Authorities have issued a health alert after 150 cases of pneumonia were recorded in a week in northern Italy.

A pneumonia-causing virus is thought to be lurking in the water supply in Brescia, located in the region of Lombardy.

Autopsies will be carried out on a 69-year-old woman and an 85-year-old man who died this week to determine whether they died from pneumonia, according to local media reports.

Samples have been taken from the water supply network for analysis, but results are not expected for several days.

Hospital emergencies in several municipalities to the south and east of Brescia identified 121 cases of pneumonia, a health officer in the Lombardy region said on television.


Image: A pneumonia-causing virus is suspected to be present in the city's water supply

At least 30 other people had been affected, a survey of general practitioners found.

Provincial health services have called on residents to take precautions - such as disinfecting tap filters and shower hoses.

Letting hot water run for a period of time with the windows open before using it has also been advised.

Pneumonia is a swelling of the tissue in one or both lungs - and is usually caused by a bacterial infection.

Tiny air sacs in the lungs become inflamed and fill up with fluid, with symptoms including chest pain and difficulty breathing.

Pneumonia can be life-threatening, especially among the elderly and those with serious health conditions.