[Potential risk factors for alveolar echinococcosis in humans in Poland]. / Potencjalne czynniki ryzyka zachorowania na alweolarna echinokokoze dla ludzi w Polsce.

The high prevalence of Echinococcus multilocularis recorded in foxes in Poland creates the risk of alveolar echinococcosis in humans. Sensational press releases on threats which had appeared during last few years do not favour the rational opinion on the risk of this dangerous disease. Based on accessible epidemiological data the potential risk factors of alveococcosis are addressed in this article.

Disease awareness and knowledge in caregivers of children who had surgery for cystic hydatid disease in Lima, Peru.

Cystic hydatid disease (CHD) is a common cause of lung and liver disease worldwide. Despite Peru being highly endemic, information about the level of knowledge is scarce and poor. A telephone survey was applied to assess the knowledge in the caregivers of patients treated for CHD at a paediatric hospital at Lima, Peru. Of the 26 contacted families, only 5 (20%) answered correctly all seven questions. A higher education degree was associated with correct answers (P = 0.002). Most respondents (17, 65%) incorrectly identified the etiologic agent and mode of transmission. Lact of knowledge is likely a major contributor to maintain the endemicity of disease in Peru.

Evaluation of Echinococcus multilocularis tetraspanins as vaccine candidates against primary alveolar echinococcosis.

Echinococcus multilocularis causes an important zoonotic cestode disease. The metacestode stage proliferates in the liver of intermediate hosts including human and rodents and forms multiple cysts. Recently, members of a transmembrane protein tetraspanin (TSP) family have been used as vaccines against schistosomosis, or as diagnostic antigens for cysticercosis. In this study, seven tetraspanins of E. multilocularis, designated as TSP1 to TSP7, were evaluated for their protective potential against primary alveolar echinococcosis. The large extracellular loop (LEL) region of these tetraspanins was cloned from a full-length enriched cDNA library of E. multilocularis metacestodes and expressed in Escherichia coli as a fusion protein with thioredoxin. Recombinant TSPs were applied as vaccines against an E. multilocularis primary experimental infection in BALB/c mice. Cyst lesions in the livers of vaccinated and non-vaccinated mice were counted. The cyst lesion reduction rates induced by the seven tetraspanins in vaccinated vis-à-vis non-vaccinated mice were: 87.9%, 65.8%, 85.1%, 66.9%, 73.7%, 72.9% and 37.6%. Vaccination conferred protective rates to mice ranging from 0% (TSP5, 6, 7) to maximally 33% (TSP1, 3). The results indicated that recombinant tetraspanins have varying protective effects against primary alveolar echinococcosis and could be used in vaccine development.

The first finding of Echinococcus multilocularis in dogs in Slovakia: an emerging risk for spreading of infection.

Alveolar echinococcosis, caused by the metacestode Echinococcus multilocularis, is a zoonosis of public health significance. Apart from red foxes, other carnivore species can also serve as definitive hosts of this parasite. This study aimed to determine the occurrence of E. multilocularis in dogs in the Slovak Republic and identify risk factors for acquiring the infection. Out of 289 dogs examined, E. multilocularis was detected in eight samples (2.8%). Positive results were observed in shepherd dogs (12.5%), guard dogs (7.1%), hunting dogs (2.4%) and in one dog with unknown usage (2.5%). Catching rodents and feeding with raw viscera were confirmed to be the most important risk factors for E. multilocularis infection. On the contrary, the way of dog use, frequency of going to the rural areas, the age and gender of animals seem not to be risk factors for infection. No significant association was observed between the positivity of dogs coming from high endemic or non-endemic regions. This is the first report of E. multilocularis in dogs in the Slovak Republic that confirms substantial contribution of dogs to the transmission of the tapeworm in this territory and urges the necessity of prophylactic measures for dog owners.

[Geography of alveolar echinococcosis]. / Où l'échinococcose alvéolaire sévit-elle?

Alveolar echinococcosis is restricted geographically to the colder areas of the northern hemisphere. In France, the highest prevalence is observed in Franche-Comtd. The yearly incidence of AE in endemic areas is generally low (0.02-0.18 per 100,000 inhabitants) but it can exceed 1 per 100,000 locally. E. multilocularis transmission has intensified in traditionally in foxes endemic areas during the last twenty years, and the parasite has extended its range to new areas and countries of Europe. The increasing proximity of fox populations to urban areas may lead to a new epidemiological pattern. Control measures are only applicable at the local scale, and are essentially based on for deworming.

