Zika Virus

Zika Virus 

Context:

The Union Health Ministry issued an advisory in response to reported cases of the Zika virus in parts of Maharashtra.

  • States are urged to maintain constant vigilance and focus on screening pregnant women for the Zika virus.
  • There is an emphasis on monitoring the growth of the foetus in expecting mothers who test positive for the Zika infection.
  • Health facilities are instructed to identify a nodal officer to monitor and take action to keep premises free of Aedes mosquitoes, the vector for the Zika virus.

Relevance:
GS-02 (Government policies and interventions, Health)

Dimensions of the Article:

  • About Zika Virus
  • Recent developments
  • About Viruses
  • Structure of Virus

About Zika Virus:

  • Zika virus is transmitted primarily by Aedes mosquitoes, which bite mostly during the day
  • The Zika virus, like several other pathogens, utilizes unique receptors on host cells for entry and infection. One such receptor is phosphatidyl serine (PS), typically expressed by dying cells as a signal for immune clearance. Viruses exploit this pathway by mimicking PS on their surfaces, allowing them to infect unsuspecting host cells.
  • Most people with Zika virus infection do not develop symptoms; those who do typically have symptoms including rash, fever, conjunctivitis, muscle and joint pain, malaise and headache that last for 2–7 days.
  • Zika virus infection during pregnancy can cause infants to be born with microcephaly and other congenital malformations as well as preterm birth and miscarriage.
  • Zika virus infection is associated with Guillain-Barré syndrome, neuropathy and myelitis in adults and children.
  • In February 2016, WHO declared Zika-related microcephaly a Public Health Emergency of International Concern (PHEIC), and the causal link between the Zika virus and congenital malformations was confirmed.
  • WHO declared the end of the PHEIC in November of the same year. Although cases of Zika virus disease declined from 2017 onwards globally, transmission persists at low levels in several countries in the Americas and other endemic regions.

Recent developments:

  • Recent research conducted at the Institute of Molecular Virology at Ulm University Medical Centre, Germany, had uncovered a novel defense mechanism against Zika and related viruses.
  • Extracellular vesicles, small structures released by cells, were found to contain PS proteins on their surfaces, akin to those exploited by viruses for entry.
  • Importantly, these vesicles were abundant in bodily fluids like saliva and semen, where viral transmission occurs.
  • Through experiments, researchers demonstrated that PS-containing vesicles compete with viruses for entry receptors, effectively blocking viral infection.
  • Implications of the Discovery:
    • The significance of this discovery extends beyond Zika virus to encompass other pathogens that utilize the PS receptor for entry, including dengue, chikungunya, and Ebola viruses.
    • By elucidating a new avenue of host defense, this research opens doors for potential therapeutic interventions against a range of infectious diseases.

 

About Viruses:

  • Viruses, unlike living organisms, are unique entities that straddle the boundary between the living and non-living world.
  • They consist of genetic material enclosed in a protein coat called capsid.
  • Their genome is either a RNA or a DNA.
  • Despite their reproductive capabilities, viruses cannot survive outside a host cell and lack essential cellular components like ribosomes. Instead, they rely on host cells for protein synthesis and energy production.

Structure of Virus:

  • A virus is essentially genetic material surrounded by either a protein shell, called a capsid, or by a membrane, called an envelope.
  • This envelope is made of lipids (fat or fat-like substances that can be broken down by soap and other detergents) derived from the host cell and proteins.
  • Viruses that infect bacteria are called bacteriophages.
  • These can have elaborate structures, such as tail fibers, that allow the virus to attach to cells and inject genetic material.

Way Forward:

Enhanced Surveillance and Public Awareness:

  • States should bolster surveillance systems to detect and respond promptly to Zika virus cases. This includes setting up monitoring mechanisms in high-risk areas and ensuring timely reporting of cases.
  • Launch comprehensive public awareness campaigns to educate communities about Zika virus transmission, symptoms, and prevention methods.

Research and Development:

  • Encourage and fund research initiatives to understand the molecular mechanisms of Zika virus and its interactions with host cells. Meanwhile, explore innovative solutions, such as the use of extracellular vesicles, to block viral entry and prevent infection.

Strengthening Health Infrastructure:

  • Ensure health facilities are well-equipped to screen for Zika virus, especially among pregnant women. Equip laboratories with necessary tools for accurate and quick diagnosis.
  • Appoint and train nodal officers in all health facilities to implement effective mosquito control measures, ensuring premises are free from Aedes mosquitoes.

International Collaboration and Support:

  • Foster international collaboration to share best practices, resources, and technologies for Zika virus prevention and control. Engage with global health organizations like WHO for guidance and support. Also, it is important to participate in joint research initiatives with countries that have successfully managed Zika outbreaks, to benefit from their expertise and apply successful strategies locally.