Almost a month ago I posted a podcast on COVID as zoonosis
(in Spanish). Since then it has rained a lot.
Now I would like to talk about other zoonotic aspects of COVID-19.
I have found an interesting blog that I recommend to all
vets and those pet owners who like reading carefully.
The author takes the trouble to answer clearly the most
frequently asked questions that veterinary clinics receive nowadays. He also
mentions a study that explains why no pets-to-human transmissions have been
observed.
When we talk about COVID19 or SARS-2 in pets we enjoy an
advantage: it closely resembles SARS, an infection that we suffered in
2002-2003 and that was already studied at the time.
In 2003 Nature published a short communication on SARS in cats and ferrets, which highlights
the possibility of experimental infection and subsequent transmission in these
species. However, natural transmission from these animals to humans was not
been observed. In 2012 another publication confirmed different degrees of compatibility between the virus and a variety of hosts. The latter was based on the
study of the expression of the angiotensin-converting enzyme receptor in human
and animal intestinal tissues.
The susceptibility of host cells to coronaviruses is mainly
determined by the viral protein (S), which induces receptor binding and virus
internalization in the cell, a process necessary to produce infection as such:
with replication and subsequent transmission. This protein binds to
angiotensin-converting enzyme (ACE2) receptors 2.
The susceptibility of different species to SARS-CoV
infection is mainly determined by the affinity between the host's ACE2
receptors and the amino acids of a specific part (RBM: receptor-binding motif)
of the receptor binding domain (RBD) of viral protein S.
A study published earlier this year in the United States has
helped to better understand how this mechanism works. There are mutations in
these specific parts of the viral genetic structure that once enabled the SARS
virus to use more than one species as a host. This study highlights the possibility that some mutations could also improve
the infectivity of COVID-19 in humans, if they favour this compatibility
between viral RBM and human ACE2. Being aware of possible virus mutations in
the future is therefore important.
There is currently NO reason to think that cats could act as
transmitters of the virus: no natural intracellular inclusion or replication of
COVID-19 has been observed in cats. However, just as we are careful with
everything we touch, we must also be aware of the close contact we have with
our pets and patients, which are, after all, a physical means on which the virus of infected
people can be deposited. Hence the preventive measures recommended by the world
health organization regarding "limiting unnecessary contact with our
companion animals". Quarantine should include them as well, limiting their
contact with other people or animals. If our neighbour walks our dog or pats
the cat with whom we share our home during our quarantine, we must be aware of
the associated risk.
It is even more important for clinical veterinarians, whose
activity has not been interrupted by recently implemented laws. Although not to
the degree that professionals in the field of human health are exposed, we also
expose ourselves to infection. The group continues to serve the public behind
closed doors, which does not necessarily imply contact with the owner but with
the animal.
The protection of the clinical veterinarian in these
circumstances is complicated by the responsibility we feel to serve the public
at the same time as we go through unprecedented financial difficulties, the
restructuring of work teams due to staff absences and the need to implement
suddenly new protocols that minimize exposure to the disease. Telemedicine,
rejected until now, has suddenly become the most important tool recommended by
the authorities. Selecting which appointments we should or should not attend,
adapting to the situation of each owner, keeping ourselves informed of
everything that may directly or indirectly affect our activity, constantly
cleaning and of course providing our beloved patients with a dedicated care,
are just a few of the aspects we are passing through in our daily practice.
Best wishes to all my fellow professional colleagues.
No comments:
Post a Comment