About the One Health Intellectual Exchange Series

This interdisciplinary course will introduce the concept of One Health as an increasingly important approach to a holistic understanding of the prevention of disease and the maintenance of both human and animal health. The list of topics will include a discussion of bidirectional impact of animal health on human health, the impact of earth’s changing ecology on health, issues of food and water security and preparedness, and the benefits of comparative medicine. Learning objectives include 1) to describe how different disciplines contribute to the practice of One Health, 2) to creatively design interdisciplinary interventions to improve Global Health using a One Health model, and 3) to interact with One Health-relevant professionals in the Triangle and beyond. The course aims to include students from Duke, UNC and NC State from diverse disciplines relevant to One Health, including: human medicine, veterinary medicine, environmental science, public health, global health, public policy, and others.

Monday, February 24, 2014

Hemotropic Mycoplasmas: Insight into reservoirs and new species: Tuesday, February 18th

The North Carolina One Health Intellectual Exchange Group was pleased to host Ricardo Maggi, MS, Ph.D., a well-travelled and highly respected researcher of microbiology and vector borne pathogens.  Dr. Maggi earned his Doctorate from the University of Puerto Rico, where he researched the development of regulated gene expression systems in certain yeasts for biotechnological applications.  Although Dr. Maggi’s research has taken him to very scenic locations such as Milan, he now calls North Carolina home.  Currently, Professor Maggi is Co-Director of the Vector Borne Diseases Diagnostic Laboratory at North Carolina State University’s College of Veterinary Medicine.  There Dr. Maggi and his team aim to develop and implement cutting edge methods and technologies to improve the diagnosis of vector-borne pathogens. 

Dr. Maggi related with the audience the importance of conducting research on hemotrophic mycoplasmas, and their relevance in combating pathogenic potential in both animals and humans.  Hemotrophic mycoplasmas are epierythrocytic obligate bacteria, so evolutionary pressures have given these bacteria the opportunity to spread with the employ of arthropods as vectors.  While the ticks feed on their host, the hemoplasmas have been provided a route to another more suitable host.  Dr. Maggi explained to the Exchange Group how infections with hemoplasmas are often regarded as chronic and largely asymptomatic, so the optimal method of detecting infection would be through serology.  Cytological examination of stained blood smears under light microscopy had been the primary method of detecting hemoplasmas in veterinary medicine, although there were limitations such as the proper categorization of the many mycoplasma varieties.  Dr. Maggi and his research team have developed methods to categorize hemoplasmas based on their genetic makeup.  The polymerase chain reaction (PCR), a biochemical technique used to amplify targeted sections of DNA, has proven to be a viable analytical tool in the proper identification of hemoplasmas. 

The gene sequences recognized and used by Dr. Maggi’s research team in the analysis and identification of hemoplasma subclusters is 16S rRNA.  These sequences are present in the Mycoplasma suis and Mycoplasma hemofelis groups.  This was an important step in the organization of the bacteria because what was found was the tip of the hemoplasma ice burg.  Dr. Maggi then explained to the Exchange how the M. suis and M. haemofelis subcluster included varietals that affected many animals that humans have established domestic or other relationships with.  Because of the genetic similarities of the 16S rRNA gene sequence similarities within the members of the two aforementioned subclusters, the bacteria may be best categorized by the host that it has invaded. 

Noting the breadth of research in the proper analysis of mycoplasmas, Dr. Maggi spoke about the prevalence of the bacterial infections in many species.  The test subjects were sourced from many regions of the world on location.  Some of these animals and respective regions included dogs from Greece and domestic cats from the United States.  Although many animals did not display any signs of infection, in some animals hemoplasma infection was associated with hemolytic anemia of variable degrees of severity.  Comparative immunology was also evaluated between selected primates and humans.  In all, research suggests that hemotrophic mycoplasmas are very adaptable organisms.  They have the ability to change to fit the physiological profiles of their respective hosts.  For this reason Dr. Maggi expressed the importance of recognizing mycoplasmas as emerging zoonotic pathogens. 

The challenge in researching the pathogen lies in the lack of “respect” for these tick-borne pathogens in the greater healthcare and government institutions.  Because ticks are largely isolated in heavily-wooded areas, the potential for human infection is greatly reduced.  This is especially so in urban areas, where ticks typically do not inhabit except through the means of a travelling host.  Dr. Maggi stressed the importance of educating the larger community of the dangers of tick-borne mycoplasmas, and the role researchers in many disciplines may play in combating the pathogen.  This includes creative means of attracting the proper funding to control the spread of the tick-borne diseases.  Ticks are very slow moving in nature, and do not travel great distances from their native regions except by latching on to a host or through other artificial transit modes. 

Another important point brought up in discussion was the growing trend to globalize markets.  Many livestock and other goods are transported to different countries, and a consequence may also be the transport of ticks and other organisms carrying pathogens.  The education of animal handlers and health workers in the proper detection and removal of ticks is essential in combating hemoplasmas.  More importantly, once the obvious obligate has been identified, it is essential to properly screen the inhabitants for the presence of hemoplasmas.  Dr. Maggi concluded his discussion with the students of One Health with a charge to expand on the research already done on mycoplasmas, a largely underappreciated pathogen with the potential to harm many species.  Perhaps comparative immunology may provide perspective on a species that is resistant to the bacteria, and may provide a vaccine.  Perhaps there may be an arthropod species that resists the invasion.  Dr. Maggi stresses the constant transparency and collaboration between human and veterinary medical disciplines, along with the cooperation of environmental and governmental agencies in identifying risk factors associated with mycoplasmas, and measures to prevent infection of a silent pathogen.

Cedric Harvey
NCSU
Senior, Biological Sciences-Human Biology

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