Patients in the city of Eluru, in the state of Andhra Pradesh, reported a range of symptoms including seizures, loss of consciousness and some nausea over the weekend, said Dolla Joshi Roy, the district surveillance officer of Eluru’s West Godavari District.

This comes as India continues to battle the Covid-19 pandemic, with the world’s second-highest number of infections. Andhra Pradesh is one of the worst-affected states, and currently has more than 800,000 confirmed cases.

But Covid-19 wasn’t the cause of the mass hospitalizations over the weekend.

“All patients have tested negative for Covid-19,” said Roy, adding that about 180 patients have now been discharged, while the rest are “stable.” The patient who died had reported similar symptoms to the others, but then had a fatal but unrelated cardiac arrest, she said.