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3rd October 2023 (9 Topics)

BSL-3 lab for Nipah confirmation

Context

Recently, ICMR permits Kerala to use TrueNat for Nipah testing.

As per a 2021 paper published in the Indian Journal of Medical Research, the sensitivity of Truenat was 97% and specificity was 100%.

Background:

  • Truenat for Nipah virus testing was granted an emergency use authorisation (EAU) by the Indian regulator in September 2021 days after the third Nipah outbreak in Kerala.
  • Both human and bat samples from Kerala were used for validating the test in 2018.
  • In 2019, NIV installed Truenat at the Government Medical College, Ernakulam during the Nipah outbreak, and at two field sites in Punjab as part of the Nipah virus surveillance in bats.

About the update:

  • Truenat will be used for testing Nipah virus at five government medical colleges that have a BSL-2 facility with BSL-3 practices.
  • Private medical colleges that have similar facilities will also be allowed to use Truenat.

What is TrueNat Test and How Does It Work?

  • TrueNat is a chip-based, battery-operated RT-PCR kit.
  • Earlier, it could only identify the E-gene in the virus that causes infections.
  • E-gene helps the virus build a spherical envelope around it.
  • But the current devices are now equipped to detect the RdRp enzyme found in the virus RNA.
  • Therefore, ICMR has ruled that these tests can be treated as a confirmation for the presence of COVID-19 virus and Nipah Virus.

Why BSL-2 facility is essential for testing Nipah virus?

A Biosafety Level 2 (BSL-2) facility is essential for testing the Nipah virus for several reasons:

  • Safety for Laboratory Personnel: Nipah virus is a highly contagious and potentially deadly virus that can be transmitted from animals to humans and between humans.
  • A BSL-2 facility provides a safe working environment for laboratory personnel by requiring appropriate protective equipment, containment measures, and strict protocols to prevent accidental exposure or infection.
  • Containment of the Virus: BSL-2 laboratories have containment measures in place to prevent the escape of the virus into the external environment.
  • These measures include controlled access, use of primary barriers like gloves and lab coats, and secondary barriers like biosafety cabinets and specialized equipment to handle infectious materials.
  • Prevention of Cross-Contamination: BSL-2 facilities are designed to prevent cross-contamination between different samples and experiments.
  • This is crucial when working with Nipah virus samples to ensure that the virus does not inadvertently infect other samples or laboratory materials.

Rules for Nipah Virus Testing:

  • The WHO document mentions that Nipah can be confirmed by detection of the virus RNA or viral culture.
  • For a reference laboratory setting, the “diagnostic options for confirmation can include laboratory NAT, NPT/POC NAT assays, virus isolation (if BSL-3/4 available), and serum neutralisation assays”.
  • Of the diagnostic options for Nipah confirmation, WHO has included both near-patient testing (NPT) and point-of-care (POC) NAT testing.
  • Truenat is a POC NAT test.

The WHO also clearly mentions that BSL-3/4 facility is needed only when virus isolation is undertaken; isolation of viruses is only for research purposes.

Nipah Virus:

  • It is a zoonotic virus (it is transmitted from animals to humans).
  • The organism which causes Nipah Virus encephalitis is an RNA or Ribonucleic acid virus of the family Paramyxoviridae, genus Henipavirus, and is closely related to Hendra virus.
  • Hendra virus (HeV) infection is a rare emerging zoonosis that causes severe and often fatal disease in both infected horses and humans.
  • It first broke out in Malaysia and Singapore in 1998 and 1999.
  • Vectors: It first appeared in domestic pigs and has been found among several species of domestic animals including dogs, cats, goats, horses and sheep.
  • Transmission:
    • The disease spreads through fruit bats or ‘flying foxes,’ of the genus Pteropus, who are natural reservoir hosts of the Nipah and Hendra viruses.
    • The virus is present in bat urine and potentially, bat faeces, saliva, and birthing fluids.
  • Symptoms:
    • The human infection presents as an encephalitic syndrome marked by fever, headache, drowsiness, disorientation, mental confusion, coma, and potentially death.
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