This is a scary book. I mean it is a very good introduction to how parasites live their life among their hosts and thrive. The book takes look at various parasites and their natural history in terms of evolution and the impact parasites have in the ecology and individuals. How many behaviours in their hosts are manifestation of parasites trying to maximise their chances of getting too they next guy in their life cycles. For example, the malarial parasite plasmodium generates chemical signals that give us fevers at very specific times of the day which coincides with the time when mosquitos are active. From evading the immune system to completely controlling organisms by taking over their nervous system parasites are highly evolved in their way of life.

Zimmer takes a perspective that parasites have a major role in any functional ecosystem and drives the evolution of their hosts as well. Earlier parasites were treated as
Low end ke forms but studies now show his little we know how they work. Almost all wild animals are full of parasites and Zimmer also makes a case that having parasites is a sign of a good ecosystem. They are not organisms in the fringes but rather a driving force across the ecological niches.

Why I said the book is scary is the sheet amount of parasites that can easily enter your body and how little we can do about it. As you read about various ways in which you can get infected leaves you scared.