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1.
Human alveolar echinococcosis (AE), caused by the metacestode stage of Echinococcus multilocularis, is a serious zoonosis which caused up to 100% lethality in untreated patients before the 1970s, when modern methods of treatment were not yet established. AE occurs in large areas of the northern hemisphere mostly with low country-wide prevalences, but high prevalences of up to 4% have been reported from small population groups in highly endemic foci, e.g. from China. AE includes many veterinary aspects which are the topic of this review. Recent studies have shown that E. multilocularis has a wider geographic range than previously anticipated. There is evidence for growing populations of red foxes (Vulpes vulpes) in some areas, for increasing invasion of cities by foxes and also for establishment of the parasite cycle in urban areas. These and other factors may lead to an increased infection risk for humans. Significant progress has been made in the development of sensitive and specific new techniques for the intra vitam and post mortem diagnosis of intestinal E. multilocularis infection in definitive hosts, notably the detection of coproantigen by enzyme-linked immunosorbent assay and of copro-DNA by PCR. Both tests can also be used for the identification of E. multilocularis in faecal samples collected in the environment. Recommendations are given for chemotherapy and chemoprophylaxis of the intestinal infection in definitive hosts. In recent years, infections with the metacestode stage of E. multilocularis have not only been diagnosed in humans in several regions, including at least eight countries in central Europe, but also in animal species which do not play a role in the transmission cycle (wild and domestic pigs, dogs etc.). From 1987 to 2000 our group in Zurich has diagnosed 10 cases of AE in dogs and 15 in captive monkeys. In 2 dogs, concurrent infections of the intestine and of the liver with adult and larval stages of E. multilocularis, respectively, were observed for the first time. Clinical data are presented, and methods of diagnosis and treatment (surgery, chemotherapy) are described. Furthermore, small liver lesions caused by E. multilocularis were diagnosed in 10% of 90 slaughter pigs, and 2.9% of 522 breeding sows had specific serum antibodies against parasite antigens. In view of the unpredictable epidemiological situation, all possible measures for preventing E. multilocularis infections in humans and in domestic animals should be initiated by the veterinary and health authorities.  相似文献   

2.
Recently, new data have been collected on the distribution and ecology of Echinococcus multilocularis in European countries. Different ungulates species such as pig, goat, sheep, cattle and horse are known to host incomplete development of larval E. multilocularis. We report a case of E. multilocularis portage in two wild boars from a high endemic area in France (Department of Jura). Histological examination was performed and the DNA was isolated from hepatic lesions then amplified by using three PCR methods in two distinct institutes. Molecular characterisation of PCR products revealed 99% nucleotide sequence homology with the specific sequence of the U1 sn RNA gene of E. multilocularis, 99 and 99.9% nucleotide sequence homology with the specific sequence of the cytochrome oxydase gene of Echinococcus genus and 99.9% nucleotide sequence homology with a genomic DNA sequence of Echinococcus genus for the first and the second wild boar, respectively.  相似文献   

3.
Commercial western blot (WB) assay was used to detect serum antibodies specific to Echinococcus multilocularis in 23 horses in which infection was confirmed by postmortem inspection at a slaughterhouse. Livers contained from 1 to >20 nodular lesions; foci diameter ranged from 1 to 25 mm. Antibody tests of serum from all 23 animals were negative for antigen bands at 7, 16, 18, and 26-28 kDa, which show specificity in the serum of human patients. However, sera from two infected horses with the largest nodules (diameter, 25 mm) showed positive response to one of the 22-kDa and 30-kDa antigen bands. It may be possible to diagnose E. multilocularis infection in horses based on the detection of these bands on commercial WB assay.  相似文献   

