The Darjeeling district health department has raised an alert after at least 29 dengue cases were reported in July from Dudhia, a tiny hamlet located on the outskirts of Siliguri.

Tulsi Pramanik, the deputy chief medical officer of health-II of Darjeeling, said around 140 blood samples had been collected from suspected dengue patients from Dudhia, under St. Mary’s — III panchayat of Kurseong block, and sent to Siliguri district hospital for examination.

Health officials have found that the mosquito variant which is causing the vector-borne disease is the Aedes albopictus.

Health officials said earlier this month, two suspected dengue patients were admitted to the primary health centre in Sukna from Dudhia. “However, in the past two weeks, the number of cases has increased to 29. We have initiated spraying of MLO (mosquito larvicide oil),” said an official.