Indian veterinarians and virologists report several cases of natural infection with the Delta variant of SARS-CoV-2 in Asian lions (Panthera leo persica, also called Persian lion). Their work was published on July 2, 2021 on the prepublication site bioRxiv.
Genomic sequencing of the virus detected in these felines kept in captivity in a zoo indicates that these infections occurred during the last week of May 2021, at a time when India was overwhelmed by the Covid-19 epidemic.
The Asian lions infected with SARS-CoV-2 lived in the Arignar Anna Zoological Park, located in the suburbs of Chennai in the state of Tamil Nadu (South India). Several of these felines presented with loss of appetite, runny nose and coughing episodes at the end of May. “Neela and Pathbanathan, two lions, succumbed to Covid-19”, say researchers from the ICAR-National Institute of High Security Animal Disease in Bhopal (Madhya Pradesh, central state of India).
Nasal and rectal swabs were taken from eleven Asian lions (6 males and 5 females) from May 24 to 29, 2021. The SARS-CoV-2 genome was detected in nine lions.
Complete viral genome sequencing was then performed from nasal swabs from four lions. This revealed that the virus harbored by these felines was the Delta variant (lineage B.1.167.2). In these four lions, identical changes were identified in the regions of the viral genome encoding the protein spike and the NS3 protein.
It is recalled that cases of natural infections by various viral lines of SARS-CoV-2 have already been reported in lions in the United States, Spain and the Czech Republic. Cases have also been reported in tigers in the Czech Republic and the United States.
Indian researchers point out that there had been no recent introduction of new animals into the zoo, that public access was prohibited due to strict containment and that zoo keepers were provided personal protective equipment. According to them, the source of the SARS-CoV-2 infection in these Asiatic lions cannot therefore be determined with certainty. They say that seven of the nine infected lions shared the same habitat including shelter, space for food and a water source. Two other lions resided in the same pit.
The infected felines in this zoo therefore shared a habitat that offered several opportunities for close physical contact. “The identification in these felines of an infection, within a short period of time, by a genetically identical SARS-CoV-2 virus clearly indicates the likelihood of lion-to-lion transmission, which could be of great concern”, conclude Anamika Misha and her colleagues.
At least ten animal species concerned
According to the World Organization for Animal Health (OIE), infection with SARS-CoV-2 has been reported in ten animal species, namely the cat, dog, snow leopard, puma, gorilla, otter, tiger, lion, pet ferret and farmed mink.
To date, in the world, there are 552 outbreaks of animal contamination in thirty countries. In most of these natural infections (thus not having been provoked for experimental purposes), caregivers or animal owners have tested positive for SARS-CoV-2. Regarding cases of infection in mink farms, the transmission of the coronavirus from humans to animals and, in return, from animals to humans, has been documented.
In the United States, a vaccine experiment will begin in several zoos. Big cats, ferrets, monkeys and bears are expected to receive an experimental coronavirus vaccine over the summer. This is particularly the case of the Oakland Zoo in California. Zoetis, a veterinary pharmaceutical company, donated 11,000 doses of a vaccine originally developed for mink. About 70 establishments (zoos, animal protection shelters, universities) from 27 American states should receive this experimental vaccine for strictly veterinary use.
Transmission of SARS-CoV-2 to dogs and cats
Two Dutch and Canadian studies, not yet published but to be presented at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) to be held online from July 9 to 12, indicate that people with COVID-19 often transmit the virus to their dogs, and even more to their cats.
The study conducted by researchers at the University of Utrecht indicates that transmission of COVID-19 from human to animal is common. She concludes that people with COVID-19 should avoid contact with pets as well as any other person. The main concern is not so much the health of the animals (which have little or no symptoms), but the risk that they represent a reservoir of the virus and that they reintroduce it into the human population.
The second study, conducted by veterinarians from the University of Guelph (Ontario), shows that the risk of infection is greater for dogs than for cats, probably because the latter spend more time with their owners , especially if they share their bed. Canadian researchers recommend that people infected with SARS-CoV-2 keep their pets away from other people and pets.
A total of 156 dogs and 154 cats from 196 homes were tested. Six cats and seven dogs had positive PCR tests. In addition, 31 cats and 23 dogs developed antibodies. Eleven owners whose pet had a positive PCR test agreed to have it undergo a second round of tests one to three weeks after the first. All eleven animals developed anti-SARS-CoV-2 antibodies. Three cats even still had a positive PCR. All of these animals developed little or no symptoms.
Prolonged infection in a cat in a nursing home
In the July 2021 issue of the journal Emerging Infectious Diseases, German researchers report the prolonged excretion of SARS-CoV-2 RNA in a “therapeutic cat” after the occurrence of an epidemic outbreak (21 cases including three deaths) in a retirement home. This domestic feline, along with two others, contributed to the well-being of the residents of this establishment.
The infected cat remained asymptomatic. In this animal, viral RNA was detected for up to 21 days from the date of first detection, the researchers say. Blood samples from this cat showed the presence of neutralizing antibodies against SARS-CoV-2. The antibody titers were at their maximum on D35. They then decreased but remained positive until the end of monitoring (D73). The other two cats at the retirement home were consistently negative for SARS-CoV-2 in PCR tests for the detection of the viral genome and in serological examinations (search for antibodies).
“Our data support the transmission of SARS-CoV-2 from humans to cats in the context of a community epidemic outbreak made up of multiple infectious events, and not zoonotic transmission. [de l’animal à l’homme] », say Claudia Schulz and her colleagues at the University of Veterinary Medicine in Hanover. The infected cat belonged to a 90-year-old resident, who died of Covid-19.
During the epidemic outbreak, the residents of the retirement home were placed in isolation (without contact between them), visits had been prohibited, strict hygiene measures had been put in place (in particular, different staff for each floor ), but the three cats had always had access to all interior spaces.
Marc Gozlan (Follow me on Twitter, Facebook, LinkedIn)
To know more :
Mishra A, Kumar N, Bhatia S, et al. Natural infection of SARS-CoV-2 delta variant in Asiatic lions (Panthera leo persica) in India. bioRxiv. Posted July 02, 2021. doi: 10.1101/2021.07.02.450663
Schulz C, Wylezich C, Wernike K, et al. Prolonged SARS-CoV-2 RNA Shedding from Therapy Cat after Cluster Outbreak in Retirement Home. Emerg Infect Dis. 2021 Jul;27(7):1974-1976. doi: 10.3201/eid2707.204670
On the Web :
SARS-COV-2 in animals – Situation report (OIE, 16th June, 2021)
Study suggests it is common for pet dogs and cats to catch COVID-19 from their owners. EurekAlert! European Congress of Clinical Microbiology & Infectious Diseases (ECCMID, 30-Jun-2021)
Cats may catch COVID-19 from sleeping on their owner’s bed. EurekAlert! European Congress of Clinical Microbiology & Infectious Diseases (ECCMID, 30-Jun-2021)
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