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Mebendazol (Vermox) was given for six months at an oral daily dose of 2 g to three patients with inoperable infestation of the liver by Echinococcus alveolaris. In two patients the general state improved greatly, with reduction in the size of the liver infiltrate, regression in serum bilirubin and alkaline phosphatase levels. Treatment continues in the third case.
This report deals with the clinical and morphological findings in a rare case of Echinococcus granulosus of the female genital tract. The symptoms are not characteristic. A preoperative diagnosis can only be suspected on serological grounds. The diagnosis is confirmed by histological examination of the specimen. The therapy of choice is the surgical removal of the cyst. Care should be taken not to open the cyst during operation. The success of the operation should be confirmed by postoperative serological, ultrasonic, scintigraphic and x-ray controls.
Casoni's intradermal test was positive in a 40-year-old woman patient, confirming the diagnosis of a subretinal echinococcus cyst. Coagulation with the argon laser brought about a rapid resorption of the contents of the cyst, which was centrally located.
We report on an 8 1/2-year-old boy with an echinococcus granulosus infection of the liver and lung, drawing particular attention to the therapy applied. This therapy consists on the one hand of medicinal treatment with Mebendazol and on the other hand of two subsequent operations with resection of the cysts. The course of the illness is illustrated by means of the most important laboratory parameters; an indication of the present serological diagnostic is also given.
The intestinal helminths infecting stray dogs were investigated in the Testour and Bouzid regions of Tunisia. Overall, 21% of the dogs necropsied were found to be infected with Echinococcus granulosus. The prevalence among the animals from Testour (27.0%) was significantly higher than that in the dogs from Bouzid (6.9%). Although the prevalence of this species in the dog populations did give a significant fit to the age-prevalence models reported earlier, the best fit was not consistent with the known biological parameters of the parasite. The frequency distribution of E. granulosus was highly aggregated, with a mean abundance of infection of 538 parasites/host and a mean intensity in infected animals of 2534 parasites/host. Several Taenia species were also found in the dogs, but none of these showed evidence of an aggregated distribution and the frequency distribution of each fitted a Poisson distribution, which is unusual for naturally acquired infections. All the other cestode species and the nematode species encountered had aggregated distributions in the dogs. As there was relatively little correlation between the worm burdens of the different parasite species in the dogs, individual dogs may not be generally susceptible or resistant to intestinal helminths of several species.
Subcutaneous inoculation of living Echinococcus granulosus protoscolices (PSC) caused blastic transformation in local lymph node cells (LNC). The effect was maximal seven days post-infection (p.i.), had declined by day 21, and was prevented by killing the PSC prior to inoculation. LNC from inoculated mice also showed marked enhancement of blastogenesis in response to a secondary stimulation by live PSC in vitro. This secondary reaction occurred after exposure to living or killed PSC. There was generally enhanced reactivity to T- and B-cell mitogens at day 7. Phytohaemagglutinin was exceptional in that the killed parasite caused early changes in reactivity as above, but the live parasite induced a rise at 56 days p.i. It is concluded that E. granulosus may cause a determinate change in T-cell function.
Some of the factors influencing the sensitivity of ELISA in serodiagnosis of infections with Echinococcus multilocularis were examined. The results obtained suggest that, in contrast to E. granulosus, the variability in the antibody-binding capacity of various samples of cyst fluid of E. multilocularis cannot be explained by differences among parasite strains, species of host, cyst locations within the host, cyst fertility or protein concentration of the sample.
The rate of acquisition of Echinococcus granulosus and Taenia hydatigena was examined in dogs treated with praziquantel in northwestern Turkana District of Kenya. An attempt was also made to assess the effect of drought on the prevalence of E. granulosus. The infection pressure to dogs with the cestodes was shown to be high, and the prevalence returned to pretreatment levels within six months. The unreliability of arecoline purging in prevalence studies of dog cestodes is shown by mathematical contrast to the results of autopsy. Arecoline purge may underestimate the real prevalence by 10-fold. Dosing intervals in hydatid control programmes utilizing mass dog-purging to estimate re-infection rates should therefore take this factor into consideration. It is proposed that a mass dog-dosing schedule in Turkana, using praziquantel, should take into consideration the short prepatent period of E. granulosus, the financial constraints, and the slaughter practices in the area. During the prolonged droughts which occur approximately every 10 years, the programme will be adjusted accordingly to cater for the initial increase in infection intensity to dogs.
