Gastrointestinal Viruses Flashcards by Frances Julia Leono

Rotavirus

family —
most important cause of gastroenteritis among —

family retroviridae
infants and children <2 yrs old

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Rotavirus

has a ssRNA anf the major cause of diarrheal illness in human infants and young animals like piglets and calves

true or false

false.
double stranded RNA icosahedral non-enveloped

classified into 5 species (A-E) + 2 tentative species (F-G)

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Rotavirus

most frequent human pathogens which the only group that causes human disease

group A rotaviruses

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Rotavirus

outer capsid proteins — carry epitopes important in neutralizing activitiy with — glycoprotein being the predominant antigen.

VP4 & VP7

VP7 - predominant antigen

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Rotavirus

implicated in large outbreaks of severe gastroenteritis in adults in China

group B rotaviruses

rotavirus infections usually predominant during the winter season

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Rotavirus

in retrovirus, genome codes for — and —

6 proteins: VP 1, 2, 3, 4, 6, 7
6 non-structural p: NSP 1-6

once in small intestine, the virus undergoes a change and becomes infective to th villi.

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Rotavirus

rotaviruses infect cells in the — and multiply into cytoplasm. they multiply in the cytoplasm of enterocytes and damage their transport mechanisms.

infect cells in the villi of small infestine (gastric and colonic mucosa are spared)

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Rotavirus

viral enterotoxin and induces secretion by triggering signal transduction pathway, in which those damage cells in the lumen of intestine will be release in stool

NSP 4

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Rotavirus

Viral excretion usually last —
incubation period: —

viral excretion: 2-13 days
IP: 1-3 days

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Rotavirus

enumerate the symptoms

watery diarrhea
fever
abdominal pain
vomiting (rapid loss of fluid leading to dehydration)

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Rotavirus

diarrhea may be due to — as damaged cells on villi are replaced by nonabsorbing immature crypt cells

impaired sodium and glucose absorption

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Rotavirus

this causes loss of electrolytes

nonabsorbing immature crypt cells

severe loss of electrolytes and fluids may be fatal unless it will be treated in infants and children.

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Rotavirus

enumerate the rotavirus vaccines

what is the mechanism of the vaccine?

oral live attenuated rhesus-based
oral bovine-based

bovine-based was introduced on 2006

it delays the onset of the rotaviruses season

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Rotavirus

the virus from the — is demonstrated by —

what is the sample needed?

sample: stool
demonstrated by enzyme immunoassay of real time PCR

PCR - most sensitive detection method

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Rotavirus

management & prevention

IV fluids to correct the loss of water and electrolytes

replacement of fluids and restoration of electrolye balance

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Calciviruses

family —
important agents of —- in humans

family CALCIVIRIDAE
important agents of viral gastroenteritis

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Calciviruses

enumerate the 4 genera

norovirus - norwalk viruses
sapovirus - sapporo-like virus
lagovirus - rabbit hemorrhagic disease
vesivirus - vesicular exanthem virus of swine, feline calicivirus, and marine viruses

norwalk viruses is the most significant member

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Calciviruses

small single-stranded RNA, round viruses of 27-30 nm in diameter. common cause of infectious gastroenteritis

incubation period: ?

norwalk virus
IP: 24-48 hrs

onset is rapid, and the clinical course is bried, lasting 12-60 hours.

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Calciviruses

MOT of norwalk virus

foodborne (common)
waterborne
person-person transmission

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Calciviruses

all of the ff are the symptoms of norwalk virus, except:
- diarrhea
- nausea
- vomiting
- low-grade fever
- abdominal cramps
- headache
- malaise

none

all are included so FAMILIARIZE!

