MYCO & VIROLOGY L7 (Semis- GIT Virus) Flashcards
Most important cause of gastroenteritis among
infants and children (<2yrs old)
Rotavirus
All RNA viruses are single-stranded EXCEPT?
Retoviridae
Virus family of Rotavirus
Reoviridae
Double-stranded RNA (dsDNA) icosahedral non-enveloped
Rotavirus (Retoviridae)
The most frequent human pathogen
Group A rotavirus
Major cause of diarrheal illness in human infants and young animals, including calves and piglets
Rotavirus (Retoviridae)
How many species of Rotaviruses?
Five species (A-E)
How many tentative species of Rotavirus?
Two tentative species (F & G)
The only group of Rotavirus that causes human disease
Group A
Rotaviruses infect cells in the ___________ (gastric and colonic mucosa are spared) and multiply into cytoplasm
villi of the small intestine
Carry epitopes important in neutralizing acitivity
VP4 & VP7
The glycoprotein being the predominant antigen
VP7
Have been implicated in large outbreaks of severe gastroenterisits in adults in China
Grooup B rotavirus
Rotaviruses multiply in the ____________ and damage their transport mechanisms
cytoplasm of enterocytes
Rotavirus infections usually predominate during the?
winter season
A 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
NSP4
Viral excretion usually lasts ______ in otherwise healthy patients but may be prolonged in those with poor nutrition.
2–12 days
Vaccines for rotavirus
1) Oral live attenuated rhesus-based rotavirus vaccine
2) Oral bovine- based rotavirus vaccine
Incubation period of Rotavirus
1-3 days
Lab dx for Rotavirus
Enyzme immunoassay and RT-PCR (most sensitive)
In what year was oral bovine based rotavirus vaccine introduced?
2006
Mechanism of oral bovine based rotavirus vaccine
Delays onset of rotaviruses season
Important agents of viral
gastroenteritis in humans
Caliciviruses or family caliciviridae
Four genera of family caliciviridae
1) Norovirus
2) Sapovirus
3) Lagovirus
4) Vesivirus
Includes vesicular exanthem
virus of swine, feline calicivirus, and marine viruses found in pinnipeds, whales, and fish.
Vesivirus
Rabbit hemorrhagic disease virus
Lagovirus
Small single-stranded RNA, round viruses of 27-30nm in diameter
Norwalk Virus
It is the common cause of infectious gastroenteritis
Norwalk Virus
Incubation period of Norwalk Virus
24-48 hours
MOT of Norwalk
- Food borne (common)
- Water borne
- Person-person transmission- can be significant
Onset is rapid, and the clinical course is brief, lasting 12–60 hours
Norwalk
These genera of caliciviridae contain human viruses that can’t be cultured
Norovirus and Sapovirus
Based on recombinant virus-like particle can detect antibody responses
ELISA immunoassay
Since Novovirus and Sapovirus cannot be detected in culture it relies on?
Immune EM and RT-PCR
These genera of caliciviridae contain animal strains that can be grown in vitro
Lagovirus and Vesivirus
The most used diagnostic test/assay for Norovirus because it detects the viral RNA in stools, vomit, and environmental samples
RT-PCR
Stool should be collected from the px with acute illness or w/in _________ after onset of the symptoms. In some cases it can be collected from ________ after recovery
48-72 hours; 2 weeks
Best sample to detect Norovirus
Stool
Small virus that can range from 32-35 nm in diamter
Sapovirus
Causes diarrheagenic viruses distingusihed by a cup-shaped morphology
Sapovirus
Is there a vaccine for sapovirus?
No vaccine
Most important method to prevent transmission
Effective handwashing
About 28-30 nm in diameter. Exhibit a distincitve star-like morphology in the electron microscope
Astrovirus
Causes diarrheal illness and may be shed in extraordinarily large quantities in feces
Astrovirus
Recognized as pathogens for infants and children, institutionalized patients and immunocompromised
persons
Astrovirus
Number 1 cause of Gastroenteritis in adults
Astrovirus
Astrovirus can be diagnosed using?
