Why can the flu virus cause pandemics?

1) How does cholera kill people?     2) What was Dr. Snow's initial hypothesis on the cause of cholera?     3) What methods did Dr. Snow use to test his hypothesis?     4) What was "The Report That Changed The World" ?     5) What is a voronoi diagram?     6) What is the definition of an "A B Test" ?     7) Name a place where cholera is still a problem today.   8)What public health policies would you apply to help that place?

Rabies a)Infects the central nervous system. b)Infects the neuromuscular junction. c)Is caused by a bacterium. d)Is caused by a virus.

Besides Lyme disease, is there another pathogen transmitted to ticks by way of the white footed mouse as its reservoir?  Also, is there another pathogen that is spread to humans by ticks either from another human or animal besides the pathogen that causes Lyme disease?

What are these organization's roles during the Global COVID 19 Pandemic? 1.United Nations? 2. World Health Organization?

Why might pathogens that have recently shifted hosts be more likely to cause pandemics?