Viral infection (H) Flashcards
which virus cause hand, foot, mouth disease?
nonpolio enteroviruses
- genus Picornaviridae family of nonenveloped RNA viruses (e.g. coxackievirus A6, coxsackievirus A16, enterovirus A71)
In the Asia-Pacific regions, which virus is the predominant etiologic agent of HFMD?
enterovirus A71
what are the symptoms of HFMD?
incubation 3-6 days, recovery within 7-10 days;
fever, malaise, sore throat, painful vesicles in the mouth, peripheral rash on hands, feet, also can be on buttocks, genitals, elbows, knees
what can be symptoms of severe and atypical cases of HMFD?
severe: brainstem encephalitis, aseptic meningitis, myocarditis, pulmonary edema, death
atypical: rash or lesion that enlarges and coalesces to form bullae; onychomadesis (shedding of the nails) and desquamation of the palms or soles can occur during convalenscence
what is henipavirus ?
enveloped, single-stranded RNA
genus Henipavirus
family Parammyxovirus
which Henipavirus species are highly virulent and cause outbreaks in humans and associated with high case-fatality ratios?
Hendra virus, Nipah virus
what is the henipavirus reservoir hosts?
which animal can transmit hendra virus to humans?
which animal can tranmit Nipah virus to humans?
Pteropid fruit bats (flying foxes)
horses (infected by bat urine)
pigs or bats; also human-to human transmission possible
in eastern China, a new henipavirus species was identified. which henipavirus is this?
Langya virus (LayV)
which country has outbreaks of Henipavirus infection / hendra virus?
Australia
which countries have outbreaks of Nipah virus?
Malaysia (1999), Singapore (1999), Bangladesh, India (yearly) - mostly bat exposure
what are the symptoms of Hendra and Nipah virus infections?
5-16 days incubation period;
severe influenza-like illness with dizziness, headache, fever, myalgias
severe encephalitis; respiratory symptoms
relapsing or late-onset encephalitis can occur months or years after acute illness.
what is case-fatality ratio of Hendra and Nipah?
57%
40-70%
how to prevent Henipavirus infections?
avoid contact with bats, sick horses and pigs and their excretions
do not consume fallen fruit, raw date palm sap, or products made from raw sap
is there a vaccine for Hendra virus?
Australia - Hendra virus vaccine for horses
what is Hepatitis A virus?
nonenveloped RNA;
picornavirus
can HAV be inactivated by cold or heat?
only heat >85 degrees for 1 minute
when is the most infectious period of HAV in infected people?
and how does the virus excreted?
1-2 weeks before the onset of symptoms
through stool and blood
what is the most common vaccine-preventable infections acquired during travel?
Hepatitis A
what is incubation time for HAV?
average 28 days (15-50 days)
what are the severities of HAV infection? in children age <6 years and older children and adults?
mild illness 1-2 weeks; severly disabling disease lasting several months
<6 years - 70% asymptomatic (jaundice is uncommon in symptomatic young children)
older children&adults - usually lasts <2 months, but 10-15% have prolonged or relapsing symptoms over 6-9 months
severe hepatic and extrahepatic complications are rare but more common in older adults and people with underlying liver disease.
symptoms of HAV?
abrupt onset of fever, malaise, anorexia, nausea, abdominal discomfort
followed by jaundice within a few days - hepatitis and liver failure if very severe
how to diagnose HAV?
positive test for HAV IgM in serum - detectable 2 weeks before the onset of symptoms to ~6 months after symptom onset.
what is commercially available for HAV detection/diagnose?
serologic total IgG and IgM tests
what does it mean if total HAV result positive, and IgM negative?
past infection or vaccination - immunity
what does IgM positive mean?
current or recent infection - does not distinguish between immunity derived from infection verses vaccination.
what is the spacing between 2 doses of Havrix (GSK) and Vaqta (Merck)?
Havrix 6-12 months
Vaqta 6-18 months
what age is junior Havrix and Vaqta indicated?
1-18 years old
what is rapid schedule for Twinrix?
0, 7, 21-30 days, 12 months
what is the dose of IG for HAV for infants younger than 6 months old or who is allergic to the vaccine?
1 dose IG at 0.2 ml/kg repeated every 2 months for the duration of travel
what is recommended for infants 6-11 montsh old for HAV?
vaccine - but expect suboptimal immune response and start routine vaccine at 12 months
what to do if people, age >40 years, immunocompromised, and with chronic liver disease travel in less than 2 weeks for HAV vaccine??
