Lecture 4. classification of inf. dis.

Classification of the infection Classification of the infection diseasesdiseases

Sorokhan V.D., MD, PhDSorokhan V.D., MD, PhD

Bukovinian State Medical UniversityBukovinian State Medical UniversityDepartment of the infectious diseases and Department of the infectious diseases and

epidemiologyepidemiology

Microbiological Classification of Infectious Microbiological Classification of Infectious DiseasesDiseases

Bacterial Gram-negativeGram-positive

Viral DNA virusRNA virusEnveloped vs non-enveloped

Fungal DisseminatedLocalized

Parasitic ProtozoaHelminths

Prion

Gram-negative bacteriaGram-negative bacteria

Gram-negative Gram-negative bacteria are bacteria are

those that are those that are stained red or stained red or

pink by pink by Gram stainingGram staining

Gram-negative Pseudomonas aeruginosa bacteria (pink-red rods)

Gram negative

CocobacilliH. Influenzae, B. PertussisBrucella spp., F. Tularensis

P. Multosida, L. pneumophila

CocciNeisseria spp.

Bacilli

N. MeningitidisGlucose andmaltose +

N. GonnorrhoeaeGlucose +

Lactose + Lactose -

Slow fermenterCitrobacter

Serratia

Fast fermenterKlebsiella

E.ColiEnterobacter

Oxidase +V.Cholerae

P. aeruginosa

Strict anaerodeB. fragilis

Oxidase -

Urease –Y. Pestis

S. DysenteriaeSalmonnela spp.

Urease +P. MirabilisH. pylori

Gram-positive bacteriaGram-positive bacteria

Gram-positive Gram-positive bacteriabacteria are those are those

that are stained dark that are stained dark blue or violet by blue or violet by

Gram stainingGram staining. This . This is in contrast to is in contrast to

Gram-negative bactGram-negative bacteriaeria

, which cannot retain , which cannot retain the crystal violet the crystal violet

stain, instead taking stain, instead taking up the up the counterstaincounterstain ( (safraninsafranin or or fuchsinefuchsine) ) and appearing red and appearing red

or pink.or pink.

Gram-positive Bacillus anthracis bacteria

(purple rods) in cerebrospinal fluid

sample. The other cells are white blood cells.

Gram positive

cocci Bacilli, CorinebacteriumClostridium, Listeria, Bacillus

Staphylococcuscatalase +

Streptococcuscatalase -

S. AureusCoagulase + Coagulase -

β-hemolytic

α-hemolyticS. Pneumoniae

S. ViridansS. Mutans

γ-hemolyticE. FaecalisE. Faecium

S. EpidermisNovobiocinsensitive

S. SaprophyticusNovobiocinresistant

Group AS. Piogenes

Group BS.agalactiae

Genus Important species

Gram staining

Shape Capsulation

Motility Respiration

Bordetella Bordetella pertussis

Gram-negative

Small coccobacilli

Encapsulated aerobic

Borrelia Borrelia burgdorferi

Gram-negative, but stains poorly

highly motile

Brucella Brucella abortus Brucella canis Brucella melitensis Brucella suis

Gram-negative

Small coccobacilli

Unencapsulated

Aerobic

Campylobacter Campylobacter jejuni

Gram-negative

Curved, spiral, or S-shapedwith single, polar flagellum

characteristic darting motion

microaerophilic

Basic laboratory characteristics


Gram staining

Shape Capsulation


Chlamydia and Chlamydophila

Chlamydia pneumoniae Chlamydia trachomatis Chlamydophila psittaci

(not Gram-stained)

Small, round, ovoid

motile Facultative or strictly aerobic

Clostridium Clostridium botulinum Clostridium difficile Clostridium perfringens Clostridium tetani

Gram-positive

Large, blunt-ended rods

mostly motile

Obligate anaerobic

Corynebacterium

Corynebacterium diphtheriae

Gram-positive (unevenly)

Small, slender, pleomorphic rods

unencapsulated

nonmotile Mostly facultative anaerobic

Enterococcus Enterococcus faecalis Enterococcus faecium

Gram-positive

Round to ovoid

Facultative Anaerobic


Gram staining

Shape Capsulation


Escherichia Escherichia coli

Gram-negative

Short rods Facultative anaerobic

Francisella Francisella tularensis

Gram-negative

Small, pleomorphic coccobacillus

strictly aerobic

Haemophilus Haemophilus influenzae

Gram-negative

Ranging from small coccobacillus to long, slender filaments

Helicobacter Helicobacter pylori

Gram-negative

Curved or spiral rodspultiple polar flagella

rapid, corkscrew motility


Gram staining

Shape Capsulation


Legionella Legionella pneumophila


Slender rod in nature, cocobacillary in laboratory.monotrichious flagella

unencapsulated

motile

Leptospira Leptospira interrogans


Long, very slender, flexible, spiral- or corkscrew-shaped rods

highly motile

Listeria Listeria monocytogenes

Gram-positive, darkly

Slender, short rods

Distinct tumbling motility in liquid medium

Mycobacterium Mycobacterium leprae Mycobacterium tuberculosis Mycobacterium ulcerans