4.
The Xinjiang plateau of western China has been shown to have a high prevalence for human cystic echinococcosis (CE) caused by Echinococcus granulosus, and human alveolar echinococcosis (AE) caused by Echinococcus multilocularis. The domestic dog is suspected to be the primary definitive host for the transmission of both E. granulosus and E. multilocularis to humans in this locality. Seventeen of 30 stray dogs from Hejing County of Xinjiang were found positive for E. granulosus post mortem, and one double infection was suspected. Worm samples were collected, dyed by carmine, and observed microscopically. Carmine staining examination clearly revealed the differences in number of proglottids and appearance of uterine branches and lateral genital pore for those two species of Echinococcus. Furthermore, gene target DNA fragments were amplified for formal identification of the two parasite species, based on 12s rRNA mitochondrial gene. The PCR products were purified and sequenced. Compared with NCBI GenBank, the DNA sequences demonstrated 100% identity with E. granulosus (sheep strain, G1 genotype) and E. multilocularis.  相似文献   

5.
Echinococcus multilocularis is a cestode helminth which, along with E. granulosus, E. oligarthus and E. vogeli is a causative agent of hydatid disease in man. In the intermediate host (including man), cysts formed by the metacestode (larval stage) develop in the internal organs, causing functional impairment which often leads to the death of the host. In this review larval E. multilocularis infection in mice, the most popular experimental intermediate host, is examined, and the immune response to the organism is described in detail. Evidence is presented which suggests that cell-mediated immunity (CMI) plays a large role in suppression of larval growth. Congenitally athymic nude mice, and mice treated to remove thymocytes had high susceptibility to infection, while mice strains assessed as having high helper T lymphocyte function showed resistance to infection. The degree of antibody response shown by the host does not correlate with the susceptibility to E. multilocularis. Infection with E. multilocularis is accompanied by immunosuppression, manifested by inhibition of effector cell chemotaxis and receptor expression, suppressor macrophage and lymphocyte activity, decline in helper T-lymphocyte activity and immune-complex deposition.  相似文献   

6.
Detection of Echinococcus multilocularis in foxes in The Netherlands   总被引：2，自引：0，他引：2  
Echinococcus multilocularis was demonstrated in 5 out of 272 foxes in The Netherlands close to the border with Germany and Belgium. Besides microscopic examination of mucosal scrapings, two different PCR assays were used based on the detection of E. multilocularis DNA in colon content. Two distinct areas in The Netherlands were positive for E. multilocularis. Two positive foxes were found in the northern province of Groningen and three positive foxes were found in the southern province of Limburg. Both PCR assays detected more positive foxes compared to microscopic examination of the intestinal content. This is the first report of E. multilocularis in foxes occurring in The Netherlands.  相似文献   

7.
A literature review on the current situation of echinococcosis in Central Europe is given. The only final host for Echinococcus granulosus in this region ist the dog. The infection rate of dogs with E. granulosus in Central Europe is less than 1%. According to meat inspection statistics in Germany less than 0.008% of sheep, pigs and horses carry larval stages of E. granulosus. Parasitologically confirmed is the occurrence of a cattle-dog strain, the cysts of which were found in 0.26% of slaughter cattle. It is not known whether this strain infects also man as does the sheep-dog strain. Cases of cystic echinococcosis (E. granulosus) diagnosed in Central Europe are often imported from mediterranean countries. In Baden-Wurtemberg, the only state where human cases of echinococcosis are recorded, 50-100 cases are diagnosed per year. In areas with endemic E. multilocularis infection also dogs and cats may be infected with the adult worm besides the red fox. Recent investigations have revealed that not only in classical endemic areas (Switzerland, Austria, Baden-Wurtemberg, Rhineland-Palatinate) foxes have infection rates of up to 67% but that E. multilocularis-infection is also wide-spread in Thuringia, Hesse, Northrhine-Westphalia and in the southern parts of Lower Saxony. The most northern infested area seems to be the region of Detmold (infection rate of foxes 9%). The infection rates with alveolar echinococcosis (E. multilocularis) in humans even in endemic areas are low. In Baden-Wurtemberg 140 new cases became known during the past ten years.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

