The disease, known as Naegleria Fowleri, which leads to 'brain eating amoeba' killed two more persons this week, taking the toll to five, Sindh Health Minister Dr Sagheer Ahmed said.
He said the disease occurs due to contaminated and stagnated water.
Over a dozen patients are being treated for the deadly bacteria in private hospitals around the city.
Ahmed said the health department had directed hospital administrations to remain on high alert and to report any cases to the government.
"It is a parasite and the amoeba passes through the nasal membranes and destroys brain tissues," Dr Asfar Ahmed, a private practioner, told PTI.
