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Session 2 Microbio19

Microbio -19- GI #3 Infection Hartley

What are the GI virus classified as enteric virus trasmitted via fecal oral route
What are some of the enteric virus Picornaviruses -poliovirus -coxsackievirus -echovirus -enterovirus -Hep A virus Rotavirus Norwalk agent related caliciviruses adenoviruses astroviruses
What are the followin Poliovirus 3 Coxsackievirus groups A and B 23/6 Echovirus 28 Human Enterovirus (68-71) 4 Hepatitis A Virus ~1 picornaviruses that cause enteric infection with the number of serotypes that cause GI infection
What does a single round of viral replication of picorna virus consist of attachment and entry tranlastion of polyprotein replication and shut down of host protein synthesis Cell Death and exit release of many new virions All takes about 6-8 hours
what is the source of infection with enteric picorna viruses fecal/oral route
What is the progression of non-HAV picornaviruses -transmission via fecal/oral route -infects intestinal epithelia and remains through disease progression -virus spreads to submucosal lymphoid tissues of the peyer's patches (or tonsils) and regional lymph nodes -Then spreads to reticuloendothelial sys
What is the reticuloendothelial system a network of phagocytic cells residing in the spleen, liver, and bone marrow where they free the blood or lymph of foreign particles
What percent of NON-poliovirus and poliovirus infection are subclinical 50% of non-polio enteric 90% of polio virus enteric infections are subclinical
When do you generally see symptomatic disease onset with enteric picorna virus infection on second viremia and tissue spread
What are the three disease states of polio abortive aseptic meningitis Paralytic Polio
What is abotive polio nonspecific febrile illness that resolves in 2-3 days without CNS involvement
What is aseptic meningitis caused by polio you get signs on meningeal involvement- stiff neck, pain, and stiffness in the back Rapid and Complete recovery in a few days
What are s/sx of paralytic polio virus Starts as minor illness followed by meningeal irritaion then asymmetric flaccid paralysis with no sensory loss. All four limbs and respiratory muscles may become paralyzed and it may take 6 months to recover
How does severity of s/sx of polio virus tie in with age at infection severity of s/sx increases with age at time of infection
how long after infection can you find polio virus in the stool two months you can find polio in stool from beginning
What branch of immune response aids in immunity to polio and other picorna viruses humoral response- patients with deficient cell mediated immunity have exacerbation of disease
What type of vaccines exists for polio which type is used in the US both inactivated (IPV) and live attenuated (OV) IPV is used in the US
Do we have vaccines for the other picorna viruses other than polio No vaccines for other serotypes of picorna
What is the tx for picorna virus infections most are mild cases and resolve on their own Ig can be given in severe cases or immune deficient patients Supportive care for cardiac or CNS patients (polio virus paralytic patients)
What does a single round of viral replication of rotavirus consist of Attachment and entry, release of outer shell Release of + RNA strands for translation New Capsid assembly and genome packaging Replication to make dsRNA budding into the ER and acquistion of outer layer to become infectious All this in less than 7
what is the source of infection with rotavirus fecal/oral route of infection from lack of sanitary practices
What is the progression of infection with rotavirus 24-48 incubation period initial infection is of the mature villis tip cells of small intestines -Tip cell death leads to cell replacement by cells that cannot absorb nutrients leading to osmotic diarrhea
What are the s/sx of rotavirus infections vomiting (1st symptom) abdominal cramps Watery diarrhea last 2-8 days
What infection typically accompanies rotavirus infections respiratory tract infection
Why do you need to complete vaccination to rotavirus by 32 months of age has potentially fatal complications in older age groups
what are the receptor targets for antibodies produced by humoral immunity that clear rotavirus from the body VP4 and VP7 are the protiens of the viruses outer shell that are targeted
What is the tx for rotavirus infections Treat with oral fluids most don't require IV rehydration
When can you detect rotavirus in the stool only during active infection is shed in large amounts in the stool
what type of virus are Norwalk agent and Noroviruses Calicivirus
what are the three serologically distinct types of norovirus Norwalk Agent Snow Mountain Agent Hawaii Agent
What is the source of infection with norovirus fecal/oral route
What types of outbreaks has noroviruses been associated with Foodborne outbreaks Waterborne outbreaks Also associated with uncooked shellfish and some other seafoods which have had no known contamination with human fecal matter
why do you get osmotic diarrhea with norovirus infections malabsorption of carbs and fats leads to diarrhea
What may be the cause of nausea associated with norovirus gastric motor function gets delayed
HOw long does norovirus infection typically last last 12-60 hours but effects last about 48 hours
What are s/sx of norovirus infeciton NAUSEA vomiting (more common in kids) cramps watery diarrhea also may see headache fever chills and myalgias
which typically has more severe symptoms rotavirus or norovirus norovirus
do you get lasting immunity to norovirus infections after you get them no, but you get immunity from same strain for 2-3 months
What link is there between individuals and infectivity of norovirus Link between ABO and Lewis blood groups and infectivity of virus
What is the tx for norovirus no tx necessary disease is so short term, self limiting, and is not severe
How can you tell picornavirus infections from others s/sx other than or in addition to vomiting and diarrhea like rashes, lesions, photophobia, tachycardia
