Viral (I-P) Flashcards
which type of influenza virus cause human illness and seasonal epidemics?
which subtypes circulate in humans worldwide?
A&B
A(H1N1), A(H3N2)
B-yamagata, B-Victoria
what is influenza virus?
RNA virus of the Orthomyxovirus genus
4 types: ABCD
what does Novel influenza refer to?
viruses with a subtype different from seasonal influenza, and is caused by influenza A among animals
avian influenza A
swine-origin variant viruses Av
incubation time of influenza?
when is the infectious period? (for healthy ppl vs infectious period for children, immunocompromised, severely ill)
-1-4 days
-1 day before symptoms to 5-7 days after symptom onset
-greatest within 3-4 days of illness onset and is correlated with fever; upto 10 days after symptom onset for children, etc.
In temperate regions, the Norther Hemisphere, influenza epidemics are expected in which months?
10-3
In temperate regions, the Southern Hemisphere, influenza epidemics are expected in which months?
April - September
globally, annual influeza epidemics results in how many cases of severe illness and how many respiratory deaths?
3-5 million severe cases, 290,000-650,000 deaths
what groups are at increased risk for influenza complications?
-65 and older
-children<2 years
-pregnant people and people within 2 weeks post-partum
-medical conditions: asthma, blood disorders, BMI >40, chronic lung disease, endocrine disorders, heart disease, immunocompromise, kidney disease, liver, metabolic disroders, neurologic and neurodevelopment conditions, history of stroke
-American Indians and Alaska Natives
-people living in nursing homes and other long-term care facilities
what is zoonotic influenza?
Influenza A viruses circulating among animal populations which occasionally infect humans.
wild birds, domestic poultry, swine, bats, cats, dogs, ferrets, horses, sea lions, seals
Avian Influenza A (H5) Lineage viruses - which countries were affected?
what is reported case-fatality ratio?
Egypt, Indonesia, China, Russia
37%
Avian influenza A (H7N9) virus - what is case-fatality ratio?
which country has been affected?
40%
China, Hong Kong Special Administrative Regions (SAR), Macau SAR, Malaysia, Taiwan
what are the symptoms of influenza?
abrupt onset of signs and symptoms - nonproductive cough, fever, headache, malaise, muscle aches, rhinitis, sore throat, vomiting, rash
illness without fever can occur in older adults and infants
children -nausea, vomiting, dairrhea
what are symptoms of variant influenza viruses (e.g. avian influenza) ?
often severe pneumonia or respiratory failure and a high case-fatality ratio
what are the complications of influenza virus infection?
viral pneumonia and secondary bacterial pneumonia.
co-infections with other viral or bacterial pathogens, encephalopathy, exacerbbation of underlying medical conditions, GBS, myocarditis, myositis, parotitis, seizures, death.
what is the treatment of influenza?
when should the treatment be initiated?
within 48 hours of symptom onset;
-oseltamivir (Tamiflu) - all ages
-peramivir (intravenous) - 2 and up
-zanamivir (inhaled) -7 and up for treatment, 5 and up for prophylaxis
-baloxavir (oral) - acute uncomplicated influenza,12 and up
what is the treatment dose of oseltamivir?
for 5 days:
<1 year: 3mg/kg BID
1 and up: <15kg - 30mg BID
15-23kg - 45mg BID
23-40kg - 60mg BID
>40kg - 75mg BID
what is the prophylaxis of oseltamivir?
7 days:
<3 months old - not recommended due to limited data in this age group
3 month - 1 year - 3mg/kg/dose QD
1 and up: same dosing as treatment but once a day dosing
when do you do postexposure prophylaxis for influenza outbreak?
-only within 48 hours of exposure
-all suspected avian influenza viruses (treatment dose)
what are the 3 categories of influenza vaccines?
- inactivated (cell-based, high-dose, adjuvanted)
- live attenuated
- recombinant
who should get 2 doses of influenza vaccines 4 weeks apart?
children aged 6 months to 8 years who have never received an influenza vaccine, or who have not previously received a lifetime total of 2 or more doses, require 2 doses of age-appropriate influenza vaccine given 4 weeks apart.
what is the age indication for cell-based inactivated vaccein, live attenuated influenza vaccine and recombinant influenza vaccine?
what is indication for other inactivated influenza vaccine (IIV)?