8.
Echinococcus multilocularis is a tapeworm having carnivores as final hosts, the red fox in particular, dog and cat less frequent. Its two host life cycle consists of a larval cycle which predominantly takes place in the liver of rodents such as mice but it can also develop in musk rats as intermediate hosts. Man can also be infected and serves as a wrong intermediate host. He develops an alveolar echinococcosis which usually ends lethal without medical treatment. The prevalence of E. multilocularis among 5.365 red foxes in Lower Saxony was monitored from 1991 to 1997. The data were analysed using spatial epidemiological methods. This evaluation is based on a significance test which was applied to the parameters of spatial autoregressive regression models (CAR) fitting to the data of two successive sampling periods from 1991-1994 and 1994-1997. The mean prevalence (spatial median) increased from 6% to 11%. The results of this epidemiological study which was restricted to Lower Saxony support for the first time the earlier reported assumption that the prevalence of foxes infected with E. multilocularis has risen in Europe in the last decade. The reasons for this development are still unknown.  相似文献   

9.
Pulmonary alveolar echinococcosis (AE) caused by the metacestode of Echinococcus multilocularis is a lethal zoonosis and is a lesion secondarily induced by hematogenous dissemination from hepatic AE lesions. In the present study, a hematogenous pulmonary AE model was experimentally induced in rats by the injection of echinococcal larval tissue homogenate to the tail vein, and then the pathological and diagnostic aspects of pulmonary AE were examined by magnetic resonance imaging (MRI). Histological primary, mature and degenerated AE lesions were observed 5, 18 and 50 weeks after injection, respectively. These lesions were discriminated as signal-void, hypointense and hyperintense regions in T1-weighted MRI (T1WI), respectively. The change in signal intensity in T1WI might reflect the content of proteinaceous fluid as a result of AE cyst degeneration. Western blot analysis of sera with antibodies of two epitopes (Em18 and Em16) of E. multilocularis provided evidence for AE infection in the early stage. T1WI in combination with Western blot analysis could possibility become definitive and early signs of hematogenous pulmonary AE infection.  相似文献   

10.
The life cycle of the zoonotic parasite Echinococcus multilocularis is predominantly sylvatic, involving foxes as definitive hosts infected by predation of rodents, the intermediate hosts. The North-Eastern French departments of Meuse and Haute-Sa?ne are highly endemic, with an estimated fox prevalence of 41% and 36% respectively. Although most of the parasites' biomass occurs in foxes, domestic dogs can also be infected, leading to a major risk of human infection due to the close proximity of dogs and owners. In the present study, dog faeces were collected after praziquantel treatment provided by veterinarians. In all, 860 faecal samples were collected throughout Meuse (n=493) and Haute-Sa?ne (n=367). Intestinal helminth eggs were isolated from the faeces using a flotation technique and observed by microscopy. Parasite species were identified in samples positive for taeniid eggs by sequence analysis after PCR amplification. To study the factors associated with infestation, each sample was linked to a questionnaire filled in by the dog owners. Taeniid eggs were observed in seven faecal samples (0.8%) but none of them were positive for E. multilocularis. Thus, the apparent prevalence of E. multilocularis in dog populations is lower than 1.00% for Haute-Sa?ne and lower than 0.75% for Meuse. In Haute-Sa?ne, a high proportion of dogs observed suspected preying on rodents were not dewormed monthly. In endemic areas, these dogs must be considered at risk of transmitting E. multilocularis to humans.  相似文献   

11.
Changes in legislation that facilitate the movement of animals within the European Union may increase the risk that some microbial and parasitic organisms, currently exotic to Ireland, will be introduced by travelled pet animals. It is possible that the fox tapeworm, Echinococcus multilocularis, might be introduced in that manner from any of the several member states in which it is endemic. Red foxes are the principal definitive hosts of E. multilocularis but dogs and cats can also be infected. Infection in the definitive host is of little clinical significance, but aberrant infection of humans results in alveolar echinococcosis, a debilitating disease that has a high mortality rate. Humans acquire the organism by ingestion of Echinococcus multilocularis eggs excreted by definitive hosts; the larval metacestodes develop primarily in the liver, in the initial asymptomatic phase as small, well-encapsulated cysts. Over time, perhaps five to 15 years, progressive local infiltration and secondary cyst development at distant sites occur with resultant clinical signs. Patients with infiltrative liver disease present with cholestatic jaundice, epigastric pain, fatigue, weight loss and hepatomegaly. If left untreated, the disease can be fatal.This paper recounts the life cycle of the parasite, and discusses the control measures on which its exclusion from Ireland depend. Strict adherence to the routine worming of travelled dogs with praziquantel, at appropriate doses, 24 to 48 hours prior to entry into the country will minimise the likelihood of introduction of this zoonosis.  相似文献   

