Calcutta, Dec. 1: At least 12 suspected cases of chikungunya have surfaced in Salt Lake slums in the past one week, prompting the North 24-Parganas administration to signal an alert.

All the cases have been detected in the Polenite area in ward 14 of the Bidhannagar Municipality behind Sector V, a health official said.

The health department today sent a team of doctors and top officials, including Bidhannagar sub-divisional officer Tapas Chowdhury and district chief medical officer of health (CMOH) Sandip Sanyal, to the area.

“So far, 12 suspected cases of chikungunya have been detected from the area. We have collected blood samples and sent them for tests to the School of Tropical Medicine,” Sanyal said.

According to health officials, at least 40 residents of the area have mild symptoms of the usually non-fatal viral disease, spread by mosquito bites.

“So far, only 12 cases with strong symptoms like high fever, joint pain and skin inflammation (red rashes) have been identified. All of them have been suffering from high fever for nearly seven days,” a health official said.

Some of them had taken medicines prescribed by local doctors but the fever did not subside. “They have also developed other symptoms that match those of chikungunya like joint pain and rashes,” the official said.

Sanyal said a health camp had been set up in the area.

“Our officials and doctors have also begun house-to-house inspections. A campaign to spread awareness has been started so that if there is any sign or symptom that bears even the remotest similarity with chikungunya, it can be promptly reported,” he added.

The Bidhannagar Subdivisional Hospital as well as Matri Sadan, a healthcare facility run by the municipality, and the health camp set up in Polenite have been asked to take “prompt action” if they receive information of anyone suffering from chikungunya symptoms.

The authorities are also distributing medicines like paracetamol and chemicals to kill mosquito larvae in drains.