Viral (V-Z) Flashcards
what is the virus causing chickenpox?
varicella-zoster virus (VZV)
Herpesviridae family
how does VZV get transmitted?
-respiratory route - inhalation of aerosols -from vesicular fluid of skin lesions
-direct contact
-enters through the upper respiratory tract or the conjunctiva
-utero infection also can occur due to transplacental passage of the virus during maternal varicella infection
-herpes zoster rash cause varicella, not herpes zoster, in susceptible people
how contagious is VZV?
what is contagious period for VZV?
-highly contagious, secondary attack 85%
-herpes zoster is 20% as infectious as varicella
-1-2 days before the onset of rash and ends when all lesions are crusted, typically 4-7 days after onset of rash
-herpes zoster: while they have active, vesicular lesions (7-10 days)
which part of the body does chickenpox rash first appear?
chesk, back and face
-then spread over the entire body in 3 successive waves and resolve by crusting
what is the chicken pox complication?
cerebellar ataxis, encephalitis, hemorrhgic conditions, pneumonia, secondary bacterial infections of skin lesions (bacteremia or sepsis)
rare death (1 in 40,000 varicella cases)
what is modified varicella?
varicella in vaccinated people - mild, <50 lesions, low or no fever, shorter duration for rash, fewer vesicles and predominance of maculopapular lesions
which testings are available for chickenpox diagnosis?
- nucleic acid amplification testing: specimen from skin lesions, PCR testing or direct flourescent antibody
- serologic testing: varicella IgG titers, to confirm disease but less reliable than PCR or direct fluorescent antibody methods for virus identification; IgM not recommended
how to treat chickenpox?
antiviral not recommended routinelyly for healthy children with varicella
-acyclovir oral
-acyclovir IV for immunocompromised
-initiate tx within 24 hours to maximize efficacy
-no aspirin or aspirin-containing products and ibuprofen
what is the VZV vaccine and dose?
1 - 12 yr: 2 doses more than 3 months apart (typical schedule: 12-15 month & 4-6 years)
13 yr and up: 2 doses 4 weeks or more apart
no recommendation for vaccine for infants aged < 12 months before international travel
what is vaccine efficacy of VZV?
80% after 1 dose;
92-95% after 2 doses
what is postexposure prophylaxis of VZV in unvaccinated people?
-vaccine ASAP - within 5 days after exposure
-immune globulin (VariZIG): immunocompromised, pregnant without evidence of immunity, some neonates and infants; ASAP but as late as 10 days is still ok.
-intravenous immunoglubulin (IVIG) 400mg/kg if VariZIG not available
-oral acyclovir 80mg/kg/day in 4 divided doses for 7 days upto max of 800mg qid, beginning 7-10 days after exposure
what are the 3 virus families and 1 order virus that cause viral hemorrhagic fever diseases (VHF)?
Arenaviridae
Filoviridae
Flaviviridae
order Bunyavirales
what viruses are Arenaviridae (arenaviruses) that cause viral hemorrhagic fever disease?
Chapare
Guanarito
Junin
Lassa
Lujo viruses
lymphocytic choriomeningitis virus (LCMV)
Machupo and Sabia varuses
what viruses are filoviridae (filoviruses) that cause viral hemorrhagic fever diseases?
Ebola, Marbur, Reston viruses
what viruses are Flaviviridae (flaviviruses) that cause viral hemorrhagic fever diseases?
Alkhurma, Kyasanur Forest disease
Omsk kemorrhagic fever
Dengue
Yellow fever viruses
what viruses in the order Bunyavirales that cause viral hemorrhagic fever diseases?