12.
A cross-sectional survey was conducted to estimate the prevalence of Echinococcus multilocularis and E. granulosus infections in domestic dogs and cats from Germany and other European countries. Faecal samples of 21,588 dogs and 10,650 cats routinely submitted to a private veterinary laboratory between June 2004 and June 2005 were examined using the ZnSO(4)-NaCl flotation method. Taeniid eggs were detected in 54 (0.25%) and 37 (0.34%) of the canine and feline faecal samples, respectively. Taeniid eggs were separated and subjected to a DNA preparation and a modified two-step PCR for the detection of Echinococcus spp. based on mitochondrial 12S rRNA genes. PCR products from Echinococcus-negative but cestode-positive reactions were cloned and sequenced to determine the Taenia species. E. multilocularis DNA was specifically amplified in 43 (0.24%) and 25 (0.23%) of the samples from dogs and cats, respectively. E. granulosus DNA was not detected in any sample, while, E. multilocularis-positive samples were detected in dogs from Germany only, those of cats originated from Germany, Denmark and The Netherlands. The prevalence of E. multilocularis egg-positive canine samples was significantly higher in southern (0.35%) than in northern Germany (0.13%). In contrast, no significant regional difference was observed in cats from Germany. Taeniid eggs from Echinococcus-negative samples and from a few samples with macroscopically detected Taenia sp. proglottids were identified as eggs of T. crassiceps (n=8), T. martis, T. serialis, T. polyacantha, T. taeniaeformis and T. pisiformis in dogs (n=1 of each) and T. taeniaeformis (n=11) in cats. The spectrum of cestodes detected in domestic dogs and cats indicate the consumption of small rodents as infection source. The high proportion of E. multilocularis-positive samples, suggest domestic dogs and cats as a possible source of E. multilocularis infection for humans.  相似文献   

13.
An investigation on the presence of larval cestodes in musk rats (Ondatra zibethicus) was carried out in two regions of the Netherlands (east Groningen and south Limburg) where in a earlier study foxes with Echinococcus multilocularis were found. A total of 1726 musk rats were dissected (1200 in Groningen, 526 in Limburg). Larval stages of Taenia taeniaeformis were most frequently found (total 44.8%: Groningen 42%, Limburg 51.3%), followed by T. martis (total 6.1%: Groningen 0.7%, Limburg 18.6%). Infections with T. crassiceps (total 0.3%: Groningen 0%, Limburg 1.0%), T. polyacantha (total 0.2%; Groningen 0.3%, Limburg 0%) and E. multilocularis (0.1%: Groningen 0.1%, Limburg 0%) were rare. Infections with T. taeniaeformis were more frequent in adults (71.8%) than in juveniles (34.2%). The same was found for T. martis: adults 15.3%, juveniles 2.5%. This difference was also reflected in the relation between weight of the animals and presence of infection. Heavier animals (>1000 g) were more often infected with T. taeniaeformis (74.1%) than animals less than 1000 g (34.8%). In musk rats weighing less than 500 g (n=155) only 5.2% were infected, but above 1200 g, 82.6%. The highest number of T. taeniaeformis was 28, of T. martis 13, of T. crassiceps >1000 and of T. polyacantha 24. The E. multilocularis was in a very young stage, a few white spots in the liver. Although E. multilocularis infections were exceptional, it is expected that with a rise in the number of infected foxes in the Netherlands the number of infected musk rats will increase.  相似文献   

