Use of sentinel lambs for early monitoring of the South Powys Hydatidosis Control Scheme: prevalence of Echinococcus granulosus and some other helminths.

Sentinel lambs were used to identify young Echinococcus granulosus infections in sheep, to provide an early indication of the progress of the South Powys Hydatidosis Control Scheme. Four sentinel lambs were purchased on each of 60 farms, from inside and outside the control area; they were examined when approximately six, 10 and 15 months of age. Gross examination, thin slicing of organs and histological examination of the lesions in the viscera revealed no E granulosus hydatid cysts in lambs born within the control area, whereas 25 per cent of the 15-month-old lambs from outside the area harboured E granulosus cysts (less than 1 to 2 mm in diameter). Lambs from E granulosus infected farms had significantly higher anti-E granulosus ELISA antibody titres than lambs from uninfected farms. It was concluded that within one year of beginning to treat dogs with praziquantel every six weeks the transmission of E granulosus to sheep had ceased. In contrast, this treatment did not prevent infections with Taenia hydatigena or T ovis; an examination of the 240 lambs revealed T hydatigena in 33.3 per cent of them, Tovis in 4.2 per cent, Dictyocaulus filaria in 12.1 per cent and Meullerius capillaris in 49.2 per cent.     

Specific antibody responses to Taenia hydatigena, Taenia pisiformis and Echinococcus granulosus infection in dogs

Groups of dogs reared free of both nematodes and cestodes were infected with Taenia hydatigena, Taenia pisiformis or Echinococcus granulosus. After infections with the Taenia spp became patent, dogs were purged to remove the worms. They were later reinfected and the second infections again removed by purging after patency. A group of 3 uninfected worm free dogs was kept as age-matched controls. The dogs were bled at intervals of 5 days and their serums tested for antibodies using the enzyme-linked immunosorbent assay (ELISA) with excretory/secretory (ES) antigens collected during in vitro incubation of evaginated scoleces (scolex ES antigen) and oncosphere antigens. Antibodies to scolex ES antigen were detected by 3 weeks after infection with each cestode species whereas antibodies to oncosphere antigen were not detected until about one week after eggs were found in the faeces of the infected dogs. Antibody responses to both oncosphere and scolex ES antigens decreased rapidly following removal of the worms by purging. Uninfected control dogs were invariably negative to both oncospheral and scolex ES antigens. There were cross-reactions between the serums from dogs infected with T. pisiformis and T. hydatigena when tested with scolex ES antigens, but oncospheral antigens showed a high degree of species specificity. Scolex ES antigens from E. granulosus were compared with those prepared from T. hydatigena and T. pisiformis for their ability to discriminate between antibodies in serums collected from dogs 31 and 32 days after infection with 100,000 protoscoleces of E. granulosus or dogs infected with Taenia spp.(ABSTRACT TRUNCATED AT 250 WORDS)     

Detection of Echinococcus granulosus coproantigens in faeces from naturally infected rural domestic dogs in south eastern Australia

OBJECTIVE: To investigate the occurrence of Echinococcus granulosus in rural domestic dogs in farming areas around Yass, New South Wales, and Mansfield and Whitfield, Victoria. DESIGN: Faeces were collected per-rectally from farm dogs voluntarily presented by their owners in four farming districts in New South Wales and two in Victoria. PROCEDURE: Faeces were collected in the field, an extract prepared from each sample and E granulosus coproantigens detected in an ELISA. Farmers were also questioned about their dog feeding and worming practices. RESULTS: Echinococcus granulosus coproantigens were detected in 99 of 344 dogs (29%) from 95 farms in south eastern New South Wales and 38 of 217 dogs (17.5%) from 43 farms in Victoria. Cross-reactions between E granulosus coproantigen trapping antibody and coproantigens in faeces from dogs monospecifically infected with other species of intestinal helminthes (Taenia ovis, T hydatigena, T pisiformis, Spirometra ericacei, Dipylidium caninum, hookworm, Toxocara canis, Trichuris vulpis) were not evident. Dietary and worming data revealed many owners fed raw meat and occasionally offal from domestic livestock and wildlife to their dogs and few owners wormed their dogs frequently enough to preclude the chance of patent E granulosus being present in their dogs. CONCLUSION: Echinococcus granulosus occurs commonly in rural dogs in south eastern Australia and an education program promoting the public health importance of responsible management of rural dogs is urgently needed.     

