Dog owners should be wary of fake rabies vaccine directly delivered to people's homes, as the poor quality of the vaccine could be dangerous for people bitten by dogs, a health expert has warned.

Director of the World Health Organisation's Collaborating Centre for Research and Training on Viral Zoonoses, Dr Thirawat Hemajutha said that fake and poor quality vaccines would not eliminate rabies in dogs.

Dog owners would develop severe complications if bitten by dogs injected with fake and poor quality rabies vaccine, he said.

The warning came after a dog breeder died on February 14 from rabies at Bangkok's Chatuchak Weekend Market.

Thirawat said the death of a female public health official, who was a dog breeder, might have been caused by fake and poor quality rabies vaccine delivered to her home.

He added that her dog did not appear to have symptoms of being unwell after receiving a vaccine as the rabies virus had infected the dog before it was vaccinated.

The incubation period for the virus after infection would normally take one, two or up to six months.

Meanwhile, the incubation period in humans would take up to a year.

"People should undergo treatment within two days after being bitten by a dog," Thirawat suggested.

"If not, it would be hard to treat people."

In a related development, a 26-year-old resident from Nakhon Ratchasima province, Pimonrat Ngiew-Klang, said an unowned cat bit her right ear but the Pak Chong Nana hospital refused to give her a vaccine against the rabies virus even though she had a right to receive it under the universal health scheme.

"I had to pay Bt398 (S$17) for a rabies vaccine from my own budget even though I hold a gold card to access the universal healthcare scheme provided by the National Health Security Office," the farmer said.