Saturday, May 28, 2022

UK HAIRS (Human Animal Infections & Risk Surveillance) Group Risk Assessment On Monkeypox

How Viruses Jump Species


On paper, Monkeypox should be fairly easy to contain.  It doesn't spread nearly as readily as influenza or COVID, we have a vaccine for it, and the number of cases remains fairly small.  Even in West and Central Africa - where the virus is endemic and outbreaks are common - we've not seen explosive growth.

Of course, that assumes that people will take the threat seriously, modify risky behavior, seek treatment if they believe they are infected (or have been exposed), and isolate when instructed. 

Sadly, based on what I've seen on social media, it appears that many have decided the best way to combat Monkeypox is to post memes that ridicule, marginalize, or even deny the existence of the virus.  

Many claim that Monkeypox is `fake', and either a) a side effect of the COVID vaccine  or b) a plot to subjugate the masses with lockdowns and forced vaccines or c) a plot by `Big Pharma' to make money. 

I've no idea how pervasive these beliefs are in general, and hope these are just the rantings of a small, but vocal, minority.  Otherwise it doesn't bode well for controlling this outbreak or any others that will follow.

And more disease outbreaks are guaranteed.  Whether it's a new, more virulent COVID variant, a novel avian or swine flu virus, or something known, but exotic - like Nipah - nature will test our readiness and resolve again. 

And probably sooner than later. 

One of the concerns about COVID is that it is now well entrenched in North American White-tail deer (see WHO/FAO/OIE Joint Statement On Monitoring SARS-CoV-2 In Wildlife & Preventing Formation of Reservoirs) and may very well have found its way into other reservoir hosts (rodents, mink, etc.) where it may follow different evolutionary pathways, mutate, and then jump back into humans. 

It's not such a far-fetched concern. In fact, we've already seen it happen (several times). 

In the fall of 2020 SARS-CoV-2 jumped from humans to farmed mink in Denmark, and began to mutate into new mink-variants (see Denmark Orders Culling Of All Mink Following Discovery Of Mutated Coronavirus).  

Several mutated viruses jumped back into humans, and began to spread in the community (see WHO 2nd Update: SARS-CoV-2 mink-associated variant strain – Denmark), forcing North Denmark To Lockdown Over Mutated Coronavirus Concerns.
This outbreak was relatively short-lived, as a more biologically `fit' Alpha variant emerged and quickly overwhelmed this `mink variant'.  Since then, we've seen other instances of suspected mink-to-human and hamster-to-human transmission of COVID. 

Previously, the biggest outbreak of Monkeypox outside of Africa (United States 2003) occurred when an animal distributor imported hundreds of small animals from Ghana, which in turn infected prairie dogs that were subsequently sold as pets to the public (see 2003 MMWR Multistate Outbreak of Monkeypox --- Illinois, Indiana, and Wisconsin, 2003).

By the time this outbreak was quashed, the U.S. saw 37 confirmed, 12 probable, and 22 suspected human cases.  Among the confirmed cases 5 were categorized as being severely ill, while 9 were hospitalized for > 48 hrs; although no patients died (cite). 

Proving that pets can be effective vectors of Monkeypox. 

So it shouldn't come as a huge surprise that public health agencies in Europe have similar concerns over the Monkeypox virus jumping to household pets - or potentially even wildlife - where it could become endemic.  

Five days ago the ECDC published their Rapid Risk Assessment (RRA) on Multi-Country Outbreak Of Monkeypox, where they warned.

Risk of spill-over event to animal species in Europe 

Currently, little is known about the suitability of European peri-domestic (mammalian) animal species to serve as a host for monkeypox virus. However, rodents, and particularly species of the family of Sciuridae (squirrels) are likely to be suitable hosts, more so than humans (see disease background), and transmission from humans to (pet) animals is theoretically possible.

Such a spill-over event could potentially lead to the virus establishing in European wildlife and the disease becoming an endemic zoonosis. In the US, there is no evidence that the virus became enzootic in wildlife, however, animal health authorities carried out systematic surveillance and an aggressive campaign for exposed animals during the 2003 outbreak [41]. The probability of this spill-over event is very low. 

Their advice regarding pets:

Exposure of pets 

Public health authorities should work together with veterinary authorities to ensure capacity is in place for quarantining and testing of mammalian pet animals that have been exposed or are at risk of exposure (i.e. pets of a close contact of a MPX case) to MPXV. Rodent pets should ideally be isolated in monitored facilities, complying with respiratory isolation (e.g. a laboratory) and animal welfare conditions (e.g. government facilities, kennels or animal welfare organisations), and tested (by PCR) for exposure before quarantine ends. Euthanasia should only be a last resort reserved to situations where testing and/or isolation are not feasible. Other mammalian pet species could be isolated at home if animal welfare conditions allow it (e.g. availability of an enclosed outdoor space for dogs, regular veterinary checks to assess the health status, preventing access to visitors, preventing pets from leaving the home).

This is obviously distressing to pet owners, but may be unavoidable.  Yesterday the UK's HAIRS (Human Animal Infections & Risk Surveillance) Group released their own risk assessment (below), which raises similar concerns. 

I've only reproduced the summary of a much longer document, which asks (and answers, with varying confidence) about a dozen questions surrounding the risk of Monkeypox spilling over into non-human hosts in the UK.   

Follow the link to read it in its entirety. 

Qualitative assessment of the risk to the UK human population of monkeypox infection in a canine, feline, mustelid, lagomorph or rodent UK pet

Published 27 May 2022

In May 2022, human-to-human transmission of monkeypox virus was observed in several non-endemic countries, including the UK.

During a previous monkeypox incident in the UK in 2018, a pet management process had to be swiftly implemented for one affected household, without conducting a risk assessment a priori.

As the numbers of affected households in the UK related to the current outbreak are rapidly increasing, this warrants a more thorough assessment of the risk posed by mammalian pets exposed to monkeypox virus to people with whom they may come into contact.

For the purposes of the assessment, it is presumed the pet is present in the contaminated household of a confirmed human monkeypox case. The risk posed is therefore to the non-infected human contacts or in-contact peridomestic or wild rodents. It is concluded that the highest risk is posed by the presence of pet rodents, more so than lagomorphs, canids, felids and mustelids.

It is unlikely (but cannot be ruled out) that an infected rodent pet could spread infection to peridomestic or wild rodents. As rodents may not show clinical signs of infection, and the incubation period is unknown, testing to detect the presence of antibodies as well as virus would provide more confidence in ruling out infection.

The evidence of susceptibility for non-rodent pets is poor or incomplete, and therefore a precautionary risk management process should be considered.

Based on current evidence, for pet rodents in households where there are infected people, temporary removal from the household for a limited quarantine period (21 days) and testing to exclude infection is recommended, particularly where there are infected human contacts who have had close direct and prolonged contact with the animal or its bedding and/or litter.

Appropriate risk management for laboratory staff handling samples, or vets and animal health professionals handling or taking samples from the pets, should also be established.

There remains a realistic window of opportunity to contain this global Monkeypox outbreak. But it will require real coordination by public health entities, and cooperation from the general public, it if is to be successful.  

Anything less, and we risk seeing this once exotic virus establish a real foothold.