Rabies and West Nile Virus Quiz

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Questions and Answers

What is the recommended timeframe for administering post-exposure prophylaxis after rabies exposure?

Within 14 days of exposure

Within 5 days of exposure

At any time after exposure

Within 10 days of exposure (correct)

Which of the following is NOT an effective preventive measure against rabies?

Using mosquito repellent (correct)

Post-exposure vaccination

Preventive veterinary vaccination

Oral vaccination of wild animals

What is the primary host for the West Nile Virus?

Birds (correct)

Ticks

Humans

Horses

What percentage of individuals infected with West Nile Virus typically experience asymptomatic cases?

80% Signup and view all the answers

Which statement reflects a characteristic of arboviruses, including the West Nile Virus?

They are transmitted by insects and can infect various mammals. Signup and view all the answers

What differentiates encephalitis from meningitis?

Encephalitis involves inflammation of the brain parenchyma. Signup and view all the answers

Which of the following viruses is primarily associated with viral meningitis?

Enterovirus Signup and view all the answers

Which of the following is NOT a classic symptom of viral meningitis?

Severe abdominal pain Signup and view all the answers

What is a common presenting symptom of encephalitis that is not typical of meningitis?

Motor or sensory deficits Signup and view all the answers

Which host immune response contributes to the pathology of the CNS in viral infections?

Cellular immune response and cytokines Signup and view all the answers

Which of the following conditions refers to simultaneous inflammation of the meninges and the brain?

Meningoencephalitis Signup and view all the answers

Which enterovirus is specifically associated with encephalitis in parts of East and Southeast Asia?

Enterovirus 71 Signup and view all the answers

Which viral illness is known to be a common cause of encephalitis?

Japanese encephalitis Signup and view all the answers

Which group is mainly affected by non-polio enteroviruses causing viral meningitis?

Infants and young children Signup and view all the answers

What characterizes the clinical presentation of viral meningitis in children?

Meningism triad Signup and view all the answers

How do non-polio enteroviruses primarily transmit to the CNS?

Through faecal-oral route Signup and view all the answers

Which of the following is NOT a common symptom of encephalitis?

Irritability Signup and view all the answers

What distinguishes sporadic from variant CJD?

Transmission method Signup and view all the answers

What is a significant characteristic of the symptoms of viral meningitis compared to bacterial meningitis?

Symptoms appear more slowly over days Signup and view all the answers

Which of the following methods is NOT a standard diagnostic test for rabies?

Complete blood count Signup and view all the answers

What is the expected CSF glucose level in viral meningitis?

Normal glucose levels Signup and view all the answers

Which virus is most commonly associated with subacute sclerosing panencephalitis (SSPE)?

Measles virus Signup and view all the answers

What is the typical clinical presentation of encephalitis caused by herpes viruses?

Symptoms of meningitis Signup and view all the answers

Which route of infection is the usual pathway for enteroviruses to reach the CNS?

Via the bloodstream Signup and view all the answers

Which of the following viruses is NOT typically associated with causing CNS infections?

Leptospira Signup and view all the answers

Post-infectious complications of measles can include which of the following?

Neurological symptoms Signup and view all the answers

Which virus is known to cause flaccid paralysis in infections?

West Nile virus Signup and view all the answers

Congenital infections affecting the CNS can be caused by which of the following viruses?

Rubella Signup and view all the answers

Which of the following is considered a typical cause of viral meningitis?

Enteroviruses Signup and view all the answers

What is the main approach for rabies prevention after a potential exposure?

Administration of vaccines within a specified timeframe Signup and view all the answers

Which population is primarily targeted for vaccination to prevent West Nile Virus transmission?

Wild animal populations Signup and view all the answers

Which of the following symptoms is characteristic of mild West Nile Virus infection?

Flu-like symptoms such as headache and generalized aches Signup and view all the answers

What percentage of people infected with West Nile Virus remain asymptomatic?

80% Signup and view all the answers

Which of the following best describes the typical environmental conditions for West Nile Virus transmission?

Late summer or early autumn in temperate regions Signup and view all the answers

Which virus is specifically associated with post-infectious complications like Subacute Sclerosing Panencephalitis (SSPE)?

Measles Signup and view all the answers

What is a primary route for enteroviruses to reach the central nervous system (CNS)?

Via the bloodstream Signup and view all the answers

Which of the following viruses is NOT typically linked with causing encephalitis?

Coxsackie virus Signup and view all the answers

Which condition is characterized by an inflammation of both the meninges and the brain?

Encephalitis Signup and view all the answers

What term describes the inflammatory response of the CNS to viral infections where the blood-brain barrier is affected?

