Yes, I’m slow commenting on hantavirus. I got a lot of media questions about it after the cruise ship outbreak started, but those were focused on basic aspects of hantavirus. Now that things have dragged on, there are more questions about companion animals. That’s not because there are major issues. It’s mainly because people are getting bored with the main talking points and are looking for other content.
However, there are some interesting aspects to consider. Dogs and cats can be exposed to hantavirus just like people, through contact with the reservoirs (rodents), or their feces, urine or saliva. Cats and dogs should be at higher risk in many ways since they are more likely to have close contact and to be sniffing around contaminated areas.
So, that gets me thinking about two relevant areas.
- What are the diseases issues with hantavirus and pets?
- Are there any issues to consider related to this cruise ship outbreak?
I’ll focus this post on #2 (and try to revisit #1 soon).
I hesitated to post this and want to start with the key point that the issues are near negligible. I’m going to talk about some areas we should be thinking about with emerging or unusual disease events because of abundance of caution, not because there’s a major concern with this specific event.
So, don’t freak out. Finding that sweet spot between awareness and panic is tough with infectious diseases.
OK…back to the story.
Despite evidence of human-human transmission on the ship, it’s still rare. If human-human transmission is rare, human-pet transmission should be at least as rare, if not even rarer.
Issues with pets and emerging diseased revolve around three main areas
- Pets getting sick (with issues for them and for them to be potential sources of infection)
- Pets getting infected and being infectious but not sick (good for the pet, but not necessarily good for us if we have infectious but apparently healthy animals around us)
- Pets acting as vectors of a pathogen whereby they are not infected but their haircoat gets transiently contaminated
We don’t know that any of these are an issue, and they are probably of no concern here. Infections in dogs and cats are rare, and if they were infected, transmission risk would be very low. However, we also look for opportunities to take some basic and practical prevention measures when the risk isn’t well known.
I haven’t seen any reports of dogs being on the ship (e.g. service animals). That removes the highest risk situation.
That leaves us thinking about animals owned by people that have come off the ship. People that have been released from the cruise ship are being monitored, and in some situations tested. Different countries are taking different approaches, but it seems like voluntary quarantine is being used in many places. Most of that is keeping potentially exposed people away from other people. However, the question I always having with household quarantine is “what about the pets”? We’re visited this question with various diseases and rarely do we get an answer.
It’s pretty simple, but rarely considered.
If someone is quarantining in a household, we need to know if they have animals, and if there is a risk to/from the animal. If there is, or if we can’t say there’s no risk, we should treat the animal like a person. If someone is staying away from other people, they should stay away from animals. That helps ensure they don’t infect the animal, both for the animal’s health and from the risk it might then pose to other animals or people.
With other infectious diseases (not likely applicable here), there can also be concerns about the animal being a mechanical vector….something that gets contaminated and then has contact with someone else. As I’m writing this, Alice (cat) is perched next to me. If I have a respiratory virus and touch my face, then her. I may have contaminated her haircoat. If she goes and visits someone else in the short term and they pet her, she might have transferred that respiratory virus. Worst case scenario….I contaminate or infect her, and she goes outside and infects another animal. Then maybe I’ve released this into the wild.
This was something we were trying to get across when voluntary isolation was used when SARS-1 hit, then when COVID emerged (rarely with any success).
Again, the issues are very limited and there’s probably no concern.
- Odds of a person that is quarantining being infected are really low.
- Odds of them infecting an animal are even lower.
- Odds them being infected, infecting their animal and that animal getting sick or transmitting the virus to someone else approach zero.
So, why bother considering it? It’s a good question. It’s a low yield area, and we probably know enough about Andes virus to say ‘don’t worry’. However, our knowledge of the potential role of pets in disease is pretty low for a lot of diseases and we can take simple practices to reduce that risk.
Overall, my emphasis here is we should default to assuming cross-species issues and application of control measures unless we determine that there’s no need, rather than waiting until we see a problem and reacting. With Andes virus, a rapid risk assessment could be done to determine the likely risk and our certainty about that, to determine whether we should tell people to isolate from animals too, or that it’s not a concern. Despite all our experiences with emerging diseases and recognition of the scope of susceptible species for many emerging diseases, we are still reactionary when it comes to animals.
Do I want people to worry about their pets if they’ve been exposed? No.
Do I want them to isolate from their pets? Maybe. If they are isolating from people, it makes sense to isolate from their pets. However, if that’s not practical or if the pet is the person’s key emotional support through quarantine, I’d have them quarantine together.
Do I want people to fear animals that might have been exposed? No. We’ve seen over-reactions in the past.
It’s a very minor issue with hantavirus, but it’s another opportunity to remind us that the difference between ‘humans’ and ‘animals’ is in our brain, it’s not biological. To a virus, we might all be a nice susceptible host.