Transcript document
Chapters 18 & 19 • Supplement to diseases already covered. – Previously covered in depth and not included here: • Viruses – HIV – Influenza (including avian and swine) • Bacterial diseases – Tuberculosis – Lyme disease – The Plague – MRSA • Protozoan diseases – Malaria • Fungal diseases – Tinea diseases – Aspergillosis – Ergot poisoning Viral Diseases of the Skin • Herpes simplex – DNA virus – Signs • • • • Cold sores Fever blisters Herpetic ulcers Herpetic whitlow – Two different viruses • HSV-1: labial herpes • HSV-2: genital herpes Courtesy of Dr. Hermann/CDC Fig. 18.1 The cold sores (fever blisters) of herpes simplex Viral Diseases of the Skin • Measles (rubeola) – – – – RNA virus Transmitted by respiratory droplets Rarely seen in US any more Signs • • • • • • • Hacking cough Sneezing Nasal discharge Eye redness Sensitivity to light High fever Characteristic red rash that eventually encompasses entire body – Extremely effective vaccine Viral Diseases of the Skin • Rubella (German measles) – – – – Different from measles Caused by rubella virus, not measles virus Occasional fever Variable, pale-pink rash – Begins on face – Spreads to trunk and extremities – Congenital rubella – Extremely effective vaccine • Mumps – Characteristic unilateral salivary gland enlargement – Obstruction of duct out of gland creates painful swelling – Extremely effective vaccine Viral Diseases of the Skin • Fifth disease (erythema infectiosum) – Caused by parvovirus B19 – DNA virus – 5th disease marked by rash • • • • I is measles II is scarlet fever III is rubella IV is roseola – Signs • • • • Fiery red rash on cheeks and ears (slapped cheek appearance) Rash may spread to trunk and extremities Rash fades within several days Leaves lacy pattern of red on skin – No available treatments Viral Diseases of the Skin • Smallpox – Caused by variola major virus – Scourge of the world – Signs • • • • Pink-red spots (macules) Appearance of large fluid-filled vessels Vesicles become deep pustules Pustules break open and emit infectious pus • If person survives, pustules leave pitted scars (pocks) – Extremely lethal – Extremely effective vaccine • Developed originally by Jenner in 1798 (first “vaccine”) – Eradicated worldwide • Officially 1980 • Last case observed 1977 in Somalia – Risk of smallpox as bioterrorism agent Courtesy of World Health Organization; Diagnosis of Smallpox Slide Series/CDC Fig. 18.3a Smallpox lesions Viral Diseases of the Skin • Warts – Caused by papilloma viruses – Small DNA viruses – Many types of warts • Cutaneous warts • Plantar warts • Genital warts – Linked to cervical cancer – Effective vaccine for genital warts Viral Diseases of the Respiratory Tract • Adenovirus infections – DNA viruses – Large family – Usually result in common cold • Rhinovirus infections – – – – RNA viruses Major cause of common cold (beyond adenoviruses) Over 100 subtypes Usual signs • • • • • Headache Dry, scratchy throat Runny nose Variable cough Little to no fever – No vaccines – No antiviral drugs – Infection and signs usually short-lived and tolerable Viral Diseases of the Nervous System • Rabies – Carried in wild animals • • • • Raccoons Squirrels Skunks Bats – RNA virus – Fatal to all animals, including humans – Transmission from infected animal into skin wound • Saliva • Urine • Blood – Incubation period of days to years Viral Diseases of the Nervous System • Yellow fever – – – – RNA virus Transmitted by bite of infected mosquito Causes liver damage that leads to jaundice (hence, “yellow”) Signs • • • • • Gums bleed Bloody stools Bloody vomit Death by rupture of capillaries: internal bleeding High mortality – Vaccine exists for high risk groups • Polio – – – – RNA virus Paralytic disease Acquired from contaminated drinking water Extremely effective vaccines • Salk: inactivated virus • Sabin: attenuated virus – Global eradication effort Viral Diseases of the Visceral Organs • Viral hemorrhagic fevers – All caused by RNA viruses – Different diseases caused by different viruses • • • • • • • • Ebola and Marburg Sin Nombre hantavirus (hantavirus pulmonary syndrome) Dengue Yellow fever Crimean-Congo hemorrhagic fever Omsk fever Rift Valley fever Lassa fever – Signs • Complete breakdown of capillaries • Uncontrollable hemorrhaging, usually ending in death Airborne Bacterial Diseases • Streptococcal disease – Streptococcus pyogenes • Strep throat • Childbed fever • Necrotizing fasciitis (flesh-eating disease) • Scarlet fever Reprinted with permission from the American Society for Microbiology (Tao, L., Tanzer, J.M and MacAlister, T.J.; J. Bacteroil, 1987 June; 169(6): 2543-2547.) – Streptococcus mutans • Tooth decay • Rheumatic heart disease – Enterococcal illnesses • GI tract infection – Treatment • Antibiotics Reprinted with permission from the American Society for Microbiology (Fluckiju, U. and Fischetti, V.A.; Infect. and Immun, 1998 March; 66(3): 974-979.) Photo courtesy of Doctor Vincent A. Fischetti. Fig. 19.1 Streptococci Courtesy of Vincent A. Fischetti, Ph.D., Head of the Laboratory of Bacterial Pathogenesis at Rockefeller University Airborne Bacterial Diseases • Diphtheria – Caused by Corynebacterium diphtheriae – Prevented by toxoid vaccination • Pertussis – – – – – – Also known as whooping cough Caused by Bordetella pertussis Disintegrating cells and mucus accumulate in airways Debris causes labored breathing Prevented by toxoid vaccination Re-emerging as problem in Eastern Europe Airborne Bacterial Diseases • Bacterial meningitis – Disease of meninges, membranes that cover brain – Most severe is meningococcal meningitis • Caused by Neisseria meningitidis • Accompanied by – Pounding headache – Stiff neck – Numbness in extremities • Starts as upper respiratory infection • Toxins can spread from bloodstream and cause rapid death • Transmissible as aerosol or through shared utensils or cups – Childhood meningitis • Typically caused by Haemophilus influenzae or Streptococcus pneumoniae • Vaccine available for both causes Airborne Bacterial Diseases • Legionairre’s disease – Caused by Legionella pneumophila • Grow in standing water – Cooling towers – Industrial air-conditioning unit – Humidifiers • Hard to grow in laboratory – Signs • Fever • Dry cough with little sputum • Potentially fatal lung infection Airborne Bacterial Diseases • Bacterial pneumonia – Microbial disease of the bronchial tubes and lungs – Infection usually results in significant fluid infiltration into lungs – Can be caused by many agents, including Streptococcus pneumoniae – Signs • • • • High fever Sharp chest pains Difficulty breathing Rust-colored sputum (from blood in lungs) – Walking pneumonia • Also called primary atypical pneumonia • Not as severe (low to no fever, no blood in lungs) • Caused by Mycoplasma pneumoniae – Treatment of both with antibiotics Foodborne and Waterborne Bacterial Diseases • Botulism – Caused by Clostridium botulinum • Spore-forming obligate anaerobes – Botulism toxin as bioterrorism agent • 1 pint of pure material could eliminate world population • 1 ounce would kill all the people in the United States – Toxin produced by spores that germinate • Canned foods – Signs • • • • Blurred vision Slurred speech Labored breathing Flaccid paralysis – Botox as cosmetic agent – Once toxin enters bloodstream, only treatment is antitoxin Foodborne and Waterborne Bacterial Diseases • Staphylococcal food poisoning • Diarrhea • Vomiting • Other signs of gastrointestinal distress © Scimat/Photo Researchers, Inc. – Caused by Staphylococcus aureus – Signs similar to most food poisoning cases • Salmonellosis Fig. 19.6 Salmonella Courtesy of Dr. W.L. Dentler – Caused by various