|Year : 2016 | Volume
| Issue : 2 | Page : 163-164
Blastocystis: Pathogen or passenger? An evaluation of 101 years of research
Subhash Chandra Parija, Shashiraja Padukone
Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
|Date of Acceptance||26-Jul-2016|
|Date of Web Publication||19-Sep-2016|
Subhash Chandra Parija
Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry
|How to cite this article:|
Parija SC, Padukone S. Blastocystis: Pathogen or passenger? An evaluation of 101 years of research. Trop Parasitol 2016;6:163-4
Editors: Heinz Mehlhorn, Kevin S. W. Tan, Hisao Yoshikawa
Year: 2012; Pages: 225
ISBN: 978-3-642-32737-7 (Print) 978-3-642-32738-4 (Online)
The first identification of Blastocystis dates back to more than 100 years even though the scientific knowledge acquired during this period to understand the taxonomy, biology, and pathogenic capabilities of Blastocystis is not entirely convincing. However, in recent decades, the studies focusing on pathogenicity and taxonomy of Blastocystis have taken up the speed. The editors Dr. Heinz Mehlhorn, Dr. Kevin S. W. Tan, and Dr. Hisao Yoshikawa have put forward a tremendous effort in bringing a book called "Blastocystis: Pathogen or Passenger? An evaluation of 101 years of research" as a part of volume 4 of Parasitology Research Monographs series published by Springer group. This book compiles a significant landmark discoveries concerning to Blastocystis and gives an idea about how future research can be designed to get conclusive results to understand Blastocystis in a better way.
This book primarily focuses on the epidemiology, clinical significance, pathogenicity, and other interesting aspects of this lesser known parasite and all this information are dealt in 11 chapters. The introductory chapter includes a list of landmark discoveries in the field of Blastocystis which transpired during the past century. This list is handy as it offers you to track down the Blastocystis research progress from 1911 to 2012 and it also provides the reliable source of references for further reading.
Blastocystis is pleomorphic in nature; thus, making the microscopic identification obscure. Chapter 2 mainly deals with the morphological appearance of both human and animal isolates of Blastocystis. Light microscopic pictures and descriptions are extremely useful for all the routine diagnosis and research purposes. Electron microscopic images reveal the internal morphology of the parasite. This chapter also has an illustrative explanation on the different modes of reproduction in Blastocystis. Expounded epidemiological data on Blastocystis prevalence are available in Chapter 3 along with information on transmission pattern and zoonotic potentials of Blastocystis in humans and animals.
The clear understanding of host and pathogen interactions is of utmost importance in unraveling pathogenicity of a microbe. In the absence of well-established animal models, in vitro pathogenicity studies have furnished the proof that Blastocystis can be a potential human pathogen. In Chapter 4, the studies related to Blastocystis pathogenicity have been discussed in an elaborative manner to identify the lacunae and to propose future research perspectives. Besides this, the authors have also clarified the pros and cons of in vitro model systems in studying Blastocystis pathogenicity.
The progress in the clinical aspects, treatment modalities, and utility of laboratory tests in the diagnosis of Blastocystis is the highlights of Chapter 5. The authors explain about varying degree of clinical manifestations associated with Blastocystis and also enlighten on how parasite density, phenotypic appearance, inter- and intra-subtype variations, and coinfection plays a role in deciding pathogenicity status of the parasite. An informative section on the role of Blastocystis cysteine proteases in irritable bowel syndrome and the association of Blastocystis with dermatological disorders are also available. The existing prevalence studies also indicate that immunocompromised individuals and animal association increase the risk of acquiring Blastocystis infection. The authors have also provided information regarding existing cost-effective antibiotic susceptibility methods for Blastocystis. Further, blastocystosis treatment options with the clinically evaluated antibiotics regime are made available along with alternative treatment possibilities such as probiotics, nitric oxide, arginine, statins, and Rho kinase inhibitors.
Chapter 6 mainly ponders on how Blastocystis shifted its taxonomical position over the past century. At present, based on SSU rDNA complete sequencing data, Blastocystis is classified as a member of stramenopiles. The extensive genetic polymorphism is also a distinct feature of this organism. Hence, consensuses terminology was built in 2007 to identify the Blastocystis isolates as subtypes based on the barcoding sequence of SSU rRNA gene. All these points were discussed in a convincing way, which makes reading easier and vibrant.
Various statistical methodologies have been used in Chapter 7 to analyze the available data on Blastocystis. This section is discussed under various headings to draw conclusions on Blastocystis pathogenicity status. The author conveys a message that in case of microbes such as Blastocystis with uncertain pathogenicity, the application of better statistical methods on data procured from the existing studies would be helpful in avoiding faulty study design which in turn helps in establishing the real cost of the microbe on disease burden. Chapter 8 concentrates on how behavioral decision plays a role in attributing pathogenicity particularly to a microbe with questionable pathogenicity status. In this chapter, the author describes the role of National Institute of Health (NIH), USA in Blastocystis controversy. NIH has reversed its funding opportunity for Blastocystis research from the mid-1990s, which culminated the Blastocystis studies in the USA. The author of this chapter Mr. Kenneth F. Boorom, Director Blastocystis Research Foundation, USA had also shared his personal experience and other communications with NIH in raising financial support for Blastocystis research.
A short and informative chapter 9 deals with all the human diarrheal pathogens other than Blastocystis. This information would be helpful in narrowing down the disease causality to Blastocystis by ruling out all other possible pathogens. Chapter 10 sheds light on zoonotic diseases in general. Since Blastocystis is also known to have zoonotic potential, it is worthwhile to understand the pathways of other established zoonotic diseases. The last chapter wraps it up with the key conclusions drawn during the 101 years of Blastocystis research. In spite of many developments in the field of Blastocystis research, many questions related to its biology and pathogenicity are yet to be answered. Thus, Blastocystis is waiting for the explorer and funding agency to take up exciting research to unlock many puzzles.
Overall, this book encompasses comprehensive and lucid information on Blastocystis. Undoubtedly, this book would serve as an excellent resource for the Blastocystis researchers, clinicians, veterinarians, laboratory technicians, and parasitologists.