SARS-CoV-2 at the Human-Animal Interface: Implication for Global Public Health from an African Perspective

Applied One Health: Nigeria National Veterinary Research Institute COVID-19 pandemic response

The COVID-19 pandemic has caused the death of 7.1 million people worldwide as of 7 July 2024. In Nigeria, the first confirmed case was reported on 27 February 2020, subsequently followed by a nationwide spread of SARS-CoV-2 with morbidity and mortality reaching 267 173 and 3155, respectively, as of 7 July 2024. At the beginning of the pandemic, only a few public health laboratories in Nigeria had the capacity for SARS-CoV-2 molecular diagnosis. The National Veterinary Research Institute (NVRI), already experienced in influenza diagnosis, responded to the public health challenge for the diagnosis of COVID-19 samples from humans. The feat was possible through the collective utilisation of NVRI human and material resources, including biosafety facilities, equipment, reagents and consumables donated by international partners and collaborators. Within 6 months of the reported COVID-19 outbreak in Nigeria, over 33 000 samples were processed in NVRI facilities covering five states. Thereafter, many field and laboratory projects were jointly implemented between NVRI and collaborating sectors including the Nigerian Centre for Disease Control (NCDC) and the National Institute for Medical Research (NIMR), which brought together professionals in the health, veterinary, education and socio-sciences. In addition, One Health grants were secured to enhance surveillance for coronavirus and other zoonoses and build capacity in genomics. Bio-surveillance for coronaviruses and other emerging zoonotic pathogens at the human-animal interface was activated and continued with sample collection and analysis in the laboratory for coronaviruses, Lassa fever virus and Mpox. One Health approach has shown that inter-sectoral and multinational collaboration for diagnosis, research and development in animals, and the environment to better understand pathogen spillover events at the human-animal interface is an important global health priority and pandemic preparedness.

SARS-CoV and SARS-CoV -2 cross-reactive antibodies in domestic animals and wildlife in Nigeria suggest circulation of sarbecoviruses

Anthropogenic exposure of domestic animals, as well as wildlife, can result in zoonotic transmission events with known and unknown pathogens including sarbecoviruses. During the COVID-19 pandemic, SARS-CoV-2 infections in animals, most likely resulting from spill-over from humans, have been documented worldwide. However, only limited information is available for Africa. The anthropozoonotic transmission from humans to animals, followed by further inter- and intraspecies propagation may contribute to viral evolution, and thereby subsequently alter the epidemiological patterns of transmission. To shed light on the possible role of domestic animals and wildlife in the ecology and epidemiology of sarbecoviruses in Nigeria, and to analyze the possible circulation of other, undiscovered, but potentially zoonotic sarbecoviruses in animals, we tested 504 serum samples from dogs, rabbits, bats, and pangolins collected between December 2020 and April 2022. The samples were analyzed using an indirect multi-species enzyme-linked immunosorbent assay (ELISA) based on the receptor binding domain (RBD) of SARS-CoV and SARS-CoV -2, respectively. ELISA reactive sera were further analyzed by highly specific virus neutralization test and indirect immunofluorescence assay for confirmation of the presence of antibodies. In this study, we found SARS-CoV reactive antibodies in 16 (11.5%) dogs, 7 (2.97%) rabbits, 2 (7.7%) pangolins and SARS-CoV-2 reactive antibodies in 20 (13.4%) dogs, 6 (2.5%) rabbits and 2 (7.7%) pangolins, respectively. Interestingly, 2 (2.3%) bat samples were positive only for SARS-CoV RBD reactive antibodies. These serological findings of SARS-CoV and/or SARS-CoV-2 infections in both domestic animals and wildlife indicates exposure to sarbecoviruses and requires further One Health-oriented research on the potential reservoir role that different species might play in the ecology and epidemiology of coronaviruses at the human-animal interface.