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![Chlamydiae
Rickettsiae
Mycoplasmas
• Like Bacteria, but…..
–NO cell wall (mycoplasma [MANY
pneumonias])
–NO ATP (chlamydia [STD, worldwide
blindness])
–NO life outside a cell (obligate
intracellular, rickettsiae [RMSF])](https://image.slidesharecdn.com/8-infectious-140902100339-phpapp01/75/8-infectious-19-2048.jpg)
![HELMINTHS
(ROUND[nematode]), TAPE[cestode])
•Roundworms, Tapeworms
• Complex Life Cycles: sexual, asexual
• ROUNDWORMS (nematodes):
ASCARIS, TOXOCARA (VLM),
STRONGYLOIDES, ENTEROBIUS
• TAPE(FLAT)WORMS (cestodes):
TAENIA (solium vs. saginata),
DIPHYLLOBOTHRIUM, Hymenolepsis](https://image.slidesharecdn.com/8-infectious-140902100339-phpapp01/75/8-infectious-25-2048.jpg)
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8 infectious
This document summarizes various infectious agents including prions, viruses, bacteria, fungi, parasites, and arthropods. It describes their characteristics, categories, habitats, life cycles, and examples of diseases they cause in humans. Key points covered include the structures and genomes of viruses, gram staining and shapes of bacteria, obligate intracellular nature of chlamydiae, rickettsiae and mycoplasmas, types of fungi and parasites, and examples of diseases caused by different pathogens.
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8 infectious
- 1.
- 2. Categories of INFECTIOUSAGENTS • Prions • *Viruses • Bacteriophages, Plasmids, Transposons • *Bacteria • Chlamidiae, Rickettsiae, Mycoplasmas • *Fungi: Yeasts, Hyphae • Parasites: Protozoa, Worms, Arthropods
- 3. Classes of HumanPathogens and Their Habitats Taxonomic Size Site of Propagation Sample Species Disease Viruses 20–300 nm Obligate intracellular Poliovirus Poliomyelitis Chlamydiae 200–1000 nm Obligate intracellular Chlamydia trachomatis Trachoma, urethritis Rickettsiae 300–1200 nm Obligate intracellular Rickettsia prowazekii Typhus fever Mycoplasmas 125–350 nm Extracellular Mycoplasma pneumoniae Atypical pneumonia Bacteria 0.8–15 μm Cutaneous Staphylococcus aureus Wound Mucosal Vibrio cholerae Cholera Extracellular Streptococcus pneumoniae Pneumonia Facultative intracellular Mycobacterium tuberculosis Tuberculosis Fungi 2–200 μm Cutaneous Trichophyton sp. Tinea pedis (athlete's foot) Mucosal Candida albicans Thrush Extracellular Sporothrix schenckii Sporotrichosis Facultative intracellular Histoplasma capsulatum Histoplasmosis Protozoa 1–50 μm Mucosal Giardia lamblia Giardiasis Extracellular Trypanosoma gambiense Sleeping sickness Facultative intracellular Trypanosoma cruzi Chagas disease Obligate intracellular Leishmania donovani Kala-azar Helminths 3 mm–10 m Mucosal Enterobius vermicularis Enterobiasis Extracellular Wuchereria bancrofti Filariasis Intracellular Trichinella spiralis Trichinosis
- 4. PRIONS, “BSE” (Cows),“CJD”, Kuru (Humans) NON-Nucleic Acid PrP = Prion Protein Diagnostic Test
- 5. Bovine Spongiform Encephalitis,Creutsfeldt-Jakob Disease
- 6. VIRUSES • Lessthan ½ micron, usually MUCH less • DNA/RNA “CORE” (genome) • Protein “CAPSID” (protein –NA “coat”) • Sometimes a lipid “ENVELOPE” • Limited number of genes coding for all other structures •NO consistent naming system
- 7. Respiratory Adenovirus AdenoviridaeDS DNA Upper and lower respiratory tract infections, conjunctivitis, diarrhea Rhinovirus Picornaviridae SS RNA Upper respiratory tract infection Coxsackievirus Picornaviridae SS RNA Pleurodynia, herpangina, hand-foot- and-mouth disease, SARS Coronavirus Coronaviridae SS RNA Upper respiratory tract infection Influenza viruses A, B Orthomyxoviridae SS RNA Influenza Respiratory syncytial virus Paramyxoviridae SS RNA Bronchiolitis, pneumonia
