"The national veterinary laboratory of Sciensano [national public health institute of Belgium] just confirmed the laboratory test results: two hippos Imani and Hermien contracted COVID-19," Zoo Antwerpen said in a statement on Friday said.
Both hippos have a mild form of the disease with only runny noses as symptoms. The animals are in isolation and security measures by zoo keepers were further tightened to prevent spreading. The hippos are undergoing daily COVID-19 tests and their condition is being monitored.
It is yet unknown how the hippos were infected with the virus given the strict sanitary measures taken by the zoo.
Last year, the zoo partnered with the University of Antwerp and tested all mammals for the disease and found no positive cases.
This is not the first time that an animal at a zoo was infected with the virus. On November 14, three snow leopards at the Lincoln Children's Zoo in the US state of Nebraska died from complications related to COVID-19.