Jawhar GHARBI ^1* Giovanni Rezza ² Manel Ben M'hadheb ¹

• ¹ King Faisal University, Al-Ahsa, Saudi Arabia
• ² Ministry of Health (Italy), Rome, Lazio, Italy

Viruses are always transmitted directly and/or indirectly from human to human and from animal to human. In host cells, virus replication frequently results in an accumulation of mutations, reassortments, homologous and heterologous recombinations, contributing to their rapid adaptation to environmental changes, often raising to the emergence of new virus variants or species. These viral characteristics, in addition to spillover events, have resulted recently in an increasing number of outbreaks, epidemics and pandemics.Emerging viruses are a very broad category that includes not only newly discovered viruses but also re-emerging variants of known viruses. In the last twenty years, an alarming number of infectious viruses have emerged or re-emerged, presenting great threats to global public health. Ebola, Marburg and Crimean Congo hemorrhagic fevers, Lassa fever, Dengue fever, Yellow fever (YFV), West Nile fever (WNV), Rift Valley fever (RVF), Nipah and Hendra viruses, Zika virus, Poxvirus, Hepatitis E Virus (HEV), Bunyavirus and Chikungunya vector-borne viruses, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS-CoV), and the most recent coronavirus disease 2019 (COVID-19) are examples of zoonoses that have spread throughout the globe with such a significant impact on public health (1,2). These viruses continue to cause mass disruption by creating constant threat to public health. The scientific community are always called for a rapid intervention in diagnosing, preventing and treating emerging infections (1,3). Vaccination is probably the most effective tool in helping the immune system to activate protective responses against pathogens, reducing morbidity and mortality, as proven by historical records and the most recently pandemic situation with the emergence of SARS-CoV-2 virus.Under health emergency conditions, new and development of alternative approaches in antiviral drug and vaccine design are imperative for a rapid and massive vaccination coverage, to manage a disease outbreak and curtail epidemic spread. The emergence and re-emergence of novel pathogens challenging the public health in regards to the development of new diagnostic methods, therapeutics and prevention strategies and maintaining an efficient epidemiological surveillance. (10) supported the integrated public health in response to the outbreaks of mosquito-borne flavivirus, the Murray Valley encephalitis virus (MVEV) infection during mosquito seasons in Victoria, Australia. They concluded that the expanded, climate-informed vector surveillance system detected MVEV in mosquitoes in advance of human cases, acting as an effective early warning system. This informed a one-health oriented public health response including enhanced human, vector and animal surveillance, integrated mosquito management, and health promotion (10). The serum of Hepatits B Virus (HBV) was supposed by Yu S. et al., (11) to be a promising biomarker for blood product safety screening and enhanced diagnostic efficiency in chronic HBV infection. They suggest that the incorporation of serum HBV RNA detection into clinical practice and the implementation of blood safety precautions helps to a more effective management of chronic HBV infection and moves the aim of HBV eradication closer to realization (11). The study conducted by Schlesinger M. et al., (12) regarding the countries management of Dengue virus outbreaks demonstrated that Migration and/or socioeconomic status are factors that might impact predictive performance and should be further evaluated. Overall early warning and response system (EWARS) performed very well, providing evidence that it should continue to be implemented in countries for outbreak prediction (12).Finally, the concept of a serious global pandemic named "Disease X" was raised and discussed in this collection. Indeed, "Disease X" refers to an unexpected and unknown outbreak of a contagious or infectious disease caused by a "Pathogen X", which is presently unidentified and capable of infecting humans. This pathogen X is most likely a zoonotic virus, (13,14). According to the World Health Organization (WHO), the "Disease X" is considered among highly contagious diseases such as Ebola, Zika, and COVID-19 (15). For Scientists, as pathogen X is an elusive pathogen, we are unable to prevent the occurrence of Disease X. However, by implementing preventative measures, we may be able to impede or minimize its transmission and possible health risks. In order to achieve this, a universal scientific protocol for managing and controlling "Disease X" would be required.