Diaherra

Adenovirus Enteric adenoviruses are another important cause of diarrhea in __________ Adenovirus family causes either ____________ disease (colds, flu-like disease, pneumonia) or _________ disease _____ virus, ____________________ Causes _____% of pediatric gastroenteritis in US. Enteric adenoviral infections are clinically and pathologically similar to _____________ Diagnosis by viral antigen detection in _______

Adenovirus Enteric adenoviruses are another important cause of diarrhea in infants Adenovirus family causes either respiratory disease (colds, flu-like disease, pneumonia) or enteric disease DNA virus, nonenveloped Causes 5-20% of pediatric gastroenteritis in US. Enteric adenoviral infections are clinically and pathologically similar to rotavirus Diagnosis by viral antigen detection in stool

CMV: Causes chronic diarrhea in immune-suppressed (especially CD4 count < 200/ul - AIDS-defining illness), causes _______, ____________

CMV: Causes chronic diarrhea in immune-suppressed (especially CD4 count < 200/ul - AIDS-defining illness), causes colitis, esophigits

MOA for cholera toxin Cholera Toxin Cholera toxin activates the _____________ ___________ enzyme in cells of the __________ ____________ leading to increased levels of intracellular _____, and the secretion of ????? into the lumen of the small intestine. The effect is dependent on a specific receptor, monosialosyl ganglioside (GM1 ganglioside) present on the surface of intestinal mucosal cells. The bacterium produces an invasin, neuraminidase, during the colonization stage which has the interesting property of degrading gangliosides to the monosialosyl form, which is the specific receptor for the toxin. The toxin has been characterized and contains 5 binding (B) subunits of 11,500 daltons, an active (A1) subunit of 23,500 daltons, and a bridging piece (A2) of 5,500 daltons that links A1 to the 5B subunits. Once it has entered the cell, the A1 subunit enzymatically transfers ADP ribose from NAD to a protein (called Gs or Ns), that regulates the adenylate cyclase system which is located on the inside of the plasma membrane of mammalian cells. Enzymatically, fragment A1 catalyzes the transfer of the ADP-ribosyl moiety of NAD to a component of the adenylate cyclase system. The process is complex. Adenylate cyclase (AC) is activated normally by a regulatory protein (GS) and GTP; however activation is normally brief because another regulatory protein (Gi), hydrolyzes GTP. The normal situation is described as follows. The A1 fragment catalyzes the attachment of ADP-Ribose (ADPR) to the regulatory protein forming Gs-ADPR from which GTP cannot be hydrolyzed. Since GTP hydrolysis is the event that inactivates the adenylate cyclase, the enzyme remains continually activated. This situation can be illustrated as follows. Thus, the net effect of the toxin is to cause cAMP to be produced at an abnormally high rate which stimulates mucosal cells to pump large amounts of Cl- into the intestinal contents. H2O, Na+ and other electrolytes follow due to the osmotic and electrical gradients caused by the loss of Cl-. The lost H2O and electrolytes in mucosal cells are replaced from the blood. Thus, the toxin-damaged cells become pumps for water and electrolytes causing the diarrhea, loss of electrolytes, and dehydration that are characteristic of cholera.

Cholera Toxin Cholera toxin activates the adenylate cyclase enzyme in cells of the intestinal mucosa leading to increased levels of intracellular cAMP, and the secretion of H20, Na+, K+, Cl-, and HCO3- into the lumen of the small intestine. The effect is dependent on a specific receptor, monosialosyl ganglioside (GM1 ganglioside) present on the surface of intestinal mucosal cells. The bacterium produces an invasin, neuraminidase, during the colonization stage which has the interesting property of degrading gangliosides to the monosialosyl form, which is the specific receptor for the toxin. The toxin has been characterized and contains 5 binding (B) subunits of 11,500 daltons, an active (A1) subunit of 23,500 daltons, and a bridging piece (A2) of 5,500 daltons that links A1 to the 5B subunits. Once it has entered the cell, the A1 subunit enzymatically transfers ADP ribose from NAD to a protein (called Gs or Ns), that regulates the adenylate cyclase system which is located on the inside of the plasma membrane of mammalian cells. Enzymatically, fragment A1 catalyzes the transfer of the ADP-ribosyl moiety of NAD to a component of the adenylate cyclase system. The process is complex. Adenylate cyclase (AC) is activated normally by a regulatory protein (GS) and GTP; however activation is normally brief because another regulatory protein (Gi), hydrolyzes GTP. The normal situation is described as follows. The A1 fragment catalyzes the attachment of ADP-Ribose (ADPR) to the regulatory protein forming Gs-ADPR from which GTP cannot be hydrolyzed. Since GTP hydrolysis is the event that inactivates the adenylate cyclase, the enzyme remains continually activated. This situation can be illustrated as follows. Thus, the net effect of the toxin is to cause cAMP to be produced at an abnormally high rate which stimulates mucosal cells to pump large amounts of Cl- into the intestinal contents. H2O, Na+ and other electrolytes follow due to the osmotic and electrical gradients caused by the loss of Cl-. The lost H2O and electrolytes in mucosal cells are replaced from the blood. Thus, the toxin-damaged cells become pumps for water and electrolytes causing the diarrhea, loss of electrolytes, and dehydration that are characteristic of cholera.

