Patients visit Tamil Nadu dental clinic for checkup, get infected with deadly disease: 8 of 10 die

A shocking new study published in The Lancet has revealed that eight people died after getting infected with a rare and deadly brain infection called neuromelioidosis. The source of the infection? A dental clinic in Vaniyambadi town in Tamil Nadu’s Tirupattur district.

The outbreak happened in 2023 but was not reported by any government agency. The infection was linked to unclean dental practices, according to a joint investigation by doctors from CMC Vellore, ICMR-NIE, and Tamil Nadu's Directorate of Public Health.

How did it happen?

The study found that a surgical tool called a periosteal elevator was used to open a saline bottle, which was later loosely closed. The same bottle was reused for other patients. At least 10 people got infected, and eight of them died, making the fatality rate 80%.

Dr Angel Miraclin Thirugnanakumar from CMC Vellore, the lead author of the study, said the bacteria entered through nerve pathways when the infected saline was used to clean patients’ mouths. This allowed the bacteria to reach the brain quickly.

Further testing showed that the bacteria had a gene that attacks the brain more aggressively.

What is neuromelioidosis?

Neuromelioidosis is a severe infection of the brain and spinal cord caused by a bacteria called Burkholderia pseudomallei. This bacteria is usually found in contaminated soil and water in tropical areas.

Symptoms include:

• Fever
• Headache
• Slurred speech
• Blurred vision
• In some cases, facial paralysis

Between July 2022 and April 2023, researchers found 21 cases in total. Of these, 10 patients had visited the dental clinic, and 9 people died overall. Most cases were from Tirupattur district.

Those who visited the clinic died faster, from symptoms to death in just 16 days, and from hospital admission to death in 9 days. In contrast, the only person who died without visiting the clinic took 56 days after symptoms started and 38 days after hospitalisation.

What did officials do?

On 9 May 2023, CMC reported the rise in cases. Four days later, Tamil Nadu health officials held a meeting with hospitals and clinics in the region. A team of doctors began investigating the cluster.

However, before they could collect samples, the dental clinic was disinfected and shut down after public complaints. Still, scientists managed to find the bacteria in a sample from the saline bottle. Other unopened saline bottles were clean.

What else did they find?

Patients who did not visit the dental clinic mostly showed swelling in the salivary gland, cheeks, or lymph nodes. But those who did visit had more serious symptoms like face swelling and soft tissue infections, likely due to swallowing the contaminated saline.

Dr T S Selvavinayagam, Tamil Nadu’s director of public health, said the outbreak has now been contained. “This is a reminder for all healthcare workers to follow proper infection control practices,” he added.