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Calciviruses

genera that cannot be detected in culture and it relies on immune EM and RT PCR

Norovirus and Sapovirus

Norwalk - outbreak during 1968 in Norwalk, Ohayo
Sapovirus - discovered in Sapporo Japan, 1977

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Calciviruses

based on recombinant virus-like particles that can detect antibody responses, with a fourfold sapovirus greater rise in IgG antibody titer

— is the indicative of a recent infection

ELISA immunoassays

convalescent-phase sera - indicative of a recent infection

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Calciviruses

most used diagnostic test/assay for Norovirus bcos it detects — and can be used to detect stools, vomit and environmental samples

RT-PCR
detects viral RNA

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Calciviruses

best sample to detect Norovirus. this should be collected from patients with acute illness or —

STOOL
patient with acute illness or within 48-72 hrs after onset of the symptoms

stool can be collected from 2 weeks after the recovery

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# Calciviruses small virus that can range from 32-35 nm in diameter. it causes diarrheagenic viruses distinguished by a ---

SAPOVIRUS distinguished by a **cup-shaped morphology**

# Calciviruses for sapovirus, there is vaccine available and the treatment is supported based on the clinical symptoms. | true or false

FALSE. **there is NO VACCINE!**

# Calciviruses - S prevention control | enumerate

- containment and disindection of soiled areas - careful processing of food and education of food handlers - purification of drinking water and swimming pool | **handwashing** is the most important method to prevent transmission

# Astrovirus family: --- with a --- morphology in EM and it contains single-stranded RNA

FAMILY ASTROVIRIDAE **star-like morphology**

# Astrovirus MOT

**fecal-oral route** through contaminated food or water

# Astrovirus recognized as pathogens for ---

- infants - children - institutionalized patients - immunocompromised persons

no.1 gastroenteritis in adults

Astrovirus ## Footnote Astroviruses cause **diarrheal illness** and may be shed in extraordinarily large quantities in feces.

# Astrovirus all of the ff are the symptoms, except: - diarrhea - headache - nausea - vomiting - low-grade fever

vomiting

# Astrovirus used for diagnosis (2)

Electron M. & Immune EM

small positive single-strand viruses and do not have lipid membrane, non-enveloped with icosahedral capsids. it is largest family in terms of number of genera. | nucleocapsids is **30 nm** naked ssRNA

PICORNAVIRIDAE

# Picornaviridae in replication, it is usually 5-10 hours but approx. it takes **8 hours to replicate** | true or false

TRUE. pico means **small**

# Picornaviridae enumerate the genera/s

- enterovirus - rhinovirus - hepatovirus - parechovirus - aphtovirus - cardiovirus | first four (HERP) are the **human pathogenic genera**

# Picornaviridae genera of foot-and-mouth disease viruses

Aphthovirus

# Picornaviridae genus Enterovirus include ---

Polioviruses and Coxsackieviruses

# Enteroviruses this enterovirus causes paralytic poliomyelitis

Polioviruses 1-3

# Enteroviruses this enterovirus has 3 serotypes and causes superficial rashes in the foot, hand, and mouth

Coxsackieviruses A1-A3

# Enteroviruses this enterovirus has 6 serotypes internal symptoms

Coxsackieviruses B1-B6

# Enteroviruses this refers to an upper respiratory tract infection, fever, and sudden sharp pain in the intercostal muscle

BORNHOLM DISEASE

# Enteroviruses HEV A, HEV B, HEV, C, HEV D

Enteroviruses 68-104

# Enteroviruses echoviruses has --- serotypes

33 serotypes

# Enteroviruses parechovirus has --- serotypes

4 serotypes

# Enteroviruses MOT

- fecal-oral - respiratory drop/aerosol inhalation - fomite

# Enteroviruses portal of entry

1. mouth/nose 2. lymphoid tissue (pharynz and gut) 3. initially will replicate > particles 4. will go to the bloodstream **viremia** 5. target organs of infection/disease **spinal cord, heart, skin**

# Enteroviruses vaccines are available for all enteroviruses. | true or false

FALSE. no vaccines are available **except for POLIO**

endemic worldwide, common infection in children bcos of poor hygiene

enterovirus

# Enteroviruses incubation period and symptoms | enumerate

IP: **3 - 35 days** symptoms: mild nausea and diarrhea *except for neonates* | neonates can be severe bcos of the **immaturity of their immune system**

# Enteroviruses fever of unknown origin, aseptic meningitis, paralysis, sepsis-like illness, myopericarditis, pleurodynia | this is associated with infections of ---

Coxsackie type **B**

# Enteroviruses conjunctivitis exanthemas is caused by ---

enterovirus serotype **71**

# Enteroviruses this has also been implicated in early on-set diabetes, cardiomyopathy, and fetal malformations | true or false

