Rabies in Children
Introduction to Rabies in Children
Rabies is a zoonotic viral disease caused by the rabies virus, a member of the Lyssavirus genus. It primarily affects the central nervous system and is almost always fatal once clinical symptoms appear. Children are particularly vulnerable due to their curiosity and tendency to approach animals. Understanding rabies in pediatric populations is crucial for healthcare providers to ensure prompt recognition, appropriate management, and effective prevention strategies.
Etiology of Rabies
Rabies is caused by neurotropic viruses belonging to the genus Lyssavirus, family Rhabdoviridae. The primary causative agent is the rabies virus (RABV), a bullet-shaped, enveloped virus with a single-stranded, negative-sense RNA genome. Other lyssaviruses can also cause rabies-like diseases. Key points include:
- Transmission occurs primarily through the saliva of infected animals, usually via bites or scratches.
- Common reservoirs include dogs (responsible for 99% of human rabies cases), bats, raccoons, skunks, and foxes.
- The virus cannot penetrate intact skin; it requires a break in the skin or contact with mucous membranes.
Epidemiology of Rabies in Children
Rabies remains a significant public health concern, particularly in developing countries. Epidemiological features in children include:
- Higher incidence in children aged 5-14 years due to increased outdoor activities and interactions with animals.
- Boys are more frequently affected than girls, possibly due to behavioral differences.
- Most cases occur in rural areas where access to post-exposure prophylaxis may be limited.
- In endemic areas, children under 15 years account for 40-50% of all human rabies cases.
- Regions with the highest burden include Asia and Africa, with India accounting for 36% of global deaths.
Pathophysiology of Rabies
The pathophysiology of rabies involves several stages:
- Inoculation: The virus enters through a break in the skin or mucous membrane.
- Replication: Initial viral replication occurs in muscle cells at the site of inoculation.
- Neural Spread: The virus enters peripheral nerves and travels to the central nervous system (CNS) via retrograde axonal transport.
- CNS Involvement: Once in the CNS, rapid replication occurs, causing neuronal dysfunction and death.
- Centrifugal Spread: The virus spreads from the CNS to other organs, including the salivary glands.
The incubation period in children is typically shorter than in adults, ranging from 2 weeks to 3 months, depending on factors such as the site and severity of exposure, viral load, and proximity to the CNS.
Clinical Presentation of Rabies in Children
The clinical course of rabies in children progresses through several stages:
- Prodromal Phase (2-10 days):
- Nonspecific symptoms: fever, malaise, anorexia, nausea, sore throat
- Paresthesia or pain at the site of the bite
- Acute Neurologic Phase (2-7 days):
- Furious Rabies (80% of cases):
- Hyperactivity, agitation, confusion, hallucinations
- Hydrophobia (fear of water) and aerophobia (fear of drafts of air)
- Autonomic dysfunction: hypersalivation, sweating, piloerection
- Paralytic Rabies (20% of cases):
- Ascending flaccid paralysis
- Sensory disturbances
- Bladder dysfunction
- Furious Rabies (80% of cases):
- Coma and Death:
- Rapid progression to coma
- Multiple organ failure
- Death usually occurs within 7-14 days after symptom onset
Diagnosis of Rabies in Children
Diagnosing rabies in children can be challenging due to its nonspecific initial symptoms. Key diagnostic approaches include:
- Clinical Diagnosis:
- History of animal exposure
- Characteristic symptoms (e.g., hydrophobia, aerophobia)
- Laboratory Tests:
- RT-PCR on saliva, skin biopsy (nuchal), or cerebrospinal fluid
- Direct fluorescent antibody test on skin biopsy
- Serum and CSF antibody detection (in unvaccinated individuals)
- Imaging:
- MRI may show T2 hyperintensities in the brainstem, hippocampus, or basal ganglia
Antemortem diagnosis remains challenging, and rabies is often confirmed postmortem through brain tissue examination.
