Imani, 14, and Hermien, 41, so far have no symptoms except for their runny noses and are “doing well,” according to the zoo, The Brussels Times reported.
They’re currently in quarantine as a precaution, with their enclosure sealed off, according to officials.
The animals’ handlers, who have all tested negative, are required to wear masks and safety glasses, and disinfect footwear before having any contact with the hippos.
“To my knowledge, this is the first time in this species. Worldwide, this virus has been reported mainly in great apes and felines,” the zoo’s chief vet, Francis Vercammen, told Reuters Saturday.
Cases have also been reported worldwide in dogs, cats, ferrets, deer, otter, mink and hyenas.
Officials are investigating the source of the hippos’ COVID. No staff member has exhibited symptoms nor tested positive for COVID-19, officials reported.
All mammals at the zoo were tested for the coronavirus last year in collaboration with the University of Antwerp and no cases were found.
Visitors to the zoo must all wear face masks and follow social distancing requirements. All animal feeding demonstrations for crowds of visitors have been canceled until further notice, according to the zoo’s website.
Three snow leopards at the zoo in Lincoln, Nebraska, died last month of complications from COVID-19. Two Sumatran tigers at the same zoo, also infected, made a full recovery, according to officials there.
Nine animals at the National Zoo in Washington tested positive for COVID-19, officials said in September. Several animals there have since been given animal-specific vaccines against the coronavirus, and other zoos are following suit.