Neuroinflammation Signup and view all the answers

What symptom might present after measles, indicating a neurological complication?

Behavioral changes Signup and view all the answers

Which virus is NOT commonly recognized for causing congenital damage to the CNS?

Measles virus Signup and view all the answers

Which type of virus is most commonly associated with viral meningitis?

Enteroviruses Signup and view all the answers

What best describes the condition referred to as meningoencephalitis?

Simultaneous inflammation of the meninges and brain Signup and view all the answers

Which virus is NOT mentioned as a cause of viral encephalitis?

Ebola Virus Signup and view all the answers

Which clinical presentation is typically associated with encephalitis but not with meningitis?

Altered mental status Signup and view all the answers

Which statement is true regarding the symptoms of viral meningitis?

Irritability may be noted in children Signup and view all the answers

What differentiates encephalitis from meningitis regarding clinical presentation?

Encephalitis affects normal brain function Signup and view all the answers

Which of the following is a common route of infection for enteroviruses affecting the CNS?

Oral-fecal transmission Signup and view all the answers

Which of the following viruses has not been identified with CNS manifestations?

Rubella Signup and view all the answers

What is the primary route of transmission for non-polio enteroviruses?

Faecal-oral route Signup and view all the answers

Which enterovirus has been associated with acute flaccid paralysis following respiratory illness?

Enterovirus D68 Signup and view all the answers

What is the typical progression of symptoms in viral meningitis compared to bacterial meningitis?

Symptoms evolve more slowly over several days Signup and view all the answers

Which of the following is true regarding the severity of illness in viral meningitis patients?

They are not usually as sick as patients with bacterial meningitis Signup and view all the answers

What CNS manifestation is associated specifically with Enterovirus 71?

Viral encephalitis Signup and view all the answers

Which laboratory test is standard for diagnosing rabies?

PCR from saliva or CSF Signup and view all the answers

What is the typical demographic affected most commonly by non-polio enteroviruses causing viral meningitis?

Infants and young children Signup and view all the answers

Study Notes

Viral Pathogens of the CNS/Encephalitis

This presentation covers viral pathogens causing central nervous system (CNS) infections, specifically meningitis and encephalitis.
Meningitis is inflammation of the meninges (membranes surrounding the brain and spinal cord).
Encephalitis is inflammation of the brain parenchyma (the actual brain tissue).
Meningoencephalitis is a condition where both the meninges and the brain parenchyma are inflamed.
Viral meningitis is more common than bacterial meningitis.
Viral encephalitis is variable, ranging from benign to deadly, impacting morbidity and mortality depending on the pathogen and host interaction.

Learning Outcomes

Differentiate between meningitis and encephalitis
Understand the causes, routes of infection, clinical presentation, diagnosis, and management of viral meningitis (mostly enteroviruses).
Learn about viral encephalitis: HSV, WNV, Tick-borne encephalitis, Japanese encephalitis, Polio, and Rabies
Discuss other important viruses (polio, Zika, measles, JC, HIV) causing CNS manifestations.
Understand the aetiology of Transmissible Spongiform Encephalopathy (TSE).
Contrast sporadic and variant CJD, and outline CJD prevention strategies.

Difference Between Meningitis & Encephalitis

Meningitis: Inflammation of the meninges. Symptoms often include fever, stiff neck, headache, etc
Encephalitis: Inflammation of the brain parenchyma. Symptoms often include altered mental status, motor/sensory deficits, seizures, etc.
If both meninges and brain are inflamed, it’s meningoencephalitis.

Viral Infections of the CNS

Viral infections can be part of a generalized infection (e.g., polio) or affect the CNS directly.
CNS infections may be evident some time after the initial infection.
Measles can cause subacute sclerosing panencephalitis (SSPE).

Viruses Causing CNS Infection

Meningitis: Enteroviruses, Herpes Viruses (HSV, VZV, HHV6), Mumps
Encephalitis: Herpes Viruses (HSV, VZV, HHV6), Enteroviruses, Mosquito-borne (West Nile, Japanese encephalitis, flaviviruses), Tick-borne flaviviruses, Rabies
Paralysis: Enteroviruses (esp. polio virus), WNV, JE, Zika, measles (post-infectious encephalitis, SSPE), VZV (vasculitis, arteritis, stroke)

Viral Meningitis in Ireland (2019)

Data from the HPSC shows trends in viral meningitis cases.
Enteroviruses and herpes simplex viruses frequently reported contributors.

Viral Encephalitis in Ireland (2019)

Data tracked the prevalence of viral encephalitis.
Herpes simplex virus type 6 and varicella-zoster virus were common contributors.

