Two adults have been confirmed with the Zika virus in Ireland, health chiefs have said.

The cases - the first of their kind in the country - are unrelated to each other and both patients are said to be currently well and fully recovered.

Both individuals have a history of travel to a Zika affected country, Ireland's Health Service Executive (HSE) confirmed.

"These are the first cases of Zika virus infection confirmed in Ireland," a HSE spokeswoman said.

"Neither case is at risk of pregnancy."

The HSE said the newly-discovered Zika cases in Ireland are "not an unexpected event" as many other European countries have reported cases as a result of people travelling to affected areas.

Health chiefs have urged Irish people who fall ill within two weeks after returning from an affected area to seek medical help.

It comes as officials confirmed the first case of the Zika virus in the United States.

The virus has been confirmed in a resident of Dallas County, Texas, with the county's Health and Human Services claiming it was contracted through sexual transmission.

In medical literature, there has only been one case of Zika transmitted sexually and one case in which the virus was detected in semen.

Officials said there are no reports of the virus being locally transmitted by mosquitoes in the area.

The county said it received confirmation of the infection from the US Centers for Disease Control and Prevention (CDC), however the CDC did not investigate how the virus was transmitted.

There have been six confirmed travel-related cases of Zika virus disease in the US, all among residents of Harris County, where Houston is located, the Texas Department of State Health Services said.

Dallas county did not identify the person infected.

The confirmation of a US case comes just a day after the World Health Organisation declared the virus an international public health emergency.