Clinical manifestations Incubation period is an average of __ days (but can range from 2 to 10 days). Manifestations range from asymptomatic infections to ____________, life-threatening illness Watery diarrhea without blood is most __________- symptom; can be accompanied by dehydration, ________ ______, abdominal pain, fever, nausea and vomiting. Immunocompetent persons: symptoms are usually _______ __________(1 to 2 weeks) Immunocompromised patients, especially those with ____ counts <200/µl: can be chronic, severe life-threatening An AIDS-defining illness

Clinical manifestations Incubation period is an average of 7 days (but can range from 2 to 10 days). Manifestations range from asymptomatic infections to severe, life-threatening illness Watery diarrhea without blood is most frequent symptom; can be accompanied by dehydration, weight loss, abdominal pain, fever, nausea and vomiting. Immunocompetent persons: symptoms are usually short lived (1 to 2 weeks) Immunocompromised patients, especially those with CD4 counts <200/µl: can be chronic, severe life-threatening An AIDS-defining illness

Cryptosporidiosis: Cause of chronic diarrhea in immune-suppressed (especially CD4 count < 200/ul - AIDS-defining illness), infect many animal species/farm ________ runoff into _________/resistant to municipal __________ _________, person-to-person possible; treated with ___________ but not effective in immune-suppressed (life-threatening in AIDS patients)

Cryptosporidiosis: Cause of chronic diarrhea in immune-suppressed (especially CD4 count < 200/ul - AIDS-defining illness), infect many animal species/farm manure runoff into streams/resistant to municipal water treatments, person-to-person possible; treated with nitazoxanide but not effective in immune-suppressed (life-threatening in AIDS patients)

Cyclospora cayetanenesis: Cause of chronic diarrhea in immune-suppressed (especially CD4 count < 200/ul - AIDS-defining illness), causes episodes of diarrhea that can be __________ & _____________ times/day, also see fatigue/malaise/anorexia/nausea/weight loss/abdominal cramping, relapsing & remitting but self-limited, transmission by consumption of fecal-contaminated food & water, diagnosed via ____________ ___________ in feces that are larger than an RBC, treated with _____________

Cyclospora cayetanenesis: Cause of chronic diarrhea in immune-suppressed (especially CD4 count < 200/ul - AIDS-defining illness), causes episodes of diarrhea that can be explosive & numerous times/day, also see fatigue/malaise/anorexia/nausea/weight loss/abdominal cramping, relapsing & remitting but self-limited, transmission by consumption of fecal-contaminated food & water, diagnosed via unsporolated oocysts in feces that are larger than an RBC, treated with TMP/SMX

Cystoisospora belli (Isospora belli) Cystoisosporiasis Infection causes acute, nonbloody __________ with crampy ____________ __________, which can last for weeks and result in malabsorption and _______ ________. In ____________________ patients, and in infants and children, the diarrhea can be severe. (CDC) Acute Symptoms: Bulky to ___________ _________ (no blood in stool) Abdominal pain Malaise Fever

Cystoisospora belli (Isospora belli) Cystoisosporiasis Infection causes acute, nonbloody diarrhea with crampy abdominal pain, which can last for weeks and result in malabsorption and weight loss. In immunodepressed patients, and in infants and children, the diarrhea can be severe. (CDC) Acute Symptoms: Bulky to Watery Diarrhea (no blood in stool) Abdominal pain Malaise Fever

Cystoisospora belli: Cause of __________ __________ in immune-suppressed (especially CD4 count < 200/ul - ______-defining illness); causes ____ to ______ diarrhea, abdominal pain/cramps, malaise, fever; __________ remain viable for months in the environment, diagnosed by recovery of immature _____-shaped oocytes in ______ & staining (_________), usually self-limited but can use _________

Cystoisospora belli: Cause of chronic diarrhea in immune-suppressed (especially CD4 count < 200/ul - AIDS-defining illness); causes bulky to watery diarrhea, abdominal pain/cramps, malaise, fever; oocytes remain viable for months in the environment, diagnosed by recovery of immature oval-shaped oocytes in feces & staining (acid-fast), usually self-limited but can use TMP-SMX

Cystoisosporiasis Oocytes remain viable for __________ in the environment so infections can occur without a current outbreak Worldwide distribution Infections of animals and humans Common where large populations reside in close quarters Common parasitic cause of diarrhea in ______ patients An _____-defining illness

Cystoisosporiasis Oocytes remain viable for months in the environment so infections can occur without a current outbreak Worldwide distribution Infections of animals and humans Common where large populations reside in close quarters Common parasitic cause of diarrhea in AIDS patients An AIDS-defining illness

