Answer:
an emerging infectious disease
Step-by-step explanation:
According to the World Health Organization (WHO), an emerging infectious disease can be defined as a newly identified and previously unknown infection in a population that may lead to serious public health concerns at local and/or international level. Emerging infectious diseases usually are caused by pathogenic organisms (like viruses) already present in the environment that acquire the ability to infect a new host species as an adaptive response to changes in ecological conditions. Some examples of emerging infectious diseases include, among others, Ebola virus disease, Chikungunya virus disease, H1N1 Influenza virus disease, etc.