Coronavirus Passed From People to Panthera in the Bronx

An American Society for Microbiology study details the genomic characteristics of viruses that infected zookeepers, tigers, and African lions at the Bronx Zoo, supporting a human-to-animal transmission pathway of the new coronavirus.

On October 13, 2020, this new study concluded that despite numerous barriers to transmission, zoonoses are the major cause of emerging infectious diseases in humans. And the human-to-animal cross-species transmission is driven by human actions.

The current SARS-CoV-2 pandemic, which presumably originated from an animal reservoir, began its outbreak during March 2020, in New York City. During this time, four tigers and three lions at the Bronx Zoo, NY, developed mild, abnormal respiratory signs.

These researchers detected SARS-CoV-2 RNA in respiratory secretions and/or feces from all seven animals, live virus in three, and colocalized viral RNA with cellular damage in one. They produced nine whole SARS-CoV-2 genomes from the animals and keepers and identified different SARS-CoV-2 genotypes in the tigers and lions.

Our data show that tigers and lions were infected with different genotypes of SARS-CoV-2, indicating two independent transmission events to the animals.

The epidemiologic and genomic data indicated human-to-tiger transmission.

Importantly, infected animals shed infectious virus in respiratory secretions and feces. A better understanding of the susceptibility of animal species to SARS-CoV-2 may help to elucidate transmission mechanisms and identify potential reservoirs and sources of infection that are important in both animal and human health.

These were the first confirmed cases of natural SARS-CoV-2 animal infections in the USA and the first in nondomestic species in the world.

The human-animal-environment interface of SARS-CoV-2 is an important aspect of the COVID-19 pandemic that requires robust One Health-based investigation. Despite this, few reports describe natural infections in animals or directly link them to human infections using genomic data.

However, the infections in the tigers and lions occurred at a time before SARS-CoV-2 testing was widely available in the USA, and when there was limited evidence of pre- or asymptomatic viral shedding.

Additionally, at that time, keepers caring for the tigers and lions did not generally wear personal protective equipment given the low risk of infectious respiratory disease transmission between humans and domestic or nondomestic felid species.

These researchers did not declare competing interests.

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