Micro Chap 22

  1. -if left undisturbed, normal biota biofilm eventually contains anaerobic bacteria that can damage the soft tissues and bones (periodontium) surrounding the teeth
    -introduction of carbohydrates to the oral cavity can result in breakdown of dentition
    tooth and gum infections
  2. -most common infectious disease of human beings
    -symptoms: often not noticeable, but range from minor disruption in the enamel to complete destruction of the enamel and deeper layers
    -deeper lesions can result in infection to soft tissue inside the tooth leading to a toothache
    -streptococcus mutans, streptococcus sobrinus, others
    dental caries (tooth decay)
  3. -97% to 100% of the population has some manifestations of it by age 45
    -most are due to bacterial colonization and varying degrees of inflammation
    periodontal disease
  4. -initial stage:gingivitis (swellings, loss of normal contour, patches of redness, and increased bleeding of the gingival)
    -if persists, periodontitis develops
    *extension of gingivitis into the periodontal membrane and cementum
    *increases the size of pockets b/w the tooth and the gingival and can cause bone resorption enough to loosen and possible lose the tooth
  5. -synergistic infections involving Treponema vincentii, Prevotella intermedia, and Fusobacterium species
    -together they produce several invasive factors that cause rapid advancement into the periodontal issues
    -severe pain, bleeding, pseudomembrane formation, and necrosis
    necrotizing ulcerative gingivitis and periodontitis
  6. -incubation period 2 to 3 weeks
    -initial symptoms: fever, nasal discharge, muscle pain, and malaise
    -may be followed by inflammation of the salivary glands, producing gopherlike swelling of the cheeks (parotitis)
    -multiplication in the salivary glands followed by invasive of other organs, especially testes, ovaries, thyroid gland, pancreas, meninges, heart, and kidneys
  7. -Helicobacter pylori thrives in the acidic environment of the stomach and has been linked to a variety of gastrointestinal ailments
    1. -sharp or burning pain emanating from the abdomen

    -actual lesions in the mucosa of the stomach
    2. -lesion in the uppermost portion of the small intestine
    -severe can be accompanied by bloody stools, vomiting, or both
    -long-term infection with H. pylori might by a contributing factor to stomach cancer
    • 1. gastritis
    • 2. gastric ulcers
  8. -in the US up to 1/3 of all cases transmitted by contaminated food
    -most cases are self-limiting and do not require treatment
    -some (E. coli 0157:H7) can be devastating
    acute diarrhea
  9. -can be severe (elevated body temp and septicemia) or mild (vomiting, diarrhea, and mucosal irritation)
    -symptoms usually spontaneously subside after 2-5 days
  10. -fever, diarrhea, and abdominalpain
    -the bacterium infiltrates the mesenteric lymph nodes and the phagocytes of the liver and spleen
    -progressive and invasive that leads eventually to septicemia
    typhoid fever
  11. -causes the most severe form of dysentary
    -uncommon in US
    -frequent, watery stools, fever, and intense abdominal pain
    -nausea and vomiting are common
    -often bloody stools
    acute diarrhea caused by shigella
  12. -most virulent strain
    -symptoms range from mild gastroenteritis with fever to bloody diarrhea
    -about 10% of patients develop hemolytic uremic syndrome (can cause kidney damage and failure)
    -can also cause neurological symptoms such as blindness, seizure, and stroke
    acute diarrhea caused by E. coli 0157:H7 (EHEC)
  13. -acute diarrhea caused by other E. coli (4 categories)
    • 1. enterotoxigenic
    • 2. enteroinvasive
    • 3. enteropathogenic
    • 4. enteroaggregative
  14. -presentation varies depending on which type of E. coli is causing the disease
    -traveler's diarrhea: watery diarrhea, low-grade fever, nausea, and vomitin
    enterotoxigenic E. coli (ETEC)
  15. -cause a disease similar to Shigella dysentery
    -invade gut mucosa and cause widespread destruction
    -blood and pus found in stool
    -significant fever
    enteroinvasive E. coli (EIEC)
  16. -profuse, watery diarrhea
    -fever and vomiting also common
    -produce effacement of gut surfaces
    enteropathogenic E. coli (EPEC)
  17. -can cause chronic diarrhea in young children and in AIDS patients
    enteroaggregative E. coli (EAEC)
  18. -most common bacterial cause of diarrhea in the US
    -frequent watery stools, fever, vomiting, headaches, and severe abdominal pain
    -symptoms may last beyond 2 weeks
    -symptoms may subside then recur over a period of weeks
    -in a small number of cases, can lead to a serious neuromuscular paralysis called Guillain-Barre syndrome (GBS)
    acute diarrhea caused by campylobacter
  19. -Y. enterocolitica and Y. pseudotuberculosis
    -uncommon in US
