G4 Influenza Virus | UPSC
New influenza virus isolated in pigs in China has pandemic potential
WHY IN NEWS:
Human-to-human transmission possible, pre-existing immunity against flu of no help
SYLLABUS COVERED: GS 3: Diseases
For PRELIMS it is important to understand the new virus ! The recent discoveries are important for prelims . Well we feel this cannot be asked . It is too controversial just like Hantavirus .
For MAINS make sure you have enough key points on influenza and modes of transmission.
G4 INFLUENZA VIRUS
The virus has shown ‘increased human infectivity’ in swine industry workers.
- The study has been published in Proceedings of National Academy of Sciences, a US journal.
- The serological exercise showed that the new gene of the H1N1 virus has efficient infectivity and transmissibility in ferret models.
- MAJOR STRAIN : The swine influenza viruses have many lineages out of which Eurasian-avian (EA) is the most dominant one.
- OUTBREAK : The 2009 pandemic virus went back to pig herds after the outbreak.
- NEW GENOTYPE : The new genotype (G4) of this EA strain of H1N1 virus produced due to reassortment was found to have acquired increased human infectivity.
- INFECTIVITY : However, the current infectivity of all the new emergent EA re-assortants in human populations was not known.
HUMAN-TO-HUMAN TRANSMISSION POSSIBLE
- DIRECT EFFECT : G4 virus could efficiently infect human airway epithelial cells found in the respiratory system.
- CELLULAR DAMAGE : The researchers also assessed replicability in normal human bronchial epithelial cells and alveolar epithelial cells also found in the respiratory system.
- REPLICABILITY : Replicability level of the G4 gene was similar to the 2009 pandemic virus at each point in time and produced virus progeny after 36-60 hours of seeding of infection.
- ORGAN FAILURE : G4 virus caused much more damage to the lungs as compared to the 2009 pandemic virus.
- The transmissibility potential of any virus is dependent on the fact as to how effective human-to-human transmission would be.
- All the four variants of this gene showed effective transmission through direct contact.
- Three of four variants of the G4 showed effective transmission through respiratory droplets too.
- The researchers also confirmed aerosol transmission in G4.
Incidentally, aerosol transmission has not been confirmed for the novel coronavirus SARS-CoV-2.
- Whether pre-existing immunity against one form of a virus will work as a shield against new types depends on the fact as to how much the ‘drift’ or change is in the antigenic properties in the latter.
- The researchers found that G4 type are antigenically distinct from the existing influenza strains.
- So far, the researchers have found five human cases of EA strain in China, of which, two belonged to the G4 type.