Arenaviridae family viruses
Crimean-Congo hemorrhagic fever virus
hantaviruses
rift valley fever virus
what are the viruses of VHF viruses that can be transmitted person to person?
arenaviruses, CCHF virus, filoviruses - direct physical contact of unprotected skin or mucous membranes and the blood
how long can Ebola virus and Marburg virus can persist in body fluids?
upto 21 days~ 33 days~ 2-3 months
what are the viruses of VHF viruses that can be transmitted through arthropd vectors?
some bunyaviruses (RVF virus) and flaviviruses (dengue and yellow fever) -mosquitoes
some bunyaviruses (CCHF virus) and flaviviruses (Alkhurma, Kyasanur Forest disease and Omsk viruses) - tick bite or crushing infected ticks
what are the viruses of VHF viruses that can be transmitted through bats?
filoviruses - Ebola, Marburg viruses
Natural reservoir for Marburg virus is the Egyptian fruit bat (Rousettus aegyptiacus)
what are the viruses of VHF viruses that can be transmitted through livestock?
some bunyaviruses (CCHF and RVF viruses) and flaviviruses (Alkhurma virus) can be transmitted during slaughter of infected animals or from the consumption of raw meat or unpasteurized milk of an infected animal
what are the viruses of VHF viruses that can be transmitted through rodents and insectivores?
Arenaviruses and some bunyaviruses (hantaviruses)
how are arenaviruses categorized?
Old world arenaviruses -
Lassa virus (Lassa fever),
Lujo virus,
LCMV (lymphocytic choriomeningitis virus)
New world arenaviruses -
Chapare virus
Guanarito (Venezuelan hemorrhagic fever)
Junin (Argentine hemorrhagic fever)
Machupo (Bolivian hemorrhagic fever)
Sabia (Brazilian hemorrhagic fever)
what are the Old World rats and mice family?
Muridae, subfamily Murinae
what are the New World rats and mice family?
family Muridae, subfamily Sigmodontinae
where is Crimean-Congo Hemorrhagic Fever (CCHF) endemic to?
Africa (including South Africa)
Eurasia (the Balkans, Middle East, Russia, Western China)
highly endemic to Afghanistan, Iran, Pakistan, Turkey
which tick is responsible for CCHF (Crimean-Congo Hemorrhagic Fever)?
genus Hyalomma - primarily associated with livestock but will also bite humans
how does CCHF virus get transmitted to humans?
tick bite;
fresh carcasses of infected animals, usually domestic livestock;
human-to-human through droplets or direct contact
What can Hantaviruses cause?
HPS - hantavirus pulmonary syndrome
HFRS - hemorrhagic fever with renal syndrome
viruses that cause HPS (hantavirus pulmonary syndrome) are found in ….?
Western Hemisphere (North, Central, and South America)
how are the viruses that cause both HPS and HFRS (hantavirus pulmonary syndrome, hemorrhagic fever with renal syndrome) transmitted to human ?
contact with urine, feces, saliva of infected rodents
human-to-human of hantavirus has been reported only with Andes virus in Chile and Argentina
Rift Valley Fever (RVF) primarily affects … through ..?
livestock - stillbirths and high mortality in neonatal cattle, goats, and sheep
through mosquitoes
if Rift valley fever affects human, what does it cause?
how does huamsn get RVF?
fever, hemorrhagic, encephalitis, retinitis
through direct contact with clinical affected animals or their body fluids
where is Rift valley fever endemic to?
Sub-Saharan Africa
which countries have Ebola virus diesease been reported?
Cote d’Ivore, Democratic Republic of the Congo, Gabon, Guinea, Liberia, Republic of the Congo, Sierra Leone, South Sudan, Uganda
Guinea near the borders with Liberia and Sierra Leone
Italy, Mali, Nigeria, Senegal, Spain, the UK, the US after infected people traveled from West Africa
which countries have Marburg virus diesease been reported?
Angola, Democratic Republic of the Congo, Guinea, Kenya, Uganda, Zimbabwe
what are the symptoms of viral hemorrhagic fever diseases?
abrupt onset of fever, headache, myalgias, prostration
then coagulopathy with a petechial rash or ecchymoses and sometimes overt bleeding in severe forms.
