A research scientist believes the US is in the middle of a 'Pig Bomb' - where feral hogs are increasing in huge numbers.

Dr. Jack Mayer, a zoologist whose been researching wild pigs for 40 years, has warned that the population could keep growing unless there is a swine flu epidemic.

His comments come just a week after a caregiver was mauled to death by wild hogs in Texas.

Christine Rollins, 59, was attacked and killed outside the home of the elderly couple she was looking after in what the local sheriff described as 'one of the worst things he has seen'.

It's unclear what provoked the attack by multiple animals, by Mayer claims that deadly wild hog attacks are more common than shark confrontations.

They are responsible for six a year on average, 'but you never read about them' he said.

'It's a crazy situation with everything that's happened in what I call the Pig Bomb, which has exploded in North America,' Jack Mayer told The Daily Beast about the wild population of six million and two million in Texas alone.

Caregiver Christine Rollins, 59, was attacked and killed by feral hogs last month. Now a research scientist has claimed a 'Pig Bomb' has blown up in the US

The attack took place outside a home in Texas where two million of the six million wild hog population lives

'There's not another animal that can put little feet on the ground quicker than a wild pig.'

Throughout the 20th Century there were about two million wild pigs across 20 states but the tripled figure accounts for 48 states.

Mayer blamed global warming for increasing the survival rate of newborn piglets and producing more acorns, bulbs, roots and tubers for them to eat.

They can start reproducing at three months old and do so twice a year.

Various sized bites on Rollins suggested she was killed by a sow and her young. They can birth as many as 20 little ones which can weigh up to 50 pounds.

But even if three quarters of the population is killed off, they would be able to fully repopulate within three years.

The author of Wild Pigs in the United States said that wild pigs may attack unprovoked if they have been hurt by hunters but added: 'Obviously, that's not the case here.'

It's unclear what happened in the case of Rollins, who was fatally injured outside the property in Anahuac. However he noted the animals may have been chased by dogs which he says the pigs are just as smart as.

A research scientist from the Savannah River National Laboratory South Carolina warned about their rate of reproduction: 'There's not another animal that can put little feet on the ground quicker than a wild pig'

Jack Mayer (left), author of Wild Pigs in the United States (right), said 'Trauma to the victim is pretty horrific' in an attack, as they will start with the legs before mauling the rest of the body

Mayer said about Rollins (left): 'If she'd been able to get on the car, climbed up on the trunk or the roof, she absolutely would have been safe up there'

'We are starting to see wild pigs move into suburban and even urban areas of late,' Mayer warned.

The situation could be made worse as Mayer mentioned YouTube videos apparently showing pigs foraging near Guadalupe dumpsters where meat confiscated from San Jose Airport had allegedly been discarded.

He said African swine fever can survive up to a week in meat and if hogs get their teeth into any food infected with the virus, it would quickly spread to farm pigs.

'If that happens, it's all over,' Mayer said, 'We'll never get it under control… You're not going to be able to afford bacon or pork chops after that.'

Mayer claims Rollins may have been able to save herself in the attack that occurred after she emerged from her car in the dark and locked the door.

He said the creatures go for the legs first to knock victims onto the ground then work away at the rest of their body.

Chambers County Sheriff previously said that wild hogs have been a problem in the area and many neighbors have called to complain that animals were tearing up their front yards

'They're not cute little pigs, they're wild animals, and they would hurt you,' he said. 'I'd try to avoid them, either back away or walk around them… Get up on something high.

'If she'd been able to get on the car, climbed up on the trunk or the roof, she absolutely would have been safe up there.'

Authorities said Rollins' cause of death was 'exsanguination due to feral hog assault' or bleeding to death.

Chambers County Sheriff Brian Hawthorn previously said that wild hogs have been a problem in this area of Texas and many neighbors have called to complain that animals were tearing up their front yards.

The Sheriff's spokesman said that five dogs live at the property, including one well-trained Labrador and four 'friendly corgis'.

Hawthorne revealed the dogs probably ran the hogs off. The dogs were discovered by Rollins' body but not on it.

'They are very capable of defending themselves,' Mayer, of the Savannah River National Laboratory South Carolina, added. 'They're large, muscular animals. They have sharp teeth.

'Trauma to the victim is pretty horrific.'