14.
The Tibetan plateau of western China has been shown to have a very high prevalence of human cystic echinococcosis (CE) caused by Echinococcus granulosus and human alveolar echinococcosis (AE) caused by Echinococcus multilocularis. The domestic dog is suspected to be the primary definitive host for the transmission of both E. granulosus and E. multilocularis to humans in this locality. A purgation study of 371 dogs in Shiqu County, Sichuan Province during 2002-2003 resulted in an E. multilocularis prevalence of 12% and an E. granulosus prevalence of 8%. These crude prevalences were then adjusted, based on the known sensitivity of arecoline purgation for the detection of E. granulosus and a suggested sensitivity for the detection of E. multilocularis. In addition, it was assumed that some immature parasites of either species could be misidentified morphologically and wrongly assigned. This resulted in credible true prevalence intervals of between 13-33% for E. multilocularis and 8-19% for E. granulosus. Prevalences of other intestinal helminthes found on purgation were: Taenia spp. 31%, Dipylidium caninum 1%, and ascarids 8%. Risk factors associated with the acquisition of canine echinococcosis were evaluated based on responses to a questionnaire administered to dog owners. Male dogs were more likely to be infected with Echinococcus spp. than female dogs (P<0.05) and dogs allowed to roam were more likely to be infected with E. multilocularis (P<0.05).  相似文献   

15.
Forty-seven wild brown rats (Rattus norvegicus) collected from the urban area of Milan (Italy) were screened for Capillaria hepatica liver infection. The liver of each rat was grossly and histologically examined for the presence of C. hepatica adults, eggs and typical C. hepatica induced lesions. In 17 rats (36%) liver lesions consistent with C. hepatica infection were detected. Grossly, white-yellow nodules of 1-5 mm in diameter were present, either scattered on the liver surface or localized in a single lobe. Histologically, granulomatous liver lesions associated with eggs and/or worms were observed. The degree of gross liver involvement was moderate in most of the positive cases (71%). About 30 cases of C. hepatica infection in humans have been documented world-wide, most of which are reported in children from 1 to 5 years of age. Our results suggest that the potential transmission of C. hepatica to children in the study area should be considered an important health issue.  相似文献   

16.
Alveolar echinococcosis (AE) is a rare, but potentially severe zoonotic disease caused by Echinococcus (E.) multilocularis. Recent findings indicated an increasing importance of AE for non-human primates living in regions endemic for E. multilocularis. The death of five cynomolgus monkeys (Macaca fascicularis) and a lowland gorilla (Gorilla g. gorilla) due to AE raised concern about the incidence of this parasite in the Basle Zoo. Consequently, a project was initiated to investigate the prevalence amongst an affected group of cynomolgus monkeys, as well as in foxes and mice. Three out of 46 monkeys were seropositive for E. multilocularis antigen. In two of these monkeys and in another three animals, which were seronegative, structures compatible with metacestodal cysts were observed using ultrasonography. Seven out of 35 free roaming foxes caught at the zoo were positive for an intestinal E. multilocularis copro-antigen ELISA, four of them shed taeniid eggs simultaneously. No lesions compatible with AE were present in 50 necropsied mice from the zoo area. These results indicate that the fox population is a potential source to introduce E. multilocularis and may thus represent a risk for the zoo animals.  相似文献   

17.

Background

The fox tapeworm Echinococcus multilocularis has foxes and other canids as definitive host and rodents as intermediate hosts. However, most mammals can be accidental intermediate hosts and the larval stage may cause serious disease in humans. The parasite has never been detected in Sweden, Finland and mainland Norway. All three countries require currently an anthelminthic treatment for dogs and cats prior to entry in order to prevent introduction of the parasite. Documentation of freedom from E. multilocularis is necessary for justification of the present import requirements.

Methods

The probability that Sweden, Finland and mainland Norway were free from E. multilocularis and the sensitivity of the surveillance systems were estimated using scenario trees. Surveillance data from five animal species were included in the study: red fox (Vulpes vulpes), raccoon dog (Nyctereutes procyonoides), domestic pig, wild boar (Sus scrofa) and voles and lemmings (Arvicolinae).

Results

The cumulative probability of freedom from EM in December 2009 was high in all three countries, 0.98 (95% CI 0.96-0.99) in Finland and 0.99 (0.97-0.995) in Sweden and 0.98 (0.95-0.99) in Norway.