Infectious Disease Notifications (Ireland 2019-2023)

Reports of viral encephalitis, hemorrhagic fevers, and meningitis trends.

Congenital Infections and CNS Damage

Certain viruses, like rubella, cytomegalovirus, and Zika virus, can cause congenital damage to the CNS.

Viral Meningitis

More common than bacterial meningitis.
Many viral causes, including: Enteroviruses (echoviruses, coxsackie B, enterovirus 71), Herpesviruses (herpes simplex, VZV), Mumps, Arboviruses (e.g., West Nile virus, Japanese encephalitis virus).
Route of infection: typically via the bloodstream or nerve pathways, but some viruses (e.g., enterovirus, can replicate in and spread from the GI tract).
HSV (Herpes Simplex Virus) infections are sometimes treated with antiviral medication like acyclovir. Note, differentiating between HSV meningitis and encephalitis is crucial

How Do Viruses Cause CNS Damage?

Pathology is multifactorial, including virus multiplication, cellular damage, and the host's immune response (cellular+cytokines).
Common symptoms include fever, headache, neck stiffness, vomiting, and photophobia.
Symptoms usually unfold more slowly than in bacterial meningitis..

Non-Polio Enteroviruses

Common cause of viral meningitis, especially subtypes like echoviruses, coxsackie B, and enterovirus 71.
Primarily impacts infants and young children, usually with mild, self-limiting symptoms.
Can be severe in neonates
Peak activity typically occurs in late spring and autumn.
Primarily a human-only reservoir
Transmission: faecal-oral route. Viruses often multiply in the gastrointestinal tract and can enter the bloodstream to seed other organs, including the CNS

Non-Polio Enteroviruses: Other CNS Manifestations

Enterovirus 71: associated with encephalitis (especially in East and Southeast Asia).
Enterovirus D68: potentially linked to acute flaccid paralysis after respiratory illness.
Enteroviral infections frequently produce other syndromes (not involving the CNS), including fever, rash, myocarditis, pericarditis, hand, foot, and mouth disease.

CSF Findings in Viral Meningitis

In viral meningitis analysis the CSF typically displays normal glucose levels, high protein levels and elevated lymphocytes
Differentiating viral meningitis from other conditions requires careful analysis of CSF characteristics such as the presence of specific microbes

Diagnosis: CSF findings in Viral Meningitis (differential diagnosis)

A lymphocytic response in CSF is seen in several other conditions, including Leptospirosis, Syphilis, Lyme Disease, Cryptococcosis, Toxoplasmosis, TB, malignant infiltration of the meninges or connective tissue diseases.

Viral Meningitis: Treatment

Generally self-limiting, especially outside the neonatal period.
Supportive care (rest, hydration, antipyretics) is usually sufficient.
Seizure management might be required.

Viral Encephalitis

Self-limiting viral meningitis is generally benign, but viral encephalitis can have substantial morbidity and mortality, depending on specific pathogen and host interaction..
Important examples include herpes simplex virus (HSV), varicella-zoster virus (VZV), rabies, West Nile virus, Japanese encephalitis, and tick-borne encephalitis.

Herpes Simplex Encephalitis

Common in Northern Europe; HSV-1 type is more common than HSV-2
Human-restricted virus
Route of infection occurs from (primary or reactivation latent sites in cranial nerve ganglia) to frontal or temporal lobes in the brain
Neonatal Herpes simplex encephalitis typically associated with primary infection acquired around the time of delivery. Usually affects the entire brain and has high mortality.
Adults and children over 3 months of age often experience HSV encephalitis restricted to the CNS and have a higher chance of recovery from the infection but still a very high mortality rate without treatment

HSV Encephalitis: Clinical Features

Symptoms include an acute neurological syndrome, such as behavioral disturbance, hemiparesis, aphasia, focal seizures.
Diagnosis relies on MRI to identify temporal lobe changes, EEG, and detection of HSV in CSF via PCR.
Treatment involves prompt intravenous (IV) acyclovir (acyclovir).

HSV Encephalitis: Neonatal

HSV usually transmitted from the mother to infant during childbirth
Typically disseminated infection, affecting the entire brain
High mortality rate.
Treatment involves IV acyclovir.
Preventing maternal transmission is crucial, with focus on genital herpes management during pregnancy.

VZV Encephalitis

Complication of either primary (chickenpox) or reactivation (shingles) of varicella-zoster virus (VZV).
Symptoms are similar to HSV encephalitis.
Diagnosis involves detection of VZV DNA in CSF through PCR.
Treatment usually includes high-dose IV acyclovir.
Prevention includes childhood chickenpox vaccination and shingles vaccinations for older adults.