2 and up for cell-based inactivated
2-49 years for LAIV
18 and up for RIV
6 months and up for IIV
what is japanese encephalitis virus?
single-stranded RNA
genus Flavivirus
japanese encephalitis virus is closely related to which viruses?
dengue, West Nile, Saitn Louise encephalitis virus
what mosquito species are associated with japanese encephalitis?
culex species
what animals are responsible for japanese encephalitis virus host?
wading birds and pigs
JE virus - in temperate areas of Asia, which season is the peak?
summer and fall
what is the overall incidence of JE among people from nonendemic countries traveling to Asia?
<1 case per 1 million travelers
expatriates and travelers who stay for prolonged periods in rural area with active JE virus transmission, what is the risk to get JE?
6-11 cases per 100,000 per year
what are the symptoms of JE?
incubation 5-15 days
-sudden onset of fever, headache, vomiting
-mental status changes, focal neurologic deficits, generalized weakness,
-movement disorders (like parkinsonian syndrome with mask-like facies, tremor, cogwheel rigidity, choreoatetoid movements)
-acute flaccid paralysis like poliomyelitis
-seizures
<1% develop neurologic disease
-acute encephalitis
-milder forms: aseptic meningitis, undifferentiated febrile illness
-case fataility rate 20-30%; 30-50% serious neurologic, cognitive, or psychiatric sequelae
how to diagnose JE?
JE virus-specific IgM-capture ELISA on CSF or serum
what is age indication for IXIARO?
2 month and up
who should get JE vaccine?
moving to JE endemic country, longer-term (>1 month), frequent travelers
JE vaccine - discard 1/2 volume from 0.5ml syringe for which age group?
2 months - 2 years
what is the schedule of JE vaccine for age 2month-17 years & >65 years?
18-65 years?
0, 28 days
0,7-28 days for 18-65 years
when do you do booster dose for JE?
1 year after completion of 2 doses
what component of JE vaccine can likely cause allergic reaction?
protamine sulfate
can pregnant women get JE vaccine?
precaution due to no studies - should defer vaccinating pregnant people
which virus causes MERS (middle east respiratory syndrome)?
single-stranded, positive-sense RNA
family Coronaviridae
genus Betacoronavirus
zoonotic virus
what is the host reservoir of MERS-CoV?
camels (dromedaries [Camelus dromedarius])
how is MERS-CoV transmitted to humans from camels?
-direct contact (grooming, petting)
-indirect contact (camel feces, camel products, being in settings where camels are present)
can MERS-CoV be transmitted from person to person?
yes - not easily - need very close contact
*large health care-related outbreaks have been documented.
which area is at risk of MERS?
Arabian Peninsula - Bahrain, Iran, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, United Arab Emirates, Yemen
North, West and East Africa - but risk is minimal
what are the symptoms of MERS?
asymptomatic infection to mild upper respiratory tract illness to severe acute respiratory failure and multiple organ dysfunction
incubation 2-14 days (avg. 5 days) - cough, fever, shortness of breath; abdominal pain, nausea, vomiting, diarrhea; arthralgias and myalgias; chillds; headache; sore throat;
initial symptoms can progress to pneumonia
serious complications: respiratory, renal injury, cardiovascular collapse
abnormal lab: elevated liver function tests, lymphopenia, thrombocytopenia
35% confirmed cases have been fatal
how to diagnose MERS?
specimens from lower respiratory tract or upper resp tract & serum can be used - PCR test
how to prevent MERS?
-general hygiene
-no raw camel milk or camel urine
-no eating meat that has not been properly cooked
what is mumps virus? (family & genus)
single-stranded, negative-sense RNA
famliy Paramyxoviridae
genus Rubulavirus
how is mumps transmitted?
respiratory droplets or saliva
-require close contact for spread
what is transmission period for mumps?
2 days before - 5 days after the onset of parotitis
what is the avg number of cases of mumps reported to WHO annually worldwide?
> 500,000 cases
what is the average incubation period for Mumps?
16-18 days
how many days does mumps symptom (parotid swelling or other salivary gland swelling) last?