- 8. Digestive Mumps virusParamyxoviridae SS RNA Mumps, pancreatitis, orchitis Rotavirus Reoviridae DS RNA Childhood diarrhea Norwalk agent Caliciviridae SS RNA Gastroenteritis Hepatitis A virus Picornaviridae SS RNA Acute viral hepatitis Hepatitis B virus Hepadnaviridae DS DNA Acute or chronic hepatitis Hepatitis D virus Viroid-like SS RNA With HBV, acute or chronic hepatitis Hepatitis C virus Flaviviridae SS RNA Acute or chronic hepatitis Hepatitis E virus Norwalk-like SS RNA Enterically transmitted hepatitis
- 9. Systemic with SkinEruptions RNA Measles (rubeola) Measles virus ParamyxoviridaeSS RNA German measles (rubella) Rubella virus Togaviridae SS DNA Erythema infectiosum, Parvovirus Parvoviridae SS aplastic anemia DNA Smallpox vaccine Vaccinia virus Poxviridae DS DNA Chickenpox, shingles Varicella-zoster virus Herpesviridae DS DNA "Cold sore" Herpes simplex virus 1 Herpesviridae DS DNA Genital herpes Herpes simplex virus 2 Herpesviridae DS
- 10. Systemic with HematopoieticDisorders Cytomegalovirus Herpesviridae DS DNA Cytomegalic inclusion disease Epstein-Barr virus Herpesviridae DS DNA Infectious mononucleosis HTLV-I Retroviridae SS RNA Adult T-cell leukemia; tropical spastic paraparesis HIV-1 and HIV-2 Retroviridae SS RNA AIDS Arboviral and Hemorrhagic Fevers Dengue virus 1–4 Togaviridae SS RNA Dengue, hemorrhagic fever Yellow fever virus Togaviridae SS RNA Yellow fever Regional hemorrhagic fever viruses Filoviridae SS RNA Ebola, disease Hantavirus SS RNA Korean, pneumonia
- 11. Warty Growths PapillomavirusPapovaviridae DS DNA Condyloma; cervical carcinoma Central Nervous System RNA Poliomyelitis Poliovirus Picornaviridae SS DNA Progressive Multifocal JC virus Papovaviridae DS Leukoencephalopathy (opportunistic) Arboviral encephalitis viruses RNA Eastern, Western, Togaviridae SS Venezuelan, St. Louis
- 12. BACTERIOPHAGES PLASMIDS TRANSPOSONS • INFECT BACTERIA, but may make a bacteria more difficult to treat because it may increase its “virulence” or its susceptibility to antibiotics
- 13. BACTERIA • GRAMstaining with CRYSTAL VIOLET –POSITIVE: THICK wall, ONE phospholipid layer –NEGATIVE: THIN wall, TWO phospholipid layers • SHAPE – COCCI (balls) – BACILLI (rods) • OXYGEN requirements – AEROBIC (NEED O2) – ANAEROBIC (do NOT NEED O2)
- 14. Species Frequent DiseasePresentations Infections by pyogenic cocci Staphylococcus aureus, S. epidermidis Abscess, cellulitis, pneumonia, septicemia Streptococcus pyogenes, β- hemolytic Upper respiratory tract infection, erysipelas, scarlet fever, septicemia Streptococcus pneumoniae (pneumoccoccus) Lobar pneumonia, meningitis Neisseria meningitidis (meningococcus) Cerebrospinal meningitis Neisseria gonorrhoeae (gonococcus) Gonorrhea Gram-negative infections, common Escherichia coli Urinary tract infection, wound infection, abscess, pneumonia, septicemia, endotoxemia, endocarditis Klebsiella pneumoniae “ Enterobacter (Aerobacter) “ aerogenes Proteus spp. (P. mirabilis, P. morgagni) “ Serratia marcescens “ Pseudomonas spp. (P. “ aeruginosa) Bacteroides spp. (B. fragilis) Anaerobic infection Legionella spp. (L. pneumophila) Legionnaires disease
- 15. Contagious childhood bacterialdiseases Haemophilus influenzae Meningitis, upper and lower respiratory tract infections Bordetella pertussis Whooping cough Corynebacterium diphtheriae Diphtheria Enteropathic infections Enteropathogenic E. coli Invasive or noninvasive gastroenterocolitis, some with septicemia Shigella spp. Vibrio cholerae Campylobacter fetus, C. jejuni Yersinia enterocolitica Salmonella spp. (1000 strains) Salmonella typhi Typhoid fever Clostridial infections Clostridium tetani Tetanus (lockjaw) Clostridium botulinum Botulism (paralytic food poisoning) Clostridium perfringens, C. septicum Gas gangrene, necrotizing cellulitis Clostridium difficile Pseudomembranous colitis
