A World Health Organization scientist said COVID-19 comes from bats and can spread among cats, amid an international debate about the virus’s origin.

The novel coronavirus comes from a group of viruses that originate or spread in bats, and it’s still unclear what animal may have transmitted the disease to humans, Peter Ben Embarek, a WHO expert in animal diseases that jump to humans, said Friday in a briefing with reporters.

The virus probably arrived in humans through contact with animals raised to supply food, he said.

Recent studies showed that cats can transmit the virus to other cats and the WHO is aware of instances of pets of Covid-19 patients being infected, it said in a statement Friday.

While precautions should be taken to avoid the infection of pets from close contact with Covid-19 human cases, further evidence is needed to understand if animals and pets can spread the disease. It’s important to find out which animals can get infected to avoid creating a “reservoir” in another species, Ben Embarek said.

Questions about the origin of Sars-CoV-2, the virus that has caused the pandemic, have intensified since U.S. President Donald Trump suggested it came from a laboratory in China.

Germany most recently questioned the claim, made by U.S. Secretary of State Mike Pompeo, Der Spiegel reported. Intelligence services from five countries, including the U.S., were unable to confirm his statements, it said. Scientists who have studied the issue maintain that the virus originated in an animal, and probably entered the human population in November.

New Mission

WHO scientists are considering a new mission to China to get more information about the virus’s animal origin, Maria van Kerkhove, one of the agency’s top epidemiologists, said at a press briefing Wednesday. Questions remain about whether the virus traveled directly from bats to people, or if other species were involved.

Pangolins, armored mammals that live in Asia, have been found to harbor versions of Sars-CoV-2 that are similar to those in people. The WHO wanted to conduct more animal investigations on an earlier mission to China, but the lockdown of the outbreak’s epicenter in Wuhan made that impractical, Ben Embarek has said.

The first human cases were detected in and around Wuhan, and most of those people had contact with the animal market, though not all, Ben Embarek said.

Trump has doubled down on claims that the Chinese mistakenly released the virus from the laboratory as the outbreak in the U.S. has grown to become the world’s largest and deadliest. Chinese officials have said that the U.S. has no evidence to back up those claims and called the allegations a blame game.