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PATHOGENIC MAMMALIAN VIRUSES

©David B. Fankhauser, Ph.D.,
Professor of Biology and Chemistry
University of Cincinnati Clermont College,
Batavia OH 45103
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This page has been accessed  Counter times since 8 August 2007.
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VIRAL DISEASES


7/27/87, rvsd 15 August 1993, 12 Aug 1996, 8/7/98, 7 Aug 06

TFC, P.346, Black's 2nd, p. 266- , Alcamo 323-, Campbell 6th: , Black’s 6th: 264-294, tbl: 270


DISCOVERY:

Chamberland                1884     developed porcelain filter to remove bacteria

Iwanowski                    1892     used filter to try to remove tobacco mosaic disease, "filterable virus"

Beijerinck                     1898    showed could be diluted out, destroyed by heat

Forsh & Loeffler          1898    foot and mouth disease caused by filterable agent

Walter Reed                 1901    yellow fever also filterable disease (in Cuba)

Twort & d'Herrelle       1917     bacteriophage


TRAITS: All viruses posses: (p 266)

             capsid             protein coat composed of capsomeres, can contain penetration enzymes

             genome           may be DNA or RNA, double stranded , single stranded, (+ = mRNA) or (-)

 

Spikes:             glycoprotein for attachment, enzymes to assist attachment

             Host range = which species infected

             specificity = which tissue affected, determined by ability to attach, multiply and release

 

three morphologies:               icosahedral (20 faces)      icosahedron       herpes, polio, cytomegaly

(p 267 for sizes and shapes)    helical                                      rabies, TMV

                                                 complex                                   small pox, coronavirus, influenza


VARIETY OF VIRUSES, p 270, characterized by comp of genome, enveloped or not, geometry, size


VIRAL REPLICATION:

Obligate Intracellular parasites, replicate inside      absorption

                                                                                 Penetration

                                                                                 Synthesis

                                                                                 Maturation

                                                                                 Release


Bacteriophage parts (p 279): capsid, genome, tail assembly, tail piece, tail fibers, tail sheath, tailcore.  Infection.

             bacteriophage replication: p 280

             lysogeny: p 283 (lysogen. In mammalian cells, called provirus)


enveloped viruses: upon release by budding from host.

             replication of enveloped virus , p 284

             Enveloped viruses     are inactivated by hi temp, hi or lo pH, lipid solv, some disinfectants (Cl, H2O2, phenol)

 

             Naked vs enveloped viruses            naked lack an envelope, resist many of the above


EXAMPLES (perhaps not presented during this lecture?)


COMMON COLD: caused in decreasing frequency by : rhinoviruses, paramyxoviruses, enteroviruses, corona viruses, reoviruses, adenoviruses. Can be mixed infection.

Portal of Entry: mucous membrane of nose and eyes.


Influenza: H = hemagglutanin, N = neuraminidase

                  Alterations in H and N make virus undetected by immune system until after infection

                  1918: Change to H3N2, killed 20 million world wide. More troops died of flu than combat.  Capable of recombination.

 

Herpes     form provirus, integrated for life into your DNA: Chicken Pox, Herpes simples I and II

 

HIV          Primarily parenteral POE, through wound or sore. Infects T cells. Forms provirus.



TABLE SUMMARIZING MAJOR CLASSES OF VIRUSES

David B. Fankhauser, PhD

15 August 1993, rvsd 12 August 1994, 15 Feb 02, 15 Feb 06, 26Apr06, 7 Aug 06, 8 Aug07

Bauman 2nd: 680-740

Cls

genome

env?, shape

example

diseases

DNA VIRUSES:

Ia

dsDNA linear

naked polyhedral

Adenovirus

40+: respiratory     1 cause of “common cold” & of pinkeye

GIitis                      (20% severe diarrhea in children) sudden onset, short duration

Ib

dsDNA linear

Enveloped polyhedral,

Herpesvirus

80+, latency characteristic, usually nerves: (p 682)

Herpes simplex 1:  oral, fever blisters (p 684)

 Herpes simplex 2:  genital (p 685)

Varicella zoster:    chicken pox, shingles (p 687, 688)

cytomegalovirus    leading teratogenic virus (T O R C H)

Rhadinovirus:       Kaposi’s Sarcoma (p 692)

Epstein-Barr:        mononucleosis. Burkitt’s lymphoma

Ic

ds DNA linear

Enveloped largest, mst complex,

Poxvirus

brick shaped, cause inclusion bodies

small pox ( p 681)

cowpox = vaccinia

certain warts (molluscum contagiosum)

II

dsDNA circular

naked polyhedral

Papovavirus

papilloma: 25+ in humans: str’n 18: cervical CA (p 693)

polyoma: 2 in humans,

vasculating. Warts (SV-40 : simian virus)

 

 

enveloped

Hepadnaviridae

Hepatitis B virus      “Serum” PoE: minor skin break (razor, toothbrush) risk of liver CA (p 698)

 

ssDNA

linear, naked polyhedral

Parvovirus

parvo (“small”) (p 699)

RNA VIRUSES:

Ia

positive (mRNA)

ssRNA, smallest rna

naked

polyhedral

Picornavirus

enteroviruses:      repl. 1st in mucous, then GI: polio (70+)

rhinoviruses:       cannot surv in GI tract, 100+, most common cause of colds. (P 704)

Hepatoviruses:    hepatitis A (fecal/oral) (compare: p 709)

Ib

positive (mRNA)

ssRNA

enveloped polyhedral

Togavirus

rubella                    german measles

many arboviruses  (arthropod borne viruses): EEE, St. Louis Enceph.,yellow fever, dengue

II

negative ssRNA

Enveloped helical

Paramyxovirus

measles                  rubeola

mumps                   infection of salivary glands, testes

viral pneumonia     upper resp and bronchitis

 

negative

ssRNA

Enveloped

helical

Rhabdovirus

some arboviruses, only rabies infects man

newcastle virus in chickens

III

negative ssRNA

enveloped helical

Orthomyxovirus

influenza A, B, C, can agglutinate RBC typed

    H: hemagglutinin, N: neuraminidase (H1N1, etc)

IV

pos ssRNA

envel,

Coronavirus

helical, 2nd cause, Common Cold, “infectious bronchitis”

V

positive ssRNA

enveloped helical

Retroviruses

requires reverse transcriptase, becomes provirus: leukemia, Human Immunodeficiency Virus (AIDS