Diagnosis and Treatment, of Cholera Diagnosis Clinical manifestation, history Rice water stools Growth on TCBS agar (Thiosulfate-citrate-bile salts-sucrose agar) Treatment Can cause death in hours in severe, untreated cases Oral Rehydration Therapy IV _______ ______________(ie, azithromycin, doxycycline, ciprofloxacin, TMP/SMX) can shorten course in severely dehydrated individuals

Diagnosis and Treatment, of Cholera Diagnosis Clinical manifestation, history Rice water stools Growth on TCBS agar (Thiosulfate-citrate-bile salts-sucrose agar) Treatment Can cause death in hours in severe, untreated cases Oral Rehydration Therapy IV fluids Antibiotics (ie, azithromycin, doxycycline, ciprofloxacin, TMP/SMX) can shorten course in severely dehydrated individuals

Diagnosis of ETEC Isolate organism from stool Use ______________ agar See notes pages Immunoassays for detection of LT and ST from cultured organisms E. coli and a non-lactose fermentation - MacConkey agar inoculated with lactose-fermenting Escherichia coli (at left) and non-lactose-fermenting _________ (at right). Lactose-fermenting bacteria appear bright _____, while non-lactose-fermenting bacteria appear _______________

Diagnosis of ETEC Isolate organism from stool Use MacConkey agar See notes pages Immunoassays for detection of LT and ST from cultured organisms E. coli and a non-lactose fermentation - MacConkey agar inoculated with lactose-fermenting Escherichia coli (at left) and non-lactose-fermenting Proteus (at right). Lactose-fermenting bacteria appear bright pink, while non-lactose-fermenting bacteria appear colorless.

Diagnosis of Rotavirus Virus does not grow in cell cultures, thus virus isolation not available Diagnosis made by viral antigen detection Most common test in hospital labs- _____

Diagnosis of Rotavirus Virus does not grow in cell cultures, thus virus isolation not available Diagnosis made by viral antigen detection Most common test in hospital labs- ELISA

Diax of Giardia Fecal O&P- may need to be repeated Trophs intermittently present in ___________ stool Cysts intermittently present in _________ stool Antigen detection tests also available- should not take place of ____ exam

Diax of Giardia Fecal O&P- may need to be repeated Trophs intermittently present in diarrheic stool Cysts intermittently present in formed stool Antigen detection tests also available- should not take place of O&P exam

Enteroaggregative E. coli: EAEC Human pathogen, animals have their own strains Cause of ____________ _______________ (>2 weeks duration), especially in infants in developing countries Can lead to ______________ and poor growth EAEC may also cause of foodborne illness in industrialized countries. Pathogenesis: EAEC adhere to the ___________ _____________ and elaborate enterotoxins and cytotoxins, which result in secretory diarrhea and mucosal damage. EAEC's ability to stimulate the release of _____________ ________________ may also play a role in intestinal illness. Aggregative pattern of adherence in the ______ assay after __ hours incubation of bacteria with _______ cells. Note bacteria (black dots) on the surface of the HEp-2 cells as well as on the glass substratum.

Enteroaggregative E. coli: EAEC Human pathogen, animals have their own strains Cause of persistent diarrhea (>2 weeks duration), especially in infants in developing countries Can lead to malnutrition and poor growth EAEC may also cause of foodborne illness in industrialized countries. Pathogenesis: EAEC adhere to the intestinal mucosa and elaborate enterotoxins and cytotoxins, which result in secretory diarrhea and mucosal damage. EAEC's ability to stimulate the release of inflammatory mediators may also play a role in intestinal illness. Aggregative pattern of adherence in the HEp-2 assay after 3 hours incubation of bacteria with HEp-2 cells. Note bacteria (black dots) on the surface of the HEp-2 cells as well as on the glass substratum.

Enterotoxigenic E. Coli Most important bacterial cause of __________ in children in developing countries Most common cause of __________ diarrhea ___________ cases/yr in travelers from US __________ is natural host (other animals have their own strains) Spread by human ______ contamination of food or water; not person-to-person Diarrhea results from action of ___________ ____________

Enterotoxigenic E. Coli Most important bacterial cause of diarrhea in children in developing countries Most common cause of traveler's diarrhea 80,000 cases/yr in travelers from US Human is natural host (other animals have their own strains) Spread by human fecal contamination of food or water; not person-to-person Diarrhea results from action of bacterial exotoxins

Epi of Giardia Transmitted in fecal contaminated water, or contaminated _____ or __________________ In US often associated with fresh water streams _________ may be a reservoir Person-to-person transmission also possible Crowded conditions, institutions, poor community sanitation Worldwide distribution Cause of traveler's diarrhea More common in __________ climates Infections more common in children In US associated with ____ _______

Epi of Giardia Transmitted in fecal contaminated water, or contaminated fruit or vegetables In US often associated with fresh water streams Beaver may be a reservoir Person-to-person transmission also possible Crowded conditions, institutions, poor community sanitation Worldwide distribution Cause of traveler's diarrhea More common in warmer climates Infections more common in children In US associated with day care

