Monkeypox surveillance helps identify variant of virus causing chickenpox

This is the first study reporting the circulations of varicella zoster virus clade 9 in India, whereas clade 9 is the most common strain in circulation in countries such as Germany, the UK, and the USA.

File photo of test tubes labelled as “Monkeypox virus positive and negative”. Monkeypox disease symptoms are frequently mistaken for chickenpox, as their clinical presentations often closely resemble each other.  | Photo Credit: Reuters

 

The Indian Council of Medical Research-National Institute of Virology (ICMR-NIV) has for the first time found the presence of Clade 9 variant of varicella zoster virus (VZV) in India.

“The multi-country mpox (monkeypox) outbreak across the globe has led to the systematic surveillance of mpox cases in India. During the surveillance of mpox, we encountered cases of VZV in suspected mpox cases amongst children and adults,” said the new study published in the Annals of Medicine journal. This study focused on the genomic characterization of VZV in India.

Chickenpox or varicella is caused by the varicella-zoster virus (VZV), a herpesvirus with worldwide distribution. It establishes latency after primary infection, a feature unique to most herpes viruses.

It added that this is the first study reporting the circulations of VZV clade 9 in India, whereas the variant is the most common strain in circulation in countries such as Germany, the UK, and the USA.

Monkeypox disease symptoms are frequently mistaken for VZV, as their clinical presentations often closely resemble each other. There is a need for clinical differentiation between mpox and VZV for accurate diagnosis, said the study.

It added that despite infection with the VZV clade 9 strain there were no significant indications of heightened disease severity in the patients.

“Further studies warrant investigating the recombination patterns among wild-type and vaccinated populations to explore the evolution to help in disease monitoring and surveillance of VZV infections in India,” it noted.

For the study, scientists took a total of 331 suspected cases, of which 22 cases were positive for monkeypox virus infection (15 from New Delhi and seven from Kerala), while 17 were positive for Enteroviruses and one case was confirmed as Buffalopox virus.

Of these 331 suspects, 28 were positive for VZV, with primary presentation of vesicular rashes all over the body. The other clinical manifestations included fever (82%), myalgia (46%), headache (36%), fatigue (29%), loss of appetite (14%), and lymphadenopathy (11%).