Two Indian states have issued a health warning over reported cases of hand, foot and mouth (HFMD) disease in a neighbouring state.
Karnataka and Tamil Nadu have asked officials to be cautious after Kerala state reported 80 cases.
The affected children, all under the age of five, have recovered after treatment.
The infection causes a rash and painful blisters, but in some cases results in brain infections which can be fatal.
Patients can also suffer from high fever, joint pain, stomach cramps, nausea, vomiting and diarrhoea.
Experts told the BBC that there was no need to panic about the virus but that authorities needed to stay alert.
"The risk of this disease is low but it can cause meningitis in rare cases. Therefore, if you notice any symptoms, you should seek the services of a doctor," Kerala's Health Minister Veena George said in a statement.
Dr Jacob John, a prominent virologist, said that HFMD is caused by two different viruses - Coxsackievirus-A16 and Enterovirus-71. The first one is milder and takes longer to spread.
It's not clear yet which of the viruses is responsible for the cases in Kerala.
"Just as we do genome sequencing to understand the nature of the Covid virus, we need to keep a check on this in the same manner. It needs to be kept under constant watch," Dr John said.
He added that the child should be quarantined as soon as the virus is identified. With proper treatment, they can recover in 8-10 days.
Both Karnataka and Tamil Nadu sounded the alert because thousands of people travel back and forth across the states for work and education.
Several media reports have termed the infection "tomato flu" because of the red boils it causes - but Dr John criticised this.
"Please do not use terms like tomato or brinjal for an infection just because of a boil," he said.
This is not the first time that Kerala has dealt with HFMD cases.
Between 2012 and 2017, the state reported 1,150 cases, according to a 2018 study.
"The new infections are not unusual because we are seeing that across the world, including in China, bacterial infections are coming down and viral infections are going up,'' said Dr TS Anish, one of the authors of the study.
One of the major reasons for a reduction in bacterial infections was that people have adopted better hygiene practises after the Covid pandemic.
"But it is very difficult to prevent viral infections from spreading because the surveillance mechanism finds it difficult to pick them up,'' he said.