Epi of cyrpto Worldwide distribution Infect many animal species Frequent parasite of _______ Farm manure runoff into streams may contaminate community ________ __________ Resistant to routine municipal water treatments (chlorine, ozone) 1993 outbreak in Milwaukee infected over 400,000 with >100 deaths Person-to-person transmission possible Fecal-oral; oral-anal

Epi of cyrpto Worldwide distribution Infect many animal species Frequent parasite of cattle Farm manure runoff into streams may contaminate community water sources Resistant to routine municipal water treatments (chlorine, ozone) 1993 outbreak in Milwaukee infected over 400,000 with >100 deaths Person-to-person transmission possible Fecal-oral; oral-anal

Examine concentrated stool sediment stained with modified _______ _______ _________ or immunofluorescence (about ____ microns- smaller than RBC) Antigen detection tests also available Treatment _____________ Only for________ ________ Not effective in immune suppressed patients- thus this infection is ______ threatening in AIDS patients Prevention is difficult as organism is relatively resistant to ___________

Examine concentrated stool sediment stained with modified acid fast stain or immunofluorescence (about 4-6 microns- smaller than RBC) Antigen detection tests also available Treatment Nitazoxanide Only for immune competent Not effective in immune suppressed patients- thus this infection is life threatening in AIDS patients Prevention is difficult as organism is relatively resistant to chlorine

Family Enterobacteriaceae Gram-negative enteric rods Other members of family: Salmonella, Shigella, Klebsiella, Enterobacter, Yersinia, Proteus, Morganella Family causes diseases of CNS, RT, GIT, UT, spticemia

Family Enterobacteriaceae Gram-negative enteric rods Other members of family: Salmonella, Shigella, Klebsiella, Enterobacter, Yersinia, Proteus, Morganella Family causes diseases of CNS, RT, GIT, UT, spticemia

Giardia lamblia Life forms: Trophozoites Found in _______ stool Cysts Found in _________ ________

Giardia lamblia Life forms: Trophozoites Found in watery stool Cysts Found in formed stools

Giardia lamblia: In US is associated with _________, transmitted in fecal contaminated water/fruit/ veggies/person-to-person; ingestion of cysts → in ____________, encystation with exposure to stomach acid releases _______________ → trophozoites multiply by longitudinal ____________ ___________ & can attach to mucosa via ventral sucking disk causing flattening of the _____ → mucosal ________________ without necrosis, malabsorption of _____ → foul-smelling, watery, ___________ stools → diagnosed with fecal O&P which may need to be repeated - _______ intermittently present in ____________ stool, cysts intermittently present in formed stool; treated with ____________________, nitazoxanide, & tinidazole; prevented by boiling/treating ______, good ________ & chlorine-cleaning in daycare

Giardia lamblia: In US is associated with daycare, transmitted in fecal contaminated water/fruit/ veggies/person-to-person; ingestion of cysts → in stomach, encystation with exposure to stomach acid releases trophozoites → trophozoites multiply by longitudinal binary fission & can attach to mucosa via ventral sucking disk causing flattening of the villi → mucosal inflammation without necrosis, malabsorption of fats → foul-smelling, watery, fatty stools → diagnosed with fecal O&P which may need to be repeated - trophs intermittently present in diarrheic stool, cysts intermittently present in formed stool; treated with metronidazole, nitazoxanide, & tinidazole; prevented by boiling/treating water, good hygiene & chlorine-cleaning in daycare

Highly contagious Persistent environmental contamination a problem Virus can remain viable after exposure to ____ or ___ppm chlorine Outbreaks frequently end within _____ weeks Infected individuals are resistant to infection for about 2-3 years Definitive diagnosis by ______ (epidemiologic studies)

Highly contagious Persistent environmental contamination a problem Virus can remain viable after exposure to 60C or 10ppm chlorine Outbreaks frequently end within 1-2 weeks Infected individuals are resistant to infection for about 2-3 years Definitive diagnosis by RT-PCR (epidemiologic studies)

Infection occurs by the ingestion of cysts in contaminated water, food, or by the fecal-oral route (hands or fomites) Encystation occurs as the parasites transit toward the colon. In the small intestine, excystation releases trophozoites (each cyst produces two trophozoites) Trophozoites multiply by longitudinal binary fission, remaining in the lumen of the proximal small bowel where they can be free or attached to the mucosa by a ventral sucking disk Both cysts and trophozoites can be found in the feces (diagnostic stages) The cysts are hardy and can survive several months in cold water. Cysts are also resistant to cholination in municapal water treatment The cyst is the stage found most commonly in nondiarrheal feces Cysts are resistant forms and are responsible for transmission of giardiasis. person-to-person transmission is possible. While animals are infected with Giardia, their importance as a reservoir is unclear.

Infection occurs by the ingestion of cysts in contaminated water, food, or by the fecal-oral route (hands or fomites) Encystation occurs as the parasites transit toward the colon. In the small intestine, excystation releases trophozoites (each cyst produces two trophozoites) Trophozoites multiply by longitudinal binary fission, remaining in the lumen of the proximal small bowel where they can be free or attached to the mucosa by a ventral sucking disk Both cysts and trophozoites can be found in the feces (diagnostic stages) The cysts are hardy and can survive several months in cold water. Cysts are also resistant to cholination in municapal water treatment The cyst is the stage found most commonly in nondiarrheal feces Cysts are resistant forms and are responsible for transmission of giardiasis. person-to-person transmission is possible. While animals are infected with Giardia, their importance as a reservoir is unclear.