(none) Long, slender rods

nonmotile aerobic


Gram staining

Shape Capsulation


Mycoplasma Mycoplasma pneumoniae

(none) Plastic, pleomorphic

Neisseria Neisseria gonorrhoeae Neisseria meningitidis

Gram-negative

Kidney bean-shaped

aerobic

Pseudomonas Pseudomonas aeruginosa

Gram-negative

rods encapsulated motile Obligate aerobic

Rickettsia Rickettsia rickettsii


Small, rod-like coccobacillary


Gram staining

Shape Capsulation


Salmonella Salmonella typhi Salmonella typhimurium

Gram-negative

Facultative anaerobic

Shigella Shigella sonnei Gram-negative

rods Facultative anaerobic

Staphylococcus Staphylococcus aureus Staphylococcus epidermidis Staphylococcus saprophyticus

Gram-positive, darkly

Round cocci Facultative anaerobic

Streptococcus Streptococcus agalactiae Streptococcus pneumoniae Streptococcus pyogenes

Gram-positive

ovoid to spherical

nonmotile Facultative anaerobic


Gram staining

Shape Capsulation


Treponema Treponema pallidum


Long, slender, flexible, spiral- or corkscrew-shaped rods

highly motile

Vibrio Vibrio cholerae

Gram-negative

Short, curved, rod-shaped with single polar flagellum

rapidly motile

Facultative anaerobic

Yersinia Yersinia pestis

Gram-negative, stains bipolarly

Small rods encapsulated

nonmotile Facultative Anaerobe

Clinical characteristicsClinical characteristics

Species of human pathogenic bacteria

Species Transmission Diseases Treatment Prevention laboratory diagnosis

Bacillus anthracis

Contact with sheep, goats and horses Inhalation or skin penetration through abrasions of spore-contaminated dust

Cutaneous anthrax Pulmonary anthrax Gastrointestinal anthrax

In early infection: Penicillin Doxycycline Ciprofloxacin

Anthrax vaccine autoclaving of instruments

Large, grayish, nonhemolytic colonies with irregular borders on blood agar Direct immunofluorescence


Species Transmission Diseases Treatment Prevention

laboratory diagnosis

Bordetella pertussis

Contact with respiratory droplets expelled by infected human hosts.

Whooping cough Complications:Secondary bacterial pneumonia

Macrolide antibiotics Azithromycin Erythromycin Clarithromycin

Pertussis vaccine, DPT vaccine

Direct immunofluorescence PCR amplification

Borrelia burgdorferi

Ixodes ticksreservoir in deer, mice and other rodents

Lyme disease Early stages: cephalosporins amoxicillin doxycycline If arthritic symptoms have appeared: Longer courses of antibiotics

Lyme vaccine wearing clothing that limits skin exposure to ticks insect repellent

Microscopy using Giemsa or Wright stain PCR serology (low precision rate)

Species of human pathogenic bacteria Species Transmission Diseases Treatment Prevention laboratory

diagnosis

Brucella abortus Brucella canis Brucella melitensis Brucella suis

Direct contact with infected animal Oral, by ingestion of unpasteurized milk or milk products

Brucellosis Combination therapy of: doxycycline streptomycin or gentamicin

Culture (difficult and time consuming) Agglutination serology

Campylobacter jejuni

Fecal/oral from animals (mammals and fowl) Contaminated meat (especially poultry) Contaminated water

Acute enteritis Symptomatically by fluid and electrolyte replacement Ciprofloxacin in severe cases




Chlamydia pneumoniae

Respiratory droplets

Community-acquired respiratory infection

Doxycycline Erythromycin

None None for routine use

Chlamydia trachomatis

Sexual (NGU, LGV) Direct or contaminated surfaces and flies (trachoma) Passage through birth canal (ICN)

Nongonococcal urethritis (NGU) Lymphogranuloma venereum (LGV) Trachoma Inclusion conjunctivitis of the newborn (ICN)

Azithromycin Erythromycin Tetracyclines Doxycycline

No vaccine Erythromycin or silver nitrate in newborn's eyes Safe sex

Cellular cytoplasmic inclusions by immunofluorescence DNA hybridization ELISA for lipopolysaccharides




Chlamydophila psittaci

Inhalation of dust with secretions or feces from birds (e.g. parrots)

Psittacosis Tetracycline Doxycycline Erythromycin (less efficient)

Rise in antibody titre Complement fixation indirect immunofluorescence

Clostridium botulinum

Spores from soil and aquatic sediments contaminating vegetables, meat and fish

Botulism Antitoxin (horse antiserum)

