[url]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7853591/[/url] or https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7853591/ ;2021 Feb; 27

Protective Immunity and Persistent Lung Sequelae in Domestic Cats after SARS-CoV-2 Infection

Severe acute respiratory syndrome coronavirus 2 readily transmits between domestic cats. We found that domestic cats that recover from an initial infection might be protected from reinfection. However, we found long-term persistence of inflammation and other lung lesions after infection, despite a lack of clinical symptoms and limited viral replication in the lungs.

-

Previous studies have demonstrated the transmissibility of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) by direct or indirect contact between domestic cats (1,2). Given the close relationship between cats and humans, further characterization of the biology of SARS-CoV-2 in cats is warranted.

We inoculated domestic cats with SARS-CoV-2, and on postinfection days 3, 6, and 10, sampled organs to titrate virus (Appendix Figure 1). In plaque-forming assays in VeroE6/TMPRSS2 cells, infectious viruses were detected in the nasal turbinates and trachea of all animals on day 3, and most on day 6, whereas virus detection in the lungs was limited on day 3 and absent on day 6 (Appendix Figure 2, panel A). 

These results suggest that the virus replicated efficiently in upper respiratory organs, which might contribute to its high transmissibility among cats. Infectious virus was cleared from the upper and lower respiratory organs by day 10 (Appendix Figure 2, panel A). No animal showed any signs of respiratory illness during the study (Appendix Figure 3). Infectious virus was not detected (detection limit 10 pfu/g of tissue) in other examined organs (e.g., brain, liver, spleen, kidney, small and large intestine, heart, and eyelids). Viral antigen was detected in nasal turbinates and trachea but was sparse within the lungs at day 3 (Appendix Figure 4).

-

Because SARS-CoV-2 did not cause acute lethal respiratory disease in the cats in our study, cats are a compelling animal model for studying the long-term effects of nonfatal infections. Cats were infected with SARS-CoV-2 and euthanized at postinfection day 28 (Appendix Figure 6, 7). 

Persistent lung lesions were observed 28 days after infection, including histiocytic bronchiolitis with luminal plugs and thickened alveolar septa, similar to lesions observed on day 10 but with more chronic features such as peribronchiolar fibrosis and vascular proliferation within the thickened interstitium. 

We observed a notable dearth of fibrosis within alveolar septa, in contrast to what has been reported for humans with severe acute respiratory syndrome or Middle East respiratory syndrome (3,4). 

One cat had severe pneumonia with fibrin in alveolar spaces and endothelialitis (Appendix Figure 8), similar to what has been reported in humans with fatal coronavirus disease (5), although this cat did not show any respiratory signs.

-

To determine whether previous infection provides protection from future potential infection by SARS-CoV-2, we performed a reinfection study with 2 groups of cats. 

We previously reported that SARS-CoV-2 was transmitted from cats inoculated with the virus to cohoused, naive cats (1). In the previous study, the 3 cats that had been inoculated with SARS-CoV-2, whose nasal swabs were virus-negative on day 6 or 7 after the initial infection (1), were reinoculated with the same virus 4 weeks after the initial infection (Figure 1; Figure 2, panel A). 

No infectious virus was detected in the nasal or rectal swabs after reinfection, suggesting that the animals were protected from reinfection. 

These cats were euthanized at 21 days after reinfection (49 days after the initial infection), and tissue was submitted for histopathologic examination. The reinfection group showed lesions that were comparable with lung lesions observed on day 28 but with less severe thickening of alveolar septa (p = 0.041, by unpaired t-test) (Figure 1; Figure 2 panel B). 

The 3 cats in the other group, which recovered from infection that was transmitted by contact with virus-inoculated cats, were reinfected with the virus at ≈4 weeks (29–32 days) after transmission. 

On day 3 after reinfection, organs were harvested; infectious virus was not detected (detection limit 10 pfu/g of tissue) in respiratory organs or other organs analyzed (e.g., brain, liver, spleen, kidney, small and large intestine, heart, and eyelids). 

These results suggest that virus infection by natural transmission between cats, as well as by experimental inoculation, induces protective immunity against a second SARS-CoV-2 infection.

DJ...this study shows lung damage in cats a month after infection. It did not find virus spreading in (other) organs/staying behind...However this study may have been on the first CoViD variants...Published february 2021 time of study will have been second half of 2020 ? 

In conclusion, SARS-CoV-2 replicated effectively in the upper respiratory tract in cats, and infectious virus was cleared from the lungs within 6 days of infection; however, histopathologic examination demonstrated chronic lung sequelae in cats even a month after viral clearance. After initial infection with SARS-CoV-2, cats were protected from reinfection, with no virus replication in respiratory organs and no additional lung damage.

DJ, so "limited risks in/for cats" based on this (older) study...Long CoViD mostly "Lung CoViD"...bloodvessels in lower respitory system may have been damaged...resulting in breathing problems in a worser scenario...

[url]https://www.elwoodvet.net/coronavirus-in-cats[/url] or https://www.elwoodvet.net/coronavirus-in-cats ;(a vet/"animal doctor" website...)

Cat coronavirus

Cats can get infected with feline coronavirus (FCoV). It’s actually extremely common. It’s highly contagious – 80–90% of multicat households are infected. It affects the gut.

-

FCoV is not the same as the coronavirus that causes COVID-19 (that virus is called severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]). While that virus has (probably) gone from bats to people, there is no evidence that FCoV can be transmitted from cats to people. 