Most infections cause acute diarrhea, although some, depending on host and pathogen, can cause chronic diarrhea Acute diarrhea has abrupt onset and episode lasts for less than ___ days; chronic diarrhea lasts for more than ___ days, has some infectious and many non-infectious causes. Acute diarrhea is often self limited, although some infectious causes many require antimicrobials High fluid content of stool is common in infectious causes of diarrhea Secondary to imbalance in absorption of water, ions, organic substrates from small or large intestine Increased frequency of bowel movements _____/day to over ___/day Impact of diarrheal disease worldwide 2 million childhood deaths/yr in developing countries 2nd most common cause of death in children worldwide

Most infections cause acute diarrhea, although some, depending on host and pathogen, can cause chronic diarrhea Acute diarrhea has abrupt onset and episode lasts for less than 14 days; chronic diarrhea lasts for more than 14 days, has some infectious and many non-infectious causes. Acute diarrhea is often self limited, although some infectious causes many require antimicrobials High fluid content of stool is common in infectious causes of diarrhea Secondary to imbalance in absorption of water, ions, organic substrates from small or large intestine Increased frequency of bowel movements 4-5/day to over 20/day Impact of diarrheal disease worldwide 2 million childhood deaths/yr in developing countries 2nd most common cause of death in children worldwide

Noroviruses Includes Norwalk-like viruses, _____________, Astroviruses Transmitted by _____________ route; person-to-person, in food/water, on fomites ie: ingestion of contaminated food or water swimming in _________ or lakes shared by infected individuals shellfish frequently implicated in transmission virus may remain viable even after cooking contaminated food.

Noroviruses Includes Norwalk-like viruses, Caliciviruses, Astroviruses Transmitted by fecal-oral route; person-to-person, in food/water, on fomites ie: ingestion of contaminated food or water swimming in pools or lakes shared by infected individuals shellfish frequently implicated in transmission virus may remain viable even after cooking contaminated food.

Other vibrio V. parahaemolyticus; V. vulnificus Found in __________ and _____________ environments Cause ___ ___________ following ingestion of poorly cooked ___________ or ____ _______ Causes aggressive soft tissue infections if wound is exposed to contaminated ______________ Cases of Vibrio wound infections can occur following _____________ in southeast US

Other vibrio V. parahaemolyticus; V. vulnificus Found in estuarine and marine environments Cause GI disease following ingestion of poorly cooked shellfish or raw fish Causes aggressive soft tissue infections if wound is exposed to contaminated seawater Cases of Vibrio wound infections can occur following hurricanes in southeast US

Pathogenesis Excystation occurs in stomach with exposure to ________ ________ Trophs are released in ____________ and ___________, multiply by _________ __________ and attach to intestinal villi, causing _____________of the villi Mucosal inflammation without ____________ Malabsorption, especially of ______, secondary to decreases in absorptive area Leads to ???? Small numbers of parasites may cause _________________ infection In heavy infections, parasites can cover mucosal surface of ______ _________, lead to malnutrition, inability to absorb ????

Pathogenesis Excystation occurs in stomach with exposure to gastric acid Trophs are released in duodenum and jejunum, multiply by binary fission and attach to intestinal villi, causing flattening of the villi Mucosal inflammation without necrosis Malabsorption, especially of fats, secondary to decreases in absorptive area Leads to foul-smelling, watery, fatty stools Small numbers of parasites may cause asymptomatic infection In heavy infections, parasites can cover mucosal surface of small intestine, lead to malnutrition, inability to absorb fat -soluble vitamins, weight loss

Pathogenesis of ETEC Ingested in fecal-contaminated ______ or _____ Bacteria adhere via _____ to specific receptors on epithelial cells of small intestine Two plasmid-associated enterotoxins are produced Heat _______ (LT) Heat _______ (ST) Mechanism of action: LT is similar to ________ toxin: leads to increased_____ ST leads to increased ______

Pathogenesis of ETEC Ingested in fecal-contaminated food or water Bacteria adhere via pili to specific receptors on epithelial cells of small intestine Two plasmid-associated enterotoxins are produced Heat labile (LT) Heat stable (ST) Mechanism of action: LT is similar to cholera toxin: leads to increased cAMP ST leads to increased cGMP

Prevention When traveling in endemic areas "if can't boil it, peel it or cook it, don't eat it!" Drink only ________ __________ Do not eat _____ _______ Do not add _____ to drinks

Prevention When traveling in endemic areas "if can't boil it, peel it or cook it, don't eat it!" Drink only bottled beverages Do not eat raw foods Do not add ice to drinks