Proper food preservation techniques

Mouse inoculation detects toxin from food, intestinal contents or serum Culture in standard aerobic culture

Species of human pathogenic bacteria Species Transmission Diseases Treatment Preventio

n laboratory diagnosis

Clostridium difficile

Spores both indoors and outdoors Human flora, overgrowing when other flora is depleted

Pseudomembranous colitis

Discontinuing predisposing antibiotic Fluid and electrolyte replacement Vancomycin or metronidazole if severe

None ELISA for Toxin ELISA for toxin A or B Endoscopy for pseudomembrane

Clostridium perfringens

Spores in soil Human flora in vagina and GI tract

Gas gangrene Acute food poisoning Anaerobic cellulitis

Food poisoning:Self-limiting; Supportive care is sufficient

Appropriate food handling

Microscopically Blood agar culture, forming double-zone β-hemolysis Sugar fermentation Organic acid production


diagnosis

Clostridium tetani

Spores in soil infecting puncture wounds, severe burns or surgery

Tetanus Tetanus immune globulin Horse antitoxin, alternatively Sedatives Muscle relaxants Mechanical ventilation

DPT vaccine (difficult)

Corynebacterium diphtheriae

Respiratory droplets Part of human flora

Diphtheria Horse serum antitoxin Erythromycin Penicillin

DPT vaccine no rapid) Culture on Tinsdale agar, followed by immunologic precipitin reaction


diagnosis

Enterococcus faecalis and Enterococcus faecium

Part of human flora, opportunistic or entering through GI tract or urinary system wounds

Nosocomial infections

Penicillin and an aminoglycoside Vancomycin Quinupristin and dalfopristin

No vaccine Hand washing and other nosocomial prevention

Culture in 6.5% NaCl Can hydrolyze esculin in presence of bile

Escherichia coli (generally)

Part of gut flora, spreading extraintestinally or proliferating in the GI tract

Urinary tract infections (UTI) Diarrhea Meningitis in infants

UTI: Co-trimoxazole Fluoroquinolone, e.g. ciprofloxacin Meningitis:Cephalosporin and gentamicin combination Diarrhea:Antibiotics above shorten duration Electrolyte and fluid replacement

(no vaccine or preventive drug) Food and water preparation Hand washing and disinfection

Culture on MacConkey agar and study carbohydrate fermentation patterns: Lactose fermentation (most E. coli strains). Gas production in glucose fermentation Mannitol fermentation



Francisella tularensis

vector-borne by anthropods Infected wild or domestic animals, birds or house pets

Tularemia Streptomycin Gentamicin

Avoiding insect vectors Precautions when handling wild animals or animal products

rarely cultured) Serology

Haemophilus influenzae

Droplet contact Human flora of e.g. upper respiratory tract

Bacterial meningitis Upper respiratory tract infections Pneumonia, bronchitis

Meningitis: (resistance-tests are required first)Third generation cephalosporin, e.g. cefotaxime or ceftriaxone Ampicillin and sulbactam combination

Hib vaccine to infants Rifampin prophylactically

Culture on chocolate agar with hemin (factor X) and NAD+ (factor V) Quellung reaction Immunofluorescence staining of capsule Detection of capsular antigen in CSF or other body fluids


Species Transmission

Diseases Treatment Prevention laboratory diagnosis

Helicobacter pylori

Colonizing stomach Unclear person-to-person transmission

Peptic ulcer Risk factor for gastric carcinoma and gastric B-cell lymphoma

Tetracycline, metronidazole and bismuth salt combination

(No vaccine or preventive drug)

Microscopically Corkscrew movement Urease-positivity by radioactively labeled urea Serology by ELISA

Legionella pneumophila

Droplet contact, from e.g. cooling towers, humidifiers, air conditioners and water distribution systems

Legionnaire's Disease Pontiac fever

Macrolides, e.g. erythromycin or azithromycin Fluoroquinolones

(no vaccine or preventive drug) Heating water

Culture from respiratory secretions on buffered charcoal yeast extract enriched with L-cysteine, iron and α-ketoglutarate Serology, including direct immunofluorescence and radioimmunoassay for antigen in urine Hybridization to ribosomal RNA using DNA probe




Leptospira interrogans

Food and water contaminated by e.g. urine from wild or domestic animals. Leptospira survives for weeks in stagnant water

Leptospirosis Penicillin G Tetracycline, e.g. doxycycline

(no vaccine) Doxycycline Prevention of exposureRodent control

Dark-field microscopy on fresh blood smear (but doesn't stain well) Serologic agglutionation tests

Listeria monocytogenes

Dairy products, ground meats, poultry Vertical to newborn or fetus

Listeriosis Ampicillin Co-trimoxazole

(no vaccine) Proper food preparation and handling

Isolation from e.g. blood and CSF Beta-hemolysis and catalase production on blood agar Microscopy for morphology and motility