Of 92 dogs examined for Echinococcus granulosus at five sites in Libya from April 1985 to September 1988 33 (35.9%) were infected, the prevalences ranging from 60% (Zawiyah) and 52.0% (Tripoli) in the north-west, to 28.6% (Benghazi) and 28.5% (Darna) in the north-east. None of eight dogs at Al-Kufra, in the south-eastern desert, were infected. Twenty dogs each had two to 200 worms, nine had 201-1000 worms and four each had over 1000 worms (one dog in Tripoli had 17,120 worms). Most infections were seen in dogs aged three to four years; 45.4% of bitches and 35.4% of males were infected.
During a survey of 14 Libyan abattoirs in 1985-1987 the carcasses of 4316 locally-bred goats, cattle and camels were inspected for cysts of Echinococcus granulosus. Of 2295 goats, 35 adults (1.5%) had cysts; no kids were infected. Thirty-one adult goats had infected livers, 28 had lung infections, and four each had cysts in their kidneys and spleens. Most (59.7%) of the infections were light, with medium infections in 31.3% and heavy infections in 8.9%; 85.7% of the cysts in the lungs and 38.7% of those in the livers were fertile; three of the four kidney infections and two of the four spleen infections were fertile. Of the 1023 cattle carcasses, mild infections with E. granulosus were seen in 55 (5.4%); all the cysts were sterile and confined to the liver. Of 998 camels, 358 (35.9%) had hydatid cysts. These involved the lungs in 96.9%, either as the sole site (74.3%) or jointly with the liver (22.6%). Lung cysts (57.6%) and liver cysts (41.2%) were fertile.
In order to evaluate the applicability of anthelminthic treatment of wild foxes (Vulpes vulpes) to limit their infection with Echinococcus multilocularis, bait pellets, each containing 50 mg praziquantel, were repeatedly distributed in an area of 566 km2 where many foxes are infected, in southern Germany. After six baiting campaigns (15-20 baits/km2) over a period of 14 months, the prevalence of the cestode in foxes, initially 32%, had fallen to 4%. The effect was most pronounced in the central part of the treated area, where no positive fox was found in the 2 months before the end of the trial. The study was controlled for other factors that could influence the parasite's prevalence, such as the availability of intermediate hosts. While the potential of this baiting method to remove E. multilocularis from wild hosts has been demonstrated, the question of its long-term efficacy and other unresolved problems have to be addressed by consecutive studies before routine application can be recommended.
A descriptive epidemiologic study was designed to test an impression that infections of Echinococcus granulosus in dogs, sheep, and human beings were concentrated in central Utah, and to determine when and how the parasite was introduced into the state, which factors were involved in the distribution of the cestode, and which factors increased either a person's risk of infection of the number of people at risk. Data were secured by review of available records, interviews, questionnaires, and field observations. It was found that 37 of 39 infections in human beings, and seven of eight counties with endemic hydatid disease in dogs and sheep, are located in central Utah. Possible factors responsible for the increasing number of people at risk were use of local people as herders, the existence of community herds, and specific dog management practices. Determinants such as trailing sheep between seasonal pastures, association of sheepmen from several counties on winter range, and sheep marketing practices undoubtedly influence distribution of infections in dogs and sheep.
