After sustained exposure to Mycobacterium leprae, only a subset of exposed individuals develops clinical leprosy. Moreover, leprosy patients show a wide spectrum of clinical manifestations that extend from the paucibacillary (PB) to the multibacillary (MB) form of the disease. This "polarization" of leprosy has long been a major focus of investigation for immunologists because of the different immune response in these two forms. But while leprosy per se has been shown to be under tight human genetic control, few epidemiological or genetic studies have focused on leprosy subtypes. Using PubMed, we collected available data in English on the epidemiology of leprosy polarization and the possible role of human genetics in its pathophysiology until September 2015. At the genetic level, we assembled a list of 28 genes from the literature that are associated with leprosy subtypes or implicated in the polarization process. Our bibliographical search revealed that improved study designs are needed to identify genes associated with leprosy polarization. Future investigations should not be restricted to a subanalysis of leprosy per se studies but should instead contrast MB to PB individuals. We show the latter approach to be the most powerful design for the identification of genetic polarization determinants. Finally, we bring to light the important resource represented by the nine-banded armadillo model, a unique animal model for leprosy.
This volume of the series Handbook of Zoology deals with the anatomy of the gastrointestinal digestive tract - stomach, small intestine, caecum and colon - in all eutherian orders and suborders. It presents compilations of anatomical studies, as well as an extensive list of references, which makes widely dispersed literature accessible. Introductory sections to orders and suborders give notice to biology, taxonomy, biogeography and food of the respective taxon. It is a characteristic of this book that different sections of the post-oesophageal tract are discussed separately from each other. Informations on form and function of organs of digestion in eutherians are discussed under comparative-anatomical aspects. The variability and diversity of anatomical structures represents the basis of functional differentiations.