果洛地区犬绦虫感染情况调查

对果洛６县的５１条犬进行绦虫感染情况调查。结果：感染犬４６条，感染率为９０．２０％，其中，棘球绦虫感染率７０．５９％。犬感染的绦虫主要有细粒棘球绦虫、多头绦虫和泡状带绦虫三种。     

The effect of oxfendazole on Echinococcus granulosus and Taenia hydatigena infections in dogs

Trials with oxfendazole carried out on 120 dogs infected with either Echinococcus granulosus or Taenia hydatigena indicated that a single treatment significantly reduced the proportion of dogs infected with tapeworms. Diarrhoea occurred occasionally when the dose rate exceeded 20 mg/kg.     

A canine purgation study and risk factor analysis for echinococcosis in a high endemic region of the Tibetan plateau

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).     

The effect of nitroscanate tablets of Echinococcus granulosus and Taenia hydatigena infections in dogs

Tablets of micronised nitroscanate (nominal particle size 2--3 microns) were given to a total of 190 dogs that had been experimentally infected with either Echinococcus granulosus or Taenia hydatigena. The efficiency of the drug in tablet form in freeing dogs from tapeworms, was investigated. The dose rate at which 50 per cent of normally fed dogs can be expected to be freed from E granulosus was found to be 89 mg/kg (95 per cent confidence limits 55 mg/kg to 140 mg/kg). The 90 per cent effective dose rate was not determined within the range 32 mg/kg to 250 mg/kg. The dose rate at which 90 per cent of normally fed dogs can be expected to be freed from T hydatigena was 37 mg/kg (95 per cent confidence limits 23 mg/kg to 60 mg/kg).     

THE ROLE OF THE TASMANIAN DEVIL IN THE EPIZOOTIOLOGY OF OVINE CYSTICERCOSIS AND ECHINOCOCCOSIS

Tasmanian devils were fed infective cystic material of Taenia ovis, T. hydatigena and Echinococcus granulosus and later killed and examined for adult tapeworms. No infections with T. ovis were found after feeding 23 cysts to 8 devils. T. hydatigena were recovered from 5 to 41 devils and 10 worms established after feeding 417 cysticerci. No E. granulosus were recovered from any of 3 devils. Specimens of T. hydatigena appeared to develop as well in devils as in dogs. From these and previous results devils could be successful hosts to T. hydatigena and T. ovis. A survey of 320 devils failed to detect any natural infections with any of these 3 species.     

Screening for Echinococcus granulosus in dogs: Comparison between arecoline purgation, coproELISA and coproPCR with necropsy in pre-patent infections

Echinococcus granulosus is an important zoonotic infection of dogs. The purpose of the present study assessed the performance of two laboratory diagnostic methods with arecoline purgation and necropsy in infected dogs. In total 65 dogs were successfully experimentally infected with protoscoleces of E. granulosus from ovine infection. At 14-34 days post-infection groups of dogs were purged with arecoline hydrobromide and then necropsied. Faecal samples were tested at weekly intervals by coproantigen ELISA and coproPCR. The necropsy infection rate with E. granulosus was 89.2 per cent. Only 43 per cent of dogs were successfully purged after one arecoline dose; this percentage increased to 76.9% for two doses of arecoline purgation. E. granulosus coproantigen was detected by coproELISA in 82.8% of faeces. The positive and negative predictive values for coproantigen ELISA were 96 and 44.4% respectively. E. granulosus DNA was detected in pre-patent faecal samples by coproPCR in 25.9% of dogs. These results indicate that coproELISA is more sensitive than arecoline purgation for the detection of pre-patent E. granulosus infection in dogs. CoproPCR detected E. granulosus DNA in dog faeces by 21 days post-infection before egg production.     

