As Brazilian authorities admit they are “badly losing the battle against the mosquito”, local insect experts say it would be remarkably easy for the Zika virus to begin spreading in the US.

All it takes is for an infected person to return from somewhere overseas (such as El Salvador or Brazil) and get bitten by a local mosquito that can carry it.

“That blood that has that virus is circulating in the body. If a mosquito bites them, that mosquito could bite someone else and the process goes on,” said Dr Barry Alto, from the Florida Medical Entomology Laboratory at the University of Florida.

“It could very well mean local mosquitoes are actually infected with the virus. And now we have a public health concern,” said Alto. But it’s unlikely the US will see a Zika epidemic like that currently facing Brazil and El Salvador, since authorities are closing monitoring what’s happening overseas and the mosquitoes are mainly limited to the south. “I don’t expect there to be as big an outbreak. The [US] infrastructure is potentially better equipped to deal with outbreaks,” said Alto.

Because the Zika virus has fewer symptoms than dengue or malaria, people are often unaware they are even suffering from it, and therefore less likely to stay inside, sick in bed – and away from the outdoors and mosquitoes.

Controlling the mosquitoes is becoming the hardest part of fighting Zika.

There are two mosquitoes that transmit Zika – as well as a host of other mosquito-borne illnesses: the Aedes aegypti (known as the yellow fever mosquito) and the Aedes albopictus (the Asian tiger mosquito).

They are a powerful duo, two invasive and very similar tropical mosquitoes.

Both are black with white coloring, the yellow fever mosquito with a lyre pattern on its thorax, the Asian tiger with its racing stripes.

“As mosquitoes go, they’re pretty,” said Bill Walton, vice-chair of entomology at the University of California, Riverside. Only the females bite – “femme fatales” as Walton dubs them – and their lifespan runs about a week.

Both live happily in the United States, particularly in the south.

Asian tiger mosquitoes smuggled themselves into the US in used tires from Japan, first turning up in tire dumps around Houston on 2 August 1985. They later spread throughout the deep south. They also popped up in California in the early 2000s, tied to a shipment of ornamental bamboo from south China.

The yellow fever mosquito, the one Brazil is struggling with right now, arrived on slave ships from Africa and lives throughout the south.

Both are particularly hardy, with larvae that “can survive potentially unfavorable conditions for weeks to months”, said Alto.

An Aedes aegypti mosquito is photographed on human skin. Photograph: Luis Robayo/AFP/Getty Images

The trick for how these mosquitos can move around the world – despite only flying within about a 1,600ft radius of where they are born – is that their larvae can go into a hibernation-like state.

The eggs can completely dry out but then hatch once they have been inundated with water, even if it is months later.

Both types breed mainly in small containers filled with water, whether that be “natural, such as bromeliads, or containers humans make, such as discarded tires, bird baths, dog dishes”, said Alto.

They are also adept at sneaking into boats or vehicles, says Walton, who notes that it would not be hard for mosquitoes to stow away in an airplane or cargo container.

“You get on a plane in tropical Mexico, they’re in the cabin with you,” said Walton.

Climate change often gets mentioned as part of the reason for their spread, although this seems debated among the two entomologists the Guardian spoke with.

“Warmer conditions can make the population grow more rapidly,“ said Alto, who ran tests on the Asian tiger mosquito in different temperatures and found that larvae in warmer conditions could reach maturity in just five to seven days, meaning it can breed more quickly.

He also noted that increased droughts, another indication of climate change, makes it less conducive for a tropical mosquito to live since it needs the small water containers.

“The climate change link is probably tenuous at this point,” said Walton.

But with the number of babies being born with abnormalities increases, attempts are being made to limit mosquito population.

One project in Brazil by UK company Oxitec is a “mosquito farm” that breeds self-exterminating mosquitoes. These genetically modified mosquitos breed with the wild mosquitoes, but their offspring die.

Another trial of the project launched in recent weeks to help try to control the spread of Zika.

“It’s a really cool thing if it works,” said Walton, although he notes there is a lot of resistance against using genetically modified insects.

There are other ways to control mosquitoes, with large-scale chemical eradication programs running during the 1950s to get rid of the yellow fever mosquito – which was originally deemed a success, until the mosquito came back.

Nowadays, there are specific bacteria that can be put into streams and then get ingested by larvae where they punch holes in its digestive tract. The mosquitofish – a relative of the guppy family that eats mosquitoes – can be used to reduce mosquito populations.

Public education programs about to encourage people not to leave out water-filled containers that easily turn into breeding grounds also help.

And what happens if these disease-carrying invasive mosquitoes were completely eradicated from the US?

It’s a mystery. “I don’t know if there’s any organism critically dependent on mosquitoes,” said Walton, who notes a potential impact on local ecosystems, but was unsure what it would be. There are too many unknowns on these mosquitoes to know what would happen if they were completely obliterated, says Alto.

“They don’t operate independently, they interact with other species. They occupy certain niches. Another mosquito species might fill that niche,” he said.

A battle against the mosquito is just one way to handle this health crisis. “The best way to control mosquito-borne diseases is a good vaccine,” said Alto.