New 30-minute rabies test causes stir
A new rabies test has stirred up intense interest – and skepticism – in the zoonosis community.
Warwick, N.Y.--based Dyne Immune announced early this month the release of a portable rabies test kit that can be used on animal saliva that gives results in 30 minutes.
“The screen allows veterinarians, animal control officers and other professionals to check for rabies in animals that are still alive, eliminating the long wait (10 to 14 days) and hefty price tag associated with typical post-mortem rabies testing,” says the company’s press release.
Dyne’s chief science officer Mike Huchital, PhD., said the test sparked a lot of interest when he participated in the Centers for Disease Control and Prevention’s monthly zoonosis conference call. Huchital said the CDC has invited him back to participate in the March conference call, but he has not committed to that yet.
Huchital said he began working on the test after his wife and two sons were exposed to rabies about seven years ago. The test is not supposed to be a replacement for the “gold standard” direct fluorescent antibody (DFA) test, he said, but rather a front line tool to help identify infected animals so they can be isolated from healthy animals and people.
“Our assay has been designed specifically to screen animals that are overtly infected,” Huchital said. “If it comes up positive, it is an animal you want to get rid of.”
At this point the test is not sensitive enough to test for the absence of the virus, since it can only measure viral load in the microgram per ml range.
“If it comes up negative it doesn’t mean they don’t have it,” he said. “What this does is limit the spread of contagion and culls out the perpetrator.”
Charles Rupprecht, VMD, PhD, chief of the CDC rabies program, said his office has received many calls about the new test, which is why he asked Huchital to participate in the monthly zoonosis call.
“We started getting queries from around the world about it,” Rupprecht said. “It was fairly clear that there was a lot of interest in this.”
Rupprecht said he is also curious about the test, and wants to continue the conversation and keep looking into it.
“It is certainly generating a lot of interest in the public health community,” he said. “We’re obviously interested in finding out more.”
Dyne is selling the test kits for about $200, but the test is not licensed with the U.S. Department of Agriculture’s Center for Veterinary Biologics (CVB).
Brie German, spokesperson for the CVB said while the test is not currently licensed, the center is checking into it.
“They’re in contact with the company right now and are looking at whether it falls under their purview,” German said.
According to a New York State health department official, the product has not even been tested successfully on rabid animals, and should not be considered a valid test.
“We’re just going to be telling people that it is an unproven test that needs to be validated,” said Robert Rudd, director of the Rabies Laboratory at the New York State Department of Health’s Wadsworth Center.
Rudd’s lab provides rabies virus diagnostic services to the entire state, and he said Dyne’s kit has not been tested thoroughly enough yet to be acceptable.
“You’re really playing with fire to use a test that has not been exhaustively validated,” Rudd said. “Rabies still is the most deadly virus known to man. You would not want to use a diagnostic procedure that has not been proven to tell if an animal does or does not have rabies.”
Rudd said Dyne sent his lab a prototype of the rabies test kit, and he found it to be “quite equivocal.” He also received a second prototype from Dyne, but did not test the second version.
“Knowing that we would have to do a more in depth study of this kit, I asked him to fund a small research project in our lab,” Rudd said. “But he did not want to. … Whenever we work with commercial entities they have to come up with a contract to reimburse the state.”
Rudd acknowledged that if Dyne’s kit were as accurate as the DFA test, they could be seen as a competitor to the state lab. But he said he thought that was unlikely, at least until the product has been more rigorously tested.
“They’ve got a lot of proving to do before they can say they are a competitor,” Rudd said.
Huchital said the company is working on making the test more sensitive.
“We are always eager to improve limit of detection and intend to do so,” he said.