[Parasite-host relationships and treatment]. / Le parasite et ses relations avec ses hôtes.

Alveolar echinococcosis (AE) is a parasitic disease caused by intrahepatic growth of the larval stage of the cestode Echinococcus multilocularis. The main definitive host in Europe is the fox. The adult worms live in the fox intestine and their oncospheres are disseminated by faeces. Wolves, dogs and cats may also serve as definitive hosts. Small rodents--especially voles in Europe and small lagomorphs in Asia--are the natural intermediate hosts. The tumour-like larva is composed of multiple vesicles which produce protoscoleces, the fertile stage of the E. multilocularis metacestode. Carnivores are infected by preying on infected rodents. Like rodents, humans are intermediate hosts and are infected either by eating uncooked vegetables and berries contaminated by faeces of infected carnivores, or by touching such animals. Humans are naturally resistant to metacestode development. Genetic characteristics are involved in susceptibility/resistance to E. multilocularis metacestodes. In humans and other intermediate animal hosts, immune suppression enhances parasite growth, which is normally controlled by cytotoxic mechanisms and delayed-type hypersensitivity. Tolerance of E. multilocularis is due in part to parasite characteristics (especially carbohydrate antigens of the laminated layer) and in part to the "anti-inflammatory/tolerogenic" cytokines IL-10 and TGF-beta. Treatment with interferon-a restores a cytokine balance favorable to the host and might be a new therapeutic option for AE patients. Vaccination is a scientifically sound but economically and politically Utopian means of preventing the disease. Prevention thus relies on simple lifestyle measures: cooking potentially contaminated food, regular treatment of domestic animals with praziquantel, and precautions when touching potentially infected definitive hosts (foxes and dogs).

Community surveys and risk factor analysis of human alveolar and cystic echinococcosis in Ningxia Hui Autonomous Region, China.

OBJECTIVE: To determine the true community prevalence of human cystic (CE) and alveolar (AE) echinococcosis (hydatid disease) in a highly endemic region in Ningxia Hui, China, by detecting asymptomatic cases. METHODS: Using hospital records and "AE-risk" landscape patterns we selected study communities predicted to be at risk of human echinococcosis in Guyuan, Longde and Xiji counties. We conducted community surveys of 4773 individuals from 26 villages in 2002 and 2003 using questionnaire analysis, ultrasound examination and serology. FINDINGS: Ultrasound and serology showed a range of prevalences for AE (0-8.1%; mean 2%) and CE (0-7.4%; mean 1.6%), with the highest prevalence in Xiji (2% for CE, 2.5% for AE). There were significant differences in the prevalence of CE, AE and total echinococcosis between the three counties and villages (with multiple degrees of freedom). While hospital records showed 96% of echinococcosis cases attributable to CE, our survey showed a higher prevalence of human AE (56%) compared to CE (44%). Questionnaire analysis revealed that key risk factors for infection were age and dog ownership for both CE and AE, and Hui ethnicity and being female for AE. Drinking well-water decreased the risk for both AE and CE. CONCLUSION: Echinococcosis continues to be a severe public health problem in this part of China because of unhygienic practices/habits and poor knowledge among the communities regarding this disease.

Trials to induce protective immunity in mice and sheep by application of protoscolex and hydatid fluid antigen or whole body antigen of Echinococcus granulosus.

In the current study, soluble proteins prepared from 200 mature Echinococcus granulosus and protoscolices of sheep hydatid cysts were applied to immunize sheep and mice respectively. The samples were mechanically homogenized in a blender, sonicated and the final yield was maintained at -20 degrees C until analysis. Hydatid fluid was isolated from liver or lung of sheep under sterile conditions. In the first experiment, 15 mice were randomly allocated to three groups of five mice each. Each mouse in groups 1 and 2 was immunized with 100 microg of hydatid fluid and protoscolex proteins in 100 microl of phosphate-buffered saline (PBS) and emulsified with an equal volume of Freund's complete adjuvant (FCA) respectively. The mice of group 3 were immunized with adjuvant in PBS. The mice were boosted 4 weeks after the first vaccination with the same preparation except that FCA was replaced by Freund's incomplete adjuvant (FIA). In the second experiment, eight male or female lambs 4-6 months of age, were allocated to two groups of four lambs each. Each lamb in the test group was vaccinated subcutaneously in the neck with a 2-ml dose of vaccine (1 mg of whole body protein of E. granulosus dissolved in 1 ml of PBS plus 1 ml of FCA). Control lambs were vaccinated with adjuvant in PBS. Lambs were boosted the same way as in the first experiment. Three weeks after the second vaccination, each mouse and lamb received a challenge infection with 2000 protoscolices intraperitoneally and each lamb additionally received 10 gravid E. granulosus. All mice and sheep were killed after 7 months and examined for hydatid cysts. In these studies, protective immunity was induced in mice with protoscolex protein and with hydatid fluid, and in sheep with whole-body homogenate of E. granulosus and the levels of protection afforded were found to be 72.1, 82.6 and 90.9% respectively.

