The condition of a British woman bitten by a crocodile in Mexico has deteriorated after she developed sepsis, her sister says.

Melissa Laurie, 28, is in an induced coma in a Mexican hospital after being attacked by the reptile while swimming in Manialtepec Lagoon, near Puerto Escondido, about 450 miles (724km) southeast of Mexico City.

Her twin, Georgia, managed to pull her to safety while punching the crocodile in the face, according to their older sister Hana.

The twins, from Berkshire, were both taken to hospital.

Georgia was released after treatment for injuries to her hands, but Melissa has developed sepsis.

Hana told BBC Breakfast: “I spoke to Georgia overnight, she’s doing much better, she’s really frightened and a little bit high on adrenaline and pain killers… but Melissa’s situation is still really serious, we’re not relaxing just yet.

“She’s still intubated, in a medically-induced coma and she has now developed sepsis.

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“She had a lot of water and grass in her lungs because crocodiles try to drown people.

“She’s got some bite wounds across her tummy and her legs, some of those have become infected as well. It managed to tear her bowel, so [it’s] quite stressful.”

Hana, 33, has previously said the family is waiting to hear how much help they will get from the twins’ insurers towards medical costs.

But meanwhile, a GoFundMe page has been set up to raise money for medical treatment – hitting £38,000 as of Wednesday afternoon – and the twins’ father, Sean, is preparing to head to Mexico.

The family has been put in touch with an English-speaking doctor, Dr Esteban Bolanos, who is keeping them updated on Melissa’s condition.

Hana has previously said that the twins booked a tour through their hostel, but later found out their guide was not registered and had taken them to what turned out to be an unsafe swimming spot.

“They asked if the water was safe and were told it was, and evidently that’s not the case,” she told BBC Breakfast.

“They’re not naive people, Georgia and Melissa are experienced with animals, Georgia’s a great diver, which is how we think she managed to save her life.

“It’s magic twin stuff meets her amazing training in water safety, and just a real big dose of that famous Laurie girl attitude.”