Viral Inf Of GI Flashcards
(58 cards)
1
Q
Acute Viral Hepatitis Symptoms - symptoms
A
- Jaundice: Yellowing of the skin and eyes due to increased bilirubin levels.
- Dark Urine
- Acholic Stool: Light or Clay-colored Stool due to reduction in bile production.
- Prodrome: 1-2 weeks prior to jaundice
- Headache, myalgia, arthralgia, fatigue, nausea, vomiting, pharyngitis, mild fever.
2
Q
billirubin in urine means
A
liver disease
3
Q
Two enzymes that are elevated with acute viral hep?
A
Alanine aminotransferase (ALT) Aspartate aminotransferase (AST)
4
Q
Chronic Viral Hepatitis
A
- Hepatitis which does not resolve within 6 months.
- Predisposes to hepatocellular carcinoma and cirrhosis
- can catch it and liver may be able to regenerate but regeneratino = cell division and potential mutations = cancer
5
Q
Fulminant Viral Hepatitis
A
- Rapid, severe hepatitis == leads to severe CNS issues
- Massive hepatic necrosis
- Encephalopathy (TOO MUCH AMMONIA PRESENT): Confusion; Disorientation; Coma
- Edema
- Complications: Cerebral edema; Brainstem compression; GI Bleeding; Sepsis; Organ Failure
- Liver Transplant can be lifesaving
6
Q
Hep A - virus family, incubation, transmission, chronic?
A
Picornavirus - +ssRNA
2-4weeks
fecal oral
NO chronic
7
Q
Hep B - virus family, incubation, transmission, chronic?
A
Hepadnavirus - dsDNA
6wks-6mo
bodily fluids
YES chronic
8
Q
Hep C - virus family, incubation, transmission, chronic?
A
Flavivirus
2mo
bodily fluids
YES chronic
9
Q
Hep D - virus family, incubation, transmission, chronic?
A
Deltavirus
2-12wks
bodily fluids
YES chronic
10
Q
Hep E - virus family, incubation, transmission, chronic?
A
Hepevirus
6-8wks
fecal oral
NO chronic
11
Q
Hep A details:
A
-Picornavirus family \+ ssRNA genome -Fecal-oral transmission -Seroprevalence 30% -All age groups susceptible, children usually asymptomatic -Incubation period ~28 days -Resolution usually within 2 months -Does not cause chronic hepatitis - resolves within 6mo -Very rarely causes fulminant hepatitis
12
Q
Hep A diagnosis
A
- Acute infection = IgM antibodies against HAV
- Anti-HAV IgG antibodies protective immunity
13
Q
Hep A prevention
A
- Inactivated vaccine available since 1995
- IM injection - 2 dose schedule
- Since 2005, ACIP recommends universal vaccination for all infants (12 -23 months of age).
- Other high risk adult groups also recommended for vaccination.
- Post-exposure Prophylaxis
- Vaccine or anti-HAV IgG antibodies
14
Q
dane particles:
A
complete Hep B virions
15
Q
tubes and spheres:
A
incomplete noninfectious particles of Hep B virions
16
Q
Hep B details
A
- Hepadnavirus family member
- Partially dsDNA genome (NO REVERSE TRANSCRIPTASE-ITS DNA)
- Reverse transcription is a part of life cycle
- Incubation period median 90 days
- Transmission route = body fluids=Sexual transmission, percutaneous needle stick (6-30%), perinatal transmission at birth (10 – 90%).
- Half of infected adults are asymptomatic
- Acute hepatitis symptoms often milder than HAV
- Risk of chronic infection: correlated with age at infection. Chronically infected are carriers.
17
Q
Heb B diagnosis
A
- Viral antigens and anti-HBV antibodies are used for diagnosis.
- -The presence of HBsAg within the blood is a marker for active infection.*
18
Q
Hep B Status: Acute infection
A
HBsAg= +
anti-HBsAg= -
anti-HBc: total and IgM = +
19
Q
Hep B Status: chronic infection
A
HBsAg= +
anti-HBsAg= -
anti-HBc: total=+ and IgM = - (no high levels of IgM bc IgM is primary response and then IgM productin drops off)
20
Q
Hep B Status: vaccinated
A
HBsAg= -
anti-HBsAg= +
anti-HBc: total= -
21
Q
Hep B Status: previous infection
A
HBsAg= -
anti-HBsAg= +
anti-HBc: total= +
22
Q
Hep B Status: susceptible
A
HBsAg= -
anti-HBsAg= -
anti-HBc: total= -
23
Q
Hep B treatment
A
- None for acute infections
- Chronic infections: -Lamivudine: reverse transcriptase inhibitor -Famcylovir/Adefovir dipivoxil: nucleoside inhibitor -Interferon-alpha
24
Q
Most susceptible indiv to chronic hep B inf?
