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General Pathology
Basic Principles
of Cellular and Organ
Pathology
Infection - I
http://www1.lf1.cuni.cz/~jdusk/
Jaroslava Dušková
Inst. Pathol. ,1st Med. Faculty, Charles Univ. Prague
Inflammation - causes


nonliving
physical
chemical
living
prions (?)
viral
bacterial
mycotic
parasitic
AUTOIMMUNE
Interaction of Organism and
Microorganism – Terms





Bacteriemia (transient)
Sepsis/ Septicemia
Pyemia
Toxemia
Viremia
Bacteriemia

transient presence of
microbes in the
bloodstream
Sepsis / Septicemia
(Severe Bacteremia)

increasing numbers
of microbes (& their toxins)
in the bloodstream
Sepsis/Septicemia
Def.
systemic response to infection
manifestating as




tachypnoe
tachycardia
temperature
leucocytosis
> 20/min.
> 90/min.
> 39 st. C.
(ev. < 36st.C)
> 15 000/1l (ev. < 4000/1l)
Sepsis – Pathogenetic Factors

Endotoxin, toxins G+
TNF, IL–1

Macrophages
TNF, IL–1, IL–6

Cytokins
NO
 PAF (Platelets
Activating Factor)

NO synthesis
vasodilation
coagulation
Syndrome of Systemic
Inflammatory Response
Def.
systemic response to an AGENT
manifestating as
 tachypnoe
> 20/min.
 tachycardia > 90/min.
 temperature > 39 st. C.
(ev. < 36st.C)
 leucocytosis > 15 000/1l
(ev. < 4000/1l)
AGENT : pancreatitis, injury, burns…..
Pyemia

presence of infected
thrombemboli bearing
virulent microbes in the
bloodstream
Toxemia

presence of microbial
toxin (s) without the
microbes themselves in
the bloodstream
Endotoxin

lipopolysaccharide component
of G- bacteria outer wall

effects: fever, shock, DIC, RDS

effects mediated by IL-1, TNF
Exotoxins -1

often enzymes (leukocidins,
hemolysins, hyaluronidases,
coagulases, fibrinolysins)
others………….
Exotoxins -2

diphteria toxin – inhibition of cellular
proteosynthesis

botulotoxin – block of the cholinergic
transmission
 choleratoxin
– increase in cAMP, losses of
isoosmotic fluid via enterocytes
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
INFECTION versus DISEASE

Pathogenicity (virulence)

Incubation Period

Carrier State
Agent – Host Interaction



cytocidal
stabilised (steady– state)
transformation –
ONCOGENS
Virus – Host Cell
Interaction



cytocidal
stabilised (steady– state)
transformation –
ONCOGENS
Inflammation - causes


non
infectious
physical
chemical
infectious
prions
viral
bacterial
mycotic
parasitic
AUTOIMMUNE
Infectious Agents of Humans



prions
viruses (DNA, RNA)
bacteria (incl. chlamydia, mycoplasma,
rickettsia – obligatory intracellular parasites)


fungi (yeasts, molds)
parasites (protozoa, helmints, ectoparasites-
insects: lice, mites, ticks; spiders)
Infectious Agents of Humans
Bacteria
simple cells – prokaryotes
 both DNA and RNA
 cocci, bacilli (AFB!), spirochetes….
 Gram positive /negative
 extra- and/or intracellular
 aerobic/ anaerobic

Infectious Agents of Humans
Fungi
complex cells – eukaryotes
 both DNA and RNA
 yeasts, molds (hyphae, pseudohyphae…)
 PAS, impregnation
 extra- or intracellular
 mostly opportune pathogens

Infectious Agents of Humans
Parasites -1
Protozoa



complex cells – eukaryotes
both DNA and RNA
extra- or intracellular
(Amebas, Trichomonas,Trypanosoma,
Toxoplasma, Plasmodium, Pneumocystis…)
Infectious Agents of Humans
Parasites -2
Metazoa (helmints and flukes)




multicellular
both DNA and RNA
flat and round worms
extracellular
(Taenia, Ascaris, Enterobius, Trichuris
Echinococcus, Clonorchis, Schistosoma,
Wuchereria…)
Infectious Agents of Humans
Parasites -3
Insecta, Arachnida



multicellular
both DNA and RNA
extracellular
(Sarcoptes scabiei, fleas, ticks, lice……)