The Annals of Ibadan Postgraduate Medicine (Journal of the Association of Resident Doctors, U.C.H. Chapter) is published bi-annually.

C.M.D. Ohia1 and E.C. Uwalaka2

  1. Department of Environmental Health Sciences, Faculty of Public Health, College of Medicine, University of Ibadan, Oyo State, Nigeria
  2. Department of Veterinary Parasitology and Entomology, Michael Okpara University of Agriculture, Umudike, Abia state


In an ever changing 21st century world, pandemics such as the Severe Acute Respiratory Syndrome (SARS-CoV-2) virus also known as COVID-19 have come to stay, especially as the world is gradually becoming a global village. The disease has caused a lot of economic and social disruptions globally. The relationship between animals, the environment and humans as hosts of the virus needs to be understood as a way to break the chain of the spread of the virus. This calls for more concerted efforts in preventive measures at the human, environmental and animal interfaces. The synergy between the various health sector (environmental, animal and human) practitioners will help curb the pandemic and also make our world a better and more environmentally-friendly place. This paper aims to elucidate the linkages between man and his environment; the implication of these infections and pandemics on public health and furthermore lends a voice to the call for a One Health approach to curbing the current COVID-19 pandemic ravaging the world. 

Keywords: COVID-19 Pandemic; Infectious diseases; One health; Global health; Public health; Inter-sectoral collaborations


Dr. C.M.D. Ohia

Dept. of Environmental Health Sciences,

Faculty of Public Health,

College of Medicine,

University of Ibadan,

Oyo State,




The world today is facing many multi-faceted problems which will need an international and multi-disciplinary approach to subdue. Emerging and re-emerging diseases have ravaged the world with various outcomes and most of these diseases are of zoonotic (animal) origin. One of such outcomes is the respiratory diseases of the Coronaviridae family of which the recent coronavirus (COVID-19) pandemic belongs. These respiratory infections represent a constant pandemic danger, of which coronaviruses and especially the Betacoronavirus in the family Coronaviridae is a subset. The human aspiratory framework is helpless against such respiratory diseases because of the contact-based inoculation of these infectious materials as droplets through the eyes, nose, or mouth. Airborne transmission is viable as observed, for example, in the variety of viral respiratory ailments influencing people of all ages.1,2 In the recent past decades, communities have been faced with various emerging and novel viral respiratory infections with pandemic potential including the Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) which occurred in China in 20023 ; swine origin pandemic (H1N1) flu- a virus that rose in Mexico in 20094 ; and the Middle East Respiratory Syndrome coronavirus (MERS-CoV) which developed in Saudi Arabia in 2012.1,5,6

History of Coronavirus and COVID-19

Coronaviruses are a wide group of viruses that cause many infections resulting in sickness with a wide range of symptoms which could progress from mild to severe.7,8 Coronaviruses are ubiquitous i.e. can be discovered everywhere throughout the world and are implicated in around 10-15% of normal colds, generally during the rainy, stormy season. There are four genera of coronaviruses (CoV) which are αβγ and δ,α-and β-CoV can affect warm blooded animals, while γ-and δ.-CoV cause infections in birds. Before the SARS-CoV-2, prevalently known as COVID-19, six CoVs have been recognized as human-susceptible infections. These are α-CoVs HCoV-229E and HCoV-NL63, β-CoVs HCoV-HKU1 and HCoVOC43.These four have low pathogenicity with accompanying mild symptoms which mostly manifest as regular cold. The other two known β-CoVs, SARSCoV and MERS-CoV cause serious and possibly deadly respiratory tract diseases.9 These infections were treated as basic and non-lethal conditions prior to 2003, however since this time, there has been an unexpected change with the identification of the Severe Acute Respiratory Syndrome (SARS) which caused a mortality of about 1000 patients from several nations.5 These nations include the United State of America, Hong-Kong, Singapore, Thailand, Vietnam and Taiwan. In 2004, a strain of the coronaviruses known as NL63 was identified in a child experiencing bronchiolitis (a lower respiratory tract disease) in the Netherlands. Scarcely a year later, another coronavirus was found in an old patient in Hong Kong. It was later named HKU1 and has been identified in populaces around the globe.7

SARS-CoV, which was first identified in November 2002, was genomically identified and confirmed in 2003 and has caused mortality of as much as 774 people from that point till the last known epidemic outbreak in 2014.10 This coronavirus is the nearest comparative with the SARS-CoV-2 (COVID-19) which at present has attained pandemic status globally.10 In 2012, another coronavirus episode prompted the identification of the novel infection named MERSCoV. The first instance of the Middle East Respiratory Syndrome (MERS) occurred in Saudi Arabia. There were two different outbreaks in South Korea and Saudi Arabia in 2015 and 2016 respectively.11,12 Likewise, Africa has also experienced the effect of this infection with practically all the nations affected.13 COVID-19 has been reported as zoonotic, i.e., having the ability to be transmitted from human to animals and animals to man.14 The animal involvement in the transmission of SARS-CoV-2 has been reported either as reservoir or intermediate hosts (Fig. 1), hence, frequent washing of hands, non-contact with animal faeces or wild life is highly recommended as this will tend to reduce the zoonotic import of the disease.

Understanding the SARS-CoV-2

The SARS-CoV-2 is a β-coronavirus, which is an enveloped non-segmented positive-sense RNA infection of the coronaviridae family. It is the seventh of the coronaviruses that has caused episodes of epidemics on the planet. A transitory name was at first given to this coronavirus as 2019-novel coronavirus (2019-nCoV) and it was later assigned as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) by the Coronaviridae - Study Group of the International Committee on Taxonomy of Viruses (ICTV). The infection was named COVID-19 (Coronavirus disease-2019) by the World Health Organization (WHO).8