Detection of Infectious Cryptosporidium parvum Oocysts in Mussels ( Mytilus galloprovincialis ) and Cockles ( Cerastoderma edule )

Abstract

Infective Cryptosporidium parvum oocysts were detected in mussels (Mytilus galloprovincialis) and cockles (Cerastoderma edule) from a shellfish-producing region (Gallaecia, northwest Spain, bounded by the Atlantic Ocean) that accounts for the majority of European shellfish production. Shellfish were collected from bay sites with different degrees of organic pollution. Shellfish harboring C. parvum oocysts were recovered only from areas located near the mouths of rivers with a high density of grazing ruminants on their banks. An approximation of the parasite load of shellfish collected in positive sites indicated that each shellfish transported more than 10 3 oocysts. Recovered oocysts were infectious for neonatal mice, and PCR-restriction fragment length polymorphism analysis demonstrated a profile similar to that described for genotype C or 2 of the parasite. These results demonstrate that mussels and cockles could act as a reservoir of C. parvum infection for humans. Moreover, estuarine shellfish could be used as an indicator of river water contamination.Cryptosporidium parvum is a cause of diarrheal disease in humans and farm animals and is a major cause of diarrhea in children and neonatal ruminants (9). Moreover, in immunocompromised subjects, this disease can be life threatening. Transmission of C. parvum occurs mainly by ingestion of oocysts either by fecal-oral contact or through contaminated food or drinking water. Localized epidemics of food-borne cryptosporidiosis have been associated with uncooked sausage, offal, raw milk, apple cider, or foodstuffs, but waterborne transmission seems to play a more prominent role and is implicated in most outbreaks of human cryptosporidiosis (16). The presence of Cryptosporidium oocysts in drinking water supplies has been well documented since 1984, and waterborne epidemics of cryptosporidiosis have been reported frequently in the United States, United Kingdom, and Japan, among other countries (25). The potential for water contamination by cryptosporidial oocysts is high in areas where dumping of raw sewage is a common practice (25). In addition, the presence of waterborne C. parvum oocysts of animal origin needs to be considered, since a single neonatal ruminant can shed up to 10 10 oocysts during the course of infection (21).The presence of oocysts in river waters may also be a source of contamination of the marine environment. Rivers polluted by anthropogenic and livestock fecal discharges could play a major role in contamination by oocysts of shellfish in estuaries and coastal environments. Experimental data show that C. parvum oocysts can survive in seawater up to 30 ppt for as long as 1 month (11,24). Oocysts also have been detected in seawater in Hawaii near a sewage discharge site (18). Moreover, oocysts with a size, shape, and appearance consistent with those of C. parvum have been detected in mussels (Mytilus edulis) from western Ireland (6) and in bent mussels (Ischadium recurvum) from Chesapeake Bay in the United States (14). Laboratory data show that the...

Detection ofCryptosporidiumoocysts in green mussels (Perna viridis) from shell-fish markets of Thailand

“…Up to 12.5 % of the samples analyzed contained Cryptosporidium oocysts. This rate is considerable high from a public health perspective and similar to those levels cited in previous reports (Gomez-Bautista et al, 2000;Lowery et al, 2001;Giangaspero et al, 2005). Moreover, water analysis in the area where the mussel samples were collected in the Chao Phraya River was also conducted.…”

“…In the naturally contaminated samples of Cryptosporidium oocysts, this paper reported 31.1 % of contamination and only C. parvum has been found. In another study, infective C. parvum oocysts were detected in mussels and cockle from a shellfish-producing region that account for the majority of European shellfish production (Gomez-Bautista et al, 2000). All these data suggested that mussels and cockles could act as a reservoir of C. parvum infections to humans (GomezBautista et al, 2000;Graczyk et al, 1998;Graczyk et al, 2001;Lowery et al, 2001).…”

“…Humans are therefore at risk of infection either by consumption of shellfish, or by taking part in recreational activities in these areas. The presence of Cryptosporidium oocysts in mussels has been reported in European countries (Gomez-Bautista et al, 2000;Lowery et al, 2001;Gómez-Couso et al, 2003;Gómez-Couso et al, 2004;MacRae et al, 2005;Li et al, 2006), USA (Graczyk et al, 1999;, and Canada (Graczyk et al, 2001). The detection of these parasites in mussels is of concern due to the potential cryptosporidiosis risk of consuming raw or light-cooked seafood.…”

Cryptosporidium parvum en gastrópodos silvestres como bioindicadores de contaminación fecal en ecosistemas terrestres

“…En invertebrados se ha detectado en moluscos bivalvos marinos (ostras, mejillones, berberechos) [13][14][15][16][17][18][19][20][21][22] , lo que sirve como indicador de contaminación fecal de las aguas. En Chile, el estudio de 642 moluscos bivalvos (choritos, ostras, almejas, machas) y muestras de agua salada obtenidas de playas de la Región de Valparaíso, usando microscopia y pruebas moleculares no ha detectado la presencia de ooquistes de Cryptosporidium como contaminante de agua ni mariscos (Neira P, datos no publicados).…”

Effectiveness of Standard UV Depuration at Inactivating Cryptosporidium parvum Recovered from Spiked Pacific Oysters ( Crassostrea gigas )

“…Raw shellfish, e.g., molluscs, oysters, clams, scallops, and other marine life, in costal waters are increasingly being implicated as potential reservoirs for the transmission of the viable and infective stages of Cryptosporidium (2,8,13,16,19). Contamination is apparent mainly in near-shore waters and estuaries where human sewage is discharged and runoff from land exposed to animal manure occurs (18,25).…”