PURPOSE OF REVIEW: Echinococcus multilocularis is a tapeworm of foxes that may cause a zoonotic infection resulting in a highly pathogenic and potentially fatal chronic liver infestation called human alveolar echinococcosis. Radical liver resection currently offers the only potential cure. Although alveolar echinococcosis is a rare parasitic disease that is restricted to transmission in the northern hemisphere, the parasite is geographically widespread being distributed from Alaska, across Canada and north central USA, through northern Europe and Eurasia to Japan. The present review summarizes the background to this helminthic infection and recent contributions in areas of pathology, diagnosis, treatment and transmission. RECENT FINDINGS: Concern is growing in Europe that the prevalence and distribution of E. multilocularis in red foxes has increased significantly in the last 10-15 years. A retrospective analysis revealed >550 cases of human alveolar echinococcosis diagnosed between 1982-2000, with the majority in France, Germany and Switzerland. Human prevalence rates >3% occur in central northwest China and the disease is of public health concern in northern Japan. Improvements in immunodiagnosis with native and recombinant antigens have enabled more accurate confirmation of hepatic image findings, while development of in-vitro culture of metacestode tissues provides a useful model for screening new anti-alveolar echinococcosis drugs as alternatives to albendazole and surgery. Recombinant molecules from the oncosphere and metacestode stages have shown potential as vaccine candidates. New tools of coproantigen and copro-DNA detection for vulpine infections have proved highly beneficial in epidemiological and transmission ecology studies, as has a landscape ecology approach to develop risk models for communities in endemic areas. SUMMARY: It is possible that human AE will become an emergent zoonosis in some regions of Europe and Eurasia. Improvements in diagnostic and treatment approaches are being investigated. Further understanding of host immune responses will aid in characterization of disease pathology. Control of E. multilocularis in its natural cycles will be difficult due to the involvement of wild animal hosts, however use of anthelminthic baits and dosing of domestic dogs may reduce transmission at local scales.
Echinococcosis, an endemic disease on the Asian continent, is caused by the tapeworm Tenia Echinococcus, which produces cysts in the liver and other organs. I reviewed 157 patients with hydatid disease of the liver. The hydatid cysts were single in 125 patients and predominantly in the right lobe, but multiple in 31 patients, localized in both lobes or in the lung, spleen, pancreas, heart, or peritoneum. In 14 patients, early complications were manifested by rupture of the cyst into the biliary tract, the lung, or the peritoneum. Infection of the cysts was rare. Late postsurgical complications, noted in 10, were the development of an abscess or cirrhosis. I evaluated the importance of computed tomography (CT) in the diagnosis of hydatidosis of the liver and other visceral organs: It made a correct and accurate diagnosis in 96% of 157 patients. But, in ruptured or infected cysts, CT scans could not distinguish between a hydatid cyst and an abscess. Surgery is still the treatment of choice in hydatid disease. It is absolutely indicated in complicated cases, and is easy and curative in uncomplicated ones. I have used Mebendazole in 18 patients for 2 years without significant benefit, except in two patients with disseminated hydatidosis. Mebendazole stabilized the disease.
Parasite-specific humoral and cell-mediated immune responses were investigated in highly susceptible (AKR and C57B1/6J) and relatively resistant (C57B1/10) mice undergoing secondary alveolar echinococcosis (infection with Echinococcus multilocularis metacestode). The parasite-specific proliferative immune response of lymph node cells upon in vitro antigen stimulation remained weak in all three mouse strains. By day 30 p.i., CD4+ lymphoblast cells dominated the total population of blast cells in all three mouse strains. There was, however, an unexpectedly high proportion of CD8+ blast cells; by day 90 p.i., a marked proportional increase in CD8+ cells was seen in susceptible (AKR and C57B1/6J), but not in resistant (C57B1/10) mice. Susceptible, but not resistant mice exhibited a significantly decreased responsiveness of lymph node cells to concanavalin A (Con A) stimulation on day 90 p.i. Analysis of the humoral immune response by ELISA showed that resistance in C57B1/10 mice was associated with the ability of the host to synthesize antibodies to Em2 of the IgG3 and IgG1 isotype. Em2 is a lectin-binding carbohydrate antigen of the laminated layer. In susceptible AKR and C57B1/6J mice, low levels of anti-Em2 antibodies of the IgG2a isotype were detected. Anti-Em2 antibodies of the IgG3/IgG1 isotype, however, were absent. Differences in subclass-specific IgG responses were confirmed by immunoblot analyses. Our findings suggest that differences in antigen recognition (with respect to subsets of humoral and cellular immune components), probably controlled by non-H-2 gene(s), coupled to immune suppression modulated by CD8+ cells and/or respective cytokines, may determine susceptibility or resistance in experimental infection with E. multilocularis.
