Authorities in Vietnam are battling to stop an epidemic of African swine fever, which has been spreading across the country.

In the past week two more provinces in southern Vietnam – An Giang and Binh Duong – have seen outbreaks of the deadly virus.

On May 21, animal health officials in Binh Doung confirmed that two infected areas in two communes had been sanitized thoroughly, the VN Express reported. More than 1,000 infected pigs were put down.

The following day, authorities in An Giang reported 52 pigs had been culled. An investigation suggested that the pigs may have been infected from leftover cattle feed.

Authorities in both provinces acted quickly in an effort to limit the spread of the virus. Checkpoints have been set up on roads and rivers to monitor the movement of pigs.

More than 1.5 million pigs in Vietnam have died or have been put down due to African swine fever, which has been found in at least 34 cities and provinces. The Minister of Agriculture and Rural Development said it would be catastrophic if the disease spreads to large farms.

African swine fever is a fatal disease that does not affect human beings. It was first detected in Vietnam in February and has since made its way to all areas of the nation.