More on dogs and Hendra virus

Neil Fearon and his family have lost three horses to Hendra virus, and are concerned about one other. They are now dealing with the implications of their dog, a Kelpie named Dusty, having tested positive for Hendra virus antibodies in its blood. As I mentioned in yesterday's post, the presence of antibodies in the blood of this dog, detected during voluntary testing as part of the outbreak response, only indicates that the dog was exposed to the virus. Viral shedding was not identified, suggesting that the exposure was a prior event and that an active infection was not present. Despite this, government authorities are requiring that the Hendra antibody-positive dog be euthanized.

Poor communication and mixed messages are often the cause of problems during outbreak management, and this seems to be the case here. Based on the news reports, there are some pretty concerning issues.

Testing of the dog was voluntary and the owner was not notified that euthanasia would be required if the dog tested positive.

  • This is rather unethical. People need to understand the implications of outbreak control measures. It's not fair to have such an aggressive response to a voluntary test without proper notification.

Mixed messages are being given about the risk the dog poses to the family.

  • Authorities want to euthanize the dog, indicating they must believe there is some risk. However, the owner is very concerned about his 11-year-old son who has slept with the dog in his bed for the last few weeks. Yet, ABC news indicates authorities reassured Mr. Fearon that the risks are minimal. If the risks are minimal from that type of prolonged, close contact during the period when the dog may have been actively infected, it's hard to justify euthanasia after the fact on the basis of the dog posing a risk to people or animals (especially when the virus is endemic in the bat population in the area).
  • Why euthanasia is being required seems to be unclear. While fear of Hendra virus shedding makes the most sense, Queensland's chief vet has stated that the dog will be euthanized as a precaution because "As a result of that infection, it may make it aggressive." It seems rather strange to euthanize a dog because of concern that an infection (which may not be active) might cause aggression, with no evidence that disease will occur or that it can cause aggression in dogs. Quarantine and observation would make more sense. There are a lot more dogs that are prone to aggression wandering around Australia.

This type of action drives things underground.

  • When overly-aggressive actions are used, and people either don't agree with them or don't understand them, faith in the system decreases. What's the likelihood that people are going to allow their pets to be tested now? I assume it's a lot lower now that they've seen what will happen. So, the ability to determine exposure of other species and the potential risks from other species will be impacted.

Hendra virus is not something with which to play around. It's a very serious disease and one must err on the side of caution. How far you err on the side of caution is the question, and it's a hard thing to determine. It's easy to be very strict when setting rules, and fear of liability or fear of making a subjective decision often override logical thought and discussion.

As a somewhat informed outsider, I have a hard time supporting mandatory euthanasia for a dog that has evidence of previous infection but no evidence of active viral shedding. Yes, no test for virus shedding is 100%, but a pretty high level of assurance can be obtained and the dog can be quarantined for further testing. There's no indication from laboratory studies that I know of that dogs (or other non-bat species) can become longterm carriers of the virus. The owners should be involved in the decision making process and be given enough information to understand the implications of keeping the dog, the risks that might be present, and what they can do to reduce the risks. Government authorities need to clearly state their concerns and the evidence supporting them. With that, it's easier to make a logical plan that protects the public but is also appropriate for the animal and its owners. If the risk is deemed to be real and/or the owners are not willing to accept some degree of risk, then euthanasia is reasonable.

"Kill the dog" is an easy knee-jerk response. I simply don't see the evidence supporting it. Is it possible that authorities have a true reason to be concerned? Sure, but if so, that indicates another communication problem. If there is really evidence that this dog is a concern, this needs to be clearly communicated so people understand what's happening and why such drastic actions are being taken.

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This Worms & Germs blog entry was originally posted on equIDblog on 27-Jul-11.

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Comments (1) Read through and enter the discussion with the form at the end
Dr Arnold L. Goldman - July 27, 2011 4:06 PM

A quarantine period of a month ought to be adequate instead, no?

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