IG (0.1ml/kg) in addition to vaccine at separate injection site
Hep A vaccines should not be administered if history of hypersensitivity to any vaccine component. Which vaccine compoents are prone to allergic reaction ?
neomycin
Twinrix, Havrix, and vial stopper, syringe plunger stopper, and tip caps of Vaqta might contain dry natural rubber (latex)
Twinrix - yeast
is HAV vaccine indicated for pregnancy?
yes - if increased risk for HAV during pregnancy, risk for having a severe outcome from HAV (with chronic liver diseaes or HIV)
if you administer IG for HAV, can you administer MMR and varicella vaccines?
no - you need to wait for 6 months
travelers exposed to HAV should receive what for postexposure prophylaxis?
- 1 dose vaccine if healthy and over 12 months old
- 1 dose vaccine plus IG (0.1ml/kg) if immunocompromised, chronic liver disease, >40 years
- IG if <12 months old or allergic to vaccine
- ASAP, ideally less than 2 weeks
what is Hepatitis B virus? (HBV)
small, circular, partially double-stranded DNA
family Hepadnaviridae
how is HBV transmitted?
contaminated blood, blood products, other body fluids (semen)
which virus is the leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma worldwide?
HBV
what is the epidmiology of HBV infection?
- in 2015, 257 million globally were living with chronic HBV infection
- that year, 887,000 death caused by HBV
which regions have 2% or more chronic HBV infection population?
western Pacific and African regions
what is the incubation period for HBV?
90 days (60-150 days)
which age group and population show asymptomatic when newly infected by HBV?
<5 years and immunosuppressed adults
what % of aged 5 and up would have signs and symptoms when newly infected by HBV
30-50%
what are symptoms of HBV infection?
abdominal pain, anorexia, fatigue, fever, jaundice, joint pain, malaise, nausea, vomiting, light stool, dark urine
what is case-fatality ratio of acute hepatitis B?
1%
what are the risk factors for actue hep B progress to chronic HBV infection?
age at the time of infection
>90% of neonates and infants
25-50% of children aged 1-5 years
<5% of older children and adults
what happens when chronic Hepatitis B infection?
- most asymptomatic, no evidence of liver disease
- 15-40% will develop liver cirrhosis, hepatocellular carcinoma, or liver failure
- 25% die prematurely from these complications
- susceptable to Hep D infection - increase risk for fulminant hepatitis and rapidly progressive liver disease
how to diagnose HBV infection?
blood markers
what are these markers show - HBsAg, total anti-HBs, total anti-HBc ?
anti-HBs (surface antigen) - immune! resolved or immune from vaccination
anti-HBc (core antigen) - infection now and before! chronic, acute, resolved
HBsAg - infection right now! acute or chronic
acute infection - positive anti-HBc (IgM); negative total anti-HBs; positive HBsAg
chronic infection - positive anti-HBc; negative total anti-HBs; positive HBsAg
resolved - positive anti-HBc; positive anti-HBs; negative HBsAg
Immune - positive anti-HBs
susceptible - all negative
what are HBV vaccine avaialble? age and dosing schedule?
Heplisav-B (>18 years) - 0, 1 month
Engerix B (0-19 yrs - junior 0.5ml ; 20 and up - adult 0.5ml) - 0, 1, 6 months
Recombivax HB (0-19 yrs - junior 0.5ml ; 20 and up - 1ml) - 0, 1, 6 months
PreHevbrio (18 and up) - 0, 1, 6 months
Twinrix (18 and up) - 0, 1, 6 months ; or accelerated 0, 7, 21-30 days, 12 month
what is alternative (accelerated) vaccine schedule for Engerix B?
what age group should use junior dose for accelerated schecule?
- 0, 1, 2, 12 months
- age 0-10 years: 0.5ml junior
- age 11-19 years: 1ml adult
what is alternative vaccine schedule for Recombivax HB for age 11-15 years? which strength do you use?
0, 4-6 months - adult strength 1ml
which Hep B vaccines are preferred for pregnancy due to safety data?
Engerix B, Recombivax HB, Twinrix
Heplisav-B or PreHevbrio lacking safety data for pregnancy and breastfeeding
what ingredients in Hep B vaccines can cause allergies to people?
-yeast
-noninfectious recombinant protein (hepatitis B surface antigen) and an adjuvant
-aluminum for Engerix B, Recombivax HB, PreHevbrio, Twinrix
what is Heplisav B (18 years and over) schedule?