Salmonella species – Sources may be poultry, contaminated animals, eggs – Signs similar to most food poisoning cases Foodborne and Waterborne Bacterial Diseases • Typhoid fever – Caused by Salmonella typhi – Spread by not washing hands during food preparation • Typhoid Mary – Signs • • • • • • Deep intestinal ulcers Bloody stools In a few days, mounting fever Lethargy Delirium If left untreated, frequently fatal – Antibiotic treatment Foodborne and Waterborne Bacterial Diseases • Shigellosis – Sometimes called bacterial dysentery – Caused by four different species of Shigella – Signs • Intense abdominal cramps • Small-volume, bloody, mucoid stools Courtesy of Louisa Howard, Dartmouth College, Electron Microsocpe Facility – Shiga toxins • Cholera – Caused by Vibrio cholerae – Severe watery diarrhea may lead to death due to dehydration Courtesy of Janice Carr/CDC Fig. 19.8 Vibrio cholerae Foodborne and Waterborne Bacterial Diseases • E. coli diarrheas – Sometimes called • “Hamburger disease” • Traveler’s diarrhea – Caused by subset of Escherichia coli • Enterohemorrhagic E. coli (EHEC) – O157:H7 • Enteropathogenic E. coli (EPEC) • Enterotoxigenic E. coli (ETEC) • Enteroinvasive E. coli (EIEC) • Enteroaggregative E. coli (EAggEC) – Spread from contaminated animal feces • Water supplies • Raw ground meat Soilborne Bacterial Diseases • Anthrax – Sometimes called wool sorter’s disease – Caused by Bacillus anthracis • Spore-forming Gram-positive bacteria – Spread by • Aerosol inhalation of spores • Ingestion of spores • Entrance of spores into open wounds – Spores germinate and vegetative cells make fatal toxin – Signs © Phototake/Alamy Images © Phototake/Alamy Images • Organs fill with black, bloody fluid • Black, crusty, boil-like lesions • Violent dysentery with bloody stool • Frequently fatal – Potential as bioterrorism weapon – Antibiotic therapy Courtesy of CDC/James H. Steele Fig. 19.10 Bacillus anthracis Soilborne Bacterial Diseases • Tetanus – Also called lockjaw – Caused by Clostridium tetani • Spore-forming obligate anaerobes – Acquired from environment • • • • Soil-contaminated nail Piece of glass Dirty needle Thorns – Spores germinate under skin – Vegetative cells produce tetanus toxin • Rigid paralysis • Can lead to death – Tetanus toxoid vaccine Sexually Transmitted Diseases • Syphilis – Caused by spirochete Treponema pallidum – Spirochetes penetrate skin and cause disease – Three stages • Primary syphilis – Chancre – Disappears after 2-6 weeks • Secondary syphilis – Systemic lesions – Fever – Rash – Patchy loss of hair on head • Tertiary syphilis – Gumma – Paralysis – Insanity Sexually Transmitted Diseases • Gonorrhea – – – – Also called “the clap” Caused by Neisseria gonnorhoeae Can cause pelvic inflammatory disease and sterility Treatment with antibiotics • Chlamydia – Caused by Chlamydia trachomatis – Frequently no signs of infection in males – Female signs and symptoms • Slight vaginal discharge • Inflammation of cervix • Burning pain upon urination – Can result in scarring of Fallopian tubes and sterility Contact and Miscellaneous Bacterial Diseases • Leprosy – Also called Hansen’s disease – Caused by Mycobacterium leprae • Acid-fast bacillus that resists desiccation – Spread by multiple skin contacts or aerosol droplets – Signs • • • • • Disfigured skin and bones Twisted limbs Curled fingers Loss of sensation in extremities Loss of extremities – Leper colonies Contact and Miscellaneous Bacterial Diseases • Conjunctivitis and trachoma – Conjunctivitis • • • • Also called pinkeye Caused by many different bacteria, including Haemophilus aegyptius Spread by aerosol droplets from close contact Effective antibiotic therapy – Trachoma • Caused by Chlamydia trachomatis • Also eye infection, like pinkeye • Spread by contaminated fingers, towels, etc. Needs figure of pinkeye