Identification and characterization of circulating coronaviruses and host receptor diversity in non-human primates
Project summary
The world population is projected to increase by 2 billion persons in the next 30 years and with this, encroachment of humans into animal habitats will continue to lead to the emergence of new as well as recurrent infectious diseases that are transmissible between wild animals, domestic animals and humans. These diseases are also known as zoonoses and are caused by agents which are thought to arise from wildlife such as non-human primates (NHPs). Zoonoses will continue to shape human life and contribute to the overall global health burden and economy. The presence of zoonotic diseases highlights the importance of conducting research in wildlife to identify disease agents that could potentially infect humans. However, disease screening in wildlife is challenging because of logistical and financial challenges associated with longitudinal sample collection especially in developing countries. There is thus scarce knowledge on disease agents that circulate in wildlife. In addition, mechanisms by which these disease agents infect multiple hosts including humans are still poorly understood. In this study, we propose screen for coronaviruses in wild NHP populations in Kenya. Results from this study can give insights into the origins of human disease agents and provide a database of disease agents in wild animals which will be useful for providing a starting point for vaccine development in the event of disease outbreaks. Because NHPs are similar to humans in many ways, they are used as disease models for pre-clinical testing of drugs and vaccines.
Project outcomes
The world population is projected to increase by 2 billion persons in the next 30 years and with this, encroachment of humans into animal habitats will continue to lead to the emergence of new as well as recurrent infectious zoonotic diseases characterized by high mortality and morbidity. Seventy five percent of zoonotic pathogens arise from wildlife such as non-human primates (NHPs), because they can cross the species barrier to infect humans. Zoonoses will continue to shape human life and will contribute to the overall global infectious disease health burden and economy. The presence of zoonotic diseases highlights the importance of continuous disease surveillance in wildlife through monitoring for the presence of pathogens known to circulate in humans and screening for known and novel species circulating in wildlife. However, disease surveillance in wildlife is challenging because of logistical and financial challenges associated with longitudinal sample collection especially in developing countries. There is thus scarce knowledge on pathogens that circulate in wildlife. In addition, mechanisms by which pathogens cross species barriers to infect multiple hosts including humans are still poorly understood. The overall objective of this study was to identify and characterize circulating coronaviruses and their associated host receptors in understudied wild primate populations in Kenya.
Our first objective was to determine the prevalence of circulating coronaviruses in Sykes monkeys (Cercopithecus mitis) and Colobus monkeys (Colobus guereza). We conducted both molecular and serological assays targeting SARS-CoV-2virus and other coronaviruses that are endemic to either humans or other mammals. The molecular assays did not pick up any coronaviruses. Serological assays showed varied responses to one human endemic virus in a few study animals but did not pick up any responses to SARS-CoV-virus. We also screened for the other respiratory viruses using basic PCR and metagenomics and are yet to finalise on data analysis. Our second objective focused on characterizing the ACE2 receptor diversity in both colobus and Sykes monkeys to determine the susceptibility of these animals to Sars-Cov-2 viral infection. In particular, we focused on the receptor binding region for the SARS-CoV-virus. For comparative purposes, we also sequenced samples from baboons and vervet monkeys. Sequences retrieved from this study were compared to available sequences from other primates and humans. Our results were consistent with previous primate studies. We found that the ACE2 receptor binding region was highly conserved and similar to the existing available sequences from online databases. Our results are confirmatory and add onto the scarce pathogen surveillance data for understudied primate species. In conclusion, continuous pathogen screening, typing and creation of a database is critical in monitoring reservoirs of epidemic pathogens and this in turn would provide a starting point for vaccine development in the event of an outbreak.
