Mpox Clade Ia has evolved to jump from humans-to-humans

Context: Scientists have been wary of
the reemergence of poxviruses, particularly mpox. In 2022-2023, the WHO
declared the mpox outbreak a ‘public health emergency of international concern.
Clade Ia is the oldest known variant of the mpox virus. It has been responsible
for sporadic infections in humans, mostly children, since 1970. But
transmission was always from animals to humans. Researchers used APOBEC
activity to show Clade Ia viruses have achieved human-to-human transmission.
This is because 63% of mutations they observed in the Clade Ia infections were
consistent with changes that could be introduced by APOBEC.

Key points

·      
Overview: In
2022-2023, the World Health Organisation (WHO) declared the then global
outbreak of mpox a public health emergency of international concern. In August
this year, the WHO declared mpox to be a public health emergency for the second
time in two years.

·      
Clade Ia: Clade
Ia is a subclade of the monkeypox virus, which is a viral illness that is also
known as mpox. The monkeypox virus has two clades: clade I and clade II. Clade
I has two subclades, Ia and Ib, while clade II has two subclades, IIa and IIb.

Ø 
Clade Ia- Clade Ia is
mostly transmitted from animals to humans and is spread mainly in children.

Ø 
Clade Ib- Clade Ib is
more contagious than previous variants, and is transmitted more rapidly between
people, including through sexual activity.

·      
APOBEC: APOBEC
(Apolipoprotein B mRNA Editing Catalytic Polypeptide-like) is a family of
proteins that deaminate cytosine to uracil in single-stranded nucleic acids. APOBEC
proteins are found in all tetrapods, including primates, and in bony fish,
including lampreys. The activity of APOBEC proteins is regulated through
genetic alterations, changes in transcription and mRNA processing, and
interactions with other macromolecules in the cell. They have a variety of
functions in human health and disease, including-

Ø 
DNA mutators:
Can generate diversity in antibody genes but can also cause genomic instability
in cancer.

Ø 
RNA editors:
Can generate diversity in the transcriptome of innate immune cells and cancer
cells.

Ø 
Restricting DNA and RNA viruses:
APOBECs can restrict DNA and RNA viruses.

Significance- APOBEC
proteins can be combined with the CRISPR/Cas9 system to perform targeted base
editing or induce hypermutagenesis. This combination improves the
CRISPR/Cas9-mediated gene editing at single-base precision.

·      
Conclusion: Clade
Ia viruses can spread from humans to humans is not likely to affect the
vaccination strategies of the affected countries. However, it is certainly
cause for worry because researchers know that the different mpox clades respond
differently to certain antiviral drugs used to treat them.