Prevention of Cholera Prevention Vaccine 2 vaccines available in other countries; provide brief and incomplete immunity No vaccine is licensed in the ___ When traveling in endemic areas "if can't boil it, peel it or cook it, don't eat it!" Drink only bottled beverages Do not eat raw foods Do not add ice to drinks

Prevention of Cholera Prevention Vaccine 2 vaccines available in other countries; provide brief and incomplete immunity No vaccine is licensed in the US When traveling in endemic areas "if can't boil it, peel it or cook it, don't eat it!" Drink only bottled beverages Do not eat raw foods Do not add ice to drinks

Rota Epi Age group most seriously affected _____ months of age Infections begin around 6 months of age due to decline in _______________ _____ Breast feeding has not been conclusively shown to decrease ____________ or disease severity Re- infections occur throughout life- re-infections are generally _________ ____________ Adults usually asymptomatically infected except travelers infected by previously un-encountered strains May be severe in elderly

Rota Epi Age group most seriously affected 6-24 months of age Infections begin around 6 months of age due to decline in maternal IgG Breast feeding has not been conclusively shown to decrease infection or disease severity Re- infections occur throughout life- re-infections are generally less severe Adults usually asymptomatically infected except travelers infected by previously un-encountered strains May be severe in elderly

Rota virus Pathogenesis Enters the body through ____________ VP4 binds to _______________ on the membrane of villus _____________ _______ in the small intestine Virus replicates in and ______ villus epithelial cells Incubation period is _______ hour

Rota virus Pathogenesis Enters the body through ingestion VP4 binds to glycolipids on the membrane of villus epithelial cells in the small intestine Virus replicates in and lyses villus epithelial cells Incubation period is 24-48 hour

Rotavirus Family ___________ Genome: 11 separate strands of ds RNA Reassortment possible in co-infected cells Estimated 80 strains infect humans ____ strains common in US Other strains common elsewhere

Rotavirus Family Reoviridae Genome: 11 separate strands of ds RNA Reassortment possible in co-infected cells Estimated 80 strains infect humans 4 strains common in US Other strains common elsewhere

Rotavirus Epidemiology Fecal-oral transmission In temperate climates, virus circulates primarily in _________ _________ Viral and host factors affecting disease rates Virus very stable in environment Several circulating virus strains with little to no cross protection Protection from reinfection requires antiviral _____ short lived

Rotavirus Epidemiology Fecal-oral transmission In temperate climates, virus circulates primarily in winter months Viral and host factors affecting disease rates Virus very stable in environment Several circulating virus strains with little to no cross protection Protection from reinfection requires antiviral IgA-short lived

Rotavirus Pathogenesis Loss of villus epithelial cells results in Decreased _________ absorption Decreased level of intestinal _________________ Decreased absorption of _________ and other ______________ Increased ______ entering large intestine Diarrhea also results from viral protein (_______) which acts as _______________- causes excess ____________ secretion __________ may occur for weeks after recovery

Rotavirus Pathogenesis Loss of villus epithelial cells results in Decreased sodium absorption Decreased level of intestinal disaccharidases Decreased absorption of lactose and other macromolecules Increased water entering large intestine Diarrhea also results from viral protein (NSP4) which acts as enterotoxin- causes excess chloride secretion Shedding may occur for weeks after recovery

Rotavirus Prevention Vaccine ???? Both about ____ effective at reducing serious disease Hand ___________ Use of __________ containing cleaning agents _______-feeding???? Rotavirus is an important ____________ pathogen Rotarix _____,_____________ human virus from a ________ ________ RotaTeq Live vaccine produced by _______________ of genes for specific viral proteins between __ human strains and a _________ strain

Rotavirus Prevention Vaccine Rotateq and Rotarix Both about 90% effective at reducing serious disease Hand washing Use of chlorine containing cleaning agents Breast-feeding???? Rotavirus is an important nosocomial pathogen Rotarix Live, attenuated human virus from a single strain RotaTeq Live vaccine produced by reassortment of genes for specific viral proteins between 5 human strains and a bovine strain

