Physiological basis of parasitism

The relationship between a parasite and its host depends upon biochemical, genetic and physiological processes. Both the hosts and the parasites play a role in these processes. With the passage of time, parasites have evolved to utilize the host's machinery more effectively. Parasites can be classifed on the basis of their life cycles, modes of transmission and host specifcity. Host specifcity of parasites is determined by both the hosts and the parasites. Parasite distribution is affected by their patterns of transmission among the host's populations. Animals and humans are carriers of parasites highly sensitive to environmental changes. The survival of parasites in the environment depends upon their physiological capabilities. The major factor for the abundance of the parasites is that they can adapt to changing environments. In order to control parasites, an understanding of their physiology and nutrient requirements is essential. Parasites also affect the hormonal system of the hosts, leading to the alteration of normal reproductive behaviour. To discern and manage drug resistance in parasites, it is essential to have a comprehensive understanding of parasite physiology.