The Northern Territory's health department is trying to work out the cause of more than 50 reported cases of salmonella in Darwin.
The Centre for Disease Control (CDC) is investigating whether there is a common food source consumed by the affected people across Darwin, Palmerston, and the rural area.
On average the department examines four to eight cases a week, Dr Peter Markey, the CDC's head of surveillance said on Wednesday.
"Given the number of cases we've been alerted to, understandably, we are very keen to quickly identify the source of the problem," Dr Markey said in a statement.
The CDC is interviewing affected people, inspecting food premises and taking samples.
Dr Markey said this strain of salmonella has been increasing in other states, so the Darwin cluster may be linked to a national increase.
What causes salmonella?
* Contaminated raw foods are a common cause, and include eggs, raw meat, poultry, seafood, fruit and vegetables, as well as condiments such as spices and sauces
* Environmental factors including geckos, frogs and family pets can also be a possible source, especially among babies and people doing dirty jobs around the home or garden
* Symptoms include fever, diarrhoea, abdominal pain, vomiting and sometimes headache
* Anyone with prolonged or severe diarrhoea who is vomiting and refuses extra fluids should see a doctor, as should anyone who has prolonged or severe diarrhoea and is unable to keep down fluids.
SOURCE: Northern Territory Department of Health, April 2016
