#17,294
The number of species that have been identified as being susceptible to the SARS-CoV-2 virus continues to expand (see USDA chart below).
A recent preprint (see Wildlife Exposure to SARS-CoV-2 Across a Human Use Gradient) found evidence of SARS-CoV-2 infection across a wide variety of small peridomestic mammals (e.g. possums, skunks, squirrels, etc.) in Virginia while another (see SARS-CoV-2 Exposure in Norwegian rats (Rattus norvegicus) from New York City) found evidence of spillover to NYC rats.
The primary concern is that these zoonotic viruses might follow divergent evolutionary paths in non-human hosts - produce new and potentially more dangerous variants - which could eventually `spill back' into humans.
It is not an idle concern, as we've already seen this happen with farmed mink (see ECDC Detection of New SARS-CoV-2 Variants Related to Mink).While unproven, there is even some evidence to suggest the Omicron Variant may have evolved after the virus jumped to mice or other rodents (see Evidence for a mouse origin of the SARS-CoV-2 Omicron variant), and then spilled back into humans (see also WOAH Statement).
All of which makes it vital to monitor the spillover and spread of the SARS-CoV-2 virus in non-human hosts.
Yesterday the CDC's EID Journal published a research letter on the finding of SARS-COV-2 among South American Coati inhabiting an urban park.
The South American Coati (Nasua) is a small, peridomestic mammal related to the North American Raccoon, that ranges as far north as Mexico. Like the raccoon, it can often be found foraging in, or near, human habitats, providing it with both direct and indirect contact with humans.
First some excerpts from the letter, then I'll return with a postscript.
Volume 29, Number 3—March 2023
Research Letter
SARS-CoV-2 Spillback to Wild Coatis in Sylvatic–Urban Hotspot, Brazil
Ana Gabriella Stoffella-Dutra, Bruna Hermine de Campos, Pedro Henrique Bastos e Silva, Karolina Lopes Dias, Iago José da Silva Domingos, Nadja Simbera Hemetrio, Joilson Xavier, Felipe Iani, Vagner Fonseca, Marta Giovanetti, Leonardo Camilo de Oliveira, Mauro Martins Teixeira, Zelia Ines Portela Lobato, Helena Lage Ferreira, Clarice Weis Arns, Edison Durigon, Betânia Paiva Drumond, Luiz Carlos Junior Alcantara, Marcelo Pires Nogueira de Carvalho, and Giliane de Souza Trindade
Abstract
We tested coatis (Nasua nasua) living in an urban park near a densely populated area of Brazil and found natural SARS-CoV-2 Zeta variant infections by using quantitative reverse transcription PCR, genomic sequencing, and serologic surveillance. We recommend a One Health strategy to improve surveillance of and response to COVID-19.
By November 2022, the COVID-19 pandemic had resulted in >630 million cases of disease worldwide (1). During the outbreak, natural occurrence of SARS-CoV-2 infections in animals was a hallmark; infections have been reported mainly in companion, domestic, captive, and farmed animals but also in wildlife (2,3). As of September 2022, the World Organisation for Animal Health had recorded 26 animal species infected with SARS-CoV-2 in 36 countries (2), indicating that the virus is able to cross the species barrier, thereby increasing risk of new transmission cycles and animal reservoirs (2,3).
Coatis (Nasua nasua) from South America are small diurnal mammals (family Procyonidae) that are omnivorous, terrestrial, synanthropic, and opportunistic. Coatis interact easily with humans and are often seen foraging for human food, especially from trash (4,5). We investigated the transmission of SARS-CoV-2 to a coati population living in an urban park near a large anthropized area of Brazil.
We collected serum and anal and oral swab samples during February–August 2021 from 40 free-living coatis inhabiting Mangabeiras Municipal Park in Belo Horizonte, Brazil (Appendix Table, Figure 1). Trained professionals captured coatis during 4 periods (February, June, July, and August), using appropriate personal protective equipment (laboratory coats, gloves, N95 face masks, and face shields) in accordance with all biosafety guidelines. Ethics approval was obtained for this study (Appendix).
(SNIP)
We detected SARS-CoV-2 RNA in 2 (5%) female coatis that had no clinical signs of infection (Table). We obtained a complete genomic sequence from the anal swab specimen from coati 535 (99% average coverage). The genomic sequence of SARS-CoV-2 obtained from the anal swab specimen from coati 535 indicated this variant belonged to the Zeta lineage (B.1.1.28.2, P.2) (Figure). The P.2 variant was initially detected in the state of Rio de Janeiro, Brazil, in July 2020 and was considered a variant of interest (9).
We performed plaque reduction neutralization tests (PRNT) on serum samples from all captured coatis to detect SARS-CoV-2 neutralizing antibodies (8). We serially diluted serum samples to obtain 1:20, 1:40, and 1:80 dilutions and measured 50% and 90% neutralizing activity against SARS-CoV-2. Twenty (50%) coatis had SARS-CoV-2 neutralizing antibodies in >1 dilution at the 50% level; at the 90% level, 13 (32.5%) coatis hprolongedad detectable neutralizing antibodies in >1 dilutions and 7 (17.5%) coatis had SARS-CoV-2 neutralizing antibodies in all 3 dilutions. We observed neutralizing antibodies in all 3 serum dilutions for coati 535 (Appendix Figure 2).
We were unable to confirm the mode of SARS-CoV-2 transmission to the coati population. However, we found evidence for human-to-animal transmission; the P.2 genomic sequence from coati 535 was the same variant circulating in humans within the area during the study period. Furthermore, 50% of the coati population had antibodies against SARS-CoV-2, suggesting a cluster of natural exposure and infections within this population. Our results support indirect contact of coatis with contaminated human trash and food scraps in dumpsters and in the bordering urban areas of the park or potential direct close contact with infected human visitors (Appendix Figure 1).
Our findings agree with results from a zoo in Illinois, USA, that also confirmed SARS-CoV-2 in a coati by using molecular methods (2,10). Those results reinforce the susceptibility of coatis to SARS-CoV-2 infection and suggest possible virus shedding and transmission capacity of coatis. Viral RNA detection in both oral and anal swab specimens from coati 535 (Table) and presence of neutralizing antibodies indicate viral replication occurred in this host. Therefore, our findings highlight possible SARS-CoV-2 enzootic maintenance in nature, including in fragmented green areas close to urban settings. Because of the potential for SARS-CoV-2 interspecies transmission, we recommend establishing a One Health strategy to improve surveillance and ability to respond to COVID-19 emergency health events.
Ms. Stoffella-Dutra is a PhD student in microbiology at the Federal University of Minas Gerais. Her primary research interests focus on virology, viral zoonoses, epidemiology, and wildlife disease ecology.
Eighteen months ago we looked at a perspective article, published in China's CCDC Weekly by two well-known Chinese scientists - George F. Gao and Liang Wang - on the continual spread of SARS-CoV-2 from humans to other animal hosts, and the impacts that could have going forward (see Perspectives: COVID-19 Expands Its Territories from Humans to Animals).
The authors warned that the potential for seeing new and dangerous variants emerge - particularly in wild and domesticated animals - was very high.
How often SARS-CoV-2 infects animals in the wild is largely unknown, but the spillover of the virus into other species is increasingly viewed as a serious threat (see WHO/FAO/OIE Joint Statement On Monitoring SARS-CoV-2 In Wildlife & Preventing Formation of Reservoirs).
Which we appear to be moving ever closer to the end of our current COVID emergency, a new zoonotic spillover of a mutated variant could represent an enormous setback for the world.
Which is why we need more surveillance, and a better understanding of the evolutionary trajectory of these viruses in the wild.
