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General Pathology
Basic Principles
of Cellular and Organ
Pathology
Infection - II
Jaroslava Dušková
Inst. Pathol. ,1st Med. Faculty, Charles Univ. Prague
Inflammation - causes


nonliving
physical
chemical
living
prions (?)
viral
bacterial
mycotic
parasitic
AUTOIMMUNE
Infectious Agents of Humans



Viruses
virion
obligate intracellular
either DNA (adeno-, herpes-, pox-,
cytomegalo-, EB, papova, HPV, ..

or RNA (picorna – entero-, polio-,
coxsackie-, arbo-, rhino-, myxo-, paramyxoRS, rubeola, rhabdo-, retro-,)
Virion

capsid
helical symmetry
icosaedral symmetry

genome
DNA
RNA
Host
General
Microorganism
Encounter
&
Successful
transmission
defenses
Site of attack
Inflammation
Number of microorg.
Immune status Pathogenicity
Natural
Host
General
– age, race, nutrition,
other diseases
(diabetes)
Natural defenses
– skin, mucose integrity
– mucus, cilliary action,
unobstructed flow
– protective secretion
(lysosym in tears,
gastric acid, IgA
Inflammation
– leucocytes
– macrophages phagocytosis
Immune
status
– immunity (or lack
of it)
active, passive
immunisation,
contact
– lymphocytes
– immunoglobulins
– complement
Microorganism
Successful transmission
 Site of attack
 Number of microorg.
 Pathogenicity
invasiveness

toxin production
multiplication
resistence to host
defence mechanisms
ability to cause necrosis
enzyme release
Virus – Host Cell
Interaction



cytocidal
stabilised (steady– state)
transformation –
ONCOGENS
Virus-Induced Injury


cell entering - surface ligands – viral tropism

translocation of the entire virus

fusion of the viral envelope with the cell membrane

receptor mediated endocytosis
intracellular replicative phase – forming of
virions using virus specific enzymes

virus assembly & release extracellular phase
Virus – Organism Interaction

infected cell
lysis by antibody and
complement

cell mediated immunity
lymphocytes
macrophages
interferon 
Virus-Induced Injury
Host cell responses:

DNA, RNA and protein synthesis
 metabolic derangements
 cell lysis / cell fusion
 multinuclear formation
 viral inclusions
Infectious Agents of Humans



Viruses
virion
obligate intracellular
either DNA (adeno, herpes, pox,
cytomegalo, EB, papova, HPV, ..

or RNA (picorna – entero, polio, coxsackie
arbo, rhino, arbo, myxo, paramyxo, RS,
rubeola, rabdo, retro,)
The Herpes viruses
 Herpes
simplex HSV 1,2
 Varicella-Zoster
chickenpox-shingles
 Cytomegalovirus CMV infection
 Epstein-Barr
virus EBV infectious
mononucleosis - glandular fever, Burkitt´s
lymphoma
The respiratory viruses






Influenza
influenza
Parainfluenza
croup, pneumonia
RS
bronchiolitis, pneumonia
Adenopharyngitis, conjunctivitis
Rhinocolds
Corona & Reocolds, SARS
Viral Infections of Childhood
 Measles
 Mumps
– parotitis epidemica
 German
 Fifth
– morbilli
measles – rubeola
disease – erythema infectiosum-
human parvovirus dis.
Poliomyelitis anterior acuta
Frequency
– United States
 No cases of wild-type poliovirus infection reported in the United
States since 1979.
 Until 1998, an average of 8-10 cases associated with the vaccine
virus every year.
 Four cases of vaccine-derived poliovirus were identified in 2005
among unvaccinated children in an Amish community in
Minnesota.
– International
 The global incidence decreased by more than 99% since 1988.
 No outbreaks reported in the western hemisphere since 1991
 An outbreak in Haiti and the Dominican Republic in 2001.
 Clusters of wild-type disease still found in some areas in Africa
and Southeast Asia.
 By 2004, the only 6 countries in which wild poliovirus transmission
had not been interrupted were India, Egypt, Nigeria, Niger,
Pakistan, and Afghanistan.
 An increase in the number of cases was observed in 2006.
Tick Born Encephalitis
 tick-borne
encephalitis virus a member
of the family Flaviviridae
 virus initially isolated in 1937.
 A closely related virus in Far Eastern
Eurasia, Russian spring-summer
encephalitis virus responsible for a
similar disease with a more severe
clinical course.
Marburg and Ebola Virus Infections
Pathogenesis
 increase in vascular permeability
 hemorrhagic diathesis
 interstitial edema in visceral organs and
brain
 DIC
 liver necrosis
 renal tubular necrosis
 terminal DIC/shock syndrome
Virus – Host Cell
Interaction



cytocidal
stabilised (steady– state)
transformation –
ONCOGENS
Oncogenic Viruses
DNA
 HPV
 SV 40 – polyoma
 Adenoviruses
 Herpesviruses
Epstein– Barr
 Hepatitis
B
RNA
 Rous sarcoma
 Leukemia
 HIV