In News:

A henipavirus, specifically the Camp Hill virus, has been detected in North America for the first time. This discovery in northern short-tailed shrews—a small mammal species found commonly in Canada and the U.S.—raises concerns over a potential zoonotic disease outbreak.

About Henipavirus

• Virus Type: Henipaviruses are zoonotic, negative-sense RNA viruses.
• Family: Paramyxoviridae.
• Natural Hosts: Pteropid fruit bats (commonly known as flying foxes).
• Other Hosts: Capable of infecting various mammals, including humans, horses, pigs, and shrews.

Notable Henipaviruses:

• Hendra virus (HeV):
  • First identified in Australia.
  • Mortality rate: Up to 70%.
• Nipah virus (NiV):
  • Found in Southeast Asia, including Malaysia and Bangladesh.
  • Case fatality rate ranges from 40% to 75%, depending on surveillance and clinical care.

Symptoms and Disease Progression

• Initial symptoms: Fever, dizziness, headache, and muscle pain (myalgias).
• Advanced symptoms: Respiratory issues, encephalitis (brain inflammation), confusion, abnormal reflexes, seizures, and coma.
• Relapsing encephalitis may occur months or years after apparent recovery.
• Fatality Risk: High, primarily due to encephalitis and multi-organ failure caused by damage to small blood vessels (microinfarction) in organs like the brain, liver, and kidney.

Why are Henipaviruses so dangerous?

• Henipaviruses produce proteins that:
  • Suppress the innate immune system.
  • Block interferon-stimulated antiviral responses, aiding viral replication.
  • Act as virulence factors, allowing widespread infection and severe outcomes.

Modes of Transmission

• Animal-to-human:
  • Direct contact with infected animals (e.g., fruit bats, pigs, horses, shrews).
  • Consumption of contaminated food or water (e.g., raw date palm sap in Nipah outbreaks).
• Human-to-human: Via bodily fluids, close contact, or respiratory droplets during caregiving.

Treatment and Prevention

• Treatment:
  • No specific vaccine or antiviral currently exists.
  • Management is symptomatic and supportive (respiratory support, ICU care).
• Prevention:
  • Vaccination of horses (in HeV-risk regions like Australia).
  • Avoiding contact with fruit bats and sick animals.
  • Isolating infected individuals and animals to prevent spread.