A 21-year-old woman who recentlyreturned to Manipur from Kolkata has tested positive for COVID-19, taking the total number of cases in the state to four, authorities of a hospital where she is being treated said on Saturday.The woman, who works as a nurse in a hospital in Kolkata, returned to Manipur in a bus on May 7 and was in a quarantine centre in Imphal West district till she tested positive for COVID-19 on Friday, the authorities of state-run Jawaharlal Nehru Institute of Medical Sciences (JNIMS) here said.With this development, the number of active cases in the state has risen to two and both the patients are being treated at the JNIMS, they said.Earlier, two other COVID-19 patients had recovered from the disease.