Species of human pathogenic bacteria Species Transmissio

n

Diseases Treatment Prevention


Mycobacterium leprae

Prolonged human-human contact, e.g. through exudates from skin lesions to abrasion of other person

Leprosy (Hansen's disease)

Tuberculoid form: Dapsone and rifampin Lepromatous form:Clofazimine

BCG vaccine shows some effects

Tuberculoid form: Hard to isolate (diagnosis on clinical findings and histology of biopsies) Lepromatous form:Acid-fast staining from e.g. skin scrapings

Mycobacterium tuberculosis

Droplet contact

Tuberculosis Standard "short" course:First 2 months, combination: Isoniazid Rifampicin Pyrazinamide Ethambutol Further 4 months, combination: Isoniazid Rifampicin

BCG vaccine Isoniazid

Ziehl-Neelsen stain showing acid-fast bacteria Hybridization probes for DNA, succeeded by PCR Culture on Lowenstein-Jensen agar

Species of human pathogenic bacteria Species Transmission Diseases Treatment Preventio

n laboratory diagnosis

Mycoplasma pneumoniae

Human flora Droplet contact

Mycoplasma pneumonia

Doxycycline and erythromycin

(difficult to culture) Serologic tests, e.g. complement fixation test DNA probes on sputum specimens

Neisseria meningitidis

Respiratory droplets

Meningococcal disease including meningitis Waterhouse-Friderichsen syndrome

Penicillin G Cefotaxime Ceftriaxone

NmVac4-A/C/Y/W-135 vaccine Rifampin

Microscopy showing gram-negative diplococci, often with PMNs Culture on chocolate agar, giving positive oxidase test and fermentation of glucose and maltose in 5% CO2 in air




Pseudomonas aeruginosa

Infects damaged tissues or people with reduced immunity

Pseudomonas infection Localized to eye, ear, skin, urinary, respiratory or gastrointestinal tract or CNS, or systemic with bacteremia, secondary pneumonia bone and joint infections, endocarditis, skin, soft tissue or CNS infections.

Aminoglycoside and anti-pseudomonal β-lactam

(no vaccine) Topical silver sulfadiazine for burn wounds

Colourless colonies on MacConkey agar. Production of pyocyanine and fluorescein Positive oxidase test. No lactose fermentation.

Rickettsia rickettsii

Bite of infected wood or dog tick

Rocky mountain spotted fever

Doxycycline Chloramphenicol

no preventive drug or approved vaccine) Vector control, such as clothing Prompt removal of attached ticks

Serology Immunofluorescence against Rickettsia antigens




Salmonella typhi

Human-human Fecal-oral through food or water

Typhoid fever type salmonellosis (dysentery, colitis)

Ceftriaxone Fluoroquinolones, e.g. ciprofloxacin

Ty21a and ViCPS vaccines Hygiene and food preparation

Isolation from blood, feces, bone marrow, urine or rose spots on skin Colorless, non-lactose fermenting colonies on MacConkey agar Serology for antibodies against O antigen

Salmonella typhimurium

Fecal-oral Food contaminated by fowl (e.g. eggs), pets and other animals

Salmonellosis with gastroenteritis and enterocolitis

Fluid and electrolyte replacement for severe diarrhea Antibiotics (in immunocompromised to prevent systemic spread)

(No vaccine or preventive drug) Proper sewage disposal Food preparation Good personal hygiene

Colourless colonies on MacConkey agar

Species of human pathogenic bacteria Species Transmissio

n


Shigella sonnei Fecal-oral Flies Contaminated food or water

Bacillary dysentery/Shigellosis

Ciprofloxacin or azithromycin

Protection of water and food supplies Vaccines are in trial stage

Culture on Hektoen agar or other media for intestinal pathogens

Staphylococcus aureus

Human flora on mucosae in e.g. anterior nares and vagina, entering through wound

Coagulase-positive staphylococcal infections: Localized skin infections Diffuse skin infection (Impetigo) Deep, localized infections Acute infective endocarditis Septicemia Necrotizing pneumonia Toxinoses Toxic shock syndrome Staphylococcal food poisoning

Incision and drainage of localized lesions Nafcillin and oxacillin Vancomycin for Methicillin-resistant (MRSA)

(no vaccine or preventive drug) Barrier precautions, washing hands and fomite disinfection in hospitals

Microscopy showing strongly positive Gram stained cells in grape-like clusters Positive Catalase test and coagulase test Culture on enriched media producing deep yellow, hemolytic colonies




Staphylococcus epidermidis

Human flora in skin and anterior nares

Infections of implanted prostheses, e.g. heart valves and catheters

Vancomycin None Microscopy showing strongly positive Gram stained cells in grape-like clusters Positive Catalase test but negative coagulase test Novobiocin-sensitivity (S. epidermidis) Novobiocin-resistance (S. saprophyticus) Culture on enriched media producing white, nonhemolytic colonies

