Mexico has confirmed 43 measles cases, 39 of which were recorded in the northern state of Chihuahua and linked to imported infections, health minister David Kershenobich told a news conference

More than half of the cases are in children under nine years old, Kershenobich said.

None of those infected in Chihuahua had been immunised, he added.

“We are strengthening the vaccination programme nationwide. There are enough vaccines available to cover all the country’s needs, so the recommendation is that at-risk populations get vaccinated,” Kershenobich said.

Measles is a highly contagious disease that causes fever, respiratory symptoms, and a rash – but can also lead to severe complications, including pneumonia, brain inflammation, and death.

In the US, misinformation about vaccines has fueled a nationwide decline in immunisation rates.

More than 300 measles cases have been reported in the US states of Texas and New Mexico, leading to a death in each state.