‘Cautious optimism’ as penguins test positive for bird flu but show no symptoms

Asymptomatic cases may seem reassuring for the penguins, but scientists fear they could act as Trojan horses' for other species

Adelie penguins in Antarctica are testing positive for bird flu without showing outward signs of disease, according to researchers who travelled around 13 remote breeding sites on an ice-breaking cruise ship.

Since bird flu arrived in the region this year, there have been concerns about the virus reaching the Antarctic's fragile penguin populations. In November last year, researchers warned in a pre-print research paper that if the virus caused mass mortality in these colonies, it could signal one of the largest ecological disasters of modern times".