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Játtað í: 2018 Granskingarøki: Náttúra og náttúrutilfeingi Verkætlanarslag: Verkætlan Verkætlanarheiti: Finnast sníkarnir Cryptosporidinum og Giardia í føroyskum seyði og neytum, og kunnu hesir dálka drekkivatnið? Játtanarnummar: 0455 Verkætlanarleiðari: Kim Steve G. Bergkvist Stovnur/virki: Heilsufrøðiliga Starvsstovan Aðrir luttakarar: Heidi S. Mortensen, Óluva Vang, Jógvan Páll Fjallsbak og Lucy Robertson Verkætlanarskeið: Planned: 01.08.2018-31.12.2019 Actual: Samlaður kostnaður: kr. 866.822 Stuðul úr Granskingargrunninum: kr. 505.777 Verkætlanarlýsing: Original The protozoan parasites Cryptosporidium and Giardia are of concern to public health worldwide. These protozoan parasites are both emerging pathogens, and are the cause of the intestinal infections cryptosporidiosis and giardiasls, respectively. Humans can acquire infections either by direct contact with infected persons (anthroponotic transmission) or from animals (zoonotic transmission) or by ingestion of food or water which is contaminated by faeces. Both parasites have been associated with community-wide outbreaks, in which contaminated drinking water has been demonstrated to be, or indicated to be, the vehicle of transmission. In the Faroe Islands no monitoring or surveillance is being done to assure consumers that the drinking water does not contain these parasites. This is particularly relevant since surface water is used for drinking water in the Faroe Islands and considering the fact that approximately 2.500 people in the Faroe Islands, corresponding to approximately 5% of the total population, still receive untreated drinking water. Hence, a study on the occurrence of these parasites is of outmost relevance and importance when considering a safe drinking water supply for people in the Faroe Islands. The main objective of the project is to study the occurrence of Cryptosporidium and Giardia in faeces from cattle and sheep in the Faroe Islands, since they may be potential cryptosporidium sources in the Faroe Islands. Especially, the approximately 70,000 sheep that walk and graze freely on the fields, also on the catchment areas of drinking water reservoirs. Subsequently, the occurrence and concentrations of Cryptosporidium and Giardia in raw water from drinking water reservoirs is investigated. As an extra input to our study, we will also study sewage influent, to assess possible human infection. Another objectlve is to implement a standardised method, as well as establishing analytical competences for analysing and identifying Cryptosporidium oocysts and Glardia cysts in environmental samples in the Faroe Islands. Final Cryptosporidium and Giardia are protozoan parasites that infect people and animals worldwide. Both are significant causes of diarrhoea and may result in chronic disease in vulnerable hosts, such as neonatal animals, young children, and immunocompromised patients. Contaminated drinking water is recognised as being a major vehicle of infection with these parasites in humans, with many extensive outbreaks documented. Nevertheless, to our knowledge, there have been no previous investigations on the occurrence of Cryptosporidium and Giardia in sheep and cattle in the Faroe Islands. Furthermore, there have apparently been no investigations on the potential for these pathogens to contaminate drinking water supplies on the Faroe Islands. In the present study, faecal samples from 140 sheep from five islands and nine cattle from one island were screened for the presence of Cryptosporidium and Giardia using staining with appropriate antibodies labelled with a fluorescent marker and immunofluorescent microscopy. The overall occurrence of Cryptosporidium and Giardia in the sheep samples was 4% and 41%, respectively. Giardia cysts were found on all five islands from where sheep samples were collected, whereas Cryptosporidium oocysts were detected in sheep samples from four islands. Among the nine samples from cattle, all contained Giardia cysts and Cryptosporidium oocysts were detected in two of them. A small subset of the positive samples was further analysed by molecular methods to determine species and subtypes and to investigate zoonotic potential (whether the parasite could infect people and animals). Cryptosporidium from one of the sheep samples and from two of the cattle samples was identified as being Cryptosporidium parvum, which is zoonotic. The subtype for all three of these C. parvum isolates was found to be IIdA19G1, a subtype which has been frequently reported from cattle, sheep, and human infections in different countries previously. In contrast, Giardia from two sheep samples was identified as being assemblage E (not zoonotic). During our study period, a human infection with the same subtype of Cryptosporidium was diagnosed at one of the farms from which one of the subtyped animal samples was collected, and we were able to associate the infection in cattle with a human infection for the first time in the Faroe Islands. However, zoonotic transmission, transmission direction, or transmission from a common source were not investigated. To investigate whether these parasites might also contaminate drinking water in the Faroe Islands, ten raw water samples from six islands were screened for the presence of Cryptosporidium oocysts and Giardia cysts, using standard methodology. Among the ten water samples, Cryptosporidium was detected in seven and Giardia was detected in eight, with both parasites detected in drinking water sources on all six islands. Both parasites were found in relatively high quantities in positive samples, with the number of parasites in ten litres of water ranging from 1-7 (median 2) for Cryptosporidium and Giardia ranging from 1-11 (median 5). In addition, to investigate whether people were infected with these parasites, six samples of sewage were collected from two locations in the municipality of Tórshavn, the capital of the Faroe Islands, with the assumption that the predominant contributor to the sewage was human waste rather than runoff from land or animal waste. All samples were found to contain Giardia cysts, with a maximum concentration of 6836 Giardia cysts/L and Cryptosporidium oocysts were found in one sample containing 128 oocysts/L. In conclusion, this study demonstrates that both these parasites are probably endemic on the Faroe Islands, infecting sheep, cattle, and people. Although the sewage data suggest that more people are infected with Giardia than Cryptosporidium, we found no evidence in the small subset of samples analysed that this was zoonotic transmission as only Assemblage E (non-zoonotic) was detected in ruminants. For Cryptosporidium, however, zoonotic transmission may occur. Our data also indicate that waterborne transmission may occur as raw water samples were found to be contaminated with both parasites. Støða: Liðug << Back |
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