2 dose - 0, 4 weeks
who should get vaccinated with Hep B vaccine?
traveling to areas with intermediate to high prevalence of chronic HBV infection - countries with HBV surface antigen positivity prevalence is 2% or more
how do you get Hep C infection?
contaminated needles or syringes, receipt of blood or blood products
tattoing, during sexual contact, perinatally from mother to child
what is hepatitis C virus?
distribution?
spherical, enveloped, positive-strand RNA virus - worldwide
can Hepatitis C be chronic disease?
which area / countries the prevalence is higher (2-4%)?
yes
eastern Europe (Ukraine, Russia, Moldova, Romania, Latvia)
Africa (Gabon, Burundi, Egypt)
the Middle East (Syria)
South Caucasus and Central Asia (Georgia, Uzbekistan, Tajikistan, Turkmenistan)
Hep C is considered a majro cause of which disease?
cirrhosis and liver cancer
what is the acute symptoms of Hep C and what % of infected people experience symptoms?
abdominal pain, anorexia, nausea, fatigue, jaundice, dark urine (not distinguishable from other hepatitis)
only 20% experience symptoms
how much of infected people have chronic infection of Hep C?
50% unless treated with antiviral medications
what is the result of chronic hep C disease?
10-20% will have cirrosis after 20-30 years (progression is often clinically silent)
what tests are available for Hep C?
- IgG assays for HCV antibodies (cannot distinguish current or previous infection)
- Nucleic acid amplification tests to detect HCV RNA in blood (viremia) (needed to confirm recent and chronic disease)
-IgM to detect early or acute infection is not available
screening is recommended for Hep C for which population?
all adults 18 and over - 1 or more screen during a lifetime
pregnant - screen for all pregnant people during each pregnancy
what is the treatment for Hep C?
8-12 weeks treatment
95% effective
all oral anti-viral
what is Hep E virus?
which genotypes cause human disease?
spherical, nonenveloped, single-stranded, single-serotype, RNA virus -
Hepeviridae family
HEV 1-4 and 7 can cause human disease
of HEV 1-4 and 7, which is most prevalent?
which causes Hep E in high-income countries?
HEV 1 most prevalent;
HEV 3-4 in high income countries
how are HEV transmitted?
HEV 1 and 2 - fecal-oral route, maintly through dringking contaminated water
HEV 3 - zoonotic foodborne transmission, uncooked or undercooked meat of boar, deer, pig, shellfish
HEV 7 - camel meat and milk
Hepatitis E, how many cases occur per year globally,
how many are symptomatic and how many death per year?
- 20 million cases yearly
- 3.3 million symptomatic Hepatitis E
- 70,000 death
During Hep E outbreaks, clinical attack rates are highest among people aged ..?
15-49 years
is Hep E (HEV-1) dangerous for pregnant women?
Yes - can progress to liver failure and death; miscarriages and neonatal deaths are common complications of HEV infection;
most risk if infected during third trimester
what age group has more symptomatic disease where HEV-3 is prevalent?
> 50 years
can Hep E become chronic?
yes, only HEV-3, among immunosuppressed, particularly solid organ allograft recipients infected with HEV-3
what are the symptoms of HEV?
-incubation 2-9 weeks (mean 6 weeks)
-most people mild, self-limiting
-only HEV-3 can progress to chronic infection
-indistinguishable symptoms from other hepatitis
how to diagnose HEV?
- HEV IgM in serum
- HEV RNA in serum or stool
treatment for HEV?
supportive but oral ribavirin has been shown to be effective in the treatment of chronic hepatitis E
what is HIV virus?
enveloped positive-strand RNA
family Retroviridae
how many people are living with HIV globally?
which area is most affected?
in 2000, 37.7 million
sub-Saharan Africa (25.4 million, 67% of all people living with HIV infection)
symptoms for acute HIV infection?
10 days after infection;
non-specific - monomucleosis-like or influenza like syndrome;
arthralgias, myalgias, fatigue, fever, headache, lymphadenopathy, maculopapular rash, malaise, ORAL ULCERS, pharyngitis, weight loss
how to diagnose HIV?
combination antigen/antibody assay (detect antibodies against HIV and the p24 antigen)
oral fluid testing avaialble for retail purchase in the US.
what meds is used for preexposure prophylaxis for HIV?
Truvada - 200mg emtricitabine + 300mg tenofovir disoproxil fumarate
Descovy - 200mg emtricitabine + 25mg tenofovir alafenamide
once daily
how soon do you need to use postexposure prophylalxis for HIV?
within 72 hours
