Summary of Awards to Date

Cyclospora prevalence in irrigation water in fresh produce growing regions in Arizona


Jan. 2, 2019 - Dec. 31, 2019

Amount Awarded



Gerardo Lopez, Ph.D.
University of Arizona


Rationale and Objectives

C. cayetanensis is a food-borne coccidian pathogen known to infect only humans that has emerged as a major cause of endemic or epidemic diarrheal illness worldwide (Chacín-Bonilla et al., 2010, Ortega and Sanchez, 2010). C. cayetanensis has been found in drinking water (Dowd et al., 2003, Giangaspero et al., 2015a), wastewater (Kitajima et al., 2014) and treated wastewater (Giangaspero et al., 2015b) used for irrigation in several countries where it can be presumably responsible for outbreaks (Chacín-Bonilla et al., 2010, Ortega and Sanchez, 2010). In the United Stated, outbreaks have been occurring almost every year since 2000 associated with this protozoan intestinal parasite (CDC, 2018a). C. cayetanensis has been identified as second to Salmonella sp. as the most common cause of diarrhea illness cases and outbreaks in the U.S. associated with imported fruits and vegetables (Murphy et al., 2017a). However, most recently, during May-August 2018, there has been a total of 2,299 laboratory-confirmed cases in 33 states in persons that have no history of international travel (CDC, 2018b). Only 761 cases were connected to two outbreaks associated with fresh produce; Del Monte – 250 and McDonalds – 511 (CDC, 2018c). The specific sources of contamination for the remaining cases were not determined, even though basil and cilantro showed to be associated with several clusters (CDC, 2018c). The disease can be transmitted by consumption of food or water contaminated with C. cayetanensis. Several cases of cyclosporiasis have not been able to be linked to outbreaks because of the lack of validated molecular typing tools (CDC, 2018b, Qvarnstrom et al., 2018, Riner et al., 2010). Methods for the detection of C. cayetanensis in environmental samples, such as irrigation water, are essential to effectively address scientific gaps to help solve outbreak investigations in a timely manner to prevent further illnesses (Murphy et al., 2017a and Qvarnstrom et al., 2015). This proposed study enables us to have a better understanding of C. cayetanensis prevalence in irrigation waters in order to help mitigate the cross contamination to fresh produce. The goal of this study is to close the scientific knowledge gaps of the occurrence, prevalence and validate a C. cayetanensis detection method for irrigation waters. Our specific objective is to:

a. Determine the prevalence of Cyclospora cayetanensis in irrigation waters in Arizona using the new BAM Chapter 19b method used for produce, with slight modifications. This will allow a determination of any risk from C. cayetanensis and to identify areas of potential risk.