Prevention of alveolar echinococcosis--ecosystem and risk management perspectives in Japan.

We focused on the epidemiology of alveolar echinococcosis especially in Japan and discussed control measures to prevent an epidemic. No effective control measures against alveolar echinococcosis have been identified thus far because it is difficult to fully understand the ecology of the parasite and its hosts, i.e. the precise infection route to humans. In Hokkaido, Japan, infection rates among red foxes have recently risen even in low endemic districts. Infection seems to be spreading not only among wild foxes but also among domestic dogs. Despite only sporadic reports of human cases in Japan, we predict that the incidence of alveolar echinococcosis will increase in the near future if no effective preventive measures are put in place. An Echinococcus multilocularis epidemic would have the potential to affect the economy of Hokkaido, due to its impact on the agricultural and tourist industries. Well-designed epidemiological surveys are, therefore, urgently required prior to large outbreaks, based on understanding of the ecosystem around E. multilocularis.

Molecular cloning of a vaccine antigen against infection with the larval stage of Echinococcus multilocularis.

Alveolar and cystic hydatidosis are caused by infection with the larval stages of Echinococcus multilocularis and Echinococcus granulosus, respectively. A host-protective antigen has been identified in E. granulosus. Here we identify the presence of a closely related protein in E. multilocularis, characterize and express a cDNA encoding the antigen (designated EM95), determine the structure of the em95 gene, and demonstrate that the EM95 recombinant protein can be used to induce significant levels of protection against challenge infection with E. multilocularis eggs in mice.

Pulmonary hydatid and other lung parasitic infections.

The lung may be infested by a great number of parasites. Hydatidosis is the most frequent parasitic lung disease. Diagnosis of lung hydatidosis is usually easy on chest radiography, ultrasonography, and CT scan, and immunodiagnosis may help in dubious cases. Surgery is necessary in most cases, but it must be conservative. Complex forms, such as disseminated disease and secondary lung hydatidosis (metastatic or bronchogenic) are difficult to treat and may be considered malignant. Medical treatment may be helpful in complex forms, in poor surgical risk patients, and in cases of preoperative spillage of hydatic fluid. Prevention programs are necessary in endemic areas, and research must be directed toward vaccination against the parasite. Other parasitic diseases are reported less frequently in the literature, and the majority of published articles are either case reports or only report a small number of cases. Clinical presentation is variable according to the great variety of parasites that may involve the lungs.

Echinococcosis in children and adolescents in Bulgaria: a comparative study.

Between 1971 and 1995, 5874 patients underwent surgery in Bulgaria because of cystic echinococcosis caused by Echinococcus granulosus. Of these 5874, 10.6% were children aged < 15 years and 5.25% adolescents aged 15-19 years, giving annual incidences of 1.25 and 2.03/100,000 inhabitants, respectively. Although the annual incidence of surgery for echinococcosis among adults (3.12/100,000) was higher than the combined value for children and adolescents (1.48/100,000), the data indicate that most human infections with E. granulosus occur during childhood and adolescence. In evaluating the epidemiology of echinococcosis or the effectiveness of a control programme, therefore, reductions or increases in the incidence of clinical disease among children and adolescents indicate an improving or worsening situation, respectively. The incidence of surgical treatment for echinococcosis was higher in males than females in all but the youngest subjects (< 5 years) and adults (> 19 years). It was also higher in rural populations than in urban populations, particularly among children and adolescents. Whereas cysts were found more frequently in the lungs of children and adolescents than their livers (51.8% v. 38.3% of the patients), most cysts found in the adults were hepatic (73.5% of patients) and relatively few were in the lungs (14.4% of patients).

Alveolar echinococcosis in humans: the current situation in Central Europe and the need for countermeasures.