Who typically is infected by rotavirus children under 2 y/o and in temperate climates they occur in winter months
In what age group are calicivirus infections more common Older Children and Adults
what can be a cause of traveler's diarrhea but not as common as e. coli rotavirus
What type of diarrhea do picrona, rota, and calici viruses cause cause watery diarrhea with little or no blood
how can you differentiate between protozoan outbreaks of diarrhea and caliciviruses caliciviruses induce a short term diarrhea most protozoan outbreaks last longer
What causes jaundice increase in serum bilirubin levels
how do viruses typically cause liver damage generally cause liver damage through immune inflammation not direct cytopathic damage to hepatocytes
What is the prodrome phase of acute viral hep. Fever, Vomiting, General Malaise, diarrhea, fatigue
What are the s/sx of classic hepatitis jaundice and pruritis
What is fulminant hepatitis classic hep w/ worsening jaundice signs of hepatic encephalopathy decreasing liver function fasting hypoglycemia easy bruising or bleeding
What should all patients with acute hepatitis be tested for tested for clotting function
how is HAV spread fecal/oral route or eating raw shellfish grown in contaminated waters
What is the progression of infection with HAV infections 1- ingestion of contaminated food or water 2- viurs gets to liver 3- infection of liver 4- tissue inflammation and damage 5- excretion of virions with bile into the stool 6- viral clearance
What are some additional s/sx of HAV infections most are asymptomatic 70% of kids 30% of adults Prodrome phase for 1 week -Diarrhea most common in kids Classic Hep A 80% of cases -dark urine, Clay colored stools tender hepatomegaly cervical lymphadenopathy
What is relapsing HAV 2 or more cases of classic hep A within 6-10 weeks
What is cholestatic Hep A 10% of cases classic Hep A with prolonged pruritis and persistant jaundice over several months
How common is Fulminant Hep A .35% of symp cases
Hep E is similar to Hep A but what is one very important difference Hep E can be fatal in pregnant women
Is there a vaccine for Hep E yes advised for healthcare workers, some travelers, and food handlers provides life-long immunity
what tx can be done within two weeks of exposure to Hep E passive immunization
What tx would you give to someone with Hep E symptoms prohibit alcohol consumption
What type of virus is HEP B HBC is ds DNA virus with gapped circle genome uses reverse transcription
what does the S gene code for in HBV codes for the "major" envelope protein HBsAg
What does the C gene code for in HBV C gene codes for two nucleocapsid proteins HBeAg and HBcAg
What does the X gene code for in HBV and what other problem may it cause codes for HBxAg may contribute to carcinogenesis by binding to p53
What body fluids contain HBV and can be source of infection Blood, Saliva, semen, breast milk infact almost all body fluids most can be a source of infection
what is the progression of infection with HBV 1- initial infection 2- viral replication in liver 3- immune inflammation and liver damage 4- clearance or progression to chronic infection
What is the prodrome associated with HBV upper abdominal discomfort
What is cholestasis associated with HBV present as infrequently jaundice may progress to pale stools and dark urine
What is chronic HEP B present as may be asymptomatic until late stage when complications present may present as prolonged classic hep
What problem of HEP B is associated with transient rasshes, arthritis in small joints and glomerulonephritis serum-sickness like disease that may occur in HEP B infections
what is the major complication associated w/ HBV cirrhosis or progressive liver failure hepatic encephalopathy, reversal of sleep wake cycles, Hepatomegaly, splenomegaly all can lead to hepatocellular carcinoma
WHat significance can a mutation in C gene of HBV mean HBeAG may not be synthesized or may be downregulated making infection harder to dx and more difficult to treat
which of the hepatitis viruses is a satellite virus HDV- it is an incomplete virus and requires another virus for help
What virus does HDV often piggyback on only occurs in HBV infected patients it need the HBV envelope protein
what are the two forms of infection with HDV Coinfection and superinfection with HBV
which form of HDV infection presents as more severe acute hepatitis, poorer prognosis and rarely becomes chronic Coinfection of HBV and HDV
Which form of HDV infection is more liekly to become chronic, may convert to asymptomatic state to a severe acute infection, High risk of HBV associated complications Superinfection of HDV
IS there any vaccine for HDV yes vaccine against surface antigen HBsAg
what is the tx for HDV most acute cases are self limiting anitvirals, interferon Alpha and other drugs can be given if needed
Which hepatitis virus is a flaviviurs and is +ssRNA enveloped HCV or HGV
what is the most common source of HCV infection and what are the rare sources IV drug use Blood tranfussion before 1990 rare long term hemodialysis needle stick injury sexual contact perinatal transmission
What is meant by HCV chronic infections are periodic in nature you have periods of massive inflammation followed by periods of almost normal liver size
what cells does HCV infect will infect hepatocytes
When are most HCV infections diagnosed most are dx when chronic problems manifest
What is acute HCV marked by few or no symptoms very few manifest classic acute hepatitis around 20% of HCV is acute
What is chronic HCV marked by still often asymptomatic prodrome after liver damage/cirrhoisis has occured Rare Rheumatic symptoms Rare Mucocutaneous symptoms
is there a vaccine for HCV no HCV mutates rapidly hindering adaptive immune response
what is the tx for HCV interferon alpha to promote sustained anti-viral response
What is the source of HGV infection IV drug usem blood transfusion
Has HGV been proven to cause hepatitis NO but it is found in 10-20% of patients w/o A-E hepatitis
Created by: Max Smith Max Smith on 2010-01-06

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