- 16. Zoonotic bacterial infections Bacillus anthracis Anthrax (malignant pustule) Listeria monocytogenes Listeria meningitis, listeriosis Yersinia pestis Bubonic plague Francisella tularensis Tularemia Brucella melitensis, B. suis, Brucellosis (undulant fever) B. abortus Burkholderia mallei, B. pseudomallei Glanders, melioidosis Leptospira spp. (many groups) Leptospirosis, Weil disease Borrelia recurrentis Relapsing fever Borrelia burgdorferi Lyme borreliosis Bartonella henselae Cat-scratch disease; bacillary angiomatosis Spirillum minus, Streptobacillus moniliformis Rat-bite fever
- 17. Human treponemal infections Treponema pallidum Venereal, endemic syphilis (bejel) Treponema pertenue Yaws (frambesia) Treponema carateum (T. herrejoni) Pinta (carate, mal pinto) Mycobacterial infections Mycobacterium tuberculosis, M. bovis (Koch bacillus) Tuberculosis M. leprae (Hansen bacillus) Leprosy M. kansasii, M. avium, M. intracellulare Atypical mycobacterial infections M. ulcerans Buruli ulcer Actinomycetaceae Nocardia asteroides Nocardiosis Actinomyces israelii Actinomycosis
- 19. Chlamydiae Rickettsiae Mycoplasmas • Like Bacteria, but….. –NO cell wall (mycoplasma [MANY pneumonias]) –NO ATP (chlamydia [STD, worldwide blindness]) –NO life outside a cell (obligate intracellular, rickettsiae [RMSF])
- 20. FUNGI • YEASTS,HYPHAE •CANDIDA, by far, the MOST PREVALENT ONE • DERMATOPHYTES, (“tinea”), i.e., trichophyton, microsporum • DEEP FUNGI (GRANULOMAS) – HISTOPLASMOSIS –BLASTOMYCOSIS –COCCIDIOMYCOSIS
- 21.
- 22. PARASITES •PROTOZOA •“META”-ZOA (HELMINTHS) • “ECTO”-PARASITES, i.e., ARTHROPODS
- 23. PROTOZOA SINGLE CELL INTESTINAL or BLOOD • PLASMODIUM (MALARIA) • LEISHMANIA • ENTAMOEBA • TRYPANOSOMA • TOXOPLASMA • GIARDIA
- 24. Species Order Form,Size Disease Luminal or Epithelial Entamoeba histolytica Amebae Trophozoite 15–20 μm Amebic dysentery; liver abscess Balantidium coli Ciliates Trophozoite 50–100 μm Colitis Naegleria fowleri Ameboflagellates Trophozoite 10–20 μm Meningoencephalitis Acanthamoeba sp. Ameboflagellates Trophozoite 15–30 μm Meningoencephalitis or ophthalmitis Giardia lamblia Mastigophora Trophozoite 11–18 μm Diarrheal disease, malabsorption Isospora belli Coccidia Oocyst 10–20 μm Chronic enterocolitis or malabsorption or both Cryptosporidium sp. Coccidia Oocyst 5–6 μm Trichomonas vaginalis Mastigophora Trophozoite 10–30 μm Urethritis, vaginitis Bloodstream Plasmodium species Hemosporidia Trophozoites, schizonts, gametes (all small and inside red cells) Malaria Babesia microti, B. bovis Hemosporidia Trophozoites inside red cells Babesiosis Trypanosoma species Hemoflagellates Trypomastigote 14–33 μm African sleeping sickness Intracellular Trypanosoma cruzi Hemoflagellates Trypomastigote 20 μm Chagas disease Leishmania donovani Hemoflagellates Amastigote 2 μm Kala-azar Leishmania species Hemoflagellates Amastigote 2 μm Cutaneous and mucocutaneous leishmaniasis Toxoplasma gondii Coccidia Tachyzoite 4–6 μm (cyst larger) Toxoplasmosis
- 25. HELMINTHS (ROUND[nematode]), TAPE[cestode]) •Roundworms, Tapeworms • Complex Life Cycles: sexual, asexual • ROUNDWORMS (nematodes): ASCARIS, TOXOCARA (VLM), STRONGYLOIDES, ENTEROBIUS • TAPE(FLAT)WORMS (cestodes): TAENIA (solium vs. saginata), DIPHYLLOBOTHRIUM, Hymenolepsis
- 27.
