Enteric Viruses Flashcards
What are the 2 human-infecting Reoviruses?
Orthoreoviruses–cause mild GI symptoms
Rotaviruses–Significant gastroenteritis
What do reoviruses have that allows for reassortment of the genome?
Segmented genome
When do most of the rotavirus infections occur?
During the winter months
What is impaired by the rotavirus that causes excessive fluid loss and complications of dehydration?
Small intestinal villi
The rotavirus has _____ that causes profuse watery diarrhea.
Nonstructural protein 4 (NSP4)–acts like an enterotoxin
–Interfers with sodium transport pumps and causes profuse watery diarrhea
What is the tx for rotavirus?
Oral rehydration
IV fluids if required
What are the 2 vaccines for rotavirus?
RotaTeq and Rotarix–approved for and may help reduce severity of disease
What is the prototypical strain in within the norovirus genus that causes disease?
Norwalk
How does Norovirus differ from Rotavirus?
It affects the microvilli of the small intestine just like rotavirus, BUT also delays gastric emptying which causes vomiting
Less dehydration and fewer complications than rota
Nausea is common with norovirus
What are the 2 major classes of Picornaviruses?
Rhinoviruses
Enteroviruses
What are the 4 classes of enteroviruses?
HepA
Polioviruses
Coxsakieviruses–A and B
Echoviruses
Enteroviruses display dual tropism–what does this mean?
Immune response to viremia clears virus, full recovery with lifelong immunity to reinfection
OR
During viremia–virus invades CNS
What does Coxsackie A cause?
Herpangina
Hand-foot-mouth dz
Acute hemorrhagic conjunctivitis
What does Coxsackie B cause?
Myocarditis and pleurodynia
What are the 2 vaccine types for Poliovirus?
Inactivated
Attenuated–virus is weak–used in eradication efforts
What receptor does poliovirus use to enter the cell?
CD155 receptor–enters and infect epithelial/lymphoid cells in the gut lining then spreads to bloodstream and regional lymph nodes
What is the big problem with poliovirus?
CD155 receptors are also found on gray matter CNS cells–allowing the virus to enter the CNS by crossing the BBB or by axonal transportation from peripheral nerve (retrograde)
What portions of the CNS does the poliovirus infect?
ANTERIOR HORN MOTOR NEURONS!!! and the brain stem–respiratory centers
What is seen on LP of pt with poliovirus?
Pressure
Protein
Pleocytosis
Virus culture
What can be seen on MRI of a pt with poliovirus?
Localization of inflammation to the spinal cord anterior horns
What is found on exam of a pt with Herpangina caused by Coxsackie A?
Small vesicular or ulcerative lesions on posterior oropharyngeal structures
When does Herpangina usually occur?
During the summer months
What are the other 2 causes of herpangina besides Coxsackie A?
Coxsackie B and other enteroviruses (enterovirus 71)
What cause rarely occur from Hand-foot-mouth disease caused by coxsackie A?
Aspetic meningitis or myocarditis, interstitial pneumonitis, and pulmonary edema
Rapid-onset painful conjunctivitis caused by coxsackie A virus?
Acute hemorrhagic conjunctivitis
Who are at highest risk of developing viral myocarditis caused by Coxsackie B?
Infants and pregnant/immunocompromised pts
What will be seen on CBC of pt with viral myocarditis caused by Coxsackie B?
Acute anemia
Lymphocytosis or neutropenia—supporting dx of viral infection
What is found on histology of a pt with myocarditis caused by Coxsackie B?
Focal or diffuse interstitial infiltrate of mononuclear cells, lymphocytes, plasma cells, and eosinophils
Necrosis and disarrangement of myocytes
In chronic and healing stages–myocytes are replaced by fibroblasts
What are the signs and symptoms seen with Pleurodynia caused by Coxsackie B?
Sudden occurrence of lancinating chest pain attacks
Fever
Malaise
HA
Pleural friction rub
What is targeted by Coxsackie B viruses that causes pleurodynia?
Infection of the striated muscle in the chest –responsible for attacks of severe CP
Viral pleurodynia has been suggested as a trigger for immune-mediated sequale, which are?
Myocarditis
Dermato-polymyositis
Chronic fatigue syndrome
Juvenile onset DM type 1
What are potential complications seen from Coxsackie B virus infection in infants?
Fulminant hepatic failure
Sepsis syndrome
Meningoencephalitis
What is the usually outcome of viral meningitis?
Usually self-limited–complete recovery in 7-10days
MUST RO bacterial or fungal meningitis
What viruses can cause septic shock in infants?
Enteroviruses and HSV