    -inflammation of the ileum and mesenteric lymph nodes gives rise to severe abdominal pain
    -infection occasionally spreads to the bloodstream
    acute diarrhea caused by Yersinia species
  20. -causes pseudomembranous colitis
    -major cause of diarrhea in hospitals
    -able to superinfect the large intestine when drugs have disrupted the normal biota
    -produces two enterotoxins (toxins A and B) that cause areas of necrosis in the wall of the intestine
    -severe cases exhibit abdominal cramps, fever, and leukocytosis
    acute diarrhea caused by Clostridium difficile
  21. -incubation period of a few hours to a few days
    -symptoms begin abruptly with vomiting
    -followed by copious watery feces called secretory diarrhea
    -can lose up to 1 liter of fluid an hour in severe cases
    acute diarrhea caused by Vibrio cholera
  22. -headache, sweating, vomiting, severe abdominal cramps, and diarrhea
    -in AIDS patients may develop into chronic persistent diarrhea
    acute diarrhea cause by Cryptosporidium
  23. -effects of infection vary with age, nutritional state, general health, and living conditions of the patient
    acute diarrhea caused by Rotavirus
  24. -many other viruses can cause gastroenteritis
    -for example adenoviruses, noroviruses, and astroviruses
    -common in the US and around the world
    -profuse, water diarrhea of 3-5 days duration
    acute diarrhea caused by other viruses
  25. -symptoms in the gut that are caused by a performed toxin of some sort
    -if the symptoms are violent and the incubation period is very short, intoxication rather than infection should be considered
    acute diarrhea with vomiting (food poisoning)
  26. -associated with food such as custards, sauces, cream pastries, processed meats, chicken salad, or ham that have been contaminated and then left unrefrigerated for a few hours
    -toxins do not noticeably alter the food's taste or smell
    -heating the food after toxin production may not prevent disease
    -symptoms: cramping, nausea, vomiting, and diarrhea
    -rapid recovery-usually within 24 hours
    food poisoning by Staphylococcus aureus Exotoxin
  27. -two exotoxins: one causes diarrheal-type disease, the other cause an emetic disease
    -the type of disease that takes place is influences by the type of food that is contaminated
    -emetic form frequently linked to fried rice, especially when cooked and kept warm for long periods of time
    -diarrheal form associated with cook mats or vegetables that are held at a warm temp for long periods of time
    food poisoning by Bacillus cereus Exotoxin
  28. -animal flesh and vegetables such as beans that have not been cooked thoroughly enough to destroy endospores
    -acute abdominal pain, diarrhea, and nausea in 8-16 hours
    -rapid recovery
    food poisoning by Clostridium perfringens Exotoxin
  29. -lasting longer than 14 days
    -infectious or noninfectious
    -AIDS patients suffer from it due to opportunistic infections
    -several microbes can be responsible
    chronic diarrhea
  30. -adheres to human cells in aggregates rather than as single cells
    -stimulates large amounts of mucus in the gut
    chronic diarrhea by enteroaggregative E. coli (EAEC)
  31. -incubation periods of about 1 week
    -watery diarrhea, stomach cramps, bloating, fever, and muscle aches
    -if prolonged, also experience anorexia and weight loss
    chronic diarrhea by Cyclospora
  32. -diarrhea of long duration, abdominal pain, and flatulence
    -stools have a greasy, malodorous quality
    -fever usually not present
    chronic diarrhea by Giardia
  33. -clinical amoebiasis exists in intestinal and extraintestinal forms
    chronic diarrhea by Entamoeba
  34. -cecum, appendix, colon, and rectum
    *secretes enzymes that dissolve tissues
    *leave erosive ulcerations as it penetrates deeper layer of mucosa
    *dysentery, abdominal pain, fever, diarrhea, weight loss
    *can also manifest hemorrhage, perforation, appendicitis, and amoebomas
    intestinal targets of Entamoeba
  35. -common target is the liver
    *amoebic hepatitis
    *rarer complications- pulmonary amoebiasis
    extraintestinal targets of Entamoeba
  36. -inflammatory disease marked by necrosis of hepatocytes and a mononuclear response that swells and disrupts the liver architecture
    -occurs when certain viruses infect the liver
    -causes jaundice when bilirubin accumulates in the blood and tissues
  37. -in general, far milder and shorted term than the other forms
    -either subclinical or vague, flulike symptoms
    -in some cases, may include jaundice and swollen liver
    -darkened urine often seen
    -not oncogenic
    -complete uncomplicated recovery
    hepatitis A virus (HAV)
  38. -may include fever, chills, malaise, anorexia, abdominal discomfort, diarrhea, and nausea
    -rashes may appear
    -arthritis may occur
    -can be serious and life-threatening
