Fears are being raised in Maine after three people in the state tested positive for the world’s deadliest disease.

The patients were diagnosed with active tuberculosis and there was no connection between them, suggesting each was infected by a different source.

They are in the Greater Portland area, officials said, and work is now underway to identify and isolate their close contacts.

Amid a rise in US cases, the United States reported 10,347 tuberculosis infections in 2024, marking an eight percent increase from the previous year. This counts as the highest number since 2011 when 10,471 cases were recorded.

But officials said the risk to the public from the latest infections was low. 

The World Health Organization deems tuberculosis the world’s deadliest disease due to its annual toll of approximately 1.25 million lives, predominantly in developing nations.

The disease has a notably high mortality rate, claiming up to half of untreated or unvaccinated patients. This rate starkly contrasts with Covid’s fatality rate of less than one percent, measles at 10 percent for untreated cases, and Legionnaire’s disease, also around 10 percent.

In the 18th and 19th centuries, tuberculosis was often a death sentence due to the lack of a cure. Today, however, it is preventable through vaccination and treatable with antibiotics.

Authorities stated that the three individuals with active tuberculosis, where the bacteria are multiplying in their lungs, are located in the Greater Portland area (the image above depicts Portland, Maine).

Tuberculosis killed more than 16,000 people in the US every year in the 1950s, but deaths have now dropped 28-fold to around 550 people annually.

According to the CDC, most US tuberculosis cases stem from immigration, with the majority of patients originating from outside the United States.

Further details on the Maine cases, including their names, ages and exact locations were not revealed.

The state’s CDC revealed the infections on Tuesday, and advised residents be aware of symptoms such as a persistent cough that does not ease within three weeks. 

The infections were described as active, suggesting bacteria was multiplying in patients’ lungs, but when they started was not clear.

But they added that the risk to the general public was low. 

Dr Dora Anne Mills, chief health improvement officer for MaineHealth, warned that tuberculosis could only be passed on if someone was in ‘close, prolonged contact’ with an infectious person.

She told the Portland Press Herald: ‘The vast majority of people do not need to worry about this.

The names and ages of the patients have not been revealed. The above shows a chest X-ray of a person with tuberculosis

Tuberculosis infections are on the rise in the US, and nationwide have now reached their highest tally since 2011

‘It’s not spread through casual contact like shaking hands or sharing a towel. It’s much less contagious than influenza or Covid.’

It can take days for the disease to infect a healthy person who lives in the same home as a patient.

Online reports had suggested the cases were linked to a shelter for asylum seekers in the area, but officials said there was no evidence that this was the case.

Officials say the cases are not yet an outbreak, which is defined as more cases than expected in a specific location or population.

Maine has already reported 28 cases of tuberculosis so far this year, figures show, just 11 cases below the 39 recorded in 2024. 

There were 26 cases reported in 2023. It wasn’t clear whether this would be a record year.

Children, older adults and those with weaker immune systems are more vulnerable to an infection.

In the early stages, symptoms of the disease include a persistent and unexplained cough and sometimes coughing up blood or chest pain. 

Patients may also suffer from unexplained weight loss, loss of appetite, fever and night sweats.

In later stages, patients may have severe breathing difficulties, extensive lung damage and the infection may spread to other organs like the liver or back, causing pain in these areas.

Patients die from the disease due to respiratory failure, or when damage to the lungs means they can no longer get enough oxygen into the body.

Doctors can treat the disease with antibiotics and can vaccinate against the disease using a shot called the BCG vaccine.

This is not routinely offered in the US, because the disease is not common, but can be requested for children, and leaves a small circular scar on the arm, a normal response and sign that the vaccine was effective.

It can also be given to adults, but it is less effective in this group and may lead to someone falsely testing positive for the disease. 

In developing countries, the vaccine is administered to children under the age of 16.