Virology 3 Flashcards
5 Distinct Hepatitis Viruses
- hepatitis A virus • ______virus/___ ____ virus
- hepatitis B virus • ______virus/____ ____ virus
- hepatitis C virus • ___virus/___ ___virus
- hepatitis D virus (delta agent) • ____-like/___ ____
- hepatitis E virus • ____-like/___ ___ virus
5 Distinct Hepatitis Viruses
- hepatitis A virus • picornavirus/naked RNA virus
- hepatitis B virus • hepadnavirus/enveloped DNA virus
- hepatitis C virus • flavivirus/enveloped RNA virus
- hepatitis D virus (delta agent) • viroid-like/enveloped RNA
- hepatitis E virus • calicivirus-like/naked RNA virus
Characteristics of HAV
- picornavirus
- ____ to pH ___, ____solvents, detergents, saltwater, groundwater, drying, temperature
- inactivated by ___, ____, ___ ___
- Naked
Characteristics of HAV • picornavirus • stable to pH 1.0, organic solvents, detergents, saltwater, groundwater, drying, temperature • inactivated by chlorine, formalin, UV radiation • Naked
HAV Infection
- spread by ___-___ route; ___/____ outbreaks; dirty hands can spread it in food service industry
- ____ onset
- ____ disease
- no___ ___ or___ ___
- Symptoms are ___, ___, ___, ____ of ___, ___ ___
- ___–icteric phase (___% of adults; ____% of kids)
- Skin turns yellow • In darker people you see It in the sclera of their eyes
- symptoms due to___ ___ ___ ____
- immune response fighting off infection in the liver.
- Liver damage as a result of this but its totally___ ___ and goes away pretty quickly
- Recall: Enveloped virus is less stable because derived from cell membrane. Liquid. Requires cell in which to live. Generally not transmitted by door handles, they don’t survive very long in environment. • Naked: Protein is stable
HAV Infection • spread by fecal-oral route; food/waterborne outbreaks; dirty hands can spread it in food service industry • abrupt onset • mild disease • no chronic infection or carrier states • Symptoms are fever, fatigue, nausea, loss of appetite, abdominal pain • jaundice–icteric phase (>70% of adults; 10-20% of kids) • Skin turns yellow • In darker people you see It in the sclera of their eyes • symptoms due to immune-mediated liver damage • immune response fighting off infection in the liver. • Liver damage as a result of this but its totally self resolving and goes away pretty quickly • Recall: Enveloped virus is less stable because derived from cell membrane. Liquid. Requires cell in which to live. Generally not transmitted by door handles, they don’t survive very long in environment. • Naked: Protein is stable
Pathogenesis of HAV
___ Acquisition→Crosses ___→ ___→ ___→ ___→ ___ (____ virus particles/mL)
Pathogenesis of HAV Oral Acquisition→Crosses Intestines→ Blood→ Liver→ Bile→ Stool (10^8 virus particles/mL)
HAV Epidemiology
- HAV causes ___% of acute hepatitis
- most infected people are infectious____ symptoms occur • They don’t know it and they can spread it
- 90% of infected kids and 25-50% of infected adults have____, but ____e infections • Don’t get sick but can spread virus
- outbreaks originate from a ___ ____ • All the pomegranate seeds in a shipment are contaminated
HAV Epidemiology • HAV causes 40% of acute hepatitis • most infected people are infectious before symptoms occur • They don’t know it and they can spread it • 90% of infected kids and 25-50% of infected adults have inapparent, but productive infections • Don’t get sick but can spread virus • outbreaks originate from a common source • All the pomegranate seeds in a shipment are contaminated
Reported number of cases Has been ____ since 2000
Reported number of cases Has been decreasing since 2000
Treatment and Control of HAV
- ___ ___ ____ 80-90% effective • For ___ ____ prophylaxis • Basically, ___ to the virus • ____ type of immunization
- ___ of ___ ___
- frequen ___ ___
- vaccine (licensed in 1995) • Havrix recommended by ___ yr of age • ___ serotype • So easy to immunize against • infects __ ____ • Twinrix combo vaccine for age 18+ • Get booster before college
Treatment and Control of HAV • immune serum globulin 80-90% effective • For post exposure prophylaxis • Basically, Ab to the virus • Passive type of immunization • chlorination of drinking water • frequent hand-washing • vaccine (licensed in 1995) • Havrix recommended by 1 yr of age • only one serotype • So easy to immunize against • infects only humans • Twinrix combo vaccine for age 18+ • Get booster before college
HBV—Pathogenesis
- Much more complex virus
- You see it occurring in ___ ___ in the blood o Filamentous o Complete viral particle
- Lots of ___ and ___ Ag
- Infection with HBV→ increased levels of ___ ___ ___
- In an immune person, ___ will block any complications from that
- Most people will have symptoms and it will ___ ___
- During process of resolving infection, virus will spread by ____ • Will be in saliva, semen, vaginal secretions, blood and mothers milk
- Here again you can prevent spread of the disease with ___
- Problem is people who become ____ infected with Hep B
o Not much of a problem in the ____, vaccine world but plenty of people still carry the virus • Virus can be transmitted ___, ___, ___ and ___ ___