A
NEWBORNS MOST susceptible… with age risk declines
25
Hep B vaccine:
- Vaccine composed of purified HBsAg protein
- IM injection – 3 dose schedule
- Recommended for all infants (1st dose soon after delivery.
- Premature infants born to mothers of unknown or HBsAg positive receive vaccine and Hepatitis B immunoglobin (HBIG) within 12 hrs of birth.
- Full term infant born to HBsAg positive receive vaccine and HBIG within 12 hrs of birth.
26
Hep C details and transmission
-Flavivirus Family Member
-Enveloped
+ ssRNA genome
-Transmission is Bloodborne and through Body Fluids: **Injection Drug Use**; Tattoos; Accidental Needle Stick (1.8%); Sexual; Perinatal (4%)
27
Hep C diagnosis
- Screening test: antibody-based test for anti-HCV antibodies
- Confirmatory test: nucleic acid based tests for detection of the viral genome
28
Hep C compared to Hep A and HepB
Hep C has milder acute symptoms but chronic infection super common
29
Hep C treatment
- Chronic genotype 1 HCV ---> Pegylated Interferon-alpha + Ribavirin + NS 3/4 A protease inhibitor (boceprevir or telaprevir).
- Chronic HCV (other genotypes)---> Pegylated interferon-alpha + ribavirin
30
Hep C prevention:
- No vaccine available
- Reduce high risk behaviors, e.g., IV drug use or unprotected sexual activities.
- Screening of blood supply
31
Hep D details:
- Small circular ssRNA genome
- Encodes two proteins (Delta-short and Delta-Long antigens) that cover the virion.
- Unique helper-dependent virus
- Hepatitis B surface antigen forms the external surface of the virion. (NEEDS PRIOR INF WITH HEP B)
- Replication requires HBV proteins: Only infects cells that have been previously or concurrently infected with Hepatitis B virus
- Hepatitis D virus is the only hepatitis virus that directly injures hepatocytes.
- Chronic infection can occur = carriers
32
Hep D transmission:
bodily fluids
33
Hep D diagnosis, treatment and prevention:
- Diagnosis: ELISA to detect anti-HDV antibodies or the delta antigens.
- Treatment: No specific antiviral treatments
- Prevention: Since HBV infection is absolutely required for HDV to infect and cause disease, vaccination against HBV prevents HDV disease.
34
Hep E details
-Hepevirus
+ssRNA genome
-Transmitted through fecal-oral route
-Does not cause chronic infection
-Most cases in US are travel related.
-Epidemics: India, Pakistan, Nepal, Burma, North Africa, and Mexico
-High Risk of death due to infection in pregnant women (~20% mortality rate).
35
Hep E treatment and prevention:
- Treatment: To alleviate symptoms
| - Prevention: Prevent spread by providing clean water and proper food handling.
36
Poliovirus virology/details:
- Picornaviridae family member
- RNA genome
- Virions stable at acidic pH
37
Poliovirus: clinical info:
- Three serotypes (P1, P2, P3)
- Transmission primarily through fecal-oral route.
- Incubation period between 6 and 20 days.
- ~95% of infections are asymptomatic
- Shed in stool for weeks following infection.
38
Poliovirus: manifestations/symptoms
- Asymptomatic (95% of infections)
- Abortive Poliomyelitis: Sore throat; Fever; Vomiting and abdominal pain; Constipation
- Nonparalytic aseptic meningitis: 1-2% infections; Nonspecific prodromal symptoms; Stiffness in back, neck, or legs; Last 2-10 days
- most severe: Flaccid Paralysis in less than 1% of infections.
39
Poliovirus diagnosis
- Virus can be isolated from stool of patients.
| - Any isolates must be sequenced to determine if originated from wild type or vaccine strain.
40
Polio vaccines:
- first one was inactivated vaccine
- next: trivalent, live attenuated oral polio vaccine (OPV) --> some strains reverted to neurotropic strain caused Vaccine-Associated-Paralytic-Poliomyelitis (VAPP)
- NOW have inactivated polio vaccine w/ no risk for VAPP
41
viral gastroenteritis which visues/details/symptoms/transmission
- Inflammation of the stomach and intestines
- Nausea
- Diarrhea
- Vomiting
- Viral Causes
- Fecal Oral Transmission
- Non-enveloped
- Types= Rotaviruses; Noroviruses; Adenoviruses; Astroviruses
42
Compare viral and bacterial gastroenteritis: setting, incubation, vomiting, diarrhea, and diagnosis:
- ---VIRAL:
- setting: Incidence similar in developing and developed countries
- incub: 1–3 days for most agents; can be shorter for norovirus
- vomit: Prominent and can be the only presenting feature, especially in children
- diarrhea: Common; nonbloody in almost all cases
- diagn: This is often a diagnosis of exclusion in clinical practice. Commercial enzyme immunoassays are for rotavirus and adenovirus.