Streptococcus pneumoniae

Respiratory droplets Often human flora in nasopharynx (spreading in immunocompromised)

Acute bacterial pneumonia & meningitis in adults Otitis media and sinusitis in children

Penicillin G Vancomycin for resistant strains

23-serotype vaccine for adults (PPV) Heptavalent conjugated vaccine for children (PCV)

Microscopy showing gram-positive, encapsulated lancet-shaped diplococci α-hemolysis on blood agar, bile-soluble, optochin-sensitive Positive Quellung reaction


diagnosis

Streptococcus pyogenes

Respiratory droplets Direct physical contact with impetigo lesions

Streptococcal pharyngitis Scarlet fever Rheumatic fever Impetigo and erysipelas Puerperal fever Necrotizing fasciitis

Penicillin G Macrolide, e.g. clarithromycin or azithromycin in penicillin allergy Drainage and debridement for Necrotizing fasciitis

No vaccine Rapid antibiotic treatment helps prevent rheumatic fever

Culture on sheep blood agar forming small, opalescent surrounded by large zone of β-hemolysis Serology for ASO Very bacitracin-sensitive

Vibrio cholerae Contaminated water and food, especially raw seafood

Cholera Fluid and electrolyte replacement e.g. doxycycline to shorten duration

Preventing fecal contamination of water supplies and food Adequate food preparation

Culture on blood or MacConkey agar, enhanced by TCBS Positive oxidase test



Yersinia pestis Fleas from animals Ingestion of animal tissues Respiratory droplets

Plague: Bubonic plague Pneumonic plague

Streptomycin primarily Gentamicin Tetracyclin Supportive therapy for shock

Formalin-killed plague vaccine Minimize exposure to rodents and fleas

Gram-negative smear If pneumonic, culture from aspirate on MacConkey or blood agar

Comparison table of clinically important virus families and species

Family Baltimore group

Important species envelopment

Virion shape Replication site

Adenoviridae dsDNA adenovirus non-enveloped icosahedral nucleus

Picornaviridae +ssRNA coxsackievirus, hepatitis A virus, poliovirus, rhinovirus

non-enveloped icosahedral

Herpesviridae dsDNA Herpes simplex, type 1, Herpes simplex, type 2, Varicella-zoster virus, Epstein-barr virus, Human cytomegalovirus, Human herpesvirus, type 8

enveloped nucleus

Hepadnaviridae dsDNA and ssDNA

Hepatitis B virus enveloped icosahedral nucleus

Flaviviridae +ssRNA Hepatitis C virus, yellow fever virus, dengue virus, West Nile virus

enveloped icosahedral

Retroviridae +ssRNA Human immunodeficiency virus (HIV)

enveloped

Comparison table of clinically important virus families and species

Family Baltimore group

Important species envelopment Virion shape

Replication site

Orthomyxoviridae -ssRNA Influenza virus enveloped spherical nucleus

Paramyxoviridae -ssRNA Measles virus, Mumps virus, Parainfluenza virus, Respiratory syncytial virus, Human metapneumovirus

enveloped spherical

Papillomaviridae dsDNA Human papillomavirus non-enveloped icosahedral nucleus

Rhabdoviridae -ssRNA Rabies virus enveloped helical, bullet shaped

Togaviridae +ssRNA Rubella virus enveloped icosahedral

Parvoviridae ssDNA Human bocavirus, Parvovirus B19

enveloped icosahedral

The clinical characteristics of viruses may differ The clinical characteristics of viruses may differ substantially among species within the same family:substantially among species within the same family:

Type Family Transmission

Diseases Treatment

Prevention


adenovirus adenoviridae

droplet contact (mainly) fecal-oral venereal direct contact (ocular infections)

acute febrile pharyngitis pharyngoconjunctival fever epidemic keratoconjunctivitis infantile gastroenteritis

None None virus neutralization hemagglutination assay ELISA

Coxsackievirus

Picornaviridae

fecal-oral, droplet contact

Coxsackie infections

None None Cell culture, antibody detection



Epstein-Barr virus

Herpesviridae Saliva infectious mononucleosis Burkitt lymphoma

None None Antibody detection immunoflourescence ELISA Nucleic acid detection

Hepatitis A virus

Picornaviridae fecal-oral acute hepatitis

Immunoglobulin (post-exposure prophylaxis)

Vaccine immunoglobulin (post-exposure prophylaxis) avoid food-contamination

antibody detection

Hepatitis B virus

Hepadnaviridae

All body fluids (blood, semen, saliva, mother's milk etc.)

