Consider the following five infectious diseases: Ebola hemorrhagic fever avian influenza SARS West Nile encephalitis mad cow disease What do these diseases have in common?

All these are emerging infectious diseases.

Explanation:

The emerging infectious diseases refer to the infections, which have appeared freshly within a population or those whose occurrence or geographic range is enhancing briskly or is threatening to upsurge in the coming time. The emerging infections can be a result of:

1. Known agents, which have dispersed to novel geographic locations or new populations.

2. Previously unknown or undetermined infectious agents.

3. Previously known agents whose function in particular diseases was not determined previously.

According to WHO, infectious diseases are emerging at a rate, which has not been noticed before. Since the 1970s, many infectious diseases have been discovered like Ebola, SARS, avian influenza, mad cow disease, and West Nile encephalitis.

With the individuals traveling much more to far greater distances in comparison to the past, encountering with wild animals, and living in more densely populated regions has caused the emerging infectious diseases to spread briskly and is resulting in global epidemics, which is a major worry.

The correct answer is - these are emerging infectious diseases.

Explanation:

Ebola is an emerging virus cause Ebola hemorrhagic fever disease that is an infectious disease that infects the people by coming in touch with the infected animal or body fluids of other human or primates.

Avian influenza is also an infectious disease contracted by the contact of the infected bird and can be infected by the human cough sneeze. Similarly, SARS, West Nile encephalitis, and mad cow are the infectious disease that is emerging and infected by the various mode of infection.

Thus, the correct answer is - these are emerging infectious diseases.