About 10% of people in North America have contracted the deadly tick-borne disease Lyme disease.

One in ten people in North America may have Lyme disease, according to new estimates.

For decades, researchers had no idea how common tick-borne disease actually was.

But now scientists at Kunming Medical University in southern China estimate that up to 50 million people, or 9.4%, on the continent are infected at some point in their lives.

Globally, up to 14.5 percent of people — or one in seven — have the disease, the researchers said.

Rates are highest in Central Europe – with an estimated one-fifth being infected – about one-seventh in East Asia and about one-tenth in Eastern Europe. North America had the fourth highest percentage.

Lyme disease is a bacterial infection spread by a tick bite. It causes a round rash and can cause flu-like symptoms, but it usually clears up with antibiotics within weeks to months. In the photo: stock

For the meta-analysis, the scientists looked at blood sample data from studies involving 150,000 people between 1984 and 2021.

Each article looked at Lyme disease rates based on the results of tests that screen the blood for antibodies to the disease.

This allowed scientists to confirm whether a person is currently infected or has been in the past.

The team said their findings, published in BMJ Global Health, are “the most comprehensive and current systematic review of the global prevalence” of Lyme disease.

They said a “more accurate” figure about the global spread of this disease would help “identify risk factors”.

As such, it “can inform the evolution of public health policies and monitoring programmes,” they added.

For now, the most accurate figures show that around 30,000 people are affected each year in the United States. However, these were often considered underestimated.

There is no figure for the number of people who die from the disease each year, although it is known to be rarely fatal.

Ticks are second only to mosquitoes in terms of the number of harmful microbes they carry.

Some carry Borrelia burgdorferi sensu lato, the bacterium responsible for Lyme disease.

The infection causes a circular, oval — or “bull’s eye” — rash around a tick bite that can appear up to three months after the bite.

Most infections can be treated with a course of antibiotics.

But if patients wait too long to seek help, the bacteria can spread to other organs and tissues, potentially affecting the nervous system, joints, heart and skin.

Long-term symptoms of illness include severe headache, facial paralysis, and irregular heartbeat.

Lyme disease is diagnosed using a simple antibody test. However, in the early stages of infection, 60% of cases are ignored because there are not enough antibodies to detect the test.

The study says that ticks have increased worldwide in recent years, significantly increasing the risk of human exposure.

This could be because of longer summers and warmer winters, animal migration, and more time outdoors.

One sub-analysis showed that people over 50, men and rural people were more likely to have Lyme disease.

Men were more likely to work in jobs that exposed them more to ticks, such as farmers, police officers, and soldiers.

The team said it was “necessary” to develop new treatments and prevention methods.

However, they noted that one-third of the studies used only one type of test to confirm Lyme disease infection.

These studies reported more cases than those who used a second test to confirm a case.

This may be because the bacteria behind Lyme are similar to other viruses like Epstein-Barr.

They said some studies have been done in areas where Lyme disease is endemic and therefore has much higher rates.