Herding cows, singing in the rain....

What do cows and people have in common?

Herds! In the book, “Guns, Germs, and Steel”, Professor Jared Diamond tried to answer the question of why certain societies flourished, and went on to be world-wide conquerors, such as the Eurasian population, and other societies either died out, or remained in an “undeveloped” state (such as New Guineans). One of the factors he mentioned was that certain populations keeping/herding domesticated animals, such cows, survived epidemics of disease, such as smallpox, because they had been exposed to cowpox….and that this exposure gave them some immunity to other related diseases.

“Herd immunity” is an epidemiological concept, referring to how resistant a population is to a disease, in which a large percentage of the group is immune to this particular disease (Gordis, 2009, p. 24). So, the more people in a group having protection against a disease, the less of a chance that the people with no protection will get the disease, and share it with another person with no protection.

 The more umbrellas, the less people get wet!

This is why it is important for populations to be vaccinated….More on immunization controversies later!

Diamond, J. (1997). Guns, germs, and steel: The fates of human societies. New York, NY: W.W. Norton & Company.

Gordis, L. (2009). Epidemiology, 4^th ed. Baltimore, Maryland: Saunders Elsevier.