Molecular Epizootiology of Toxoplasma gondii and Cryptosporidium parvum in the Eastern Oyster ( Crassostrea virginica ) from Maine (USA)

• Published in: Pathogens (Basel) Vol. 8; no. 3; p. 125
• Main Authors: Marquis, Nicholas D, Bishop, Theodore J, Record, Nicholas R, Countway, Peter D, Fernández Robledo, José A
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 13.08.2019; MDPI
• Subjects: Crassostrea virginica; Cryptosporidium; Cryptosporidium parvum; Dissolved oxygen; Epizootiology; Estuaries; Gastroenteritis; Gills; Hydrocarbons; Instrumentation; Maine; Mantle; Oysters; Parasites; Pathogens; Protozoa; Public health; qPCR; Retention; Samples; Shellfish; Statistical analysis; Statistical methods; Toxoplasma; Toxoplasma gondii; Toxoplasmosis; United States > US; Maine; Toxoplasma; Cryptosporidium; qPCR; oysters; Maine; epizootiology
• ISSN: 2076-0817; 2076-0817
• DOI: 10.3390/pathogens8030125

Shellfish are known as a potential source of (responsible for toxoplasmosis), and , which is one of the major causes of gastroenteritis in the world. Here we performed a comprehensive qPCR-based monthly survey for and during 2016 and 2017 in oysters ( ) (n = 1440) from all six sites along the coast of Maine (USA). Pooled samples (mantle, gills, and rectum) from individual oysters were used for DNA extraction and qPCR. Our study resulted in detections of qPCR positives oysters for and at each of the six sites sampled (in 31% and 10% of total oysters, respectively). The prevalence of was low in 2016, and in September 2017 several sites peaked in prevalence with 100% of the samples testing positive. The prevalence of was very low except in one estuarine location (Jack's Point) in June 2016 (58%), and in October of 2016, when both prevalence and density of at most of the sampling sites were among the highest values detected. Statistical analysis of environmental data did not identify clear drivers of retention, but there were some notable statistically significant patterns including current direction and nitrate along with the prevalence. The major retention event (in October 2016) corresponded with the month of highest dissolved oxygen measurements as well as a shift in the current direction revealed by nearby instrumentation. This study may guide future research to locate any contributing parasite reservoirs and evaluate the potential risk to human consumption.