AuCoin 3: + strand non-enveloped viruses

Question 1

What are TWO non-enveloped + strand RNA viruses?

Answer 1

picornaviruses

calici

Question 2

What are the three subclasses of picornaviruses?

Answer 2

enterovirus
rhinovirus
hepernavirus

Question 3

Describe the genetic structure of the picornaviruses.

Answer 3

naked virion
small
icosahedral capsid
ssRNA genome

Question 4

Which type of picornavirus is resistant to pH 3-9, detergents, sewage treatment and heat?

Answer 4

enteroviruses

ex: poliovirus, coxsackie A and B, echovirus, enterovirus

Question 5

The genome of picornaviruses is (blank), which infers that it could be infectious without its capsid; the genome replicates in the (blank); the viral genome produces (blank)

Answer 5

mRNA; cytoplasm; polyproteins

Question 6

What enzyme is essential for replication of RNA viruses in the cytoplasm?

Answer 6

RNA-dependent RNA polymerase

Question 7

Do + sense RNA viruses need RNA-dependent RNA included in the virion?

Answer 7

no - they are mRNA, but RNA dependent RNA polymerase makes - strand RNA as a template for more + strand RNA

Question 8

How are picornaviruses, like enterovirus and poliovirus, transmitted?

Answer 8

fecal-oral route

Question 9

What % of picornaviruses are clinically apparent?

Answer 9

1%

Question 10

Where does initial replication occur for the picornaviruses?

Answer 10

in the oropharynx and small intestine, leading to nausea and vomiting

Question 11

What can the poliovirus cause?

Answer 11

disease ranges from asymptomatic to paralytic poliomyelitis, which is an acute viral infection of the meninges and the motor neurons of the spinal cord and brainstem

Question 12

What clinical clues would cause you to expect a case of paralytic poliomyelitis?

Answer 12

individual has acute onset of flaccid paralysis

stool sample or swab of pharynx with poliovirus

Question 13

In what countries is poliovirus still endemic in? Is it seen in the Western hemisphere?

Answer 13

Nigeria, Pakistan, Afghanistan; eradicated from the Western hemisphere

Question 14

What do enteroviruses cause?

Answer 14

viral meningitis

Question 15

Which is worse, viral or bacterial meningitis?

Answer 15

bacterial

Question 16

Who gets viral meningitis? How do they get it?

Answer 16

younger children less than 5yo; changing a diaper or not properly washing their hands after fecal contact

Question 17

What clues would tell you that a patient has viral meningitis?

Answer 17

sudden onset of fever, headache, stiff neck; accompanied by nausea, vomiting, photophobia, altered mental status

**symptoms last 7-10 days and then the patient usu recovers

Question 18

If meningitis is expected, what should you obtain from the lab?

Answer 18

CSF sample and a blood sample

Question 19

Coxsackie viruses are non-polio enteroviruses. What are the two flavors, and what does each cause?

Answer 19

Group A causes herpangina - ulcers in oropharynx, fever, sore throat (hand-foot-and-mouth-disease) and Group B causes pleurodynia - fever, pleuritic chest pain, myocarditis

Question 20

Groups A and B Coxsackie viruses can cause what condition?

Answer 20

aseptic meningitis

mild paralysis

Question 21

Who usually gets Coxsackie viral infections? How do you diagnose it?

Answer 21

young people with naive immune systems; diagnosed by PCR of enteroviral RNA in spinal fluid

Question 22

The echovirus (ECHO = enteric cytopathic human orphan) is another type of non-polio enterovirus. How is this virus transmitted?

Answer 22

fecal-oral route, transmitted in pools

Question 23

What do echoviruses cause?

Answer 23

aseptic viral meningitis
upper respiratory tract infection
febrile illness
infantile diarrhea
hemorrhagic conjunctivitis
hand foot and mouth disease

Question 24

How do you diagnose echovirus?

Answer 24

PCR

Question 25

This virus is the main cause of the common cold; there are over 100 serological types; transmitted by aerosolized droplets or fomites

Answer 25

rhinovirus

Question 26

How do you get infected with rhinovirus? What does it infect?

Answer 26

through the upper respiratory tract; infects nose rather than lower resp tract

Question 27

How would you know if someone had the rhinovirus?

Answer 27

after 2-4 days of incubation, they will be sneezing w nasal discharge, sore throat, cough, headache (usu no fever or aches) **illness lasts about 1 week

Question 28

Fever and extreme exhaustion are not usually seen with rhinovirus infection. What are these more commonly symptoms of?

Answer 28

influenza infection

Question 29

What does the Heparnavirus cause?

Answer 29

Hep A

Question 30

What is the heparnavirus also known as? How is it transmitted?

Answer 30

enterovirus 72; one serotype; transmitted by fecal-oral route in areas of poor sanitation and poor hygiene - infection occurs from fecally contaminated water and food

Question 31

What are the clinical symptoms of heparnavirus infection?

Answer 31

``` fatigue fever nausea vomiting JAUNDICE dark urine, pale feces elevated liver enzymes ``` * *may be asymptomatic, mild illness, or debilitating illness * *15-50 day incubation period

Question 32

How do you diagnose heparnavirus?

Answer 32

IgM antibodies or 4-fold rise in IgG 1-3 weeks after infection

Question 33

How do you recover from heparnavirus?

Answer 33

usu just resolves in 2-4 weeks, no chronic infection

Question 34

What vaccine would you recommend for people who travel?

Answer 34

heparnavirus! **international travel is considered the number one risk factor for HAV infection in the US

Question 35

Everything discussed so far was PICOrna viruses. Now onto CALICviruses. What is the main pathogen in the calicivirus family?

Answer 35

Norovirus - Norwalk virus

Question 36

How is Norwalk virus transmitted? What do people usually ingest that causes infection?

Answer 36

fecal-oral route; contaminated seafood or water (on cruiseships, in pools)

Question 37

What are the symptoms of Norwalk virus?

Answer 37

``` most common cause of viral gastroenteritis in older children and adults in the US sudden onset of vomiting diarrhea (non-bloody) low grade fever abdominal cramping ``` **short incubation period (24hrs)

Question 38

How do you diagnose Norwalk virus infection?

Answer 38

clinically | can use PCR on stool