As the US battles measles outbreaks in 24 states, debate over the reasons for the resurgence of the illness has become heated.

Key points: The number of measles cases worldwide has increased 300 per cent compared to the first quarter of 2018

The number of measles cases worldwide has increased 300 per cent compared to the first quarter of 2018 One US county has banned unvaccinated children from school and public places to stop the spread

One US county has banned unvaccinated children from school and public places to stop the spread New York's Orthodox Jewish community has rejected claims it is to blame for the outbreak

Rockland County, located just north of New York City, is at the centre of the conversation.

It is home to the largest Orthodox and Hasidic Jewish population per capita of any US county.

It is also the centre of one of the largest measles outbreaks in the country, with 225 people affected.

"This is not a Jewish problem. It's an anti-vaccine problem," Shoshana Bernstein, an Orthodox Jewish mum and advocate for vaccination, said.

The outbreak in Rockland County began when an infected child visited from Israel where more than 3,500 people have contracted the disease in the last year.

Mrs Bernstein said the resulting outbreak had led to the entire Orthodox Jewish community being unfairly stereotyped as anti-vaxxers who are responsible for a global surge in cases.

"There's a lot of blame being attached and a lot of infighting," she said.

Measles on the rise after near-eradication

Measles was all but eradicated from the United States in 2000 due to a nationally implemented vaccination program.

At its worst, it killed hundreds of people each year in the US and tens of thousands ended up in hospital.

Some experienced complications like encephalitis and permanent hearing damage.

It is an extremely contagious illness, spread by coughing and sneezing, and infecting 90 per cent of those who come into contact with it if they do not have immunity from previous exposure or vaccination.

"They feel that measles is a benign disease," Dr Ruppert says of local people resisting vaccinations. ( ABC News: Niall Lenihan )

Doctors in Rockland County said some people had become complacent about measles because it was considered rare — until now.

"They feel that measles is a benign disease — fever, rash — you know, why make a fuss about it?" Rockland County health commissioner Patricia Ruppert said.

"They just let it go through the entire family."

In a bid to stop the spread of disease, the county banned unvaccinated children from schools and public places and is actively enforcing fines on those who do not comply.

The move drew criticism from some anti-vaccination advocates and led to a lawsuit against the county.

Dr Ruppert said her initial orders, issued last fall, prevented 6,000 students in 61 schools from attending.

That number is now down to 1,600 after the mass delivery of free vaccinations.

However, she had to legally compel some parents to bring in their children to be vaccinated.

"[They hang] up the phone once they know it's the local health department. Or if we go to the house and knock on the door, they say, 'we won't speak to you'," she said.

"So for those people, I have sent subpoenas to require them to participate."

Families withdraw amid fear of infection

The Moes are keeping their children Sophia and Nicholas away from crowds due to the Rockland measles outbreak. ( ABC News: Niall Lenihan )

This year has seen by far the highest number of cases in the US since the mid 1990s, mirroring a worldwide trend.

Globally, measles cases in the first three months of 2019 were up 300 per cent compared to the same time last year.

At least 880 people have been diagnosed with measles in the US in 2019, according to the Centres for Disease Control.

The Jewish community in Rockland County and the nearby New York City boroughs of Brooklyn and Queens are not the only populations in the US experiencing an outbreak.

The Eastern European community in Washington state is also experiencing a surge in measles cases.

But Orthodox Jews have been targeted on social media as Americans look for answers.

"I think people are very quick to point fingers at just anybody because they don't know who to point at," Mitchell Moe, a resident of Rockland County, said.

Like many local parents, Mr Moe is grappling with the risk measles poses to his family.

"I think people are afraid to go out in public and talk about it. Even though the signs were there, it happens so quickly that I think people are just adjusting now and realising how this is impacting everything," he said.

He and his wife have ensured their two young children, Nicholas and Sophia, have both been vaccinated.

But they are avoiding crowded public places and spending more time at home to stay safe.

"It's just sheer fear of being subjected to this. With everything that is happening in America — with shootings and stuff like that — you just don't want to be around people anymore," Mr Moe said.

Anti-vaccination groups target Orthodox Jewish community

Ms Bernstein says some orthodox Jews may be susceptible to misinformation from anti-vaxxers. ( ABC News: Niall Lenihan )

There are several possible factors driving the spread of the illness in Rockland County.

Close-knit communities who spend a lot of time together in small spaces like schools and synagogues provide the perfect environment for such a contagious illness.

"In an insular community, you have people who aren't online. They're not going to libraries, reading newspapers or listening to the radio," Shoshana Bernstein said.

"They are therefore not only limited in their access to education, but also extremely susceptible to the misinformation, which has been a very strong voice."

Ms Bernstein was referring to a concerted campaign from small but vocal anti-vaxxer groups.

Last week, hundreds of ultra-Orthodox Jews attended an anti-vaccine rally that was held in the county. The event was denounced by local health officials and some rabbis.

New York is just one of the three US states where parents can opt out of vaccinating their children if they cite religious exemptions.

Paediatricians are now pushing the State Government to abolish the right to religious and ideological objections, saying medical complications should be the only reason for avoiding vaccination.

Mr Gestetner says the Jewish faith is not against vaccinations. ( ABC News: Niall Lenihan )

Yossi Gestetner from the Orthodox Jewish Public Affairs Council rejected the suggestion religion had anything to do with the problem.

He said there was no basis for religious exemption from vaccination in the Jewish faith.

"It's garbage. I have yet to find one such person. Everyone who is against vaccines is against it based on stories they've heard, concerns that they have or health challenges they may have in their household," he said.

Mrs Bernstein said when it came to educating the Jewish community, there was more work to be done.

"We need to be reaching the people who have questions and providing answers," she said. "At the end of the day, we're all mums who want the best for our kids."