The outstanding relevance of the One Health approach

The resurgence of infectious diseases of zoonotic origin observed in recent years, including Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS), has caused severe increase in morbidity and mortality for humans globally.¹ Zoonotic diseases account for approximately 60% of all emerging infectious diseases,² and play a profound economic impact, which has been estimated to exceed 120 billion dollars during the period between 1995 and 2008.³ The SARS-CoV-2, which has resulted in remarkable health, social, economic and political impacts, is very likely to be another disease in the list of those that crossed the animal–human barrier.

Although zoonosis remains a major global concern, low- and middle-income countries (LMICs) remain at higher risk of zoonotic diseases, given the nature of contact between animals and humans, limited surveillance capacities and the limited availability of resources. This is particularly true in several countries of the Middle East; aspects like limited access to safe and clean water, presence of domestic animal that act as the reservoir for the sandflies and lack of effective vector control programs in recent years have resulted in up to 60% of the worldwide burden of cutaneous leishmaniasis in the Eastern Mediterranean Region (EMR) of the World Health Organization.⁴ However, the proliferation of water storage tanks as an adaptation strategy during drought conditions in the same region created a potential for transmission of diseases like chikungunya and Rift Valley fever.⁴ Emerging infectious and parasitic diseases are responsible for around 15% of the EMR morbidities and mortalities.⁵ Also, continuous conflicts and humanitarian emergencies led to extreme population movements (internal displacement and migration) in the last decades, which contribute to the spread of infections and re-emergence of infectious diseases in countries hosting refugees. However, mass gathering events like during Islamic pilgrimage (Hajj) further contribute to increasing the risk of zoonotic disease transmission at regional and global levels because of the massive slaughter of millions of livestock within a short period.⁶

Current and past zoonotic outbreaks, such as the SARS and MERS outbreaks in 2002 and 2012,⁷ represent another urgent call on the need of public health preparedness, readiness and response through the human–animal–environment interface using the One Health (OH) approach. The OH approach refers to the human–animal–environmental interdependence through a multisectoral, collaborative, and transdisciplinary approach working at the local, national, regional, and global levels.⁸ Such an approach would be able to ensure timely and effective zoonotic diseases' prevention and control, also covering broader socio-economic and ecological determinants of health.⁹

Across the continents, several LMICs have embarked on activities to prioritize zoonotic diseases: the Democratic Republic of Congo, Thailand, Ethiopia, Azerbaijan, Uganda, Kenya, Tanzania, Cameroon and South Africa prioritized diseases on a national level with a goal to strengthen multisectoral collaboration and focus laboratory, surveillance, and prevention efforts.¹⁰ The multisector strategy would guarantee a successful joint response, especially in detecting the emergence of a Public Health Emergency of International Concern through real-time surveillance, which could effectively mitigate outbreak risks. The strategy would additionally reduce the demand for scarce financial and personnel resources.

Operationalization of the OH approach should be a priority agenda item globally and at national level, particularly low resourced settings that are currently ravaged by the COVID-19 pandemic and where efficient all-of-society and all-of-sector mitigation measures could play in mitigating the impact of future epidemics.