surface ▪ icosahedral with 252 capsomeres responsible for clinical syndrome ▪ Adenovirus- properties released by exocytosis ▪ Stable in the environment ▪ Relatively resistant to disinfection HEPATITIS ▪ Stable in GI tract inflammatory condition of the liver may be asymptomatic Pathogenesis with carrier state ▪ Infects mucoepithelial cells of respiratory, GI and GU tracts may be chronic and may lead to cirrhosis (viremia occurs) ▪ produces cytopathic changes DEFENSES: antibody and cell mediated responses are not protective Diagnosis - fever, headache, malaise, jaundice - serology Control - screening of blood - vaccine 3) Herpes Viridae - enveloped DISEASES ( ADENOVIRUSES) - replication occurs in the host’s nucleus - may cause recurrent infections 1. Acute Febrile Pharyngitis - with latency - common to children - indistinguishable from common colds and flu Neurotropic - latency in nerve cells (HSV 1 &2, VZV) 2. Pharyngeal-conjunctival Fever - Main adenovirus types: 3, 4, 7, 14 Lymphotropic - Contaminated water in swimming pools, fomites - latency in lymphocytes (EBV, CMV) - some are associated with cancers 3. Acute Respiratory Disease - humans are the natural host - common to military recruits - with rashes Pathogenesis commonly infects skin and 4. Pneumonia mucous membranes (HSV, VZV) 5. Gastroenteritis internal infection (CMV, EBV) Host Defenses produces intranuclear no antibodies produced inclusions and cytotoxic T-cells kill infected cells early multinucleated giant cells Epidemiology DIAGNOSIS - common to children below 6 1. characteristic lesion - predominant in cold climate 2. Intranuclear inclusions on DIAGNOSIS: Smear Culture in HeLa, HEK cell lines 3. TZANCK TEST Shell vial cell culture scraping of an ulcer base DFA to look PCR, nucleic acid probes for Tzanck cells (multinucleated giant cells) PREVENTION: AKA: Tzanck smear, Good handwashing chickenpox Contact precautions skin test and the herpes skin Chlorination of water test Disinfection or sterilization of ophthalmologic Control equipment - avoid contact Use of single dose vials - vaccines Oral vaccine- restricted use - Acyclovir 2) Hepadnaviridae PATHOGENESIS Hepatitis B Virus a. HSV-1 - double stranded and enveloped - Gingivostomatitis - virion also referred to as “DANE - recurs as cold sores (herpes PARTICLE” labialis) - with several antigens - herpetic keratitis - leads to scarring and 1) HBsAg blindness - whitlows - lesions on the fingers