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Diseases

Diseases. Chapters 21-26. Microorganisms and human Disease. Things to cover Diseases of Skin and Eyes Diseases of the Nervous system Diseases of the Cardiovascular & Lymphatic System Diseases of the Respiratory System Diseases of the Digestive System. How I will tackle these.

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Diseases

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  1. Diseases Chapters 21-26

  2. Microorganisms and human Disease • Things to cover • Diseases of Skin and Eyes • Diseases of the Nervous system • Diseases of the Cardiovascular & Lymphatic System • Diseases of the Respiratory System • Diseases of the Digestive System

  3. How I will tackle these • Structure and function. • Normal Microbiota • Some of the diseases (More diseases to come) • Bacterial • Viral • Other • You will provide more of the details

  4. Skin and EyesCh 21 • Physical and chemical barrier against microbes • Moist areas have greater number of bacteria

  5. Epidermis contains flattened cells of keratin and is essentially waterproof. • Dermis is the living part, contains follicles, ducts and glands that act as week point for bacterial invasion. • Sebum and perspiration can inhibit growth of microbes. • Same also provide nutrients to microbiota • The body and body cavities are lined with epithelia cells. • Mucous membranes secrete mucus.

  6. What does the integument system do?

  7. Microbiota • Divide rapidly, resistant to desiccation and high salt. • Mostly gram positive cocci. • Never completely absent. • Propionibacterium metabolize oil • Pityrosporum ovale are yeast that grow in oily secretions, cause dandruff.

  8. Staphylococcal Skin Infections • Folliculitis • Infections of hair follicles • Sty • Folliculitis of an eyelash • Furuncle • Abscess; pus surrounded by inflamed tissue • Carbuncle • Inflammation of tissue under the skin

  9. Staphylococcal Skin Infections • Impetigo of the newborn • Toxemia • Scalded skin syndrome • Toxic shock syndrome Figure 21.4

  10. Streptococcal Skin Infections • Streptococcus pyogenes • Group A beta-hemolytic streptococci • M proteins Figure 21.5

  11. Streptococcal Skin Infections • Erysipelas • Impetigo Figure 21.6, 7

  12. Invasive Group A Streptococcal Infections • Streptokinases • Hyaluronidase • Exotoxin A, superantigen • Cellulitis • Necrotizing fasciitis Figure 21.8

  13. Infections by Pseudomonads • Pseudomonas aeruginosa • Gram-negative, aerobic rod • Pyocyanin produces a blue-green pus • Pseudomonas dermatitis • Otitis externa • Post-burn infections

  14. Warts • Papillomaviruses • Treatment: • Removal • Imiquimod (stimulate interferon production) • Interferon

  15. Poxviruses • Smallpox (Variola) • Smallpox virus (Orthopox virus) • Variola major has 20% mortality • Variola minor has <1% mortality • Monkeypox • Prevention by smallpox vaccination Figure 21.9

  16. Measles (Rubeola) • Measles virus • Transmitted by respiratory route • Macular rash and Koplik's spots • Prevented by vaccination • Encephalitis in 1 in 1000 cases • Subacute sclerosing panencephalitis in 1 in 1,000,000 cases Figure 21.14

  17. Cutaneous Mycoses • Dermatomycoses: tineas or ringworm • Metabolize keratin • Trichophyton infects hair, skin, nails • Epidermophyton infects skin and nails • Microsporum infects hair and skin • Treatment • Oral griseofulvin • Topical miconazole

  18. Cutaneous Mycoses Figure 21.16

  19. Candidiasis • Candida albicans (yeast) • Candidiasis may result from suppression of competing bacteria by antibiotics • Occurs in skin; mucous membranes of genitourinary tract and mouth • Thrush is an infection of mucous membranes of mouth • Topical treatment with miconazole or nystatin

  20. Candidiasis Figure 21.17

  21. Pediculosis • Pediculus humanus capitis (head louse) • P. h. corporis (body louse) • Feed on blood • Lay eggs (nits) on hair • Treatment with topical insecticides Figure 21.19

  22. Microbial Diseases of the Eye • Conjunctivitis (pinkeye) • Haemophilus influenzae • Various microbes • Associated with unsanitary contact lenses • Neonatal gonorrheal ophthalmia • Neisseria gonorrhoeae • Transmitted to newborn's eyes during passage through the birth canal • Prevented by treatment newborn's eyes with antibiotics

  23. Nervous SystemCh22 • CNS is brain and spinal cord. Is encased and protected by bone and membranes. • PNS are nerves outside of the Central nervous system. Is not protected as extensively and is a rout into the CNS. • Membranes of the CNS • Dura mater, arachnoid and piamater

  24. More nervous • Cerebrospinal fluid instead of blood circulates between the arachnoid and piamater in the subarachnoid space. • Cerebrospinal fluid is totally separate from the blood and circulatory system. • Blood brain barrier • Entry to CNS by bacteria is through peripheral nerves, though blood and lymphatic system.

  25. Meningitis is an infection of the meninges • Encephalitis is an infection of the brain.

  26. What does the Nervous system do?

  27. Normal Microbiota?

  28. Bacterial Meningitis • Fever, headache, stiff neck • Followed by nausea and vomiting • May progress to convulsions and coma • Diagnosis by Gram stain of CSF • Treated with cephalosporins

  29. Bacterial Meningitis Table 22.1

  30. Tetanus • Clostridium tetani • Gram-positive, endospore-forming, obligate anaerobe • Grows in deep wounds • Tetanospasmin released from dead cells blocks relaxation pathway in muscles • Prevention by vaccination with tetanus toxoid (DTP) and booster (dT) • Treatment with tetanus immune globulin

  31. Botulism • Clostridium botulinum • Gram-positive, endospore-forming, obligate anaerobe • Intoxication due to ingesting botulinal toxin • Botulinal toxin blocks release of neurotransmitter causing flaccid paralysis • Prevention: • Proper canning • Nitrites prevent endospore germination in sausages

  32. Botulism • Treatment: supportive care and antitoxin • Infant botulism results from C. botulinum growing in intestines • Wound botulism results from growth of C. botulinum in wounds.

  33. Transmissible Spongiform Encephalopathies • Caused by prions • Sheep scrapie • Creutzfeldt-Jakob disease • Kuru • Bovine spongiform encephalopathy • Transmitted by ingestion or transplant or inherited • Chronic, fatal

  34. Transmissible Spongiform Encephalopathies Figure 22.17a

  35. Cardiovascular and Lymphatic Systems Ch 23 • Consists of heart, blood and blood vessels • Lymph, lymph vessels, lymph nodes and lymphoid organs.

  36. Body Fluids and Flow • Heart circulates substances to and from tissue cells. • Blood is a mixture of plasma and cells. • Most substances are dissolved in plasma • RBC’s carry oxygen. • WBC’s are involved in defense. • Interstitial fluid is essentially plasma and exits from capillaries

  37. Normal Microbiota? • Life Loads?

  38. Sepsis and Septic Shock • Sepsis • Bacteria growing in the blood • Severe sepsis • Decrease in blood pressure • Septic shock • Low blood pressure cannot be controlled Figure 23.3

  39. Sepsis • Gram-negative Sepsis • Endotoxins caused blood pressure decrease • Antibiotics can worsen condition by killing bacteria • Gram-Positive Sepsis • Nosocomial infections • Staphylococcus aureus • Streptococcus pyogenes • Group B streptococcus • Enterococcus faecium and E. faecalis

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