- ---BACTERIAL:
- setting: More common in settings with poor hygiene and sanitation
- incub: A few hours to 7days
- vomit: Common with bacteria producing preformed toxins; less prominent in diarrhea due to other agents
- diarrhea: Prominent and frequently bloody with agents causing inflammatory diarrhea
- diagn: Culture of stool specimens, sometimes on special media, can identify several pathogens
43
Signs of severe dehydration: (viral gastroenteritis)
-rapid, weak pulse, sunken eyes, tears absent, skin tenting, lack of urination
MILD Treatment: oral rehydration
SEVERE: IV rehydration
44
Rotavirus details:
- most severe disease among 3-24mo children
- most common children 3-35mo
- segmented genome which remain in "core" particle during infection: turrets exchange stuff into cell once inside
- G1 and G2 are first two most prevalent
45
rotavirus clinical/symptoms:
- Incubation period 1-3 days
- Vomiting and Diarrhea duration 4-7 days, occasional cough and coryza.
- 1/3 patients have fever >102º F
- Risk for life threatening complications in very young, immunodeficient, or malnourished.
46
rotavirus pathology:
- 10 billion particles released/g stool
- Malabsorptive diarrhea
- Additionally, Rotavirus produces a toxin (NSP4) that causes Ca2+ release.
- virus gets into vili and replicates in the vili = shortening o vili = vili blunting = less SA = malabsorption
47
rotavirus daignosis, treatment, prevention/vaccines
- Diagnosis: EIA from stool sample; Less commonly: EM, RT-PCR
- Treatment: Oral Rehydration Therapy; IV Rehydration Therapy with Severe Dehydration
- Prevention: Prevent fecal-oral transmission Sanitize fomites, e.g., toys; Handwashing; IgA in colostrums
- Vaccines = Two live attenuated , oral vaccines; universal vaccination of infants before 12 wks.; No increase risk of intussusceptions.
48
Noroviruses - details and virology
-#1 cause of nonbacterial gastroenteritic
-Caliciviridea family
-Non-Enveloped
+ ssRNA genome
-Norwalk virus founding member.
-Bind to histo blood-group antigens which are also found on vlli tips --> THIS VIRUS LIKES TO BIND TO H AND A ANTIGENS PRESENT ON CELLS (NOT B)
-As little as 100 virions can cause infection.
49
Noroviruses-symptoms
- Incubation period 24-48 h
- Nausea, vomiting, diarrhea for 24-60 hrs
- Low grade fever in about half of patients.
- Afflicts all age groups
- Pathology similar to Rotavirus
50
Noroviruses - transmission:
- Fecal-Oral
- Person-to-person: Close personal contact & Droplets from Vomitus
- Fomites
- Waterborne
- Contaminated Food: Food Handler & Contamination prior to preparation & SHELLFISH!
51
Noroviruses major route of spread and where?
- FOODBORNE MOST COMMON
| - FOUND IN LONG TERM CARE FACILITIES AND CRUISE SHIPS
52
Adenoviruses - details:
- dsDNA genome
- Naked Capsid
- Fiber Protein at vertices - directly toxic to cells
- Serotypes 40 and 41 cause gastroenteritis
- Shed from the GI tract
- Primarily in children.
- Incubation Period 8-10 days
- Watery, non-bloody diarrhea 7-8 days
- May be accompanied by vomiting and fever
- No seasonal variation
53
Adenoviruses - dagnosis
antibody based-serology
54
Sapoviruses
-Another Caliciviridea family member
55
AStroviruses details:
-Star-shaped viruses
+ ssRNA genomes
-Susceptible: infants, young children, elderly, or healthy adults exposed to contaminated food and drink.
56
e-antigen present in patient means?
Virus is currently highly infective and replicating! Measure of viral replication
-determines if chronic replicative or chronic non-replicative
57
How does a Hepatitis infection (except hEp D) destroy the liver?
Trick question mofo-- Hep doesnt directly destroy anything ... its the CTL mediated immune repsonse that effs thing up for the liver.
58
Hep B vaccine has what? What kind of immunity?
HBsAg = humoral immmunity
