As of this week, a total of 131 ferret-badgers, one Asian house shrew and a puppy bitten by a ferret-badger have tested positive for rabies infection, the Central Epidemic Command Center reported yesterday, adding that the number of cities and counties that have confirmed cases of rabid animals remained unchanged at nine.
A total of 556 wild carnivores, 273 wildlife animals of other types, 714 dogs, 49 cats and 42 bats have been tested as of Tuesday, and the main species found infected with the disease remains the wild Formosan ferret-badger, the center said.
The authority also reported a case in Taitung in which a man was attacked by a ferret-badger on Sunday.
The man was bitten on his right index finger and right ankle. He received a post-exposure rabies vaccine on Tuesday when he sought medical attention, and subsequently received human rabies immune globulin (HRIG) on the same day at another facility, Centers for Disease Control Deputy Director-General Chuang Jen-hsiang (莊人祥) said.
The man was scheduled to receive the second dose of vaccine yesterday.
The ferret-badger that caused the injury was sent for testing on Tuesday and was confirmed of infection on Wednesday night, bringing the total number of infected ferret-badgers to 132.
Meanwhile, the first rabies infection in a dog, confirmed last week, has stirred another round of debate on whether animal experiments on dogs are to be conducted.
The Council of Agriculture said that it would “definitely” conduct animal experimentation.
“Experimentation on animals still has to be conducted because the virus strain found in the Formosan ferret-badgers is already an idiosyncratic branch,” the council’s Bureau of Animal and Plant Health Inspection and Quarantine Director Chang Su-san (張淑賢) said, adding that the infectivity of the virus in both ferret-badgers and dogs has to be assessed.
However, Tunghai University life science professor Lin Liang-kong’s (林良恭) suggested the opposite.
He said that following the news about the rabies-infected puppy, a group of researchers have been considering the possibility, based on studies and observation, that bats are the reservoir host of the rabies virus, while ferret-badgers are just the victims.
There is no need for testing on dogs, Lin said, adding that healthy ferret-badgers should be captured to see whether they are infected with rabies.
Lin said ferret-badgers would be proven “innocent” — as in not being the reservoir host of the virus — if found with no virus.
Bats belonging to genera Eptesicus and Myotis have been confirmed in the US to be the reservoir host, or carrying rabies virus without exhibiting symptoms, according to Lin.
“Bats of both genera can be found in Taiwan. There are seven species of Myotis bats in the country,” Lin said.
The bats living in forests or flying around can easily elude surveillance and their numbers are difficult to estimate. It is possible that the virus had spread to ferret-badgers through the food chain, Lin said.
“If a bat, weakened by the virus, falls to the ground, and its body is then eaten by a ferret-badger, the latter would be running around with the virus and spreading it among its population,” Lin said.
As the genetic sequence has shown that the virus strain found in Taiwan has evolved independently for more than 50 years it is reasonable to assume that it did not evolve with ferret-badgers, which did not exhibit symptoms or infect dogs until very recently, Lin added.
It shows that ferret-badgers might be the victims, rather than the reservoir host that has been carrying the virus for more than 50 years, Lin said.