Residents in Los Angeles and Orange County warned to check for symptoms after an infected NZ teen visited theme parks including Disneyland and Universal Studios earlier this month.

Californian health authorities have issued warnings to residents and visitors after a New Zealand teenager was found to have spent five days in the US state while infectious with measles. The reports come as both the US and New Zealand grapple with the worst outbreaks of measles for more than two decades, with scientists sounding the alarm about insufficient take-up of vaccination.

The New Zealander stayed at Desert Palms Hotel from August 11 to 15, and visited Disneyland on August 12, said the Orange County Health Care Agency in a statement.

The Los Angeles Department of Public Health issued its own alert, listing the dates and times that the tourist was at locations including LAX airport, Universal Studios, TCL Chinese Theatres, Madame Tussauds and Santa Monica Beach. “Anyone who may have been at these locations on these dates may be at risk of developing measles for up to 21 days after being exposed,” it said.

It added: “Public Health urges residents, especially those who travel internationally and those who have not been fully protected against measles, to get the measles immunization in order to better protect their individual health and to prevent the spread of measles to others.”

Auckland health authorities issued a warning on Friday to those who may have travelled on the same flight as the teenager. Air New Zealand Flight NZ1 that departed from Auckland for Los Angeles on Thursday August 15 “may have been exposed to measles”, said the Auckland Regional Public Health Service in a statement.

The service’s public health medicine specialist Dr Maria Poynter said: “There is some risk that other passengers may contract measles if they are not immune. We would ask that anyone on this flight checks their medical records if they are under 50 years to see if they have had a least one MMR vaccination, or have had the measles previously, making them immune.

“They should also watch out for symptoms over the next few days – a fever, runny nose, cough, sore red eyes and then a rash. Unfortunately people are infectious five days before the rash appears, so don’t usually know they have measles. They continue to be contagious for five days after this.”

The news delivers an international embarrassment to New Zealand in the same week that the domestic measles outbreak worsened further, with the highest number of confirmed cases for more than 20 years.

With another 106 cases in the previous week, the Institute of Environmental Science and Research reported the total number of individuals who had been confirmed infected for 2019 at 639, the highest since the 1997 epidemic. There are four ongoing outbreaks across the country.

The agency reported that there were 65 new cases in the Counties Manukau DHB, bringing the total in the region to 329. Other cases were confirmed in the week to August 19 in Waitemata, Auckland, Bay of Plenty, Hawkes Bay and South Canterbury.

Total hospitalisations for measles around the country numbered 237, ESR reported.

The level of infection was “completely unacceptable”, Dr Nikki Turner, director of the Immunisation Advisory Centre, told RNZ this week.

“It’s very simple with measles. If we have enough of our population immunised, we should not see this disease. It is unacceptable that we have children right now in intensive care. Counties has opened a measles ward. We do not need to see this,” she said.

High vaccination rates were critical, she said.

“New Zealand has what we call ‘elimination’, which means we do not have measles circulating in our population. If we don’t do something about this, we’re going to lose it. These measles outbreaks have started from cases being brought in from overseas. If the New Zealand community had higher immunisation rates, they would not then transmit through the New Zealand community.

“So we’ve got a choice. We can go back to the days where we see measles, we accept it’s a normal part of life, and some of our kids are severely damaged. Or we can get our act together and do something about it.”

In the US, authorities say reported measles cases are at their highest for 25 years, with more than 1,200 cases across 30 states since October 2018.

In 2015, a measles outbreak linked to Disneyland saw more than 70 reported cases of infection among people who had visited the Anaheim theme park.

At the time, surgical oncologist and science writer David Gorski suggested low vaccination uptake in parts of California could be to blame, pointing the finger at “pockets of affluent, entitled parents full of the Dunning-Kruger effect who think that they can learn as much about vaccines and autism via Google University as pediatricians and researchers who have devoted their entire professional careers to studying them.”

ESR advice on measles prevention is as follows:

“The currently-available vaccination is the best protection people can have against measles. They need to have two MMR (measles, mumps, rubella) vaccinations, as part of the National Immunisation Schedule (age 15 months and 4 years). Anyone born in or after 1969 who has not had two documented doses of vaccine can be vaccinated for free if their GP has sufficient supplies.

“Anyone who suspects they may have measles should avoid contact with other people, especially those who are not fully immunised, and should phone their GP or call Healthline on 0800 611 116 for advice. It is important to call first because measles is highly infectious, and people with measles can infect others in the waiting room.”