In the recent reports published by WHO and UNICEF about the polio virus spread in the country, the P1 virus has been reported mainly from Delhi or its neighbouring districts in Uttar Pradesh like Ghaziabad and J P Nagar.

According to experts, a significant number of cases are being reported from the migrant population in the state. Owing to this, the health agencies are now trying to figure out better ways to monitor the immunisation status of the migrant population who frequently keep moving out from Uttar Pradesh.

The most recent case of type 1 polio virus reported from Delhi has a clear history of migration from Uttar Pradesh. The two-year-old boy, who was infected with the virus, hails from Uttar Pradesh. After investigation, the health officials found that he had a history of travelling to Uttar Pradesh along with his family.

“This recent case indicates that there is an ongoing circulation of type 1 polio virus in Delhi. As far as the strain of virus is concerned, we expect it to be of the UP strain, which we can ascertain only after the genetic sequencing of the virus,” said an expert with UNICEF.

Another case of P1 virus which was reported last week from Ghaziabad — Uttar Pradesh district neighbouring Delhi — has a similar case history.

“The child, who has been infected in Ghaziabad, belongs to a humble background, with a history of migration and poor immunisation status. We are trying to monitor the immunisation status of all such migratory population,” said Dr SK Pathyarch, regional coordinator of the National Polio Surveillance Project.