Dogs + Ebola: What Every Owner Needs to Know From the American Kennel Club and the AKC Canine Health Foundation
In recent weeks, dog owners, supporters and donors have looked to the AKC Canine Health Foundation (CHF) and the American Kennel Club for credible information regarding Ebola virus in dogs.
At issue is whether humans can get Ebola from dogs, and whether dogs can even get Ebola in a form that is transmittable. Due to the complexities of the virus, only time and research will answer these questions.
“In humans, Ebola virus is detected using a diagnostic test for Ebola RNA. In dogs, scientists will have to establish the presence of Ebola virus RNA along with whether the virus is replication competent and infectious,” said Shila Nordone, Ph.D., Chief Scientific Officer for the AKC Canine Health Foundation. “Only then will we have evidence that canine infection is a public health threat. All told, this will take many months.”
Ebola: Understanding Viral Transmission, Pathogenesis and Why the Dog is Part of the Conversation
In the news recently there have been reports of three health care workers, one in Spain and two in the United States, who have been diagnosed with Ebola virus. Two of these women are also dog owners. The dog in Spain was euthanized in the interest of public health. The dog in the United States is currently quarantined.
To better understand why dogs are part of the conversation and why these two countries reacted differently, a better understanding of Ebola virus is necessary.
Viruses are ranked on a biosafety level (BSL) scale from 1 – 4, with 4 being the most severe. Ebola is a BSL4 pathogen, for which there are no approved therapeutics or vaccines. The virus is transmitted from one individual to another through the exchange of bodily fluids and enters the body through exposed cuts or mucous membranes, such as an individual’s mouth or nose.
Public health officials are concerned about the role of dogs in Ebola virus transmission because there is scientific evidence that another mammal, the bat, is a reservoir for the disease. A reservoir host is one that carries the virus, is asymptomatic (displaying no symptoms of infectious virus), and that transmits the disease to humans or to other animals.
Based upon a research study in 2005 we know that feral dogs in African villages where there have been large scale epidemics seroconvert to Ebola. Seroconversion means the dogs have been exposed to virus and have produced antibodies specific for Ebola virus. Seroconversion does not imply production of infectious virus that can be transmitted to people or other animals. In other words, this study indicates that Ebola virus breached the dog’s mucosal barrier, was recognized by the canine immune system as being foreign and the body responded by producing anti-Ebola antibodies. In this study, dogs were described as being asymptomatic, and there was no evidence that virus was transmitted between dogs or from dogs to any other host.
In summary, there is currently no evidence that exposed dogs become productively infected and shed Ebola virus. So while there have been documented cases in Africa where dogs are exposed and respond to this exposure by producing anti-Ebola antibodies, there has been no evidence that the dogs infect people or other animals. Because there are unknowns in the Ebola chain of transmission, public health officials in Spain erred on the side of caution and chose to humanely euthanize the dog. In the United States, public officials have quarantined the dog in order to monitor him and perhaps arrive at a better understanding of what role, if any, the dog may have in the chain of transmission.
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Are dogs part of the chain of transmission of virus?
Infectious virus must be produced in a sufficient quantity and be provided a method of transport in order to be spread from host to host. Based on other better established viral transmission models, we know that viral amplification in an intermediate host is a prerequisite for transmission. As mentioned above, we do not know if the dog’s intracellular machinery can support viral replication, packaging and formation of infectious viral particles, nor do we know how the dog might shed virus for transmission to another host if it is asymptomatic. Extensive research is necessary to answer this question. The American Veterinary Medical Association (AVMA) is currently working on recommendations for handling, testing and treatment of companion animals associated with human cases, and that information will be forthcoming.