PUNE/CHENNAI: A 10-year-old boy who passed away at Chennai’s Institute of Child Health on January 31 has been confirmed as Tamil Nadu’s first Guillain-Barre Syndrome (GBS) victim, bringing the total death toll from the rare but treatable infection to seven since last month.

Pune, which has recorded five of the GBS-related deaths nationwide, saw its case count rise by three to 166 on Tuesday. The Maharashtra health department identified Campylobacter jejuni as the cause of the outbreak, confirming that the infection was primarily waterborne.

“Of the 70 stool samples collected from patients, 27 tested positive for C. jejuni, reinforcing suspicions that contaminated drinking water was the source of the outbreak,” a senior health department official told TOI.

Authorities ruled out a foodborne origin, explaining that food-related outbreaks typically follow a point-source epidemic pattern, with cases linked to a common food item consumed within a specific timeframe.

At least 87 cases have been reported within a 5km radius of the contamination zone. “Wells in the affected area receive untreated water from the Khadakwasla dam, which is then supplied directly to the community,” the official added.

In response, authorities have instructed the water supply department to maintain a minimum chlorine level of 0.2 ppm in all households.