Conclusions

Results from the model confirm that there is a high probability that in 2009 the countries were free from E. multilocularis. The sensitivity analyses showed that the choice of the design prevalences in different infected populations was influential. Therefore more knowledge on expected prevalences for E. multilocularis in infected populations of different species is desirable to reduce residual uncertainty of the results.  相似文献   

18.
Infections of dogs with Toxocara canis and Echinococcus multilocularis pose an infection-risk particularly for contact persons. We examined specimens of hair coat and faeces of 124 farm dogs, 118 household dogs, 49 kennel dogs, 15 puppies from two litters, and 46 red foxes. Microscopically identified eggs of Toxocara or taeniids were further investigated by species-specific PCRs. In farm dogs, eggs of E. multilocularis or T. canis were identified in each 2.4% of faecal samples, eggs of T. cati (gastrointestinal passage) in 7.3%, respectively. Household dogs excreted eggs of T. canis (0.8%) and of T. cati (2.5%). In kennel dogs, eggs of T. canis (4.1%), but not of T. cati were detectable. Coat samples contaminated with eggs of Toxocara spp. were found from farm dogs (5.6%), household dogs (1.7%) and kennel dogs (2.0%). Taeniid eggs were isolated from the coat samples from only two farm dogs (1.6%); a molecular species determination was not achieved. In six intrauterinely infected puppies, Toxocara-eggs were found in 17/38 samples taken within six weeks. No intact Toxocara eggs could be isolated from the coat of nine puppies from a second litter 13 days after deworming. Of the 46 red foxes investigated (dissection and faecal samples) 13 (28.3%) were infected with E. multilocularis and 20 (43.5%) with Toxocara. Eggs of taeniids and Toxocara were found in 13% (in three cases confirmed as E. multilocularis) and 21.7%, respectively, of the coat samples. None of the retrieved Toxocara eggs in the coat samples were embryonated. Thus, an infection of humans through the transmission of E. multilocularis eggs after direct contact with dogs or foxes is conceivable, whereas a corresponding infection risk by Toxocara eggs must be critically challenged.  相似文献   

19.
Alveolar echinococcosis was diagnosed in 12 cynomolgus monkeys (Macaca fascicularis) at postmortem examination within a period of 6 years. Besides consistent involvement of the liver, parasitic lesions were also present in mesenteric lymph nodes, pancreas, lung, and kidney. In the liver, various patterns of host's responses to parasitic tissue could be distinguished. Infiltration of macrophages, often multinucleated, around usually intact metacestodes was the main feature of one pattern. A second pattern was characterized by the presence of abundant, normally degenerate granulocytes in addition to macrophages surrounding collapsed laminated structures. Finally and as a third pattern, some cysts were surrounded by marked collagen deposition, which was usually not a significant feature of the other foci. Parasitic cysts with protoscolices were observed in foci with the first and third pattern but not in the second one. The simultaneous occurrence of all three patterns was observed in most animals. Type AA amyloid was identified either in the space of Dissé, macrophages or blood vessel walls in nine animals using immunohistochemistry. Identity of parasitic structures such as metacestodes of Echinococcus multilocularis was confirmed immunohistochemically. All animals that could be tested serologically (7/12) had detectable antibodies against the E. multilocularis-specific Em2 antigen. Liver lesions of six animals were additionally analyzed by polymerase chain reaction, yielding the amplification of a specific E. multilocularis DNA fragment in each case.  相似文献   

20.
A high prevalence of larval Echinococcus multilocularis (Em) infection was found in zoo primates in Hokkaido, Japan. In October 1997, a Japanese monkey (Macaca fuscata) died and histopathologically diagnosed as alveolar hydatidosis. Serum samples were collected from the remaining Japanese monkeys and examined for antibodies against Em by enzyme-linked immunosorbent assay and western blotting. Serological tests showed 12 more animals of the remaining 57 monkeys were possibly infected. Ultrasonography revealed that nine of these 12 animals had a cystic lesion in the liver. The band patterns of western blotting in the monkeys were very similar to those in human.  相似文献   

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