5 days
what are nonspecific prodromal symptoms of Mumps before parotitis??
anorexia, low-grade fever, headache, malaise, myalgias
what are the complications of Mumps?
aseptic menigitis, encephalitis, hearing loss, mastitis, oophoritis, orchitis, pancreatitis
how does Mumps diagnosed?
rRT-PCR or virus isolation by culture
-serologic testing IgM antibodies can aid in diagnosis - but not confirmatory
what is the schedule and indicated age for MMRV?
1 dose at 12 month old, and 1 more 28 days after
indicated age 12 months - 12 years
what is norovirus infection caused by?
nonenveloped, single-stranded RNA
genus Norovirus (Norwalk-like viruses, small round-structured viruses)
how does norovius transmit?
fecal-oral
contaminated food or water
fomites
aerosols of vomitus
what food is particularly risky for norovirus transmission?
ready-to-eat cold foods like salads, sandwiches
raw shellfish, osyters
ice
what season does norovirus occur most in temperate climates?
during winter
globally, norovirus causes ….% of acute gastroenteritis cases and could be responsible for …. deaths annually.
18%
200,000 death
what is the incubation period of norovirus?
how long does it take to fully recover?
12-48 hours
1-3 days for recovery
what test is available for norovirus diagnosis?
PCR-based multipathogen diagnostic panels
RT-qPCR - use stool specimens
EIAs - stool specimens (lower specificity and sensitivity compared to RT-qPCR)
what is polioviruses?
genus Enterovirus
small, nonenveloped viruses with a single-stranded RNA genome
3 serotypes - 1, 2, 3 minimal heterotypic immunity between them.
polioviruses are rapidly inactviated by 1… 2… 3… 4…
chlorine,
formaldehyde
heat
UV light
how is polio transmitted?
nasopharyngeal secretions (for 1-2 weeks), stools (3-6 weeks);
virus enters through mouth and fecal-roal routes
which type of polio still circulates in Afghanistan and Pakistan?
type 1
how much chance is there to get paralysis from Polio?
1 in 200 to 1 in 2000 infections are associated with paralysis
25% minor illness
most asymptomatic
what is post-polio syndrome?
weakness or parlaysis occuring 20-30 years later after recovery of polio
how to detect polio?
clinical specimens (usually stools - detected longer upto 60 days compared to oropharyngeal specimens) obtained and virus isolation in cultured cells;
PCR testing of poliovirus isolates can identify the serotype and whether it is WPV, VDPV, or the vaccine (Sabin) strain
what does IPV (inactivated polio vaccine) contain that may cause allergic reaction?
neomycin, polymyxin B, streptomycin
what is dosing schedule for polio vaccine for infants?
4 doses:
2, 4, 6-18 months
4-6 years
if baby got polio at 2, 4 month then third dose after 4 years, does 4th dose needed?
no, only if 3rd was administered at 4 years and older, and 6 or more months after the previous dose.
if baby needs polio protection fast, what is the rapid schedule for polio?
1st dose: 6 weeks old
2nd dose: 4 weeks after
3rd dose: 4 weeks after
4th dose: 6 months after dose 3
then one more when 4 years and up
what is the schedule of polio vaccine in adults who are unvaccinated, incompletely vaccinated, or whose vaccination status is unknown?
3 doses - 2 doses 4-8 weeks apart; 3rd dose at 6-12 months after second dose.
if a person, unvaccinated polio, going to travel in less than 4 weeks, what do you do?
give 1 dose ASAP
if a person, unvaccinated polio, going to travel in 4-8 weeks, what do you do?
2 doses of polio - 4 weeks apart
if a person, unvaccinated polio, going to travel in >8 weeks, what do you do?
3 dose polio, 4 weeks apart
if a person stayed more than 4 weeks in the area with risk for polio, what is the requirement to come back to the country from risky area?
get vaccine 4 weeks to 12 months before the date of departure; proof of polio vaccination on ‘International Certificate of Vaccination or Prophylaxix (ICVP)
If you go to areas where WPV or VDPV is circulating, what is the recommended prophylaxis?
a single lifetime IPV booster dose
if you go to areas that border areas with WPV circulation, and you will be involved in working in health care settings, refugee camps, or other humanitarian aid settings, what is the recommended prophylaxis?
a single lifetime IPV booster dose
