Institute for Microbiology, Medical Faculty of Masaryk University Institute for Microbiology, Medical Faculty of Masaryk University and St. Anna Faculty Hospital in Brno and St. Anna Faculty Hospital in Brno

Miroslav Votava, Vladana WoznicováMiroslav Votava, Vladana Woznicová

COURSE AND FORMSCOURSE AND FORMSOF INFECTION – IOF INFECTION – I

Lecture for 2nd-year studentsLecture for 2nd-year studentsMay May 1818thth, 200, 20099

Course of infectionCourse of infection – I – I

Incubation time Incubation time salmonellosis ½–1 day, influenza 1–2 days, salmonellosis ½–1 day, influenza 1–2 days, tbc 2–8 weeks, hepatitis B 90–100 days tbc 2–8 weeks, hepatitis B 90–100 days

ProdromsProdroms not not always; nonspecific ( always; nonspecific ( T, headache, feeling T, headache, feeling ill etc.), several hours till etc.), several hours too days days

Typical syndrome of infectious disease Typical syndrome of infectious disease as described in textbooksas described in textbooks

Convalescence Convalescence from subsiding troubles till normalization from subsiding troubles till normalization of resultsof results

Course of infectionCourse of infection – II – II Relapse Relapse

the same agent,the same agent, infection comes on again infection comes on again during the convalescenceduring the convalescence

Recurrence Recurrence the agent remains in the body, infection comes the agent remains in the body, infection comes on again only after recovery (Brill-Zinsser on again only after recovery (Brill-Zinsser disease = recurrence of epidemic typhus)disease = recurrence of epidemic typhus)

Reinfection Reinfection new infection by the same agent from outsidenew infection by the same agent from outside

Superinfection Superinfection infection by infection by ananother agent before recovery from other agent before recovery from the first infectionthe first infection

Forms of infectionForms of infection

Inapparent infection (without symptoms)Inapparent infection (without symptoms) production of antibodiesproduction of antibodies

Manifest infection (with symptoms)Manifest infection (with symptoms)::

subclinicalsubclinical: : nonnon--characteristic signs onlycharacteristic signs only

abortiveabortive: : some symptoms only or merely some symptoms only or merely little expressed oneslittle expressed ones

clinicalclinical: : typical signs as in textbooktypical signs as in textbook

foudroyant, fulminantfoudroyant, fulminant:: very abrupt, with very abrupt, with dramatic symptomsdramatic symptoms

Duration of infectionDuration of infection

Acute: daysAcute: days (common cold, salmonellosis) (common cold, salmonellosis) till weeks (majority of infections)till weeks (majority of infections)

Subacute: monthsSubacute: months – either as a complication – either as a complication of any infection, or as the rule (some kinds of any infection, or as the rule (some kinds of hepatitis, warts, sepsis lenta)of hepatitis, warts, sepsis lenta)

Chronic: yearsChronic: years (tbc, lepra, dermatomycoses, (tbc, lepra, dermatomycoses, parasitic infections)parasitic infections)

Fulminant, foudroyant:Fulminant, foudroyant: very rapid course – very rapid course – hourshours (meningococcal sepsis) (meningococcal sepsis)

http://bioinfo.bact.wisc.edu

Special types of chronic infectionsSpecial types of chronic infections

Inapparent chronic infections Inapparent chronic infections can be divided intocan be divided into

1. latent: 1. latent: agent hides in aagent hides in a non-infectious non-infectious form, or it form, or it escapes from the infected cell after an activation escapes from the infected cell after an activation of infection onlyof infection only

HSV and VZV:HSV and VZV: nerve ganglia cells, nerve ganglia cells, CMV: CMV: kidney kidney and salivary glands cells,and salivary glands cells, EBV: EBV: lymphocyteslymphocytes

2. persistent: 2. persistent: agent can be detected byagent can be detected by routine routine methods, methods, because it is present mostly in anbecause it is present mostly in an infectious forminfectious form

Both can beBoth can be activated activated

Examples of persistent infectionsExamples of persistent infections

Bacterial: Bacterial: Rickettsia prowazekii Rickettsia prowazekii (activation of (activation of exanthematic typhus = m. Brill-Zinsser,exanthematic typhus = m. Brill-Zinsser, SalmonellaSalmonella Typhi Typhi (carriers),(carriers), Mycob. tbc Mycob. tbc (lymphatic nodes)(lymphatic nodes)

Viral: HBV Viral: HBV (hepatocytes),(hepatocytes), adenoviruses adenoviruses (adenoids),(adenoids), JCV JCV and and BKV BKV (kidneys), (kidneys), congenital infections bycongenital infections by CMV CMV and and rubella rubella virus virus

Parasitary: Parasitary: hypnozoites ofhypnozoites of Plasmodium ovale Plasmodium ovale and and P. vivax P. vivax (liver), (liver), Toxoplasma gondii Toxoplasma gondii bradyzoites (nodes, muscles, brain)bradyzoites (nodes, muscles, brain)

Primary infectionsPrimary infectionsprimary primary × secondary infection: × secondary infection: before the first before the first

(primary) infection is over the (primary) infection is over the secondarysecondary infection infection (superinfection) (superinfection) caused by caused by another microbeanother microbe supersedes supersedes

primary primary × postprimary infection: × postprimary infection: inin tbc only tbc only;; in postprimary in postprimary infection the infection the latelate hypersensitivityhypersensitivity has developed has developed

primary primary × recurrent infection: × recurrent infection: duringduring latent latent infections,infections, e.g.e.g. HSV HSV:: primary infection = primary infection = gingivostomatitis aphthosa; recurrent one gingivostomatitis aphthosa; recurrent one = herpes labialis= herpes labialis

