Introduction to Epidemiology 6th Edition by Ray M Merrill

Exercise 19

From your reading and study thus far and from studying “Age-group specific number of females for every 100 males in the United States, 1978 and 2008” (see Figure 1), explain and discuss polio as a biphasic (two-phase) disease and the problems this two-phase process posed in investigating polio epidemics.

Figure 1

Step 1 of 5

The viral agent causing polio is considered small as compared to other viruses like chicken pox and smallpox. The virus responsible for causing polio falls in the class Enterovirus belonging to the group Picornavirus. It is considered to be a contagious infection and the mode of transmission is oral-fecal and pharyngeal-oropharyngeal route.