Ten people have been hospitalised after a typhoid outbreak in Auckland and more cases are expected.

Both children and adults have been affected and those being treated were from Mt Roskill, Manurewa and Blockhouse Bay, at this stage. Health experts were not sure of the origin of this latest outbreak but said it was likely to have been brought into the country from Asia or the Pacific.

Typhoid is a serious illness and is potentially fatal, but it can be treated with antibiotics.

Medical Officer of Health Dr David Sinclair said he would not be “surprised if there were more cases”. The first cases were notified at the end of last week.

The Auckland Regional Public Health Service (ARPHS) is tracing people who have been in contact with the confirmed cases and is following usual protocols to control the spread of the disease.

ARPHS provides public health services on behalf of the three district health boards that cover Auckland.

Sinclair said typhoid is spread primarily through water and food but can be spread person to person. Large outbreaks were uncommon in New Zealand.

The last major outbreak was in 2013 but in general there were about 20 to 30 cases a year.

He said the latest outbreak was likely from returning travellers.

“The most likely thing that’s happened is somebody coming back and there’s been some spread in their group.”

Sinclair said good basic hand-washing is one of the best means of protecting yourself.

ARPHS has alerted the health sector to the outbreak.

Sinclair urged anyone with those symptoms who was feeling very unwell to see their doctor or an after-hours clinic.

Typhoid is a fever caused by infection with salmonella typhi bacteria.

Symptoms include a high fever developing over several days, headaches, general weakness and muscle aches. Stomach pain and constipation are also common but some people get diarrhoea.

The disease is spread by eating or drinking food or water that has been contaminated with the faeces of an infected person.

University of Otago Professor of Public Health Michael Baker said in general New Zealand had been successful at eradicating typhoid.

Typhoid rates declined during the 20th century due to improved sanitation and the use of antibiotics, however there are still millions of new cases worldwide each year.

Infections resulted in about 149,000 deaths in 2015 – the last year for which figures were available.

Those figures were collated as part of the Global Burden of Disease study which was published in the Lancet medical journal.

Typhoid is most common in India.