acute hepatitis chronic hepatitis hepatic cirrhosis hepatocellular carcinoma

immunoglobulin Adefovir Entecavir Pegylated interferon alfa-2 Lamivudine

vaccine immunoglobulin (perinatal and post-exposure prophylaxis)

viral antigen detection antibody detection nucleic acid detection

The clinical characteristics of viruses may differ substantially among species within the same family:




Hepatitis C virus

Flaviviridae blood (sexual)

acute hepatitis chronic hepatitis hepatic cirrhosis hepatocellular carcinoma

Pegylated interferon alfa-2 Ribavirin

None antibody detection nucleic acid detection

Herpes simplex virus, type 1

Herpesviridae direct contact with saliva and lesions

primary HSV-1 infection (gingivostomatitis in children, tonsillitis & pharyngitis in adults, keratoconjunctivitis) latent HSV-1 infection (herpes labialis, cold sores)

acyclovir famciclovir foscarnet penciclovir

None immunofluorescence immunoperoxidase nucleic acid detection


Type Type Family Family TransmissiTransmissionon

Diseases Diseases TreatmTreatment ent

PreventioPrevention n

laboratorylaboratory diagnosisdiagnosis

HerpesHerpes simplexsimplex virusvirus, , typetype 2 2

HerpesviridaeHerpesviridae sexually sexually

birth birth primaryprimary HSV-2 HSV-2 infectioninfection

latent HSV-2 latent HSV-2 infection infection

aseptic aseptic meningitis meningitis

acycloviracyclovir

famciclovfamciclovir ir

foscarnet foscarnet

penciclovpenciclovir ir

cidofovir cidofovir

contact-contact-avoidance avoidance with lesions with lesions

safe sex safe sex

cell culture cell culture

immunofluoresceimmunofluorescence nce

immunoperoxidasimmunoperoxidase e

nucleic acid nucleic acid detection detection

cytomegalovircytomegalovirusus

HerpesviridaeHerpesviridae tears tears

urine urine

semen semen

saliva saliva

vaginal vaginal secretions secretions

mother's milk mother's milk

crosses crosses placentaplacenta

blood blood

infectiousinfectious mononucleosismononucleosis

Cytomegalic Cytomegalic inclusion inclusion disease disease

ganciclovganciclovirir

cidofovir cidofovir

foscarnet foscarnet

NoneNone antibody and antibody and nucleic acid nucleic acid detection detection




Human herpesvirus, type 8

Herpesviridae Kaposi sarcoma multicentric Castleman disease primary effusion lymphoma

many in evaluation-stage

None Nucleic acid and antibody detection

HIV Retroviridae sexual blood mother's milk

AIDS HAART zidovudine (perinatally) blood product screening safe sex

nucleic acid, p24 antibody detection




Influenza virus

Orthomyxoviridae

droplet contact

influenza (Reye syndrome)

amantadine rimantadine zanamivir oseltamivir

Influenza vaccine amantadine rimantadine

Hemagglutination assay antigen detection

measles virus Paramyxoviridae

droplet contact

measles postinfectious encephalomyelitis

None MMR vaccine antibody detection





Mumps virus Paramyxoviridae

droplet contact

Mumps None MMR vaccine

antibody detection

Human papillomavirus

Papillomaviridae

direct contact

direct contacthyperplastic epithelial lesions (common, flat, plantar and anogenital warts, laryngeal papillomas, epidermodysplasia verruciformis) 55+ (hands/ feet) 30+ (anogenital/ some are oral/ throat/ respiratory) Malignancies for some species (cervical carcinoma, squamous cell carcinomas)

liquid nitrogen laser vaporization cytotoxic chemicals interferon cidofovir

HPV vaccine wart tissue avoidance safe sex

Visual inspection Antigen detection Nucleic acid detection




Influenza virus

Orthomyxoviridae

droplet contact

influenza (Reye syndrome)

amantadine rimantadine zanamivir oseltamivir

Influenza vaccine amantadine rimantadine

Hemagglutination assay antigen detection

measles virus

Paramyxoviridae

droplet contact

measles postinfectious encephalomyelitis

None MMR vaccine antibody detection





Parainfluenza virus

Paramyxoviridae droplet contact

croup pneumonia bronchiolitis common cold

None None Antibody detection

Parainfluenza virus

Paramyxoviridae droplet contact

croup pneumonia bronchiolitis common cold

None None Antibody detection




Poliovirus

Picornaviridae

fecal-oral Poliomyelitis

None Polio vaccine

Antibody detection

Rabies virus

Rhabdoviridae

Animal bite droplet contact

Rabies Post-exposure prophylaxis

Pre- and postexposure prophylaxis

Histology (postmortem)



Diseases Treatment

Prevention laboratory diagnosis

Respiratory syncytial virus

Paramyxoviridae

droplet contact, hand-to-mouth

bronchiolitis pneumonia influenza-like syndrome severe bronchiolitis with pneumonia

