NParks steps in to curb fatal rabbit disease that emerged last year

Some rabbits in Singapore were hit last year by rabbit haemorrhagic disease, a viral illness that had never been seen here before.
Some rabbits in Singapore were hit last year by rabbit haemorrhagic disease, a viral illness that had never been seen here before.PHOTO: SHUE YIN

SINGAPORE - The first case of rabbit haemorrhagic disease (RHD) in Singapore, a viral illness that cannot be passed on to humans, was spotted by a private vet in late August last year (2020).

She saw some peculiar signs like lethargy, a huddled posture and fever in a few pet rabbits taken to her practice, and raised the issue with the National Parks Board (NParks). Some of the rabbits died.

Dr Charlene Judith Fernandez, director of the Centre for Animal and Veterinary Sciences, said the rabbits had been tested for various common illnesses but nothing was found.

"We requested some liver samples and used a polymerase chain reaction (PCR) test for the RHD virus. We were floored when the PCR test detected the RHD virus."

This virus had never been seen in Singapore before.

NParks' veterinary rapid response investigation team then visited the clinic to establish the extent of the disease.

Dr Kelvin Ho, a senior vet at the Animal and Veterinary Service, said one of the primary objectives was to communicate the findings to stakeholders.

He said: "We identified a few vets that tend to see more rabbit cases and approached their clinics to see if they had been seeing cases of dying rabbits with increased liver values or that just died suddenly without any signs."

After identifying more cases from other clinics, the team had to establish what signs to look out for in a rabbit with RHD.

These included anorexia, dullness, groans and cries, and breathing difficulties.

This information was passed on to vets and they started reporting more cases. They sent blood samples to Dr Fernandez's lab where the team started compiling data of all the cases.

Contact tracing was part of the investigation, so Dr Ho's team identified the cases and got the rabbits' history from the vets.

He said: "We were surprised to find out that there was such an active scene out there, such as rabbit parties. That was concerning from a disease point of view because we didn't want them to congregate and start sharing feed."

However, Dr Ho added that the spread of the virus was limited as the outbreak occurred during the pandemic. There were no rabbit parties as Covid-19 restrictions were in place.

Dr Ho and his team found a vaccine, but it was not available in Singapore. They facilitated the import of the vaccine from France to make it available to local rabbit owners and vets here began encouraging their clients to get their rabbits vaccinated.

Dr Ho said: "We found at least 11 cases during the investigation, but we didn't find any more cases by the end of November."