- 30. ARTHROPODS: INSECTS/ARACHNIDS •LICE • BEDBUGS • FLEAS • MITES • TICKS • SPIDERS
- 31. CLASS INSECTA C R A B L O U S E L O U S E BEDBUG FLEA
- 32. CLASS ARACHNIDA TICKLARVAL MITE ADULT MITE BLACK WIDOW BROWN <--RECLUSE
- 33.
- 34. BARRIERS • ALLANATOMIC MUCOSAL POSSIBILITIES –SKIN –GI –RESPIRATORY –UROGENITAL
- 35. SPREAD SAME ASTUMOR? •DIRECT EXTENSION •LYMPHATICS •BLOOD •NERVE
- 36. RELEASE (TRANSMISSION) •SKIN SHEDDING • COUGHING/SNEEZING • URINE • FECES • BLOOD • VECTORS, e.g., insects, “zoonosis” • “STDs” (Sexually Transmitted Diseases)
- 37. INFECTIVITY, GENERAL •AGENT HOST CELL • AGENT TOXINS NECROSIS • AGENTHOST CELLULAR REACTIONDAMAGE/DEATH
- 38. INFECTIVITY, VIRAL •ATTACHMENT • ENTRY • TRANSCRIPTION • TRANSLATION – INCLUSIONS –REDUCED HOST CELL FUNCTION –CELL INJURY, LYSIS, DEATH –LATENCY –NEOPLASM?
- 39. INFECTIVITY, BACTERIAL •ADHERENCE • ENTRY • TOXINS –ENDO, Gram - , bacterial components –EXO, Gram -/+, secreted proteins
- 40. IMMUNE EVASION •INACCESSIBILITY to host defense (Mr. Myagi) • VARYING (mutating) antigens • SHEDDING antigens • RESISTING INNATE (NATURAL) immunity • IMPAIRING T-CELLS
- 41. INFECTIONS of IMMUNOSUPPRESSEDHOSTS • Protozoal/Helminthic: Cryptosporidium, PCP (Pneumocystis Carinii Pneumonia), Toxoplasmosis • Fungal: Candida, and the usual 3 • Bacterial: TB, Nocardia, Salmonella • Viral: CMV, HSV, VZ
- 42. DIAGNOSTIC TECHNIQUES •DIRECT PATHOGEN IMAGING • GRAM STAIN • “SPECIAL” (NOT H&E) STAINS • AGAR, e.g., CULTURES • TISSUE CULTURE, CPE (CytoPathological Effect) • ANTIBODIES (SEROLOGY) • PCR, POLYMERASE CHAIN REACTION, e.g., viral “LOAD”
- 43. CELLULAR HOST RESPONSES • SUPPURATIVE (NEUTROPHILS, PMNs) • MONO-NUCLEAR, i.e., Lymphocytes, Macrophages (i.e., Monocytes), GRANULOMAS • FIBROSIS • HEMOSIDERIN • CALCIFICATION
- 44.
- 45.
- 46.
- 47.
- 48.
- 49. H E M O S I D E R I N H & E PRUSSIAN BLUE
- 50.
- 51. The 4 Biggies •VIRAL •BACTERIAL •FUNGAL •PARASITIC
- 52. VIRAL • TRANSIENT,ACUTE, e.g. Measles, Mumps, Polio, West Nile • CHRONIC LATENT (HERPES FAMILY), HSV, CMV, VZ • CHRONIC (HEPATITIS), Hep A, B, C • “TRANSFORMING” (Epstein-Barr EBV, Human Papilloma, HPV)
- 53. BACTERIAL •Gram+ •Gram- • MYCO-bacteria • SPIROCHETES • ANAEROBIC • “OBLIGATE” INTRACELLULAR
- 54. FUNGAL • YEASTS –CANDIDA –CRYPTOCOCCOSIS • MOLDS (HYPHAL) –ASPERGILLIS –MUCORMYCOSIS (ZYGOMYCOSIS)
- 55. PARASITES •PROTOZOA (GI, BLOOD) •METAZOA (WORMS)
- 56. VIRAL • TRANSIENT,ACUTE –Measles: Skin, Lung, GI, Cornea, Brain –Mumps: Parotitis, Orchitis, Pancreas, CNS –Polio: Myelitis (Anterior horn motor neurons) –West Nile (arbo-): Meningoencephalitis
- 61. VIRAL •CHRONIC LATENT (HERPES FAMILY), HSV, CMV, VZ –Herpes Simplex Virus –CytoMegalo Virus –Varicella-Zoster Virus
- 62.
