Iowa reported an outbreak of highly lethal avian influenza in a commercial flock of egg-laying chickens on Friday, raising the risk for further infections in the top US egg-producing state, reported Reuters.

Iowa was already facing restrictions on exports of poultry products after a commercial turkey flock tested positive for the disease on Sunday.

In 2015, Iowa was at the centre of the biggest-ever US outbreak of avian flu, which killed about 50 million egg-laying chickens and turkeys.