Other types of infectionOther types of infection – I – I

OpportunistOpportunisticic infection infection:: infection on a weakened infection on a weakened terrain, often secondary oneterrain, often secondary one

DuringDuring AIDS AIDS: CMV retinitis, CMV or candidal : CMV retinitis, CMV or candidal esophagitis, herpes zoster, cryptococcal esophagitis, herpes zoster, cryptococcal meningitis, toxoplasmatic encephalitis, meningitis, toxoplasmatic encephalitis, cryptosporidial or microsporidial enteritis, cryptosporidial or microsporidial enteritis, colibacillary and other types ofcolibacillary and other types of sepsissepsis

Nosocomial Nosocomial (hospital-acquired) (hospital-acquired) infectioninfection:: in connection with the stay in connection with the stay in a hospitalin a hospital, , often opportunist oneoften opportunist one

Iatrogenic infectionIatrogenic infection:: caused by a caused by a medical medical interventionintervention

Other types of infectionOther types of infection – II – II

Community-acquired infection:Community-acquired infection: infection obtained infection obtained in common populationin common population

Pyogenic infection: Pyogenic infection: is manifested by is manifested by suppurationsuppuration

Specific infection: Specific infection: usually with typical pathology usually with typical pathology and histology, thereforeand histology, therefore syphilis syphilis oror tuberculosis tuberculosis

Exogenous infection: Exogenous infection: agent enters the body agent enters the body from from outsideoutside

Endogenous infection: Endogenous infection: agent =agent = member of normal member of normal microflora microflora (the disease is not contagious, it is (the disease is not contagious, it is not possible to determine the incubation time)not possible to determine the incubation time)

www.skininfection.com

http://imagehost.revealedsingularity.net/mrsa.jpghttp://www.bioquell.com

Other types of infectionOther types of infection – III – III

Anthroponoses = Anthroponoses = infections transmisible infections transmisible among among human beings only human beings only (typhoid fever, shigelloses, (typhoid fever, shigelloses, exanthematic viroses, venereal infections etc.)exanthematic viroses, venereal infections etc.)

Zoonoses = Zoonoses = infections transmisibleinfections transmisible from animals to from animals to man man and vice versaand vice versa (salmonelloses, tularemia, (salmonelloses, tularemia, lyme borreliosis, tick-borne encephalitis, some lyme borreliosis, tick-borne encephalitis, some types of ringworm etc.)types of ringworm etc.)

Sapronoses = Sapronoses = infections acquired infections acquired from the from the environmentenvironment,, in which the agent actively in which the agent actively multiplies (tetanus, gas gangraene, multiplies (tetanus, gas gangraene, legionellosis, histoplasmosis, amoebic legionellosis, histoplasmosis, amoebic meningoencephalitis etc.)meningoencephalitis etc.)

Outcome of infectionOutcome of infection – I – I It depends on both participants:It depends on both participants:

Microorganism:Microorganism:

pathogenicity pathogenicity virulence virulence dosis dosis portal of entryportal of entry

Macroorganism: Macroorganism: species resistancespecies resistance

individual’s immunityindividual’s immunity

non-specific (innate)non-specific (innate)

specific (acquired)specific (acquired)

intensity of reactionintensity of reaction

Outcome of infectionOutcome of infection – II – II

Complete recovery Complete recovery (restitutio ad integrum)(restitutio ad integrum):: banal respiratory, urogenital, intestinal and banal respiratory, urogenital, intestinal and infant generalized infectionsinfant generalized infections

Recovery with sequelaeRecovery with sequelae:: paralysis after encephalitis, deafness after paralysis after encephalitis, deafness after otitis, scar after abscess, cavern after lung otitis, scar after abscess, cavern after lung tuberculosistuberculosis

Persistent infectionPersistent infection:: if the immune system is not able to eliminate the if the immune system is not able to eliminate the

agentagent

Death Death (exitus letalis)(exitus letalis)

Outcome of infectionOutcome of infection – III – III • Species pathogenicitySpecies pathogenicity• Strain virulenceStrain virulence• High dosisHigh dosis• Uncommon portal of entryUncommon portal of entry• Exaggerated reaction Exaggerated reaction

Death of the Death of the

hosthost

• High resistance of the host High resistance of the host as a speciesas a species• High non-specific resistance of the individual High non-specific resistance of the individual

no risk factors no risk factors no no functional or anatomical functional or anatomical defectsdefects

• Specific immunity and its qualitySpecific immunity and its quality

Elimination of Elimination of the microbethe microbe

= = recovery, or no recovery, or no infectioninfection

Recommended reading materialRecommended reading material Paul de Kruif: Microbe HuntersPaul de Kruif: Microbe Hunters

Paul de Kruif: Men against DeathPaul de Kruif: Men against Death

Axel Munthe: The Story of San MicheleAxel Munthe: The Story of San Michele

Sinclair Lewis: ArrowsmithSinclair Lewis: Arrowsmith

André Maurois: La vie de Sir Alexander FlemingAndré Maurois: La vie de Sir Alexander Fleming

Hans Zinsser: Rats, Lice, and HistoryHans Zinsser: Rats, Lice, and History

Michael Crichton: Andromeda StrainMichael Crichton: Andromeda Strain

Albert Camus: PesteAlbert Camus: Peste

Victor Heisser: An American Doctor OdysseyVictor Heisser: An American Doctor Odyssey

Richard Preston: The Hot ZoneRichard Preston: The Hot Zone

David Tyrrell David Tyrrell & Michael Fielder: Cold Wars& Michael Fielder: Cold Wars

Mika Waltari: The EgyptianMika Waltari: The Egyptian

Please mail me other suggestions at:Please mail me other suggestions at:

mvotava@med.muni.cz

Thank you for your attentionThank you for your attention