I've been distracted with other things for a few days, but want to redress the rabies testing comments. On April 26, Ferret McDuff wrote: >I am not confusing Jeff Johnston with "the enemy". I am merely commenting >that, as he freely admits, he speaks their language, including the many >partial truths that are so convincingly used to mislead the unknowing >public when it comes to ferrets, rabies, shedding studies and post exposure >treatment. An "admission" implies guilt. Just because I can speak like other professionals in my field I am not guilty of being as uninformed or mislead as the worst members of the my profession. On the issue of rabies tests: >There are tests which detect the presence of rabies in saliva and spinal >fluid which are currently at least as reliable as the immunofluorescence >antibody testing. These, however, are not the current standard and public >health is slow to change to a new method over an old accepted one. Yes, public health can be slow to change to new techniques or methods. Immunofluorescence ("IF") has not been accepted as the definitive test. At the moment, it will not accepted as an alternative in all cases. As we know with ferrets, the virus is not always expressed in saliva. To know whether rabies has infected an animal that may not shed the virus in saliva, some type of neural tissue must be sampled. I've read studies that tested for rabies using IF with neural tissue from skin biopsies. If that could be validated as a sensitive and specific test, it would be great, but health officials would want to see those data since the rabies virus makes a beeline for the brain once it gets into the body. I'd wonder if rabies could always be found in the fine network of neurons in the skin. I'd also like to see the data on how sensitive IF is for rabies in spinal fluid. Same caveats apply. >the error rate can be as high as 82% with an average of over 40% (mostly >false positives). Criticizing the reliability of current testing is unproductive without having a better, alternative test available. Anyone can try to discredit a test by describing the maximum error rate ever found, but the *average* error rate is more important in terms of public health. As for specific types of errors, a high rate of false positives is not necessarily bad for the purposes of testing. Yes, this means that some ferrets will be wrongly identified as having rabies, but NO test, not IF or any other is 100% perfect. That's reality. The HIV test has lots of false positives...the first test is highly sensitive but results in quite a few false positives. The test is repeated using the same assay, and if still positive, a second type of assay is used that has very few false positives. The important aspects of a test for guarding public health are having a low *false negative* rate and a high positive predictive value, all of which I can explain in detail to anyone who wants to email me. The savage reality of rabies is that the virus usually must be found in nerve tissue, and that usually means the death of the animal. IF just isn't going to replace microscopic examination of brain tissue right now. I don't approve, I only predict how the public health community will react. >[The rabies shedding studies in ferrets] already [comprise] more data on >more strains than were tested to establish a quarantine for dogs. How much >is enough?? Unfortunately, a few more ferrets will probably pay with their lives in additional shedding studies if *all* public health officials are to be convinced. The alternative is that even more ferrets will die following bite incidents. As for dogs--dogs have been *the* major source for rabies transmission to humans for *millennia* and using quarantines for dogs was well established by the time anyone got around to studying it scientifically. Although we know better, public health directors are generally not aware that ferrets have been domesticated for more than 1,000 years (probably longer) and kept as pets for centuries. Even though no cases of ferret-to-human rabies transmission have been documented, the stigma remains that ferrets are "exotic" and "wild." I can't change that perception alone. Every ferret owner must be an ambassador to represent them in the proper light. >>Rabies is one of the few viral illnesses that is 100% fatal in humans once >>symptoms develop. >Let's look calmly at the *facts*. <SNIP> Rabies is not adapted to a human >host. Even if you are bitten by an obviously rabid, foaming at the mouth >animal, your chances of contracting rabies from a single exposure are, at >best, 15-20%. Rabies can be effectively treated in humans with near 100% >results up to the time clinical signs begin <SNIP>. If caught immediately >rabies can still be treated with a 1-3 chance upon onset of symptoms. All true, but it doesn't change the irrational attitude toward certain infections by the public or by public health officials who are supposed to know better. When Laurie Garrett, author of "The Coming Plague," returned from Surat, India, after investigating the outbreak of pneumonic plague, she was greeted at the airport by a infectious disease team that forced her to sterilize all of her possessions and shower with disinfectant, even though plague is easily treated with the simplest of drugs and its mode of transmission is well known. BUT, after returning from Kikwit, Zaire, where Ebola had reemerged, she breezed through customs and no one stopped her, even though Ebola is fatal in 85% infected persons, it is not easily treated at *all* and, at the time, its mode of transmission wasn't fully known (it CAN spread by air). How can public health officials be "truthful and realistic about the risk" of rabies when so many of them don't know jack about the risks of MANY infectious diseases or are unwilling to stand up to a hysterical parent of a bitten child and refuse to destroy an animal that has almost zero risk of carrying rabies. There is no shortage of stupidity on the part of many people when it comes to protecting their backside, avoiding a scandal or making/saving money. Tell me why Britain will slaughter 11 million otherwise healthy cattle to assuage the fears over BSE? I can't take credit for the stupidity or intransigence of others even when they're colleagues. I *can* help by telling folks on the FML how many public health officials will react to changes in rabies testing and allow FML members to prepare appropriately. Arguing the unfairness of current health policies will upset many people here but won't matter a whit to the officials who decide which animals live or die. I anguish over the fact that ferrets will die in rabies shedding studies, but to convince all public health officials that ferrets pose a near-zero risk of transmitting rabies, those studies are the shortest way to that end. Certainly, some people *can* be convinced based on existing data--but not all. Here in North Carolina our state vet doesn't like ferrets and feels they shouldn't be pets. He campaigned against their legalization. And some health officials are more hostile and resistant to change and less willing to learn than he is. With shedding studies complete for all forms of rabies, ferret owners in North America could take the data to state or provincial legislatures and ask for legislation to override such health officials. Without complete data, it's more likely we'd get shot down and probably make entrenched enemies of ferrets among some health officials. --Jeff Johnston ([log in to unmask]) [Posted in FML issue 1554]