Researchers monitoring the genetic makeup of the new coronavirus say a very similar virus found in bats and pangolins does not match perfectly with the virus.

Renowned veterinary specialist and epidemiologist, Dr Maarten Hoek, says efforts to identify the potential animal sources of Covid-19 are yet to yield positive results.

"They (researchers) are still looking for the exact animal source, and may never find it if it is from obscure animal from illegal animal trade," he said.

But researchers have strong indications that Covid-19 came from a pangolin-like animal and civet.

The Netherlands-based scientist who is researching the coronavirus pandemic says there is no scientific evidence infected pets can transmit the disease to humans.

He says pet owners should not rush into dispensing with such animals.

Dr Hoek was answering questions at a webinar conference organised by Internews' Earth Journalism Network for science journalists across the world.

The video conference was on a theme: Zoonotic Disease: How the wildlife trade and the disruption of ecosystems have increased the spread of epidemics.

Questions ranged from replication of viruses in humans to how their genetic materials change were answered.

"Each time a virus replicates in human cells, its genetic material changes due to errors in replications. And in most cases, this result in virus not being viable - not being infectious and some in cases result in virus being more infectious," Dr Hoek says.

The veterinary doctor indicates a lot needs to be done in finding a vaccine.

"We still have a lot of work to do on vaccine. We are still far away," he said.

"When animals and humans are stressed, their immune system is suppressed and therefore the virus is less controlled and able to infect more cells within the bodies," he added.

He cites the 1918 Spanish influenza outbreak to further explain how people were stressed in many ways resulting to poor functioning of the immune system.

Dr Hoek dismissed claims that the virus is transmitted through waterways.

The issue of bats being the key in outbreak situations came up during the conference. Dr Hoek explained that bats are critical to most outbreaks because they live in a huge colony.

"Because they live in a large population, pathogens have a lot opportunity to infect bats," he said.

Dr Maarten Hoek is also risk analyst, medical consultant in public health and non-executive director at Madaktari Africa, a non-profit organisation working to educate and train health care workers in Sub-Saharan Africa.

He has worked on health strengthening projects in Africa for eight years.