Treatment of Rabies in Children
Once clinical symptoms appear, rabies is almost invariably fatal. Management focuses on supportive care and palliative measures:
- Supportive Care:
- Maintenance of airway, breathing, and circulation
- Sedation and analgesia for comfort
- Management of seizures and autonomic dysfunction
- Prevention of secondary complications
- Experimental Approaches:
- Milwaukee Protocol: Induced coma and antiviral therapy (limited success)
- Favipiravir and other novel antivirals (under investigation)
The primary focus remains on prevention through proper wound care and timely administration of post-exposure prophylaxis (PEP) following potential exposure.
Prevention of Rabies in Children
Prevention is crucial and involves several strategies:
- Pre-exposure Prophylaxis (PrEP):
- Recommended for children at high risk (e.g., living in or traveling to endemic areas)
- Consists of a series of rabies vaccinations
- Post-exposure Prophylaxis (PEP):
- Immediate wound cleansing with soap and water
- Rabies immunoglobulin (RIG) infiltrated around the wound
- Series of rabies vaccinations (day 0, 3, 7, 14, and sometimes 28)
- Animal Control and Vaccination:
- Mass vaccination of domestic dogs
- Control of stray animal populations
- Education:
- Teaching children about animal behavior and avoiding contact with unfamiliar animals
- Raising awareness about the importance of seeking medical care after animal bites
Rabies in Children
- What is the causative agent of rabies?
Rabies virus (a Lyssavirus) - Which animal is the most common source of rabies transmission to humans worldwide?
Dogs - What is the primary mode of rabies transmission to humans?
Animal bites - What is the average incubation period for rabies in humans?
1-3 months (can range from 1 week to 1 year) - Which of the following is NOT a typical symptom of rabies in children?
Prolonged fever without neurological symptoms - What is the term for the fear of water associated with rabies?
Hydrophobia - Which part of the nervous system does the rabies virus primarily affect?
Central nervous system - What is the recommended first aid for a potential rabies exposure?
Thorough washing of the wound with soap and water - Which of the following is NOT a category III exposure according to WHO classification?
Licks on intact skin - What is the name of the test used to diagnose rabies in humans ante-mortem?
RT-PCR on saliva, skin biopsy, or CSF - How many doses of rabies vaccine are recommended for post-exposure prophylaxis in previously unvaccinated individuals?
4 doses (day 0, 3, 7, and 14-28) - What is the name of the immunoglobulin used for passive immunization in rabies post-exposure prophylaxis?
Rabies Immunoglobulin (RIG) - Which of the following is a contraindication for rabies vaccination?
There are no absolute contraindications for rabies PEP - What is the recommended site for intramuscular administration of rabies vaccine in children?
Anterolateral thigh - Which of the following animal exposures does NOT typically require rabies post-exposure prophylaxis?
Exposure to vaccinated domestic dogs and cats - What is the name of the characteristic microscopic finding in rabies-infected brain tissue?
Negri bodies - Which of the following is NOT a typical clinical presentation of rabies in children?
Gradually progressive paralysis over weeks - What is the survival rate for symptomatic rabies infection?
Near 0% (only a few documented survivors) - Which country was the first to eliminate dog-mediated rabies?
United Kingdom (in 1902) - What is the name of the global initiative to eliminate dog-mediated rabies by 2030?
Zero by 30 - Which of the following is NOT a component of the rabies virus?
Envelope glycoprotein E - What is the recommended observation period for a healthy dog or cat that has bitten a person?
10 days - Which of the following is NOT a typical prodromal symptom of rabies?
Hemiparesis - What is the term for the aggressive, excited form of rabies?
Furious rabies - Which of the following is the gold standard for rabies diagnosis post-mortem?
Direct fluorescent antibody test on brain tissue - What is the recommended route of administration for Rabies Immunoglobulin (RIG)?
Infiltration into and around the wound - Which of the following is NOT a typical CSF finding in rabies encephalitis?
Markedly elevated protein with normal cell count - What is the name of the protocol used to treat clinical rabies in the Milwaukee rabies survivor?
Milwaukee protocol - Which of the following is NOT a recommended method for rabies prevention in dogs?
Annual deworming - What is the minimum age for pre-exposure rabies vaccination in children?
There is no minimum age (can be given to infants if indicated) - Which of the following is NOT a typical feature of paralytic rabies?
Ascending paralysis starting from the bite site - What is the term for rabies transmitted by bats in the Americas?
Sylvatic rabies