Alveolar echinococcosis (AE) in humans is caused by a larval stage (metacestode) of Echinococcus multilocularis, which exhibits a tumor-like growth, initially in the liver, with the potential to induce serious disease. At the end of the 1980s, E. multilocularis was known to occur in four countries of Central Europe, but has now been identified in ten countries. Red foxes are the principal definitive hosts of E. multilocularis and sources of human infection, but dogs and cats can also be infected. Growing populations of foxes and their increasing immigration to urban areas are new risk factors. Human AE is rare but its potential high fatality rate, considerable costs of treatment and the persisting infection risk should be reasons for health authorities in European countries to establish coordinated systems of surveillance and risk assessment in combination with measures to reduce morbidity and mortality of AE in the human population. Here, J. Eckert and P. Deplazes outline the current epidemiological situation in Central Europe, and discuss options for surveillance, prevention and control.

[A case of Echinococcus granulosus hydatid cyst in a zoo born dromedary in the Berlin-Fridrichsfelde zoo]. / Echinococcus granulosus-Hydatidenbefall bei einem zoogeborenen Dromedar im Tierpark Berlin-Friedrichsfelde.

In Germany, the threat to human health by the small fox tapeworm (Echinococcus multilocularis) has been increasingly discussed in the last few years. On the other hand, the hydatid worm of the dog (Echinococcus granulosus) became more and more rare in Germany and was often declared to be eradicated. This paper presents a case of hydatid infection of the lung in an adult dromedary (Camelus dromedarius), which was born and kept all its life at Tierpark Berlin-Friedrichsfelde. Questions connected with E. granulosus infection are discussed from an ecological point of view: history, urbanisation, biology, clinical signs, potential threat to man, prophylaxis and treatment. In view of the extensive and sometimes uncontrolled dog keeping in urban households it must be stressed that careful documentation and surveillance of this life-threatening zoonosis, which was the main reason for its decline in the past, has not yet lost its importance.

Evaluation of diagnostic ultrasound as a mass screening technique for the detection of hydatid cysts in the liver and lung of sheep and goats.

Ultrasound examination of the liver and lung followed by post-mortem examination was performed in 16 sheep and 284 goats. Thirty-one (10.3%) were positive for hydatid cysts on ultrasound examination and 46 (15.3%) were positive on post-mortem examination. Twenty-one positive on post-mortem examination were falsely identified as negative on ultrasound examination. Of the 254 animals negative on post-mortem examination, six (2.4%) were falsely identified as positive on ultrasound examination. The sensitivity and specificity of ultrasound examination for detecting hydatid cysts in sheep and goats was 54.36% and 97.64%, respectively (positive predictive value: 80.64%; negative predictive value: 92.19%).

Control of hydatid disease in Wales.

OBJECTIVES: To evaluate the success of the south Powys hydatid control programme by analysis of trends in cystic disease in humans and sheep and dog infestation. DESIGN: A review of hospital admissions for human hydatid disease in 1984-90, abattoir prevalence surveys of hydatid cysts in adult sheep, arecoline acetarsol and coproantigen surveys of prevalence of Echinococcus infestation in dogs. SETTING: All hospitals in England and Wales, three abattoirs, and dog populations in mid ands south east Wales. SUBJECTS: Residents of England and Wales admitted to hospital between 1984 and 1990 with a new diagnosis of human hydatid disease (International Classification of Diseases (ICD), ninth revision, code 122) acquired in the United Kingdom. RESULTS: The average annual incidence of human hydatid disease in Powys, mid-Wales, fell from 3.9x10(-5) in 1974-83 to 2.3x10(-5) in 1984-90. Age specific incidence rates in Wales declined over this period only in children, and no cases occurred in children (<15 years) in Powys. Two Welsh children who lived in Gwent and mid-Glamorgan were infected. Prevalence of hydatid cysts in old sheep from south Wales declined during the control period, but in 1993 prevalence of cysts was 13%. Prevalence of E granulosus infestation was zero in the control area in 1993, but it was 2.4% in Powys dogs outside the control area in 1989 and 9.2% in dogs in Gwent in 1991. CONCLUSIONS: Human hydatid disease has been successfully controlled in south Powys but cystic echinococcosis is still endemic in sheep in mid-Wales, and there is a focus of infection in humans, sheep, and dogs in the bordering areas of Gwent and mid-Glamorgan. There is considerable potential for an upsurge in human cases if control measures are relaxed.