New Coronavirus Discovered in South American Bats – Could It Infect Humans?

Discovered in the state of Ceará, Brazil, the novel coronavirus shares similarities with the virus responsible for Middle East respiratory syndrome, first identified in 2012. Experiments to determine its potential to infect humans are scheduled for 2025.

Researchers from the Brazilian states of São Paulo and Ceará, in collaboration with colleagues from Hong Kong University (HKU) in China, have discovered a novel coronavirus in bats. This is the first virus found in South America that is closely related to Middle East respiratory syndrome coronavirus (MERS-CoV).

The findings are detailed in an article published in the Journal of Medical Virology (JMV).

“Right now we aren’t sure it can infect humans, but we detected parts of the virus’s spike protein [which binds to mammalian cells to start an infection] suggesting potential interaction with the receptor used by MERS-CoV. To find out more, we plan to conduct experiments in Hong Kong during the current year,” said Bruna Stefanie Silvério, first author of the article.

Silvério earned a master’s degree from the Federal University of São Paulo’s Medical School (EPM-UNIFESP) with a scholarship from FAPESP and is currently a PhD candidate at the same institution.

The researchers identified seven coronaviruses in five out of 16 oral and rectal swabs from bats collected by the Central Health Laboratory (LACEN) of Ceará in Fortaleza, the state capital. The article highlights the significant genetic diversity of the coronaviruses in question. The five bats belonged to two different species (Molossus molossus, an insectivore, and Artibeus lituratus, a frugivore).

In an earlier study by the groups at LACEN Fortaleza and UNIFESP, rabies virus variants closely related to variants present in marmosets were found in bats.

“Bats are important viral reservoirs and should therefore be submitted to continuous epidemiological surveillance. This monitoring helps identify circulating viruses and risks of transmission to other animals, and even to humans,” said Ricardo Durães-Carvalho, last author of the article, a professor at EPM-UNIFESP and Silvério’s thesis advisor.

Durães-Carvalho is the principal investigator for the project “Bats: epidemiological surveillance, high-resolution phylodynamics, search and design of peptides of biotechnological interest in emergent and reemerging viruses”, which is supported by FAPESP.

MERS-CoV

The MERS coronavirus was first identified in 2012 in Saudi Arabia. In total, 27 countries have reported cases since 2012, leading to 858 known deaths due to the infection and related complications.

In the viruses they found, the Brazilian researchers identified a genetic sequence with 71.9% similarity to the MERS-CoV genome. The gene that encoded the spike protein exhibited 71.74% similarity with MERS-CoV’s spike protein, which was isolated from humans in Saudi Arabia in 2015.

To find out whether it can bind to human cells, experiments will have to be conducted at high-biosecurity laboratories. These trials are scheduled to take place at HKU during 2025.

Silvério is preparing for an internship at HKU’s School of Public Health, where she will be supervised by Professor Leo L. M. Poon, Chair of Public Health Virology and Head of Public Health Laboratory Sciences, and penultimate author of the JMV article.

Same bat, different virus

A previous paper published in JMV by the same group of researchers reported the detection of a human-associated gemykibivirus-2 in one of the M. molossus bats analyzed at LACEN Fortaleza.

According to the authors, it was highly similar to a gemykibivirus identified in samples of human cerebrospinal fluid. The same virus was also identified in samples from blood banks, giving rise to a study led by researchers supported by FAPESP at the Ribeirão Preto Blood Center and Butantan Institute in São Paulo state.

Previous research detected the gemykibivirus in patients with HIV, sepsis of unknown origin, recurrent pericarditis, and unexplained cases of diarrhea and encephalitis. This is the first time the virus has been identified in bats.

Discovery of the virus required the development of novel primers (short single-stranded RNA molecules used in genomics to initiate DNA synthesis). In this case, the primers were based specifically on the genetic sequence from the gemykibivirus detected in humans.

“A lack of viral sequences available from databases prevented us from analyzing these viruses in greater depth. At the same time, the fact that we identified such little-known viral agents makes our findings a basis for future investigations,” Silvério said.

Durães-Carvalho concurred. “Our studies show the importance of making this type of analysis more systematic, optimized and integrated, with several sectors participating and generating data on unified platforms that can be used by health systems to monitor and even prevent epidemics and pandemics,” he said. The research was also supported by FAPESP via other projects and scholarships (22/12861‐0, 24/09079‐3, 19/14526‐0, 20/05146-7, and 20/08943‐5).

Reference: “Coronavirus Cryptic Landscape and Draft Genome of a Novel CoV Clade Related to MERS From Bats Circulating in Northeastern Brazil” by Bruna Stefanie Silvério, Mariana Dias Guilardi, Junior Olímpio Martins, Rodrigo Lopes Sanz Duro, Larissa Leão F. de Sousa, Gustavo Cabral-Miranda, Luiz Mário Ramos Janini, Leo L. M. Poon and Ricardo Durães-Carvalho, 18 January 2025, Journal of Medical Virology.
DOI: 10.1002/jmv.70173

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