Washington, Jul 5 (IANS): The US has issued a health warning for Pakistan, alerting people against an ongoing outbreak of "extensively drug-resistant" typhoid fever that does not respond to most antibiotics.

In a statement issued here on Wednesday, the US Centre for Disease Control and Prevention urged all travellers to "Pakistan or anywhere else in South Asia" to take extra care with food and water and get a typhoid vaccination, reports Dawn online.

It said the level-2 alert had been triggered by the observation that several travellers to Pakistan returned to their home countries with the disease.

"All travellers to Pakistan are at risk of getting XDR typhoid fever. Those who are visiting friends or relatives are at higher risk than are tourists and business travellers," the CDC warned.

The outbreak of XDR typhoid fever began in Hyderabad, Sindh province, in November 2016.

This strain of Salmonella Typhi does not respond to most antibiotics used to treat typhoid fever.

The outbreak has spread to the city of Karachi and to multiple districts. Several deaths have also been reported, Dawn reported.

Public health authorities in Pakistan are identifying possible typhoid fever cases, starting typhoid vaccination campaigns in the most affected districts and spreading educational messages about proper hand-washing and safe food and water practices.