Rabies

Viral zoonotic disease causing acute encephalitis.
High global mortality rates are observed.
The majority of human cases stem from dog bites.
Incubation time depends on distance the virus needs to travel to reach the CNS.
No effective antiviral treatment exists and is mostly fatal

West Nile Virus (WNV)

Arbovirus transmitted by the bite of infected mosquitoes.
Birds are the primary reservoir hosts.
Primarily affecting temperate zones (e.g., Northern North America) during late summer and early autumn.
Often asymptomatic cases, but can lead to severe neurological symptoms including encephalitis and/or meningitis.
Diagnosis is usually reliant on detecting West Nile IgM in blood or CSF.

Japanese Encephalitis (JE)

Arbovirus, closely related to WNV, found in Asia.
Humans are incidental hosts to the virus.
Infection cycle involves mosquitos and vertebrate host (pigs are most common).
Prevalent in agricultural areas (e.g., rice paddy fields).
The disease is often asymptomatic, but can cause severe neurological complications (encephalitis).
Prevention is largely dependent on immunization measures

Tick-Borne Encephalitis (TBE)

Caused by RNA flaviviruses within the arbovirus family.
Transmission occurs via infected Ixodes ticks.
Typically found in forest regions of Central and Eastern Europe, Russia, Mongolia, and China.
3 subtypes exist. Distribution varies geographically.
Symptoms include fever, headache, mild to severe neurological complications.
Diagnosed from testing for viral RNA and TBEV in blood or CSF
Prevention includes avoiding tick bites, protective clothing, and vaccination.

Other Causes of Viral Encephalitis

Enteroviruses (including polio virus): often cause meningitis but sometimes encephalitis.
Other arboviruses affect specific regions worldwide.

Poliovirus

Important cause of paralysis before vaccination.
Human-only reservoir (fecal-oral).
Now significantly less prevalent despite cases occurring globally
Prevention is through vaccination programs.
WHO polio eradication campaign has reduced wild polio outbreaks.
Wild poliovirus type 1 is now exceedingly uncommon despite cases persisting in certain parts of globe.
Polio presents with varying degrees of disease and paralysis,

Paralytic Polio

Spinal (80%): asymmetrical lower limb paralysis—damage to motor neurons in spinal cord
Bulbar: cranial nerve nuclei in brainstem—tongue/pharyngeal muscles, resulting in weakness/paralysis.
Bulbospinal: combination of the two.
Post-Polio Syndrome: years after infection, characterized by weakness, muscle pain, and further neurological issues.

Polio Re-emergence

Waning vaccine coverage and disruptions to vaccination campaigns contribute to polio re-emergence in previously eradicated locations

Zika Virus

RNA virus (Flaviviridae family) transmitted primarily by Aedes mosquitoes.
Can infect CNS and peripheral nervous system.
Congenital Zika syndrome (severe microcephaly and brain damage in newborns) highly correlated
Linked to Guillain-Barre syndrome (post-infectious paralysis).

Chronic CNS Viral Infections

Subacute sclerosing panencephalitis (SSPE): a lingering measles infection, develops years after initial disease.
HIV encephalopathy; causes neurological dysfunction in HIV-positive patients.
Progressive multifocal leukoencephalopathy (PML): a rare opportunistic infection mostly impacting immune-compromised individuals.

TSE (Transmissible Spongiform Encephalopathy) = Prion Diseases

Fatal degenerative brain diseases (e.g., Creutzfeldt-Jakob Disease (CJD)).
Caused by abnormal prion proteins that accumulate in the brain; these proteins are resistant to conventional sterilization.
Various subtypes of CJD (sporadic, inherited, variant).
Variant CJD is often linked to consuming BSE-contaminated products.

CJD: Sporadic vs. Variant

Sporadic CJD has a late-onset (typically in the 60s) and relatively rapid progression.
Variant CJD often affects younger individuals and has a slower progression

CJD: Diagnosis

Diagnosis relies heavily on post-mortem histological examinations.

CJD: Treatment & Prevention

No effective treatment exists.
Prevention focuses mostly on protecting the blood supply and food chain with policies like barring feeding bone meal to livestock and properly sterilizing surgical instruments to prevent transmission.

Additional Topics (not in Summary)

Prescribing Safety Assessment (details not explicitly summarized).
Sample PSA MCQ (details not explicitly summarized).

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Test your knowledge on rabies exposure management and West Nile Virus characteristics. This quiz covers important preventive measures, host information, and the prevalence of asymptomatic cases. Perfect for students and professionals in health-related fields.