HBV—Pathogenesis • Much more complex virus • You see it occurring in many forms in the blood o Filamentous o Complete viral particle • Lots of enzymes and core Ag • Infection with HBV→ increased levels of HBV surface Ag • In an immune person, Ab will block any complications from that • Most people will have symptoms and it will resolve infection • During process of resolving infection, virus will spread by viremia • Will be in saliva, semen, vaginal secretions, blood and mothers milk • Here again you can prevent spread of the disease with Ab • Problem is people who become chronically infected with Hep B o Not much of a problem in the developed, vaccine world but plenty of people still carry the virus • Virus can be transmitted neonatally, blood, sexually and thru drug abuse
HBV Infection/Epidemiology
- parenteral (___ borne) and ___ ____ (thru mucous membranes)
- ____, insidious onset→ not as ___ as HAV
- fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, __ ___, ___ ___, jaundice • Signs/symptoms pretty much the same as HAV
- Can result in ___ ___ and ___ ___
- 800,000-1.4 million in U.S. have chronic infection
- 350 million worldwide have chronic infection
- 786,000 deaths annually worldwide from HBV-related liver disease
- Carriers can transmit it
- Associated with ___ ___ ____
- Liver is a regenerative tissue • As SC continue to replicate they become more sus to other damage to their DNA and you can get the formation of a tumor
HBV Infection/Epidemiology • parenteral (blood-borne) and sexual transmission (thru mucous membranes) • slow, insidious onset→ not as acute as HAV • fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, joint pain, jaundice • Signs/symptoms pretty much the same as HAV • Can result in chronic infection and carrier state • 800,000-1.4 million in U.S. have chronic infection • 350 million worldwide have chronic infection • 786,000 deaths annually worldwide from HBV-related liver disease • Carriers can transmit it • Associated with primary hepatocellular carcinoma • Liver is a regenerative tissue • As SC continue to replicate they become more sus to other damage to their DNA and you can get the formation of a tumor
Reported number of cases
____a huge problem in US anymore bc we have immunized against it.
Reported number of cases Not a huge problem in US anymore bc we have immunized against it.
HBV Carriers—
Worldwide Prevalence
Areas where hepatocellular carcinoma is also very prevalent
Developed world, ___________
HBV Carriers—Worldwide Prevalence Areas where hepatocellular carcinoma is also very prevalent Developed world, its not a problem
Transmission of HBV Modes
- ____ with an infected partner
- _____ drug use that involves sharing needles, syringes, or prep equipment
- ___ to an___ ___.
contact with ___ or ___ ___ of an infected person
- needle sticks or sharp instrument exposures
- sharing items like ___ or____ with an infected person
Risk Groups
- ___born to infected mothers
- __ ___ of infected persons
- sexually ____ individuals
- ___ who have sex with ___
- injection __ ___
- ___ ___ of persons with chronic HBV infection
- ___ __ ___and public safety workers at risk for occupational exposure to blood or blood-contaminated body fluids
•_____ patients
• residents and staff or facilities for the ___ ___
___ to ____with intermediate or high prevalence of HBV infection
Transmission of HBV Modes • sex with an infected partner • injecting drug use that involves sharing needles, syringes, or prep equipment • birth to an infected mother • contact with blood or open sores of an infected person • needle sticks or sharp instrument exposures • sharing items like razors or toothbrushes with an infected person Risk Groups • infants born to infected mothers • sex partners of infected persons • sexually promiscuous individuals • men who have sex with men • injection drug users • household contacts of persons with chronic HBV infection • health care workers and public safety workers at risk for occupational exposure to blood or blood-contaminated body fluids • hemodialysis patients • residents and staff or facilities for the developmentally disabled • travelers to countries with intermediate or high prevalence of HBV infection
HBV Treatment/Vaccines
- ___ ____inhibitors
- ___ __ ___• Amped up with polyethylene glycol that makes it stick together better and be more effective and gives ___ ___
- vaccination
- ___ ___ Hep B vaccines (2)
- Vaccine used to be made with Hep B surface Ag that was purified from the plasma of infected people, but now we have the ____ vaccine
- ____ Vaccines (3)
HBV Treatment/Vaccines • reverse transcriptase inhibitors • pegylated α-interferon • Amped up with polyethylene glycol that makes it stick together better and be more effective and gives higher dose • vaccination • Single Ag Hep B vaccines (2) • Vaccine used to be made with Hep B surface Ag that was purified from the plasma of infected people, but now we have the recombinant vaccine • Combo Vaccines (3)
Hepatitis C Virus (HCV)
• Flavivirus—identified in ___; ___ genotypes o Analogous to west nile and others that are arthropod transmitted, but it is not transmitted that way
o Knowing which genotype person has can direct treatment
- Most infected people get ____ disease as opposed to ____ disease
- establishes ___-____, _____ infections leading generally to _____ disease (70%)
- accounts for ____% of cases of non-A non-B hepatitis; genotype ___most prevalent
- HCV chronic disease (3.2 million Americans) ___ prevalent than ___ ____ disease (800,000-1.4 million Americans)
- prevalence worldwide is 2%=123,000,000 people
- ___ ___ for ___ ____
o Bc so many people become chronically infected, their liver gets destroyed