Rotavirus Structure and Strains dsRNA genome in ___ separate strands Rotavirus genus consists of 7 groups, A-G Only _____ , especially ___, cause infections in humans The virus can be neutralized by antibody to ____ and ____ Serotypes of rotavirus are classified according to antigenic differences in these 2 proteins. Strains are divided into __ strains and __ strains (see notes pages) Bottom line- there are MANY serotypes of rotavirus, with little/no immune cross protection between them Rotavirus comprises a genus of the virus family Reoviridae. The non-enveloped virion consists of 3 concentric capsids that surround a double-stranded RNA genome. The genome is divided into 11 segments that encode 6 structural proteins and 6 non-structural proteins. Rotaviruses are divided into 7 groups, A-G, of which only A, B, and C infect humans. Group A causes the vast majority of human infections and is the focus of vaccination efforts.1 The outer capsid consists of 2 structural proteins, VP4 and VP7. Both proteins induce a neutralizing antibody response during natural infection2 The 2 outer capsid proteins provide the rotavirus serotype classifications P and G, so named because VP4 is cleaved by protease and VP7 is glycosylated. At least 14 G serotypes and 20 P serotypes exist, and because the genes encoding VP4 and VP7 segregate separately, several dozen different PG combinations could exist in theory. Clinically, however, only a handful of PG serotypes predominate. Table 1 summarizes the major rotavirus serotype classifications. Table 1: Rotavirus Serotypes GeneVP7 VP4 SerotypeG P Number of serotypes14 20 Most commonG1, G2, G3, G4 P4, P8 EmergingG9 P6 In the United States, G1, G2, G3, and G4 serotypes predominate, accounting for nearly 90% of strains in circulation; an estimated 80% are P[8] and 11% are P[4].3 Worldwide, 88.5% of rotavirus diarrhea cases were caused by 4 serotypes: P[8]G1, P[4]G2, P[8]G3, and P[8]G4.1 Serotype distribution can vary quite dramatically among different regions. For example, the aforementioned worldwide serotypes cause over 90% of infections in North America, Europe, and Australia, as shown by an extensive examination of rotavirus strains collected from 1973-2003 and a review of 124 studies published between 1989 and 2004. In contrast, in South America and Asia, these same 4 serotypes represented only 68% of infections; in Africa, only 50%. In certain regions, serotypes P6, G8, and G9 appear to be increasing, with important implications for vaccine development. For example, data showed that in Africa, G8 strains represented

Rotavirus Structure and Strains dsRNA genome in 11 separate strands Rotavirus genus consists of 7 groups, A-G Only A-C, especially A, cause infections in humans The virus can be neutralized by antibody to VP4 and VP7 Serotypes of rotavirus are classified according to antigenic differences in these 2 proteins. Strains are divided into G strains and P strains (see notes pages) Bottom line- there are MANY serotypes of rotavirus, with little/no immune cross protection between them Rotavirus comprises a genus of the virus family Reoviridae. The non-enveloped virion consists of 3 concentric capsids that surround a double-stranded RNA genome. The genome is divided into 11 segments that encode 6 structural proteins and 6 non-structural proteins. Rotaviruses are divided into 7 groups, A-G, of which only A, B, and C infect humans. Group A causes the vast majority of human infections and is the focus of vaccination efforts.1 The outer capsid consists of 2 structural proteins, VP4 and VP7. Both proteins induce a neutralizing antibody response during natural infection2 The 2 outer capsid proteins provide the rotavirus serotype classifications P and G, so named because VP4 is cleaved by protease and VP7 is glycosylated. At least 14 G serotypes and 20 P serotypes exist, and because the genes encoding VP4 and VP7 segregate separately, several dozen different PG combinations could exist in theory. Clinically, however, only a handful of PG serotypes predominate. Table 1 summarizes the major rotavirus serotype classifications. Table 1: Rotavirus Serotypes GeneVP7 VP4 SerotypeG P Number of serotypes14 20 Most commonG1, G2, G3, G4 P4, P8 EmergingG9 P6 In the United States, G1, G2, G3, and G4 serotypes predominate, accounting for nearly 90% of strains in circulation; an estimated 80% are P[8] and 11% are P[4].3 Worldwide, 88.5% of rotavirus diarrhea cases were caused by 4 serotypes: P[8]G1, P[4]G2, P[8]G3, and P[8]G4.1 Serotype distribution can vary quite dramatically among different regions. For example, the aforementioned worldwide serotypes cause over 90% of infections in North America, Europe, and Australia, as shown by an extensive examination of rotavirus strains collected from 1973-2003 and a review of 124 studies published between 1989 and 2004. In contrast, in South America and Asia, these same 4 serotypes represented only 68% of infections; in Africa, only 50%. In certain regions, serotypes P6, G8, and G9 appear to be increasing, with important implications for vaccine development. For example, data showed that in Africa, G8 strains represented

Rotavirus is easily transmitted Important ___________ pathogen Very hardy outside of the cell Lacks a ____________ Able to remain viable for _______ -days on environmental surfaces, in water and on hands Can withstand a range of pH (______) Relatively resistant to surface and hand disinfecting agents Susceptible to __________-containing cleaning agents

Rotavirus is easily transmitted Important nosocomial pathogen Very hardy outside of the cell Lacks a membrane Able to remain viable for hours -days on environmental surfaces, in water and on hands Can withstand a range of pH (3-10) Relatively resistant to surface and hand disinfecting agents Susceptible to chlorine-containing cleaning agents

Rotavirus: Reoviridae, _______, most important cause of gastroenteritis in infants & young children _______________, _____________ transmission, circulates primarily in winter months, very stable in environment, important ________________ pathogen, very short incubation period, most seriously infects 6-24 month olds (decline in maternal ____); viral protein _____ binds ________________ on membrane of villus epithelial cells in small intestine, replicates & lyses cells, ______ viral protein causes diarrhea via excess _____________ secretion, shedding for weeks after recovery; diagnosed by______ in hospital labs, vaccine available (_______ - live virus from single strain; _______ - live virus from bovine + human strains), _______-washing & chlorine cleaning agents; same clinical picture as enteric ______________

