Abstract:Echinococcus multilocularis is a parasite that can cause alveolar echinococcosis disease. After the first positive finding of E. multilocularis in Sweden in 2011, a consulting group with representatives from relevant authorities was summoned. In this group, all relevant information was shared, strategies for information dissemination and any actions to be taken due to the finding of E. multilocularis were discussed and decided. The present paper describes the actions taken during 2011 and the results thereof, … Show more
“…From these results, three positive foxes (out of 2985 examined) in three different regions (Borlänge, Katrineholm, Uddevalla) (Fig. 1) were identified, and the prevalence of E. multilocularis was estimated to be ~0.1% on a national level [4]. However, questions still remained about the true parasite distribution, the role of the intermediate hosts, and the transmission dynamics on a local level.Fig.…”
Section: Introductionmentioning
confidence: 99%
“…1Map showing the southern half of Sweden and study regions (boxes). Black stars indicate areas where intestinal samples from shot foxes were identified as positive for Echinococcus multilocularis through national monitoring (2011) before this study began (2013) [4]. Black diamonds indicate additional areas identified positive for E. multilocularis by the conclusion of this study (2015).…”
BackgroundLocalized concentrations of Echinococcus multilocularis eggs from feces of infected red fox (Vulpes vulpes) can create areas of higher transmission risk for rodent hosts and possibly also for humans; therefore, identification of these areas is important. However, in a low prevalence environment, such as Sweden, these areas could be easily overlooked. As part of a project investigating the role of different rodents in the epidemiology of E. multilocularis in Sweden, fox feces were collected seasonally from rodent trapping sites in two regions with known parasite status and in two regions with unknown parasite status, 2013–2015. The aim was to evaluate background contamination in rodent trapping sites from parasite eggs in these regions. To maximize the likelihood of finding fox feces positive for the parasite, fecal collection was focused in habitats with the assumed presence of suitable rodent intermediate hosts (i.e. targeted sampling). Parasite eggs were isolated from feces through sieving-flotation, and parasite species were then confirmed using PCR and sequencing.ResultsMost samples were collected in the late winter/early spring and in open fields where both Arvicola amphibius and Microtus agrestis were captured. Fox feces positive for E. multilocularis (41/714) were found within 1–3 field collection sites within each of the four regions. The overall proportion of positive samples was low (≤5.4%) in three regions, but was significantly higher in one region (22.5%, P < 0.001). There was not a significant difference between seasons or years. Compared to previous national screenings, our sampling strategy identified multiple E. multilocularis positive feces in all four regions, including the two regions with previously unknown parasite status.ConclusionsThese results further suggest that the distribution of E. multilocularis is highly aggregated in the environment and provide support for further development of a targeted sampling strategy. Our results show that it was possible to identify new areas of high contamination in low endemic environments. After further elaboration, such a strategy may be particularly useful for countries designing surveillance to document freedom from disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1897-3) contains supplementary material, which is available to authorized users.
“…From these results, three positive foxes (out of 2985 examined) in three different regions (Borlänge, Katrineholm, Uddevalla) (Fig. 1) were identified, and the prevalence of E. multilocularis was estimated to be ~0.1% on a national level [4]. However, questions still remained about the true parasite distribution, the role of the intermediate hosts, and the transmission dynamics on a local level.Fig.…”
Section: Introductionmentioning
confidence: 99%
“…1Map showing the southern half of Sweden and study regions (boxes). Black stars indicate areas where intestinal samples from shot foxes were identified as positive for Echinococcus multilocularis through national monitoring (2011) before this study began (2013) [4]. Black diamonds indicate additional areas identified positive for E. multilocularis by the conclusion of this study (2015).…”
BackgroundLocalized concentrations of Echinococcus multilocularis eggs from feces of infected red fox (Vulpes vulpes) can create areas of higher transmission risk for rodent hosts and possibly also for humans; therefore, identification of these areas is important. However, in a low prevalence environment, such as Sweden, these areas could be easily overlooked. As part of a project investigating the role of different rodents in the epidemiology of E. multilocularis in Sweden, fox feces were collected seasonally from rodent trapping sites in two regions with known parasite status and in two regions with unknown parasite status, 2013–2015. The aim was to evaluate background contamination in rodent trapping sites from parasite eggs in these regions. To maximize the likelihood of finding fox feces positive for the parasite, fecal collection was focused in habitats with the assumed presence of suitable rodent intermediate hosts (i.e. targeted sampling). Parasite eggs were isolated from feces through sieving-flotation, and parasite species were then confirmed using PCR and sequencing.ResultsMost samples were collected in the late winter/early spring and in open fields where both Arvicola amphibius and Microtus agrestis were captured. Fox feces positive for E. multilocularis (41/714) were found within 1–3 field collection sites within each of the four regions. The overall proportion of positive samples was low (≤5.4%) in three regions, but was significantly higher in one region (22.5%, P < 0.001). There was not a significant difference between seasons or years. Compared to previous national screenings, our sampling strategy identified multiple E. multilocularis positive feces in all four regions, including the two regions with previously unknown parasite status.ConclusionsThese results further suggest that the distribution of E. multilocularis is highly aggregated in the environment and provide support for further development of a targeted sampling strategy. Our results show that it was possible to identify new areas of high contamination in low endemic environments. After further elaboration, such a strategy may be particularly useful for countries designing surveillance to document freedom from disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1897-3) contains supplementary material, which is available to authorized users.
“…Most likely, the actual prevalence was lower than the target design prevalence of 1% prevalence. In some situations, EM was detected by more sensitive surveillance systems (Tackmann et al, 1998;Wahlström et al, 2012).
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“…Echinococcus multilocularis was first detected in mainland Fennoscandia in Denmark in 2005 [7] and in neighbouring Sweden in 2010 [8] and has been detected on the Norwegian high-Arctic island of Svalbard [9]. In Sweden, only four of the 2985 foxes examined during 2011 surveillance programme harboured E. multilocularis worms [10], highlighting the extremely low prevalence of this parasite in this region (0.1%). Recently, E. multilocularis has been detected in four foxes from Denmark in a study of 679 wild carnivores, indicating a countrywide E. multilocularis prevalence of only 0.7% [11].…”
BackgroundIn endemic areas with very low infection prevalence, the frequency and intensity of Echinococcus multilocularis can be extremely low. This necessitates efficient, specific and sensitive molecular tools. We wanted to compare the existing molecular tools, used in the Norwegian national surveillance programme, and compare these with new techniques for detection of this zoonotic pathogen in fox faeces. Here we present the results of screening samples containing a known level of E. multilocularis eggs with two highly sensitive DNA isolation and extraction methods combined with one conventional PCR and three real-time PCR methods for detection.MethodsWe performed a comparison of two extraction protocols; one based on sieving of faecal material and one using targeted DNA sampling. Four methods of molecular detection were tested on E. multilocularis-egg spiked fox faeces.ResultsThere were significant differences between the multiplex PCR/egg sieving DNA extraction methods compared to the new DNA fishing method and the three real-time PCR assays. Results also indicate that replicates of the PCR-reactions improve detection sensitivity when egg numbers are low.ConclusionsThe results indicate that the use of real-time PCR combined with targeted DNA extraction, improves the sensitivity of E. multilocularis detection in faecal samples containing low numbers of E. multilocularis eggs. Results also indicate the importance of replicates of the PCR-reactions when pathogen levels are low.
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