GI symptoms common
Vascular endothelial damage leads to shock and pulmonary edema; liver injury is common
what are syndromic findings associated with specific Arenaviridae infections?
pharyngitis, retrosternal pain, hearing loss in adults;
anasarca (edema) in newborns (Lassa);
spontaneous abortion and birth defects (Lassa fever, LCMV);
what are syndromic findings associated with specific Bunyavirales infections?
ecchymoses and bruising (CCHF virus);
renal failure (hantavirus, HFRS);
retinitis and partial blindness (RVF)
what are Two FDA-approved treatments are available for Ebola virus?
Ebanga (single monoclonal antibody) and Inmazeb (triple monoclonal antibody cocktail)
who is at risk of acquiring a Viral Hemorrhagid Fever for travelers?
animal research
healthcare workers
how to prevent viral hemorr fever?
-avoiding unprotected contact
-not visit locations where outbreaks are occurring.
-avoid contact with bats and rodents, and avoid blood or body fluids of livestock in RVF- or CCHF-endemic areas.
-use insecticide-treated mosquito nets and use insect repellent
who should get ERVEBO?
18 years and over
-those responding to outbreaks of EVD due to Ebola virus (species Zaire ebolavirus)
-health care personnel at federally designated Ebola treatment centers in US
-lab workers at Biosafety Level 4 facilities in US
where is YF enedmic to?
sub-saharan Africa
Tropical South America
what are teh mosquitoes that transmit YF?
Aedes or Haemagogus spp
what are 3 transmission cycles of YF?
Sylvatic (jungle) - monkey to mosquitoes (Aedes spp.)
Intermediate (savannah) - mosquitoes (Aedes spp.) to human in jungle border areas
Urban - humans to peridomestic mosquitoes (Ae. aegypti)
what are the countries with risk for YF?
Angola
Benin
Burkina Faso
Burundi
Cameroon
Central African Republic
Chad2
Congo, Republic of the
Côte d’Ivoire
Democratic Republic of the Congo
Equatorial Guinea
Ethiopia2
Gabon
The Gambia
Ghana
Guinea
Guinea-Bissau
Kenya2
Liberia
Mali2
Mauritania2
Niger2
Nigeria
Senegal
Sierra Leone
South Sudan
Sudan2
Togo
Uganda
- Argentina
Bolivia2
Brazil2
Colombia2
Ecuador2
French Guiana
Guyana
Panama2
Paraguay
Peru2
Suriname
Trinidad and Tobago2
Venezuela2
what is the incubation period for YF symptom development?
3-6 days
what is the initial symptoms of YF?
nonspecific: backache, chills, fever, headache, myalgia, nausea and vomiting, and prostration.
what % of infected patients of YF progress to a more serious form of the disease?
≈12%
what are the more serious form of the disease YF characterized by?
what is fatality rate for severe cases?
hemorrhagic symptoms, jaundice, and eventually shock and multisystem organ failure;
30-60%
what medications should be avoided when YF?
aspirin, NSAID
what is the age indication of YF vaccine?
9 months and up
what is the contraindication of YF vaccine?
-age < 6 months
-allergy: chicken proteins, eggs, gelatin –> skin testing & desensitization needed
-HIV or CD4 T lymphocyte counts <200/ml (or 15% of total lymphocytes in children aged <6 years)
-malignant neoplasms
-thymus disorder associated with abnormal -immune cell function (e.g. myasthenia gravis, thymoma)
-transplantation
what are the precautions of YF vaccine?
Age 6–8 months
Age ≥60 years
Breastfeeding
HIV infection (asymptomatic) and CD4 T lymphocyte counts 200–499/mL (or 15%–24% of total lymphocytes in children aged <6 years)2,3
Pregnancy
can you vaccinate YF vaccine and other inactive vaccines together?
yes
can you vaccinate other live attenuated viral vaccines and YF vaccine together?
if not together, how far should the vaccines apart?
yes; however, one study demonstrated that YF and MMR together reduces seroconversion of all antigens, except measles - therefore, better apart if possible
if separate, wait 30 days
can you vaccinate live bacterial vaccines and YF together?
if not together, how far apart?
yes (Ty21a - vivotif) - ok to give at any interval
no data for Vaxchora and YF
ACIP guideline specifies additional doses of YF vaccine recommendation - which group of travelers shoudl get 1 more dose before travel?