    -some patients develop glomerulonephritis and arterial inflammation
    -complete liver regeneration and restored function occur in most patients
    -small number of patients develop chronic liver disease (necrosis or cirrhosis)
    hepatitis B virus (HBV)
  39. -"silent epidemic"
    -takes may years to cause noticeable symptoms
    -shares many symptoms of HAB but is more likely to become chronic
    -cancer may also result
    hepatitis C virus (HCV)
  40. -usually provoke an increase in granular leukocytes called eosinophils (eosinophilia)
    -most spend part of their life cycle in the intestinal tract
    helminthic intestinal infections
  41. -localized hemorrhage of the bowel caused by worms burrowing and piercing intestinal mucosa
    -heavier infections can cause dysentery, loss of muscle tone, and rectal prolapse
    Trichuris trichiura
  42. -pronounced anal itching when the mature female emerges from the anus and lays eggs
    -can also suffer from disrupted sleep, nausea, abdominal discomfort, and diarrhea
    Enterobius vermicularis
  43. -few symptoms
    -occasionally proglottids in stool
    -sometimes vague abdominal pain and nausea
    Taenia solium
  44. -possible abdominal discomfort or nausea
    Diphyllobothrium latum
  45. -mild symptoms
    -most common tapeworm infections in the world
    Hymenolepsis species
  46. -larvae and adult stages in humans
    -releases eggs in feces which are then spread to other humans
    -ingested eggs hatch in intestine
    -larvae then penetrate intestinal wall, enter the lymphatic and circulatory systems, sweep into the heart, arrive at the capillaries of the lungs
    -then larvae migrate up the respiratory tree to the glottis
    -worms are swallowed and returned to the small intestine, reach adulthood, and reproduce
    -can also invade biliary channels of the liver and gallbladder, and sometime emerge from the nose and mouth
    -severe inflammatory reactions mark the migratory route
    Ascaris lumbricoides
  47. -larvae hatch outside the body
    -infect by penetrating the skin (usually through bare feet)
    -actively burrow into the skin, reach the lymphatic or blood circulation, carried to the heart and lungs
    -larvae proceed up the bronchi and trachea to the throat
    -swallowed and arrive in the small intestine, where they anchor, feed on blood, and mature
    -eggs appear in the stool about 6 weeks after the time of entry
    -symptoms follow the progress of the worm in the body
    Necator americanus and Ancylostoma duodenale
  48. -can complete its life cycle either inside the human body or outside in moist cell
    -larvae penetrate the skin
    -worm enters the circulation, carried to the respiratory tract and swallowed, enters the small intestine to complete development
    -eggs are laid in the gut, eggs hatch into larvae in the colon
    Strongyloids stercoralis
  49. -Opisthorchis sinensis and Clonorchis sinensis
    -Fasciola hepatica
    liver and intestinal disease
  50. -chinese liver flukes
    -complete their sexual development in mammals; intermediate development in snail and fish hosts
    -ingest cercariae in inadequately cooked or raw freshwater fish
    -larvae hatch and crawl into the bile duct
    -mature and shed eggs into the intestinal tract
    -feces containing eggs passed into standing water
    -eggs infect snails that release cercariae that invade fish
    -symptoms are slow but include thickening of the lining of the bile duct and possible granuloma formation in the liver
    Opisthorchis sinensis and Clonorchis sinensis
  51. -occasionally transmitted to humans, common in sheep, cattle, goats, and other mammals
    -complex life cycle
    -symptoms of vomiting, diarrhea, hepatomegaly, and bile obstruction
    Fasciola hepatica
  52. -trichinosis
    -life cycle spent entirely within the body of a mammalian host
    -human eats undercooked pork; cyst envelope digested in the stomach and small intestine, and larvae is liberated
    -larvae burrows into the intestinal mucosa and reach adulthood and mate
    -larvae then penetrate the intestine and enter the lymphatic channels and blood
    -final development occurs when the coiled larvae are encysted in the skeletal muscle
    -symptoms may be unnoticeable or life-threatening, depending on how many larvae were ingested
    -first symptoms mimic influenza or viral fevers with diarrhea, nausea, abdominal pains, fever, and sweating
    -second phase produce puffiness around the eyes, intense muscle and joint pain, shortness of breath, and pronounced eosinophilia
    muscle and neurological symptoms
  53. -first symptoms: itchiness in the area where the worm enters the body
    -followed by fever, chills, diarrhea, and cough
    -chronic infection can lead to hepatomegaly and liver disease and splenomegaly
Card Set
Micro Chap 22
the gastrointestinal tract and its defenses