- 63. BASOPHILIC CONGENITAL IMMUNOSUPPRESSED CMV pneumonia
- 64.
- 65. VIRAL • CHRONIC(HEPATITIS), Hep. A, B, C –A, Mildest, most universal –B, Most dangerous in the acute phase –C, Most common cause of persistent transaminitis
- 66.
- 67.
- 68. VIRAL “TRANSFORMING” Epstein-Barr,EBV, lymphoma Human Papilloma, HPV, cervical cancer (squamous cell)
- 69. PHARYNX NODES SPLEEN LIVER HETEROPHILE MONONUCLEOSIS, caused by EBV
- 70. “MALIGNANT” cells onPAP smear, caused by HPV
- 71. BACTERIAL •Gram+ (Staph,Strep) •Gram- (rods) • MYCO-bacteria (TB) • SPIROCHETES (SYPHILIS) • ANAEROBIC (ABSCESSES) • “OBLIGATE” INTRACELLULAR
- 72. BACTERIAL • Gram+cocci (Staph, Strep) SKIN RESPIRATORY TRACT
- 73. S T A P H
- 74. STREP: SKIN RESPIRATORY ERISIPELAS
- 75. GRAM POSITIVE RODS • DIPTHERIA • LISTERIA • ANTHRAX------ • NOCARDIA • CLOSTRIDIUM
- 76. GRAM NEGATIVE COCCI •Neisseria –GONORRHEA –MENINGITIS
- 78. GRAM NEGATIVE RODS • Bordetella pertussis • Pseudomonas aeruginosa • Klebsiela/Aerobacter • Yersinia pestis (plague) • Hemophilus ducreyi (chancroid) •E. COLI
- 79. MYCOBACTERIA (acid fast) •Tuberculosis • “Atypical” mycobacteria, the most important of which is MAC (Mycobacterium Avium Intercellulare Complex, in HIV patients) • Leprosy
- 81. MORE ACID-FAST BACILLI,AFB (MAC)
- 82. SPIROCHETES •SYPHILIS ( Treponema pallidum) • RELAPSING FEVER (Borrelia sp.) • LYME DISEASE (Borrelia burgdorferi)
- 83. SYPHILIS • PRIMARY(CHANCRE) • SECONDARY (MANY skin manifestations) • TERTIARY (GUMMAS, CNS, BONE) • CONGENITAL
- 84. ANAEROBES • Clostridium(Gram + bacillus) –Cause of many/most cases of “gas” gangrene
- 85. “OBLIGATE” intracellular bacteria • Chlamydia trachomatis –Conjunctivitis –LGV (LymphoGranuloma Venerium) – Urethritis • Rickettsia (Rocky Mountain Spotted Fever, Typhus) • Mycoplasma (very common cause of pneumonias)
- 87.
- 88. FUNGAL • YEASTS –CANDIDA –CRYPTOCOCCOSIS • MOLDS (HYPHAL) –ASPERGILLIS –MUCORMYCOSIS (ZYGOMYCOSIS)
- 89. Candida albicans •Oral • Vaginal • Esophageal • All of the above are “moist” non-keratinized squamous mucosa • Immunocompromised, e.g., HIV, Diabetes
- 90. Budding Yeasts and“PSEUDO” hyphae
- 91. Budding cryptococcal yeasts,India ink prep, CSF
- 92. MOLDS • Aspergillus • Zygomycosis (Mucormycosis)
- 93. DERMATOPHYTES (“TINEAS”) (superficialfungi) •EPIDERMOPHYTON •MICROSPORUM •TRICHOPHYTON
- 100. SIGNIFICANT FUNGI (deep) • HISTOPLASMOSIS • BLASTOMYCOSIS • COCCIDIOMYCOSIS
- 102. PROTOZOA • MALARIA(Plasmodium sp., of which falciparum is the most serius) • Babesiosis, transmitted by deer tick • Leishmaniasis • Trypanosomiasis (sleeping sickness) • Chagas disease (also a trypanosome) • Entamoeba histolytica
- 106. GAMETOCYTES Are COMMON And SAUSAGE shaped
- 107.