(ribavirin) hand-washing avoidance palivizumab in high risk individuals

antibody and antigen detection

Rubella virus

Togaviridae droplet contact

German measles congenital rubella

None MMR vaccine

Antibody detection




Varicella-zoster virus

Herpesvirida droplet contact

Varicella herpes zoster

Varicella: acyclovir famciclovir valacyclovir Zoster:acyclovir famciclovir

Varicella vaccine varicella-zoster immuneglobulin

Cell culture antigen and nucleic acid detection

Mycosis

Mycosis is a condition in which fungi pass the resistance barriers of the human or animal body and establish infections. Mycoses can result when the climate is hot and humid, and when people live in crowded conditions. Some fungi reproduce through tiny spores in the air. People inhale those spores or they land on the skin. Therefore, fungal infections often start in the lungs or on the skin.

Disseminated fungal infectionsDisseminated fungal infections

CandidaCandida species species are important are important human pathogens human pathogens that are best that are best known for causing known for causing opportunist opportunist infections in infections in immunocompromisimmunocompromised hosts (e.g. ed hosts (e.g. transplant patients, transplant patients, AIDS sufferers, AIDS sufferers, cancer patients).cancer patients).

Candida albicans at 200X magnification.


Aerosolized Aerosolized AspergillusAspergillus spores spores are found nearly are found nearly everywhere so we everywhere so we are routinely and are routinely and almost constantly almost constantly exposed to them. exposed to them.

Aspergillosis. H&E stain.


Cryptococcus neofCryptococcus neoformansormans can cause a can cause a severe form of severe form of meningitismeningitis and and meningo-meningo-encephalitis in encephalitis in patients with patients with HIVHIV infection and infection and AIDSAIDS..

Cryptococcus. FNA specimen. Field stain.


Histoplasma capsulHistoplasma capsulatumatum can cause can cause histoplasmosishistoplasmosis in in humans, dogs and humans, dogs and cats. cats.

Histoplasmosis. PASD stain.


Pneumocystis jirovePneumocystis jiroveciicii (or Pneumocystis (or Pneumocystis carinii) can cause a carinii) can cause a form of form of pneumoniapneumonia in people with in people with weakened weakened immune systemsimmune systems, , such as premature such as premature children, the elderly, children, the elderly, and and AIDSAIDS patients. patients.

P. jirovecii cysts in tissue

Protozoan infectionProtozoan infection

Examples of human Examples of human diseases caused by diseases caused by protozoa:protozoa: MalariaMalaria AmoebiasisAmoebiasis GiardiasisGiardiasis ToxoplasmosisToxoplasmosis CryptosporidiosisCryptosporidiosis TrichomoniasisTrichomoniasis LeishmaniasisLeishmaniasis Sleeping SicknessSleeping Sickness DysenteryDysentery

Leishmania donovani, (a species of protozoa) in a

bone marrow cell

AmebiasisAmebiasis

Entamoeba histolyticaEntamoeba histolytica is an is an anaerobicanaerobic parasitic parasitic protozoanprotozoan, , part of the part of the genusgenus EntamoebaEntamoeba. . Predominantly Predominantly infecting humans and infecting humans and other primates, other primates, E. E. histolyticahistolytica is is estimated to infect estimated to infect about 50 million about 50 million people worldwide.people worldwide.

Entamoeba histolytica cyst

GardiasisGardiasis

Giardia lambliaGiardia lamblia (synonymous with (synonymous with Lamblia intestinalisLamblia intestinalis and and Giardia Giardia duodenalisduodenalis) is a ) is a flagellatedflagellated protozoanprotozoan parasiteparasite that colonises and that colonises and reproduces in the reproduces in the small intestine, small intestine, causing causing giardiasisgiardiasis. .

Giardia cell, SEM

ToxoplasmosisToxoplasmosis

Toxoplasmosis is a Toxoplasmosis is a parasitic diseaseparasitic disease caused caused by the by the protozoanprotozoan Toxoplasma gondiiToxoplasma gondii. The . The parasite infects most parasite infects most generagenera of of warm-bloodedwarm-blooded animals, including humans, animals, including humans, but the primary host is the but the primary host is the cat familycat family. Animals are . Animals are infected by eating infected infected by eating infected meat, by ingestion of meat, by ingestion of fecesfeces of a of a catcat that has itself that has itself recently been infected, or recently been infected, or by transmission from by transmission from mother to fetus. mother to fetus.

