Preface

The analysis of ribosomal sequences of parasitic life agents has shown the extreme differentiation of the groups to which they belong, with distances magnitudes greater than those observed between mammals and fish. Hence there is a need for continuous research of the different aspects that determine parasitic life. These include microbial and parasite biology, ecophysiology, genetics, and molecular biology. In addition, knowledge of the pathogenesis, epidemiology, symptomatology, immune reaction, diagnosis, treatment, and prevention of parasitic diseases is of the utmost importance.

It is absolutely clear that systematic research is the only way to unveil the intricate mechanisms involved in parasitic associations. For example, with description of the direct dependence of the parasite on the genetic expressions of the hosts, with the adaptive convergences among which include the successful evasion of the immune system (to the point of not being considered strange), and with the chemical dialogue, so to speak, that occurs between molecules, specifically, in the molecular exchange. Likewise, research has shown parasitism as the basic mechanism that allowed the differentiation of eukaryotes.

It should be understood that variability as a result of genetic and phenotypic adaptation is key in parasitism in order to maintain the species, which ranges from microscopic to macroscopic organisms, with multiple forms of reproduction. The study of the antagonistic association that defines parasitism is fascinating and essential, particularly the physiological aspects, biochemical interdependence, and loss or mutual acquisition of genetic information.

In this sense, this book brings together in three sections current information in the fields of microbiology and parasitology. The first section covers aspects of cytokines and receptors on parasites and microbes. In the second section we dive into the study of the biology of parasites and microbes. Finally, in the third section we discuss the state of the art of parasitic diseases. I would like to acknowledge the extraordinary investigative work carried out by the chapter authors as well as their great commitment to enriching world knowledge on such an interesting subject. Finally, I express my sincere thanks to the IntechOpen publishing team for their advice in all stages of the construction of this book.

> **Gilberto Bastidas** Department of Public Health and Center for Medical and Biotechnological Research, Faculty of Health Sciences, University of Carabobo, Venezuela

> > **Asghar Ali Kamboh** Sindh Agriculture University, Pakistan

Section 1

Cytocises and Receptors

on Parasites and Microbes

**1**

Section 1