TRUE | portal or entry: alimentary or via mouth/nose

can result in the virus spreading from these locations to the spinal cord, heart, and skin. this refers to ---

viremia

# Enteroviruses specimens of choice (5)

- stool (prolonged period of infection) - rectal swabs - throat swabs (replication) - washings - CSF

# Enteroviruses this is associated with acute hemorrhagic conjunctivitis | what could be the specimen of choice?

Enterovirus 70 | specimen of choice: **conjunctival swabs and tears**

this virus has no group antigen so it is being identified individually by **serum neutralization test**

enterovirus

# Enteroviruses for specific confirmation (2)

- cell culture neutralization - type-specific antisera

# Enteroviruses diagnosis is made by ---

nucleic acid amplification (PCR) | CSF - **PCR**

# Enteroviruses used to detect presence of acute infection of enterovirus

ELISA: IgM (antibody titer)

flaccid muscle paralysis, this refers to ---

paralytic poliomyelitis

# Polio this is a type of neurological conditions characterized by ---

paralysis and reduced muscle tone

# Polio most diseases are from --- | incubation period ?

**Polio type 1** | IP: **7-14 days**

# Polio infection is restricted to the gastrointestinal tract and it is characterized by mild fever with diarrhea to flaccid paralysis. this refers to ---

Asymptomatic polio infection | most common cases of infection

# Polio minor illness, first asymptomatic result is febrile disease, general malaise with vomiting and sore throat

Abortive poliomyelitis

# Polio mild diseases/infection (2)

Asymptomatic & Abortive

# Polio this disease occurs during the 1st week of infection of abortive polio

febrile disease

# Polio stiff neck and vomiting as a result of muscle spasm. it may progress to the brain and may upgrade to infect meninges > aseptic meningitis | this refers to ---

non-paralytic polio | small percentage of this disease may advance to paralysis

# Polio resulting from a lower motor neuron damage, this refers to ---

classic paralysis

# Polio arrange in order: - affects anterior horn cells of the SN to the brain - affects motor neurons/cortex of the brain - spreads from the blood - results to spinal paralysis/bulbar p

- spreads from the blood - affects anterior horn cells of the SN to the brain - affects motor neurons/cortex of the brain - results to spinal paralysis/bulbar p

# Polio paralysis is more pronounced in very young and very old patients | t or f

true

# Polio complete flaccid paralyssi since one or more limbs are affected

spinal paralysis

# Polio affects the cranial nerves & respiratory

bulbar paralysis

# Polio result of physiologic and aging changes in a paralytic patient that already burdened by the loss of neuromuscular functions

progressive post-poliomyelosisits muscle atrophy

# Polio this is observed in individual decades after the experience of paralytic polio

muscle wasting

# Polio portal of entry: ? primary multiplication site: ?

Portal of entry: **mouth** multiplication site: **oropharynx or intestine**

# Polio virus can bee seen in --- of patients with non paralytic polio and the virus invades a certain type of ---

seen in **blood of patients** invades in **nerve cells**

# Polio in the process of intracellular multiplication, it may damage or completely destroy these cells resulting in a ---

loss of neuromuscular functions

# Polio Jonas Salk discovered what type of vaccine?

**Intramuscular Polio Vaccine** in U.S. since 2000

# Polio CDC recommended that children will get 4 doses of polio vaccine: 1 dose of each ff stages ---

- 2 mnths old - 4 mnths old - 6-18 mnths old - 4-6 yrs old

# Polio he discovered the **Oral Polio Vaccine** which is a live attenuated vaccine

Albert Sabin | OPV contains polio virus 1, 2, 3 serotypes

# Polio formalinized vaccine (Salk) is prepared form virus grown in ---

monkey kidney cultures

# Polio killed virus vaccine induces humoral antibodies which induces local intestinal immunity. | t or f

FALSE **does not induce** so that virus is still able to multiply in the gut

enteric cytopathogenic human orphan virus, this refers to ---

Echoviruses

# Echovirus this infect human enteric tract associated with --- (3)

- aseptic meningitis - rashes - infantile diarrhea

this has been isolated from patients with meningitis, encephalitis, and paralysis resembling poliomyelitis

enterovirus 71

enterovirus 71 causes the ---

hand-foot-and-mouth disease

# enterovirus 71 enumerate the symptoms

fever and blisters on the hands, palate, and feet