Fernando Méndez-Hermida

Batch solar disinfection inactivates oocysts of Cryptosporidium parvum and cysts of Giardia muris in drinking water

Aim:  To determine whether batch solar disinfection (SODIS) can be used to inactivate oocysts of Cryptosporidium parvum and cysts of Giardia muris in experimentally contaminated water.

Cryptosporidium Contamination in Harvesting Areas of Bivalve Molluscs

Cryptosporidium contamination was evaluated in areas in Galicia (northwestern Spain) where bivalve molluscs are harvested. Galicia is the main mussel-producing region in Europe. Data were collected on water contamination of effluents that are discharged into these areas. Cryptosporidium spp. were detected by immunofluorescence microscopy and molecular methods in 71% of the river water samples (n = 7), 64% of raw sewage samples (n = 11), 50% of effluents from wastewater treatment plants (n = 16), and 29.3% of the mussel samples (Mytilus galloprovincialis, n = 184). Cryptosporidium parvum was identified in all samples of contaminated mussels, Cryptosporidium muris was found in three samples of effluent from wastewater treatment plants, and Cryptosporidium baileyi was found in a sample of raw sewage. Further studies are needed to determine the parasitological quality of water in these shellfish harvesting and recreational areas. Cryptosporidium could be a public health risk from consumption of raw or undercooked contaminated molluscs and use of contaminated waters for recreational purposes.

First report of Cryptosporidium parvum ‘ferret’ genotype in American mink (Mustela vison Shreber 1777)

A total of 51 faecal samples from wild and farmed mink were analysed by a direct immunofluorescence antibody test. Cryptosporidium oocysts were identified in eight, apparently healthy, farmed American mink (Mustela vison). The isolates were identified as Cryptosporidium parvum ‘ferret’ genotype by PCR-RFLP and sequencing analysis of a 341-base-pair fragment of the Cryptosporidium oocyst wall protein (COWP) gene. This is the first report of Cryptosporidium in American mink.

Cooking mussels (Mytilus galloprovincialis) by steam does not destroy the infectivity of Cryptosporidium parvum.

The consumption of shellfish has increased considerably worldwide, with an associated increase in foodborne illnesses. Among the bivalves, the mussels are usually cooked by steam, which constitutes a typical dish in several regions. In this article, we demonstrate that this preparation is not sufficient to destroy completely the infectivity of Cryptosporidium parvum. Oocysts recovered from experimentally contaminated mussels (Mytilus galloprovincialis) were infectious to neonatal mice after cooking. Although, to date, no official cases of cryptosporidiosis linked to shellfish consumption have been reported, we recommend that people with reduced immunity avoid this type of food because they are at high risk of being infected with Cryptosporidium spp. after eating raw or undercooked contaminated bivalves.

Artemia is capable of spreading oocysts of Cryptosporidium and the cysts of Giardia.

ABSTRACT. The capability for ingesting and spreading the fixed oocysts of Cryptosporidium and fixed cysts of Giardia, two waterborne protozoan parasites, by Artemia franciscana, a microcrustacean widely used as live diet in fish and shellfish larviculture, was demonstrated using differential interference contrast and immunofluorescence microscopy. Our findings suggest the possibility that this microcrustacean could serve as a disseminating vehicle of both parasites in aquatic environments.

Occurrence of Giardia Cysts in Mussels (Mytilus galloprovincialis) Destined for Human Consumption

Between January and June 2004, a total of 200 nondepurated mussel samples of the Galician coast (northwest Spain) were examined for Giardia cysts with a direct immunofluorescence antibody test. Giardia cysts were found in mussels from all of the estuaries studied, with an overall rate of contamination of 41.5%. There was relation between the presence of Giardia cysts, the microbiological contamination (expressed as most probable number of Escherichia coli) detected in the samples, and the harvesting area. This is the first work that describes the presence of Giardia cysts in mussels (Mytilus galloprovincialis) destined for human consumption.