- 108. Affected RBC’s areNOT enlarged NO SCHUFFNER’s DOTS
- 109.
- 110.
- 111. METAZOA (ROUNDworms/FLATworms) •Strongyloides (microscopic roundworm) • Tapeworms (Beef, Pork, flatworm) • Trichinosis (larva in skeletal muscle) • Schistosomiasis (bladder cancer) • Filariasis (elephantiasis) • VERY OFTEN, COMPLEX LIFE CYCLES
- 112.
Editor's Notes
- #5 Interest in “infectious” diseases caused by prions, i.e., NON-nucleic acid infectious agents, seems to be growing rapidly. PrP, also called prion related protein, or protease resistant protein, is the infectious substance, and discovering it led to a Noble Prize in 1997. PRI-ON itself Stands for PRO-teinaceous IN-fectious particle
- #6 BSE, or “Mad Cow” diease is the animal counterpart to human CJD or Creutsfeld-Jakob Disease, also commonly called Jakob-Creutsfeld Disease. Vacoulization (sponginess) of CNS tissue is the consistent diagnostic finding (identify the vacuoles).
- #7 Nucleic acid “core”, capsid, envelope are the three common features of all viruses.
- #13 These primitive organisms are not often implicated in human diseases DIRECTLY, but indirectly.
- #19 Gram + bacilli (rods) and Gram – cocci Remember the exception rule: Cocci are Gram+ EXCEPT for neisseria. Bacilli are Gram- EXCEPT for Bacillus (anthracis), Cornyebacterium, Clostridium, Lactobacillus, Listeria, Propionibacterium (acne) (ABCCLLP)
- #20 The OBLIGATE intracellular organisms, because they are obliged to live IN human cells to survive. They have no cell walls, and no mitochondria, and therefore no ATP.
- #21 Fungi occur in tissues
- #23 ONE celled parasites are (Proto-zoans), multi-celled parasites (META-zoan) are worms (i.e., helminths) and arthropods
- #26 Classical (top 4) human helminth diseases
- #28 Ascaris life cycle
- #29 Taenia solium (cysticercosis) life cycle
- #30 T solium, T saginata, D latum, H nana,
- #36 Infectious agents spread geographically in the body exactly via the same routes which tumor cells do.
- #38 An infectious “agent” can attack a host cell directly, damage a host cell by its toxins, or by creating a host inflammatory response which damages host tissues
- #41 Main concepts of an infectious agent’s immune evasion.
- #42 By no surprise the common infections in immunosuppressed hosts theoretitally, parallels the common opportunistic infections seen in AIDS patients.
- #43 Common diagnostic techniques for identifying infectious agents.
- #44 The spectrum pattern of host responses parallels the entire spectrum of ALL inflammatory morphologies.
- #48 Granulomatous reactions are commonly seen with mycobacteria, fungi, sarcoid, foreign bodies, and rarely with almost anything.
- #53 Four types of viral infections: 1) Transient acute, 2) Chronic latent, 3) Chronic, 4) Transforming. There is no consistent uniformity for viral taxonomy, so viral diseases can be classified according to their severity and/or abruptness of clinical expressions.
- #54 The common types of bacteria which infect humans. This is not at all a totally logical classification.
- #55 Morphologic types of fungi: yeasts and mold, independent of whether they are superficial, deep, or systemic
- #56 Protozoans are single celled organisms. Although metazoans technically are any multicellular organisms, they are often generally used synonymously with the word “worms”.
- #57 Classical viral infections which are TRANSIENT and ACUTE
- #58 Measles “giant” cell in measles pneumonia. The measles virus is a highly contagious airborne pathogen which spreads primarily via the respiratory system. The virus is transmitted in respiratory secretions, and can be passed from person to person via aerosol droplets containing virus particles, such as those produced by a coughing patient. Once transmission occurs, the virus infects the epithelial cells of its new host, and may also replicate in the urinary tract, lymphatic system, conjunctivae, blood vessels, and central nervous system
- #59 Parotitis, orchitis.