• most ___ ___ ___ ____ in U.S. • The real problem in this family
Hepatitis C Virus (HCV) • Flavivirus—identified in 1989; 6 genotypes o Analogous to west nile and others that are arthropod transmitted, but it is not transmitted that way o Knowing which genotype person has can direct treatment • Most infected people get CHRONIC disease as opposed to acute disease • establishes non-cytolytic, persistent infections leading generally to chronic disease (70%) • accounts for 90% of cases of non-A non-B hepatitis; genotype 1 most prevalent • HCV chronic disease (3.2 million Americans) more prevalent than HBV chronic disease (800,000-1.4 million Americans) • prevalence worldwide is 2%=123,000,000 people • leading indication for liver transplantation o Bc so many people become chronically infected, their liver gets destroyed • most common blood-borne infection in U.S. • The real problem in this family
Pathogenesis of HCV
- viremia lasts ____ months in acute infection o During that time they are infectious. o This is longer duration that HAV, HBV acute
- viremia lasts ___ years in persistent infection
- ____ (immune response) leads to ___ ___ (liver)
- continual ___ ___ and induction of cell growth during __ ___ predisposes to liver cancer development
- _____ are ___ ____ so difficult to make a vaccine
- ____ ___ ___ blocks ___ of ___ ___ ___o Virus makes serine protease
- ____ _____ may prevent HCV from blocking interferon (Used in treatment of HCV)
Pathogenesis of HCV • viremia lasts 4-6 months in acute infection o During that time they are infectious. o This is longer duration that HAV, HBV acute • viremia lasts 10 years in persistent infection • CMI (immune response) leads to tissue damage (liver) • continual liver repair and induction of cell growth during chronic infection predisposes to liver cancer development • Antibodies are not protective so difficult to make a vaccine • HCV serine protease blocks activation of interferon regulatory factor o Virus makes serine protease • Protease inhibitors may prevent HCV from blocking interferon (Used in treatment of HCV)
HCV—
Transmission Modes
- ___ __ ____ (most common)
- needlestick injuries in __ ___ settings
- ____ to an HCV-infected mother
- inefficient modes
- ___ with an HCV-infected person
- ____ personal items contaminated with infectious blood
- invasive health care____
Risk Groups
- current or former __ ___ ___
- recipients of donated blood, blood products, and organs prior to ____ • It took us some time to get a test to screen for HCV
- ___ ___ ___ at risk for occupational exposure to blood or blood-contaminated body fluids
- persons with ____ infection • Bc of suppresed immune system
- ___ ___ to HCV-positive mothers
HCV—Transmission Modes • injection drug use (most common) • needlestick injuries in health care settings • birth to an HCV-infected mother • inefficient modes • sex with an HCV-infected person • sharing personal items contaminated with infectious blood • invasive health care procedures Risk Groups • current or former injection drug users • recipients of donated blood, blood products, and organs prior to 1992 • It took us some time to get a test to screen for HCV • health care workers at risk for occupational exposure to blood or blood-contaminated body fluids • persons with HIV infection • Bc of suppresed immune system • children born to HCV-positive mothers
Reported number of Acute HCV cases
____ for awhile but its been going __ ___
Still a major problem bc we have no way to __ ___other than being careful.
Reported number of Acute HCV cases Dipped for awhile but its been going back up Still a major problem bc we have no way to prevent transmission other than being careful.
Diagnosis and Control of HCV
- diagnosis based on detection of ____; seroconversion in ____ weeks; antibody ___ __ ___ in viremic people making serologic diagnosis of acute disease difficult
- Ab aren’t ___ but they are still an ___
- People will generally ____ over time but people who have viremia do not always have Ab, so difficult to diagnose using serology.
- ___ ___in serum better indicator • Test to look for RNA of virus in the serum
- controlled by ____ of blood supply and avoidance of ___ __ ___
Diagnosis and Control of HCV • diagnosis based on detection of antibody; seroconversion in 7-31 weeks; antibody not always present in viremic people making serologic diagnosis of acute disease difficult • Ab aren’t protective but they are still an indicator • People will generally seroconvert over time but people who have viremia do not always have Ab, so difficult to diagnose using serology. • virion RNA in serum better indicator • Test to look for RNA of virus in the serum • controlled by screening of blood supply and avoidance of high-risk behaviors
Treatment for Hepatitis C
- Considerations
- HCV ____
- __ ___→Serum RNA
- past ___
- degree of ___ ___
____status
- Drugs—combination therapies
- __ ___
- __ ___
- __ ___ • Interfere with repl of viral NA
- ___% cure rate • newer drugs very ____ Some say they are 90% effective in curing
Treatment for Hepatitis C • Considerations • HCV genotype • viral load→Serum RNA • past treatment • degree of liver damage • transplant status • Drugs—combination therapies • pegylated interferon • protease inhibitors • nucleoside analogues • Interfere with repl of viral NA • >80% cure rate • newer drugs very expensive Some say they are 90% effective in curing
