Tackling COVID-19 through the One Health Approach

*Ayodele Oluwaseun Ajayi, Olawale Peter Odeleye and Oluwabukola Atinuke Popoola*

## **Abstract**

The Covid-19 pandemic is currently ravaging the globe with enormous morbidity and mortality. This pandemic, caused by the SARS-CoV-2 started from China and has spread across the globe. Initial reports indicated that the SARS-CoV-2 initially emerged among animals from where they transfer to humans. Different strategies deployed to curtail the pandemic have yielded little result. Therefore, the One-Health concept may compliment existing strategies. The One Health places emphasis on the between the animal-human-ecosystem interface and how this can be used to tackle public health problems, including the COVID-19 pandemic. One Health Surveillance will involve tracking viral pathogens in animals to access risk of transfer to humans. It will also stimulate targeted approaches for prevention and treatment of viral zoonotic infections. There should be an integrated and interdisciplinary One-Health surveillance that should incorporate veterinary, medical or public health and environmental scientists to synergise surveillance effort to track emergence of infectious diseases in the future.

**Keywords:** Surveillance, One-Health, COVID-19, SARS-CoV-2

#### **1. Introduction**

The One Health is an interdisciplinary concept that encompasses animal health, human health and the ecosystem with huge emphasis on how public health problems can be solved at the interface between these entities [1–3]. The interface between humans, animals and the ecosystem are intricately interconnected to the extent that whatever happens in any of these entities most likely affects others [4]. Therefore, the concept of One Health relies on the understanding that human health, animal health and the environment are intricately linked together and they can be affected simultaneously [5]. Historically, the nature of the intricate interactions between animals, humans and the ecosystem have continued to shape human events and local or global public health [6].

There has been a historical consensus that some factors that affect human health can be traced to animal factors and origins [7]. Humans have coexisted with animals and this has formed the basis for studying the human-animal interface [8, 9]. For example, it has been confirmed that close to 70% of all infectious diseases have zoonotic origins [10–12]. It has also been implied in some scientific contexts that the control of aetiological agents in animals could prove effective in controlling such agents within the human population to improve public health [13, 14].

Another imperative of the One Health is the growing interconnectedness between the ecosystems of humans, animals and the environment, which may include wildlife, urban areas and farming systems [15, 16]. The increasing anthropological activities of humans have diminished the delineation between these ecosystems and have increased the frequency of contact between animals and humans [17]. Humans now stand at increased risk of having contact with animals that have been displaced from their original ecosystems. This has further increased the risks of emerging and re-emerging infectious diseases and their attendant burdens on humans and global economy [18]. Some infectious diseases that were hitherto absent in human populations are now common due to the increased contact of humans with animals [19].

It has also been noted that some environmental factors affect the health of humans and animals [20]. The increasing anthropogenic activities have led to a distortion of the delicate natural environmental balance [21]. Intense industrial activities release greenhouse gases into the environment, leading to climate change and increased risk of respiratory problems among humans and animals. The activities of chemical and pharmaceutical industries have also been linked with the release of chemicals into the environment, particularly soil and water; and they can be absorbed by humans, animal and plants [22]. For instance, some studies have confirmed the residual amounts of antibiotics found in urine of animals are partly due to the release of pharmaceutical wastes into the environment [23]. Several pathogens, particularly viruses and bacteria, have been confirmed to be carried by environmental reservoirs and matrixes from where they can be transmitted to humans and animals to cause diseases [24]. One of the fallouts of globalization is the increased speed and frequency of travels by different channels of transportation, namely air, sea and land. This has facilitated the massive movement of humans and animals across transcontinental boundaries [25]. Unfortunately, humans that carry active infectious diseases serve as reservoir through which infectious pathogens can be transmitted or transferred across international boundaries [26, 27]. In addition, massive demand for protein and animal products increases the number of animals that are transported across international borders with increased risk of transfer of resident zoonotic flora and pathogens across international boundaries [28]. This factor has contributed to the increased interface between animals and humans.

It is within this context that different countries and international organizations, particularly the World Health Organization, (WHO), Organization for Animal Health (OIE) and Food and Agricultural Organization (FAO) agreed on a global consensus that some problems of global importance can be tackled through the One Health approach [29]. It places emphasis on multi-sectoral collaborations and frameworks to solve pertinent global health problems, both nationally and internationally. They also encourage different countries to come up with their One Health policies with a view to enhance the quality of their public health. Many countries across the globe have responded to this challenge and institutionalized One Health into their surveillance systems to improve public health. For instance, the African Center for Disease Control has incorporated the One Health framework into its activities with a view to tackle the periodic problem of emerging infectious diseases within the continent.

#### **2. Brief review of zoonotic viruses and their epidemiology**

Zoonotic infections are those infections that originate from animals and are transmitted through the agency of animals or insects to humans [30, 31]. It has since been on record that the vast majority of emerging infectious diseases have zoonotic origins [32, 33]. It has also been established that many viruses have animals as their reservoirs and some even exist as part of the natural flora of the animals. Many animals that have served as proven reservoirs of viruses include bats, dogs, primates, and many other exotic species of animals [34]. It has been recognized that the knowledge of viruses and their natural hosts or ecosystems is important to effectively recognize measures to combat zoonotic infections, including those caused by viruses [35]. Such knowledge will enable scientists determine the possible viral flora of such animals, detect any seasonal changes in the carriage of such viruses that may negatively impact public health and allow medical practitioners, veterinary physicians and epidemiologists to predict possible emergence of viral infections, risks and threats to humans and public health [36–38].

A vast majority of infectious diseases that have significant toll on public health, in terms of mortality and morbidity, have zoonotic origins [39]. Similarly, viral zoonoses contribute a significant proportion of infectious diseases across the globe with significant economic burden running to billions of US dollars annually [37]. Furthermore, Africa and other developing countries appear to have the highest burden of viral zoonotic infections, with significant mortality and morbidity [40, 41]. The diminishing demarcation between the animal wildlife and human ecosystems increases the risk of contact and interaction between humans and animals with consequent increase in the surge of emerging and re-emerging infectious diseases in Africa and across the globe [42]. As stated above, Africa has its fair share of zoonotic viral diseases with well documented mortality and morbidity attributed to them. The following are examples of past or recent wave of zoonotic viral diseases in Africa.


regions where the disease is common. Relative to the high mortality associated with this disease, it is estimated that 99% of close to 59000 deaths caused by this disease are originated from dogs [55]. The virus also circulates in wildlife, especially wild bats and racoons where they can also be transmitted to domestic animals that come in contact with them [55]. The strong knowledge of the transmission link of the virus between dogs and humans led the effective control of the disease through vaccination of dogs and this has proven effective till date [56–58].

iv.**Human Arbovirus infections:** This represents the categories of infections that are caused by mosquitoes and ticks that feed on blood and transmit viruses to susceptible hosts during the process [59]. These Arboviruses still present a huge threat to public health especially in developing countries [60]. The morbidity and mortality associated with diseases caused by arboviruses is significant [61]. However, the increasing rate of urbanization and other related anthropogenic forces increase the chance of transmission of arboviruses to humans [62]. The most prominent arboviral infection among humans is the Dengue fever caused by the Dengue virus which accounts for more than 40.000 deaths per annum [63]. Around 2015, the Zika virus infection caused some morbidities and mortalities in Brazil and neighboring countries and still a threat till date [64].

It has been noted that the zoonotic origins, epidemiological burden and transmission cycles of the viral infections emphasize the need for effective control of zoonotic viral infections through the One Health approach, especially in the paradigm of other measures that have been adopted and have not effectively controlled the diseases.