-people who were pregnant when they received their initial vaccine
-people who received a hematopoietic stem cell transplant after receiving a dose
-people infected with HIV when they received their last dose (Q10years recommended if they continue to be at risk for YF)
you can consider a booster dose of YF to travelers who received their last dose 10 years or longer ago. which group?
go to higher-risk settings based on activities, duration of travel, location, and season
-prolonged stay in endemic area
-peak transmission season
-areas with ongoing outbreaks
what is YF vaccine-associated neurologic disease? (YEL-AND)
acute disseminated encephalomyelitis,
Guillain-Barre syndrome,
meningoencephalitis, and rarely, cranial nerve palsies
0.8 per 100,000 doses, but greater in >60 years old
<6 months old, incident is high (50-400 cases per 100,000 infants) thus, contraindication!
what is YF vaccine-associated viscerotropic disease?
severe illness similar to wild type YF disease - virus proliferates in multiple organs, often leading to multiorgan dysfunction or failure and occasionally death.
0.3 per 100,000 doses; greater in >60 yrs (1.2 case) and >70 years
if a person has YF vaccine and she is planning to get pregnant, what is the advice?
wait 4 weeks before conceiving
for breastfeeding mom, what is the direction for breastfeeding after YF vaccine ?
do not breast fed for 2 weeks!
risk of YEL-AND for infants
what are the countries that require proof of YF vaccination?
AFRICA:
Angola
Benin
Burkina Faso
Burundi
Cameroon
Central African Republic
Congo, Republic of the
Côte d’Ivoire
Democratic Republic of the Congo
Gabon
Ghana
Guinea
Guinea-Bissau
Mali
Niger
Sierra Leone
South Sudan
Togo
Uganda
- THE AMERICAS:
French Guiana
which virus cause zika?
zika virus, single stranded RNA, Flaviviridae family, genus Flavivirus
how does zika get transmitted?
Aedes species mosquito
Intrauterine, perinatal, sexual, lab, possible transfusion-associated transmission have been reported
in breast milk - but transmission through breastfeeding is unknown
where have zika cases occurred?
tropical and subtropical regions;
the Pacific Islands and in SE Asia;
Western Hemisphere - large outbreaks in Brazil, then spread throughout much of the Americas
what are the symptoms of zika?
most asymptomatic or mild;
acute onset of fever, arthralgia, nonpurulent conjunctivitis, maculopapular rash;
edema, headache, lymphadenopathy, myalgia, retro-orbital pain, vomiting;
severe disease and death uncommon - Guillain-Barre syndrome and rare encephalopathy, meningoencephalitis, myelitis, uveitis, thrombocytopenia
vertical transmission - conenital zika virus infection (microcephaly with brain anomalies and other serious neurologic consequences, and fetal loss
if patient is suspected zika due to clinical presentation, what other disease is possible?
mostly dengue;
adenovirus, chikungunya, enterovirus, leptospirosis, malaria, measles, parvovirus, rickettsiosis, rubella, group A strep infections
what diagnostic tests are done for zika?
nucleic acid amplification test (NAAT)- early in the course of infection - amniotic fluid, whole blood, cerebrospinal fluid, semen, serum, tissues, urine –> negative NAAT does not always exclude recent Zika virus infection; IgM antibody testing might be recommended in certain situations
serologic testing - IgM test - toward the end of the 1st week of illness and can remain detectable for months to years after infection –> false positive possible due to cross-reacting antibodies against related flaviviruses (eg. dengue virus, YF virus)
-Plaque reduction neutralizaiton testing (PRNT) can be used to discriminate between cross-reacting ABs in primary flavivirus infections
confirmatory neutralizing antibody testing
what to advise for moms breastfeeding after possible zika virus exposure?
keep breastfeeding - benenfit more