T. gondii tachyzoites

HelminthsHelminths

Parasitic worms or helminths are a division Parasitic worms or helminths are a division of eukaryotic of eukaryotic parasitesparasites that live inside that live inside their host. They are worm-like their host. They are worm-like organismsorganisms that live and feed off living that live and feed off living hostshosts, , receiving receiving nourishmentnourishment and protection and protection while disrupting their hosts' while disrupting their hosts' nutrientnutrient absorption, causing weakness and absorption, causing weakness and diseasedisease. Those that live inside the . Those that live inside the digestive tractdigestive tract are called are called intestinal parasitesintestinal parasites. They can . They can live inside humans as well as other live inside humans as well as other animals. Approximately 3 billion people animals. Approximately 3 billion people globally are infected with helminths.globally are infected with helminths.

CategorizationCategorization

Cestodes (tapeworms) Trematodes (flukes) Nematodes (roundworms)

Shape Segmented plane Unsegmented plane Cylindrical

Attachment organs

Sucker or bothridia, and rostellum with hooks

Oral sucker and ventral sucker or acetabulum

Lips, teeth, filariform extremities, and dentary plates

Example diseases in humans

Tapeworm infection Schistosomiasis, swimmer's itch

Ascariasis, dracunculiasis, elephantiasis, enterobiasis (pinworm), filariasis, hookworm, onchocerciasis, trichinosis, trichuriasis (whipworm)

Cestoda (Cestoidea)Cestoda (Cestoidea)

Cestoda (Cestoidea) live Cestoda (Cestoidea) live in the in the digestive tractdigestive tract of of vertebratesvertebrates as adults, as adults, and often in the bodies and often in the bodies of various animals as of various animals as juveniles. Several juveniles. Several species species parasitiseparasitise humans after being humans after being consumed in consumed in underprepared meat underprepared meat such as pork (such as pork (T. soliumT. solium), beef (), beef (T. saginataT. saginata), ), fish (fish (DiphyllobothriumDiphyllobothrium spp.), poor hygiene ( spp.), poor hygiene (HymenolepisHymenolepis spp. or spp. or EchinococcusEchinococcus spp.). spp.).

Scolex (head) of Taenia solium, a tapeworm.

TremotodesTremotodes

Schistosomiasis is a Schistosomiasis is a parasitic diseaseparasitic disease caused caused by several species of by several species of tremotodestremotodes ("flukes"), a ("flukes"), a parasitic wormparasitic worm of the of the genus genus SchistosomaSchistosoma. The . The urinaryurinary form of form of schistosomiasis is schistosomiasis is associated with associated with increased risks for increased risks for bladder cancerbladder cancer in in adults. Schistosomiasis adults. Schistosomiasis is the second most is the second most socioeconomically socioeconomically devastating parasitic devastating parasitic disease after disease after malariamalaria..

Skin vesicles on the forearm, created by the

penetration of Schistosoma. Source: CDC

Nematodes Nematodes

A pinworm infection or A pinworm infection or enterobiasis is a enterobiasis is a human parasitic diseahuman parasitic diseasese and one of the most and one of the most common childhood common childhood parasitic worm parasitic worm infections in the infections in the developed world. It is developed world. It is caused by infestation caused by infestation with the parasitic with the parasitic roundworm roundworm Enterobius Enterobius vermicularisvermicularis, , commonly called the commonly called the human human pinwormpinworm..

Two pinworms

PrionPrion

A A prproteinaceous oteinaceous iinfectious particle, or nfectious particle, or prionprion, is an , is an infectious agent composed primarily of protein, infectious agent composed primarily of protein, unlike viruses which consist of two or three parts: a unlike viruses which consist of two or three parts: a helical molecule, protein coat and sometimes a viral helical molecule, protein coat and sometimes a viral wrapper.wrapper. Prions are the cause of a number of Prions are the cause of a number of diseases in a variety of mammals, including bovine diseases in a variety of mammals, including bovine spongiform encephalopathy (BSE, also known as spongiform encephalopathy (BSE, also known as "mad cow disease") in cattle and Creutzfeldt–Jakob "mad cow disease") in cattle and Creutzfeldt–Jakob disease (CJD) in humans. In general usage, disease (CJD) in humans. In general usage, prionprion refers to the theoretical unit of infection. All known refers to the theoretical unit of infection. All known prion diseases affect the structure of the brain or prion diseases affect the structure of the brain or other neural tissue and all are currently untreatable other neural tissue and all are currently untreatable and universally fatal.and universally fatal.

Creutzfeldt–Jakob disease Creutzfeldt–Jakob disease

Creutzfeldt–Jakob Creutzfeldt–Jakob diseasedisease or or CJDCJD is a is a degenerative degenerative neurological disorder neurological disorder (brain disease) that is (brain disease) that is incurable and incurable and invariably fatal. It is the invariably fatal. It is the most common among most common among the types of the types of transmissible transmissible spongiform spongiform encephalopathy found encephalopathy found in humans.in humans.

Microscopic "holes" are characteristic in prion-

affected tissue sections, causing the tissue to develop

a "spongy" architecture.

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Lecture 4. classification of inf. dis.

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Transcript of Lecture 4. classification of inf. dis.