Risk of Handling as a Route of Exposure to Infectious Waterborne Cryptosporidium parvum Oocysts via Atlantic Blue Crabs ( Callinectes sapidus )

Abstract

Commercial Atlantic blue crabs (Callinectes sapidus) were exposed to 2.0 ؋ 10 4 infectious waterborne oocysts of Cryptosporidium parvum. The study demonstrated that blue crabs can transfer C. parvum oocysts to persons involved in handling or preparing crabs and that they may contaminate other surfaces or products during storage.Cryptosporidium parvum is a human enteric pathogen that can be transmitted very efficiently via the fecal-oral route (i.e., autoinfection and person-to-person) and indirectly via contact with contaminated water, including consumption and recreational activities (5). Edible crabs may take up and retain human-virulent bacterial contaminants (1, 10, 11, 13) and organic and inorganic pollutants from ambient water and sediments at levels posing risks to consumers (12). There is no published information on contamination of crabs with Cryptosporidium, a waterborne pathogen commonly reported from coastal waters (3, 6). However, our previous study demonstrated mechanical passage of C. parvum oocysts via handling of fish caught in urban watersheds to the hands of recreational anglers (16). The purposes of the present study were to determine if commercially harvested Atlantic blue crabs (Callinectes sapidus), which are widely consumed, can serve as a vehicle for infectious waterborne oocysts of C. parvum and if the handling of crabs collected from Cryptosporidium-contaminated water can result in oocyst transfer to the handler's hands.A 120-liter-capacity marine tank was filled with 4 liters of artificial seawater of 12-ppt salinity (9) to which 2.0 ϫ 10 4 C. parvum oocysts were added. The oocysts were tested and found to be infectious to neonatal BALB/c mice (6). C. parvum oocysts were eluted from 12 blue crabs (C. sapidus) purchased from a local market by sprinkling 0.5 liter of the eluting fluid (4) on the crabs' surfaces and then collecting all the fluid into a single plastic bottle. The crabs were alive and actively ventilating with their mouthpart appendages during the experiments. The crabs were left in the tank for 24 h, and then the oocysts were eluted from the individual surfaces of six randomly selected crabs as described above and the fluid was collected into six corresponding plastic bottles. The oocysts were eluted collectively from the surfaces of the remaining crabs, and the fluid was collected into a single plastic bottle. The crabs were handled by a single person, and the hands of that person were washed in a plastic ziplock bag (16) containing 0.5 liter of eluting fluid (4). The tank water was collected into a plastic container, and the tank was washed with 1 liter of the eluting fluid (4), which was added to the container. The samples were processed by a cellulose acetate membrane filter dissolution method (4), and the recovered material was tested by combined fluorescence in situ hybridization and a direct immunofluorescent antibody assay for C. parvum (7-9).

A role of some food arthropods as vectors of human enteric infections

“…Their biology and ecology makes control of these parasites difficult. So, good hand washing in food preparation [4], controlleddissemination of cysts and oocysts in the farming environment via human waste management and good water management used to wash fresh products should prevent gastroenteritis in any group at risk and eliminate the spread of outbreaks.…”

“…Edible crabs may take up and retain human-virulent bacterial contaminants [13,14] and organic and inorganic pollutants from ambient water and sediments at levels posing risks to consumers [15]. And there is very little information on contamination of crabs with Cryptosporidium [4]. The authors demonstrated a mechanical passage of C. parvum oocysts via handling of fish caught in urban watersheds to the hands of recreational anglers.…”

“…Handling of crabs collected from Cryptosporidium-contaminated water can also result in the transfer of oocysts from crabs to handlers [4]. Cryptosporidium oocysts were detected in sample fluid from blue crabs and may cause food borne cryptosporidiosis when the preparing process and storage are suboptimal or improper [4]. The infection of more than 400,000 people in Milwaukee, Wisconsin, in 1993 with Cryptosporidium through ingestion of contaminated drinking water highlights the importance of research and testing for this parasite.…”

“…This study also found that commercially harvested Atlantic blue crabs (Callinectes sapidus), which are widely consumed, can serve as a vehicle for infectious waterborne oocysts of C. parvum. Handling of crabs collected from Cryptosporidium-contaminated water can also result in the transfer of oocysts from crabs to handlers [4]. Cryptosporidium oocysts were detected in sample fluid from blue crabs and may cause food borne cryptosporidiosis when the preparing process and storage are suboptimal or improper [4].…”

“…In recent years there are so many travelers and large exports/imports of seafood such the infections can produce dangerous outbreaks spread in to a large regions. Many of the protozoan parasites such as Cryptosporidium parvum and Giardia are found on the surface of foods that have been washed with contaminated water harboring these parasites [2][3][4][5][6]. Similarly to waterborne prorozoan parasites, some bacterial pathogens such as Vibrio spp., especially V. cholerae 01 can be readily spread with the water and contaminated food [7][8][9][10].…”