Tuesday, March 24, 2020

Can pets carry COVID-19 virus? Should we have simultaneous quarantine of pets from owners testing positive for COVID-19?


Can pets carry COVID-19 virus? Should we have simultaneous quarantine of pets from owners testing positive for COVID-19?
https://brs1762.in/2020/03/25/covid-19-what-next/
COVID-19 turned to be true zoonosis now. There were reports that dogs, cats, and the tiger got COVID19 from their caretakers, now caretakers got the infection from minks. https://www.sciencemag.org/news/2020/06/coronavirus-rips-through-dutch-mink-farms-triggering-culls-prevent-human-infections

Currently, there is limited evidence-based on two dogs (one Pomeranian and other German Shepherd got infected probably from their COVID-19 positive owners) that companion animals can be infected with SARS-Cov-2. Though understanding about COVID-19 is rapidly evolving, there is no evidence that pet dogs or cats can be a source of infection to other animals or humans. (https://wsava.org/wp-content/uploads/2020/03/COVID-19_WSAVA-Advisory-Document-Mar-19-2020.pdf). Considering the facts of poor understanding of COVID-19 spread the CDC recommends “You should restrict contact with pets and other animals while you are sick with COVID-19, just like you would around other people. Although there have not been reports of pets or other animals becoming sick with COVID-19, it is recommended that people who are sick with COVID-19 try to limit the amount of contact they have with their pets. When possible, have another member of your household care for your animals while you are sick. If you are sick with COVID-19, limit the amount of direct contact as much as possible, including petting, snuggling, being kissed or licked, and sharing food. If you need to care for your pet or be around animals while you are sick, ensure you continue to maintain good hygiene practices, such as washing hands before and after interacting with pets and wear a facemask.” (www.cdc.gov/coronavirus/2019- ncov/faq.html#2019-nCoV-and-animals If my pet has been in contact with someone who is sick from COVID-19, can it spread the virus to other people?). 
The first dog in Hon Kong tested positive on 28 Feb 2020 for COVID-19, 17-year-old Pomeranian did not develop symptoms of illness after it contracted a "low-level" COVID-19 infection from its owner, a 60-year-old woman. The owner was tested positive on 25th Feb 2020 and recovered from infection 8 March 2020. The dog was quarantined from February 26 to March 14, after it finally tested negative for the virus but died on 16th March 2020. The cause of death could not be ascertained because the owner didn’t allow post-mortem (https://www.livescience.com/coronavirus-first-case-human-to-dog-transmission.html). A second pet dog, a German Shepherd was sent for quarantine along with another mixed-breed dog from the same residence in Hong Kong, repeatedly tested positive for the Covid-19 virus after its owner was confirmed as being infected. However, the mixed-breed dog remained negative all the time (https://www.bloomberg.com/news/articles/2020-03-19/second-dog-in-hong-kong-tests-positive-for-covid-19-virus).
Considering the intimacy and animal husbandry practices of India risks already felt about pet dogs in Hong Kong and advisory from CDC there is an urgent need for:
1. Quarantine for pets and other domestic animals from owners testing positive for COVID-19 virus. It is already practised in Hong Kong.
2. Repeated testing of pets and domestic animals from houses of owners tested positive for COVID-19 for the possible presence of the virus and monitoring for any possible vertical and horizontal transmission to their progeny and other pets or the in-contact humans, respectively.
3. Similar hygienic and isolation protocols for pet and domestic animals (from households having any COVID-19 positive human case) as advised for human beings at least for the time it is proven scientifically that there is no risk of transmission of COVID-19 among animals or to humans.
4. A pilot longitudinal survey at the earliest for COVID-19 virus and specific antibodies in domestic and pet animals in the areas where positive human cases are reported to determine the extent of infection level and longevity of the carriage of infection by animals.
5. Globally, infections have also been confirmed in tigers, lions, mink, snow leopards, cougars, ferrets, dogs, and domestic cats, but the fact that great apes are susceptible to the SARS-CoV-2 virus has scientists especially concerned (https://www.nationalgeographic.com/animals/article/first-great-apes-at-us-zoo-receive-coronavirus-vaccine-made-for-animals).  (Some 12,000 have died from COVID-19 on fur farms in the U.S. alone, and are believed to have transmitted the virus to humans in some cases (https://www.nationalgeographic.com/animals/article/denmark-mink-culling)
Covid-19 in big apes
 Gorillas:  https://www.nationalgeographic.com/animals/article/first-great-apes-at-us-zoo-receive-coronavirus-vaccine-made-for-animals?
 In January 2021, a troop of eight gorillas at the San Diego Zoo Safari Park became the first great apes in the world to test positive for the novel coronavirus. The silverback, 49-year-old Winston, fell ill with heart disease and pneumonia, but following experimental antibody treatment, he is recovering, as are the others. With Winston, the silverback who developed pneumonia and heart disease, including severe arrhythmia, it’s unclear if the virus exacerbated an underlying condition (heart disease is common in geriatric gorillas), or caused his symptoms. 

Diagnostic tests and their efficacy is another big problem due to their sensitivity, high-negative and high-positive predictive values.

False-positive (https://pubmed.ncbi.nlm.nih.gov/32133832/?fbclid=IwAR3LHLplRtmPZED3jt_Hjf2ZKysmDcXMU5LgVgNPcqNAtb9EzcQBKMtCIoI) can be tolerated in the wake of epidemic control, however, it increases the burden on the health care system.  The real danger is from the high negative predictive value of the current RT-PCR based test, the high number of missed cases may be vital in the fast spread of the epidemic. 
The analysis revealed that In patients with negative RT-PCR results, 75% (n = 308) had positive chest CT findings for COVID19, which means repeated testing and parallel testing is a must find real positive and real negative cases. A long road to go. Karen, the orangutan, was the first great ape to receive the vaccine, she is the one who also had the first open-heart surgery a few years back.
Minks: https://www.nationalgeographic.com/animals/article/what-the-mink-coronavirus-pandemic-has-taught-us

COVID-19 Vaccine for animals
The Virus Spike protein adjuvanted vaccine: Zoetis Pharmaceuticals developed the first COVID-19 vaccine for animals in a way similar to its human variant (Novavax). The vaccine had only been tested on cats and dogs, and recently in February 2021 in bonobos and orangutans at the San Diego Zoo. Zoetis is also conducting trials of its vaccine in mink, with plans to apply for commercial authorization once trials are complete.

The emergence of variants in animals:
The variants of SARS-CoV-2 that keep emerging aren’t just a human problem, scientists found the first evidence that dogs and cats can become infected by B.1.1.7, a recent variant of the pandemic coronavirus that transmits more readily and also appears more lethal (https://www.sciencemag.org/news/2021/03/major-coronavirus-variant-found-pets-first-time).

Therefore, it is time to develop not only better diagnostic tests but also better sampling and diagnostic protocols along with a suitable vaccine.
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