- #60 Poliovirus enters the body through the mouth, infecting the first cells it comes in contact with—the pharynx (throat) and intestinal mucosa. It gains entry by binding to a immunoglobulin-like receptor, known as the poliovirus receptor or CD155, on the cell surface.[26] The virus then hijacks the host cell&apos;s own machinery, and begins to replicate. Poliovirus divides within gastrointestinal cells for about a week, from where it spreads to the tonsils (specifically the follicular dendritic cells residing within the tonsilar germinal centers), the intestinal lymph nodes including the M cells of Peyer&apos;s patches, and the deep cervical and mesenteric lymph nodes, where it multiplies abundantly. The virus is subsequently absorbed into the bloodstream
- #61 Lymphocytic infiltrates in the “Virchow-Robbins” space IS classic for encephalitis.
- #62 The viruses in the Herpes/CMV family are CHRONIC and LATENT, often recurrent, and often travel along nerves and involve skin.
- #66 The hepatitis viruses are classifies as chronic
- #68 The arrowed “Councilman” bodies are rather diagnostic of viral (B) hepatitis. The inflammatory pattern is periportal at first but can soon become PAN-lobular. Chronic hepatitis is chiefly periportal.
- #69 Transforming viruses cause tumors.
- #70 “Mono” is severe pharyngitism, adenopathy, splenomegaly, and hepatitis. The classical “mono” cells are really lymphocytes, and “heterophile” antibodies are fairly diagnostic.
- #71 Bridging the gap between infection and neoplasms, HPV viruses cause squamous cell cancer of the cervix.
- #72 Gram + bacilli (rods) and Gram – cocci Remember the exception rule: Cocci are Gram+ EXCEPT for neisseria. Bacilli are Gram- EXCEPT for Bacillus (anthracis), Cornyebacterium, Clostridium, Lactobacillus, Listeria, Propionibacterium (acne) (ABCCLLP)
- #75 A strep infection in immunocompromised hosts, often the very old and very young.
- #80 “MAC” is the most common and serious “atypical” mycobacterium, seen very often in AIDS patients.
- #81 Necrotizing (i.e., caseating) granulomas filled with acid fast bacilli. This is CLASSIC for TB.
- #82 The acid fast stain for acid fast bacteria is also called the Ziel-Neilseon stain, or simply AFB stain
- #87 A leading cause of worlwide blindness, this keratoconjunctivitis affects 400 million people world wide.
- #88 The agent of RMSF is an obligate intracellular Rickettsia rickettsii organism carried by the tick Dermacentor andersoni, evoking microvasculitis and thrombosis of small vessels. Other rickettsia cause typhus.
- #89 Yeasts are balls, hyphae are long cylindrically shaped structures, often arising from yeasts
- #90 Without a doubt, by far, the most common and ubiquitous of all fungal agents.
- #91 Classical patterns of Candida, budding yeasts and PSEUDO-hyphae, staining very RED with the PAS stain and many others. The upper photo of budding yeasts could be from a culture because it has no tissue in it.
- #93 Both of these “mold” diseases can cause human diseases often in immunocompromised hosts.
- #94 Submit this to memory.
- #95 Ringworm of scalp
- #96 Tinea barbae
- #97 Ringworm
- #98 Tinea cruris, or jock itch
- #99 Athlete’s foot, or tinea pedis
- #100 Onychomycosis
- #101 These usually evoke granulomatous reactions in tissues. Histoplasmosis organisms are very small and often pack histiocytes, blastomycosis and coccidiomycosis are much larger round balls.
- #103 These should all be recognized as protozoal diseases.
- #104 Anopheles species mosquito of malaria
- #106 The various types of malaria are differntiated by the appearance of the RBCs and the forms of the parasites in them. Plasmodium falciparum is potentially the most deadly, and is gives rise to “blackwater fever”, i.e., marked hemoglobinuria and renal failure. Gametocytes (upper) are common to be seen in falciparum.
- #111 This is a very serious concern in Africa, in which the bite of the tsetse fly transmits the protozoan. This is a classical diagnostic appearance on a routine blood smear. South American trypanosomiasis is called “Chagas” disease.
- #113 Ascaris life cycle
- #114 Taenia solium (cysticercosis) life cycle