CNS
Page 1: Overview of Central Nervous System Viruses
Viral Pathogens in the CNS
Types of Viruses:
Arboviruses: La Crosse virus, St. Louis virus, West Nile virus, Zika virus
Cytomegalovirus
Enteroviruses: Echovirus, Parechovirus, Poliovirus
Herpes family viruses: Herpes simplex virus, Varicella virus
Transmission: Primarily mosquito-borne for arboviruses.
Page 2: CNS Viruses Continuation
Additional CNS Viruses:
Human immunodeficiency virus (HIV)
John Cunningham virus (JCV)
Lymphocytic choriomeningitis virus (LCMV)
Measles virus
Mumps virus
Rabies virus
Abbreviations:
AV: alphaviruses
BV: bunyaviruses
CMV: cytomegalovirus
HEV: human enteroviruses
HIV: human immunodeficiency virus
HSV: herpes simplex virus
JCV: John Cunningham virus
JEV: Japanese encephalitis virus
LCMV: lymphocytic choriomeningitis virus
MeV: measles virus
Nipah virus
PV: poliovirus
RV: rabies virus
SLEV: St. Louis encephalitis virus
TBEV: tick-borne encephalitis virus
WNV: West Nile virus
Page 3: Arboviruses Insight
Enveloped RNA Viruses:
Key Arboviruses:
California serogroup virus (including La Crosse virus)
St. Louis encephalitis virus
West Nile virus
Zika virus
Transmission Routes:
Via arthropod vectors (mosquitoes)
Congenital transmission (specific to Zika virus)
Sexual transmission (Zika virus only)
Blood transfusion (Zika & West Nile viruses)
Epidemiology:
Disease incidence correlates with vector distribution and is more common in summer.
At-risk Populations:
Individuals with outdoor exposure and those traveling to endemic regions.
Page 4: La Crosse Virus - Clinical Characteristics
Clinical Syndrome:
Incubation Period: 5 to 15 days
Symptoms:
Asymptomatic in most cases
Mild symptoms: Fever, headache, nausea, fatigue
Severe symptoms include seizures and possible coma, especially in children <16 years old.
Reservoirs: Chipmunks and squirrels are natural reservoirs for La Crosse virus (LACV).
Page 5: La Crosse Virus - Diagnosis and Treatment
Diagnosis Methods:
Antibody detection (note issues with cross-reactivity with other arboviruses)
Molecular detection of the virus
Treatment/Prevention:
No approved antivirals; supportive care only.
Recommend insect repellent to prevent mosquito bites.
St. Louis Encephalitis Virus:
Similar clinical syndrome with asymptomatic cases and severe symptoms in >60 years population.
Page 6: St. Louis Encephalitis Virus Overview
Clinical Presentation:
Similar incubation and symptom profile as La Crosse virus.
Biological risk factor for severe disease noted in older adults.
Transmission:
Also transmitted by infected female mosquitoes, primarily birds as reservoirs.
Page 7: West Nile Virus - Overview
Clinical Syndrome:
Incubation Period: 5 to 15 days
Asymptomatic in about 80% of cases
Symptoms can include mild WNV fever and severe cases leading to neurologic symptoms.
Mortality rate of about 10% in severe cases.
Page 8: West Nile Virus - Diagnosis and Treatment
Diagnosis:
Antibody detection with potential cross-reactivity issues
Molecular detection of the virus
Treatment/Prevention:
No approved antivirals; supportive care only.
Public education on insect repellent use and mosquito control.
Page 9: Zika Virus - Clinical Features
Clinical Syndrome:
Incubation: 3 to 14 days
Mostly asymptomatic; mild symptoms include fever, headache, and joint pain.
Risks to pregnant women include serious birth defects like microcephaly.
Page 10: Zika Virus - Overview, Diagnosis, and Treatment
Public Health Impact:
First identified in 1947; outbreaks significantly occurred in the US since 2015.
Diagnosis and Treatment:
Diagnosis through antibody detection, issues with cross-reactivity noted.
No approved antivirals; supportive care recommended, including public education.
Page 11: Cytomegalovirus Overview
General Information:
An enveloped DNA virus with life-long infection.
Asymptomatic to mild disease; can lead to serious conditions in immunocompromised individuals.
Page 12: Cytomegalovirus - Clinical Features
Clinical Presentation:
Rash, jaundice, microcephaly, and retinitis in congenital cases.
Hearing loss is common among survivors.
Page 13: Cytomegalovirus - Diagnosis and Prevention
Diagnosis Methods:
Includes antibody detection and molecular methods.
Treatment/Prevention:
Supportive care and education with hygiene practices highlighted.
Page 14: Enteroviruses Overview
Types:
Includes Poliovirus, Echovirus, Parechovirus.
Transmission primarily through fecal-oral route or respiratory secretions.
Page 15: Poliovirus Specifics
Clinical Syndrome:
Asymptomatic in about 70% of cases; severe disease can lead to meningitis and paralysis.
Post-polio syndrome can occur years later.
Page 16: Poliovirus - Diagnosis and Treatment
Diagnosis:
Culture, antibody detection, molecular detection from stool specimens.
Treatment/Prevention:
Vaccine availability (Salk and Sabin) with no approved antivirals.
Page 17: Echovirus and Parechovirus Insights
Clinical Syndrome:
Generally asymptomatic but can cause severe illness, particularly aseptic meningitis.
Page 18: John Cunningham Virus Overview
Transmission:
Via urine or respiratory secretions.
Most individuals are infected by adolescence.
Page 19: JC Virus Disease Course
Clinical Implications:
Progressive multifocal leukoencephalopathy (PML) occurs in immunocompromised individuals, characterized by damage to the myelin in the brain.
Page 20: Lymphocytic Choriomeningitis Virus (LCMV) Overview
Transmission:
Rodent reservoirs; zoonotic infection.
Found in urine, saliva, and droppings of infected mice.
Page 21: LCMV Clinical Features
Clinical Presentation:
Biphasic febrile illness with potential CNS involvement.
Page 22: LCMV Diagnosis and Treatment
Diagnosis:
Antibody detection and molecular methods; no approved antivirals available.
Page 23: Rabies Virus Overview
Transmission:
Primarily from wild animal bites, especially bats and dogs being major reservoirs.
Page 24: Rabies Virus Clinical Syndrome
Clinical Picture:
Incubation can vary significantly; includes prodrome and neurologic phases leading to potential death.
Page 25: Rabies Virus Diagnosis and Treatment
Diagnosis Methods:
Clinical observation and various molecular and antigen detection methods.
Treatment/Prevention:
Emphasis on post-exposure prophylaxis to prevent CNS invasion.