Chronic infection by Echinococcus granulosus results in establishment of fluid-filled cysts (hydatid cysts) in liver or lungs of infected hosts, which can escape destruction by the host immune system for long periods. This study explores the modulation by hydatid cyst fluid of the in vitro human monocyte to dendritic cell (DC) transition induced by granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). Addition of the fluid to adherent peripheral blood monocytes cultured in GM-CSF/IL-4 stimulates release of prostaglandin E2 (PGE2) and IL-6. Exposure of differentiating DC to the fluid during the 7-day culture in GM-CSF/IL-4 impairs their subsequent ability to secrete IL-12, IL-6 or PGE2 in response to lipopolysaccharide (LPS) stimulation. This inhibition is not dependent on the initial release of PGE2. The presence of hydatid cyst fluid also modulates the phenotype of the cells generated during culture, resulting in increased CD14 expression and decreased expression of CD1a. Finally, hydatid fluid can stimulate predifferentiated DC to mature, as evidenced by release of IL-12 and IL-6, and by up-regulation of class II major histocompatibility complex and CD86. The possible role of dendritic cell modulation in regulating the host immune response to hydatid cysts is discussed.
The 'arc 5' precipitin band, formed when test human serum is reacted against immunoelectophoresed hydatid cyst fluid antigen, has provided a positive diagnosis of Echinococcus granulosus infection. These antibodies to 'arc 5' antigen have now been found in the sera of sheep. They appear 2 weeks after infection with Taenia ovis, after 3 weeks with T. hydatigena and after 16 weeks with E. granulosus. An antigen similar to the 'arc 5' antigen of E. granulosus cyst fluid was also demonstrated in cyst fluid from T. hydatigena, but it would not be positively identified in T. ovis cyst fluid. The presence of 'arc 5' in immunoelectrophoresis tests is not suitable for specific immunodiagnosis of E. granulosus infections in sheep in New Zealand. 'Arc 5' antibodies were only associated with living E. granulosus cysts and were not present if cysts were dead. The location of the cysts in either liver or lungs and the onset of brood capsule production did not influence the presence of 'arc 5' antibodies.
Alveolar hydatid cysts (AHC) were isolated from C57BL/6J and BALB/c mice at 8 and 12 weeks post-infection from subcutaneous and intraperitoneal foci and cultured in vitro. Freshly isolated as well as in vitro-grown cysts were incubated with Fc or F(ab')2 fragments of human, rabbit, mouse, goat or sheep immunoglobulins, then washed and incubated with a fluorescein-conjugated rabbit or goat F(ab')2 fraction of antisera to each of the above primary sera. Significant fluorescence on the surface of AHC was detected when they were incubated with human, rabbit or mouse Fc fractions followed by the addition of goat or rabbit fluorescein-conjugated antiserum. No fluorescence was detected when the AHC were incubated with the F(ab')2 fragments and fluorescein-conjugated antiserum, except when the primary antiserum was mouse F(ab')2 fractions. Cysts grown in vitro retained their binding ability to human, rabbit or mouse Fc fractions. However, the intensity of fluorescence decreased proportionally with time. The maximum intensity of staining was observed with small cysts. Large cysts showed diminished fluorescence. The non-specific binding of human, mouse or rabbit immunoglobulins (Fc fractions) to AHC was also confirmed by rosetting with sheep erythrocytes (SRBC) which suggests that the larvae of Echinococcus multilocularis may utilize the presence of Fc receptors on their surface in order to elude immune destruction by the host.