Rotavirus: Reoviridae, dsRNA, most important cause of gastroenteritis in infants & young children worldwide, fecal-oral transmission, circulates primarily in winter months, very stable in environment, important nosocomial pathogen, very short incubation period, most seriously infects 6-24 month olds (decline in maternal IgG); viral protein VP4 binds glycolipids on membrane of villus epithelial cells in small intestine, replicates & lyses cells, NSP4 viral protein causes diarrhea via excess chloride secretion, shedding for weeks after recovery; diagnosed by ELISA in hospital labs, vaccine available (Rotarix - live virus from single strain; RotaTeq - live virus from bovine + human strains), hand-washing & chlorine cleaning agents; same clinical picture as enteric adenovirus

Treatment and Prevention Treatment (3) Prevention When hiking/camping, _____ water or treat with chlorine or iodine When traveling, remember this rule- if you can't biol it, peel it or cook it, don't eat it! Day care etc. good ___________, _____________-containing cleaners

Treatment and Prevention Treatment Metronidazole (met-ro-NID-ah-zole) Nitazoxanide (nye-tah-ZOX-ah-nide) Tinidazole (te-NID-ah-zole) Prevention When hiking/camping, boil water or treat with chlorine or iodine When traveling, remember this rule- if you can't biol it, peel it or cook it, don't eat it! Day care etc. good hygiene, chlorine-containing cleaners

Treatment of ETEC Oral Rehydration Therapy http://rehydrate.org/solutions/homemade.htm For mild cases, nonprescription anti-motility medications: bismuth subsalicylate and loperamide. The use of an antibiotic can reduce the duration of illness from days to hours _________ may be required for or moderate to severe diarrhea (3) Which classes of antibiotics do these represent and what is their mechanism of action? (testable!)

Treatment of ETEC Oral Rehydration Therapy http://rehydrate.org/solutions/homemade.htm For mild cases, nonprescription anti-motility medications: bismuth subsalicylate and loperamide. The use of an antibiotic can reduce the duration of illness from days to hours Antibiotic may be required for or moderate to severe diarrhea Trimethoprim-sulfamethoxazole Ciprofloxacin or similar drugs Doxycycline (Vibramycin) Which classes of antibiotics do these represent and what is their mechanism of action? (testable!)

Vibrio cholerae Gram-__________ __________ rods Free-living in bodies of ___________ (i.e. rivers, estuaries) Causes disease only in humans Many serotypes (>140), but only 2 serotypes cause cholera 01 and ______ produce cholera toxin Toxin is encoded on phage genome Transmitted in contaminated food and water Associated with ____________ and ______________

Vibrio cholerae Gram-negative curved rods Free-living in bodies of water (i.e. rivers, estuaries) Causes disease only in humans Many serotypes (>140), but only 2 serotypes cause cholera 01 and 0139 produce cholera toxin Toxin is encoded on phage genome Transmitted in contaminated food and water Associated with epidemics and pandemics

Vibrio cholerae: Gram-negative curved rod, free-living in bodies of water, only in humans, transmitted in contaminated food & water, associated with epidemics & pandemics; cholera toxin (active (__) subunit & bridging piece (__), encoded in phage genome) activates _________ __________ enzyme in cells of intestinal mucosa leading to increased levels of intracellular cAMP & secretion of ________________ into ________ of __________ ____________; causes voluminous rice water stools, grows on________ agar, treated with oral rehydration therapy, antibiotics (empirical ____________) can shorten course; prevented by vaccine, in endemic areas "if you can't boil it, peel it or cook it, don't eat it"

Vibrio cholerae: Gram-negative curved rod, free-living in bodies of water, only in humans, transmitted in contaminated food & water, associated with epidemics & pandemics; cholera toxin (active (A1) subunit & bridging piece (A2), encoded in phage genome) activates adenylate cyclase enzyme in cells of intestinal mucosa leading to increased levels of intracellular cAMP & secretion of H2O/Cl/bicarb into lumen of small intestine; causes voluminous rice water stools, grows on TCBS agar, treated with oral rehydration therapy, antibiotics (empirical TMP/SMX) can shorten course; prevented by vaccine, in endemic areas "if you can't boil it, peel it or cook it, don't eat it"

Virulence factors of E. coli (5) Strains of E. coli that cause GI disease are subdivided into 5 groups These strains are different from our gut commensals ETEC- enterotoxigenic E. coli EAEC- enteroaggregative E. coli EPEC- enteropathogenic E. coli EHEC- enterohemorrhagic E. coli EIEC- enteroinvasive E. coli

Virulence factors of E. coli Capsule LPS Adhesins (pili) Exotoxins Antibiotic resistance mechanisms Strains of E. coli that cause GI disease are subdivided into 5 groups These strains are different from our gut commensals ETEC- enterotoxigenic E. coli EAEC- enteroaggregative E. coli EPEC- enteropathogenic E. coli EHEC- enterohemorrhagic E. coli EIEC- enteroinvasive E. coli