Cats do have the receptors in their respiratory tracts that SARS-CoV-2 binds to. In experimental conditions, cats could be infected the original SARS virus and spread to it other cats. They did not become sick and did not spread it to people. No cases of SARS-CoV-2 have been identified in cats at this time.

-

Most infected cats show no symptoms. 

If they do develop signs, then we usually see mild, self-limiting diarrhoea (due to some damage to the small intestinal cells).

While FCoV does not cause serious disease as it is, it can undergo a genetic mutation in some cats and become a very serious (typically fatal) disease called feline infectious peritonitis (FIP). Why this mutation occurs is unknown. The signs of FIP include:

• intermittent fever

• extreme lethargy

• failure to grow in kittens

• jaundice (DJ-hepatitus)

• fluid build-up in the abdomen and/or chest

• difficulty breathing

• eye problems

• seizures

Although FCoV is extremely common, FIP is not. The vast majority of cats that get FCoV will recover uneventfully.

-

We rarely test for FCoV. It’s not that we can’t, it’s just that it’s so common (in both sick and well cats) that a positive result is relatively meaningless.

DJ...so here a cat-specific coronavirus is discussed...other studies may suggest CoViD-19 can spread in cats and may result in at least some of the (FIP-like) symptoms...

[url]https://www.wur.nl/en/article/coronavirus-and-covid-19-in-animals.htm[/url] or https://www.wur.nl/en/article/coronavirus-and-covid-19-in-animals.htm This article was last updated on 19 February 2022.

Based on research information to this date, pets and farm animals do not seem to play a role in the epidemiology of the coronavirus (SARS-CoV-2), that causes the disease COVID-19. This article contains information on the coronavirus in relations (domestically) kept animals.

-

[url]https://www.wormsandgermsblog.com/2024/02/articles/animals/cats/updated-fip-treatment-guidance/[/url] or https://www.wormsandgermsblog.com/2024/02/articles/animals/cats/updated-fip-treatment-guidance/ 

DJ...statistics could show if cat owners are over- or under-represented in CoViD cases...however it is not a question asked often in CoViD-cases...pets are ignored often. 

So "based on no testing no links were found"....one can not call that science, an assumption based on wishfull thinking...On the other hand-if some animals did see high risks-like minks- it will show itself...

[url]https://www.scottishdailyexpress.co.uk/news/weird-news/scots-cat-believed-first-world-26366027[/url] or https://www.scottishdailyexpress.co.uk/news/weird-news/scots-cat-believed-first-world-26366027 ;

• 2 MAR 2022

A Scottish couple have told how they believe their cat could be the first feline in the world to have suffered long Covid after losing his sense of taste and smell when he contracted the virus.

Catherine Watson, 47, an account manager and her music producer partner Gordon MacKinnon, 50, who live in Glasgow, were horrified when their cat Bruce lost these vital senses after catching the coronavirus and became so gravely ill he needed to be fed through a tube for over a month.

The vaccinated couple, who had mild Covid in late November 2021, feel sure they passed it on to Bruce, a house cat, while they were isolating.

The couple had to spend two and a half hours a day feeding their pet through a tube in his neck until he finally started to nibble food again in early January.

Bruce, an eight-year-old Ragdoll cat, did have Covid, as was proved by a blood test conducted by Margaret Hosie, Professor of Comparative Virology at the University of Glasgow – and though the expert cannot say he had long Covid, she has confirmed she has not seen any other reports of cats losing their sense of taste and smell.

Now Catherine wants to warn other cat owners who catch the virus to avoid their pets.

Remembering how unwell Bruce became, she said: “It was such a scary time. Bruce was so listless, ill and just wouldn’t eat a thing. We now know that’s because he couldn’t smell or taste – a very dangerous thing for cats.”

--------

Professor Hosie said: “As he was losing weight and condition, his owners contacted me to ask when they might expect Bruce to regain his sense of smell and I was unable to provide any answers as nobody had previously reported this clinical sign in cats with Covid.

“I wouldn’t say that Bruce had long Covid, but I haven’t seen any reports of cats losing their sense of taste and smell.

“Fortunately Bruce received excellent intensive care from his local vet and subsequently made a good recovery.”

DJ "weird news" ...the basic story is the cat lost smell and stopped eating...NOT "Long CoViD" but a serious complication in cats...

DJ-My (non expert, limited) view;

-Cat like animals may run a relative high risk for CoViD

-UK numbers may "hint" possibly 5% of UK cats could have had a CoViD infection (maybe even more than once)

-If 10% of those "CoViD-cats" develop Long CoViD it could mean 0,5% (between 0,2-0,8%) of cats have L.C.

-Indications are most-if not all-cats catch CoViD from "their" humans (so far cat-to-cat spread of CoViD likely very limited...maybe a mother cat may give an infection to the kittens...sexual transmission of CoViD)

-It will be VERY, VERY rare to see human-cat-human spread

-Lack of testing means "we do not know".....

DJ-It would be welcome to see more testing in pets for (old) CoViD infections and compare findings with (possible) findings in pet owners. 

The outcome very likely will see very low human-pet-human spread. 

However does this trajectory bring mutations ? New variants ? Recombinations that may bring/increase other risks ? 

Not only the "numbers/statistics" matter also the (possible) risks matter !

If 1-in a-million human-pet-human cases could see a high risk new variant it may worsen the pandemic !