Electron Microscope and Immune EM
Largest family in terms of number of genera
Picornaviridae
Small positive single-strand viruses and do not have lipid membrane
Picornaviridae
In replications of Picornaviridae, usually ________, but approximately it takes _______ to replicate
5-10 hours; 8 hours
Identify: Non-enveloped with icosahedral capsids. Their nucleocapsids is 30 nm in diameter, naked, ssRNA
Picornaviridae
4 Human Pathogenic Genera of Picornaviridae:
- Enterovirus (enteroviruses),
- Rhinovirus (rhinoviruses),
- Hepatovirus (hepatitis A virus),
- Parechovirus (parechoviruses),
Foot-and-mouth disease viruses
Aphthovirus
MOT of Poliovirus, Coxsackie, Echovirus, Enterovirus
Fecal to oral
Causes paralytic poliomyelitis
Polioviruses 1-3
Causes superficial rashes at: hand, foot and mouth
Coxsackieviruses A1 to A3 (3 serotypes)
Internal symptoms and BORNHOLM disease (upper
respiratory tract infection > fever, sudden sharp pain in the intercostal muscle)
Coxsackieviruses B1 to B6 (6 serotypes)
MOT of Enteroviruses
Respiratory drops and also fecal oral route
How many serotypes of:
a) Enteroviruses
b) Echovirus
c) Parechovirus
a) Enteroviruses 68 to 104 (HEV A, HEV B, HEV C, and HEV D)
b) Echoviruses 1 to 33 (33 serotypes)
c) Parechovirus 1 to 4 (4 serotypes)
Portal of entry of Enteroviruses
Mouth or Nose >
Lymphoid tissue (pharynx and gut) >
initially will replicate >
particles >
blood stream (viremia) >
TARGET ORGANS (spinal cord, heart & skin) >
infection/ disease
Incubation period of Enterovirus
3-35 days
New human enterovirus classifications
Enterovirus A-D and poliovirus
Endemic worldwide, common infection in children due to poor hygiene
Enterovirus
The only enterovirus that has a vaccine
Poliovirus
Small naked viruses that can cause various diseases
Enteroviruses
Test for enteroviruses
Seum neutralization test
Implicated in early-onset diabetes, cardiopathy, and fetal
malformations
Enteroviruses
Enteroviruses Replicate initially in the?
lymphoid tissue of the
pharynx and gut
Enteroviruses Replicate in the?
respiratory epithelium and gut
Can result in the virus spreading from these locations to the spinal cord, heart, and skin
Viremia
Causes acute hemorrhagic conjunctivitis
Enterovirus 70
Enterovirus70 is retrieved using what spx?
conjunctival swabs and tears
Enterovirus has no group antigen, therefore, it is
being identified individually by?
serum neutralization test
Used for specific confirmation of enterovirus (2pts)
Cell culture neutralization and type-specific antisera
PCR for enterovirus can examine what spx?
CSF
Type of neurological conditions, characterized by paralysis and reduced muscle tone
Polio viruses
Incubation period for poliovirus
7- 14 days (range: 3-35 days)
Most dieases of poliovirus is from what type?
Poliovirus type 1
Most common cases of infection. Infection is restricted to the GIT and is characterized by mild fever with diarrhea to flaccid paralysis
Asymptomatic polio infection
Stiff neck and vomiting as a result of muscle spasm (2% of px)
Non-paralytic poliomyelitis
These are mild diseases. infection of polio virus (2pts)
Asymptomatic polio infection & Abortive poliomyelitis
Minor illness, first symptomatic result is febrile disease, and general malaise (w/ vomiting & sore throat)
Abortive poliomyelitis
This may progress to the brain and may upgrade to infect meninges (aseptic meninges)
Non-paralytic poliomyeletis
Recovery is rapid and complete. Small percentage of this disease may advance to paralysis
Non-paralytic polimyeletis
Classic paralysis that result from a lower motor neuron damage
Paralytic polio
Paralytic polio happens after how many days after the end of the first minor symptoms occur?
4 days
Complete flaccid paralysis since one or more limbs are affected
Spinal paralysis
Affects the cranial nerves & respiratory
Bulbar paralysis
Observed in individuals decades after the experience of paralytic polio
Muscle wasting (Progressive Post-Poliomyelitis Muscle Atrophy)
Portal of entry for poliovirues
mouth
Polio Virus can be seen in blood of px with
non- paralytic polio myelitis
In 1950s, these scientists discovered two separate vaccines for polio virus
Jonas Salk and Albert Sabin
Primary multiplication site of poliovirus
Oropharynx or intestine
Discovered the Inactivated polio vax
Jonas Salk
The most common vaccine in US since 2000. It is being administered by intramuscular vaccine
Inactivated polio vaccine (IPV)
Discovered oral vaccine or oral polio vaccine.
Albert Sabin
This polio vax is a live attenuated vax
oral polio vaccine (OPV)
CDC recommended that children will get how many doses of polio vax? (State in what ages as well)
4 doses of polio vax.
At 2 months old (1), 4 months (1), 6-18 months (1), and 4-6 yrs old (1)
This is prepared from the virus grown in monkey kidney cultures
Formalinized vaccine (Salk)
Inactivate polio vax, administered intramuscularly (IM)
Salk
Induces humoral antibodies but does not induce local intestinal immunity so virus can still multiply in the gut
Killed-virus vaccine
Contains live attenuated vaccine for polio virus 1, 2, and 3 serotypes
Sabin or Live attenuated polio vaccine
Enteric cytopathogenic human orphan viruses
Echoviruses
Symptoms include fever and blisters on the hands, palate, and feet
Enterovirus 71
Sugar cube coated with the vaccines
Oral vaccine
Has been isolated from px with meningitis, encephalitis, and paralysis resembling poliomyelitis
Enterovirus 71
Causes Hand-foot-and-mouth disease (HFMD)
Enterovirus 71
Infect the human enteric tract, associated with aseptic meningitis, rashes, and infantile diarrhea
Echoviruses
