Jan. 2, 2019 - Dec. 31, 2019Amount Awarded
Gerardo Lopez, Ph.D.
University of Arizona
Cyclospora cayetanensis is an intestinal parasite that has been causing foodborne outbreaks in the United States almost every year since the 1990s. Most foodborne outbreaks are attributed to imported fruits and vegetables. Contamination is thought to be caused by contaminated irrigation water. Cases of cyclosporiasis are not able to be linked to outbreaks because of the lack of validated molecular typing tools. Studies determining the diversity of Cyclospora cayetanensis should be performed. From January 2017 to December 2018, samples from 3 wastewater treatment plants and 4 canals were collected in Arizona and Texas for a project funded by the Center of Produce Safety (CPS). There have been approximately 106 positive samples for C. cayetanensis using qPCR detection techniques. To determine diversity, the 18S region of C. cayetanensis will be targeted deep amplicon sequencing. 18S is part of the ribosomal RNA, one of the basic components of eukaryotic cells and is one of the most frequently used genes for diversity studies. After, sequences will be compared to determine the diversity between samples. The results could aid in understanding diversity of C. cayetanensis and aid in validating molecular typing tools that will help in outbreak investigations in the future.
Cyclospora cayetanensis has been implicated in recent outbreaks. Outbreaks have been associated with imported produce and water, more recently to produce grown in the United States. Information on the sources of the outbreaks and occurrence of this pathogen is still very limited due to lack of validated methods and genomic data available on environmental samples. Recently, the whole genome sequence of C. cayetanensis was obtained by clinical samples. Gathering genomic information on C. cayetanensis present in environmental sources will assist in linking cases of cyclosporiasis and will expedite the tracking and control of future outbreaks. C. cayetanensis only infects humans and it is only transmitted through the fecal-oral route. Being able to compare sequences of C. cayetanensis can aid in determining the source of contamination, which will improve food industry control practices. Our specific objectives are to: a) determine the most efficient DNA extraction method for C. cayetanenesis in environmental water samples, b) develop a method for purification and concentration of C. cayetanensis oocysts in environmental samples using a FACS machine, c) perform Next Generation Sequencing (NGS) on samples with presence of C. cayetanensis and d) determine the diversity of C. cayetanensis present in Arizona and Texas using Next Generation Sequencing. This data will allow us to validate methods that will lead to an improvement in outbreak’s investigation and control practices. This study will help gather information on the best available practices to collect genetic information from C. cayetanensis in environmental samples, a practice that has not been very well studied, per our knowledge. Gathering information in environmental samples is essential for understanding and improving outbreaks’ surveillance, as well as improving control practices in food and water that are in risk of contamination of this pathogen.