Comparative effects of uredofos, niclosamide, and bunamidine hydrochloride against tapeworm infections in dogs.

A single dose of a new broad-spectrum anthelmintic, uredofos, was more effective than single doses of either bunamidine hydrochloride (HCI) or niclosamide in removing natural infections of Dipylidium coninum from pound dogs, as determined by necropsy examination for scolices. The efficacy of uredofos was equal to that of bunamidine HCI and exceeded that of niclosamide in removing Taenia spp from his host. All of 12 dogs harboring D caninum and all of 5 dogs harboring Taenia spp were completely cleared of tapeworm infection following treatment with uredofos at 50 mg/kg of body weight. Bunamidine HCl cleared 9 of 11 dogs (82%) of D caninum and 5 of 5 dogs of Taenia spp. Niclosamide had the least anticestodal activity of the 3 drugs; 2 or more scolices of D caninum were found at necropsy in each of 12 dogs treated with this drug. Four of 5 dogs were cleared of Taenia spp following niclosamide therapy. Untreated control dogs did not shed tapeworms of either species during a 3-day period of posttreatment fecal collections, but did have tapeworms at the time of necropsy.     

Echinococcus granulosus in farm dogs and dingoes in south eastern Queensland

Twenty-nine farms with a prevalence of greater than 20% of hydatidosis in cattle were visited in south eastern Queensland between August and December 1982. All farms carried beef cattle but none sheep. Twenty-four had dingoes and wallabies but only 8 had feral pigs. On 17 farms either macropods were killed for dog food or dogs were suspected of hunting macropods or scavenging their carcases. Purge samples were collected from 45 dogs from 23 of the 29 farms visited. The Australian sylvatic strain of Echinococcus granulosus was found in low numbers in purged intestinal content from one dog from each of 2 farms. Also, 50 intestinal tracts from dingoes from southern Queensland were examined between October 1981 and November 1983. The sylvatic strain of E. granulosus was found in 36 dingoes, the Australian mainland domestic strain in 4, and a further 5 dingoes were infected but the strain was not identified. This work indicates that domestic dogs are probably not important definitive hosts for E. granulosus in south eastern Queensland but could be an occasional source of infection for man. Dingoes are the major definitive host and worm numbers can be very high. Small foci of the domestic strain of E. granulosus may be maintained in a cycle involving dingoes, macropods and possibly feral pigs in cattle raising areas of coastal Queensland.     

The prevalence of cestodes in farm dogs in mid-wales

Five hundred and eight farm dogs in mid-Wales were treated with arecoline acetarsol during 1975. Cestodes recovered from their faeces were identified as follows: Echinococcusgranulosus, Taenia hydatigena, Taenia multiceps, Taenia ovis, Taenia pisiformis, Taenia serialis, and Dipylidium caninum.Many dogs were treated on three different occasions during the 12 months, and changes in the prevalence over this period were shown. The greatest rise in prevalence rate from January to May was seen for E. granulosus while T. hydatigena was most prevalent in January. All other species, except T. serialis, were found in low numbers throughout the year.     

Screening of dogs for Echinococcus granulosus coproantigen in a low endemic situation in Cyprus

In the framework of an echinococcosis surveillance and control programme in Cyprus, a commercial enzyme-linked immunosorbent assay (ELISA) (CHEKIT ECHINOTEST) designed for the detection of Echinococcus granulosus and E. multilocularis coproantigens was used in 1997-2000 for the investigation of large numbers of dogs. Most of the animals originated from areas where approximately 0.2% of the dogs had been found to be infected with E. granulosus in previous (1993-1996) arecoline surveys. The sensitivity of the coproantigen test was 83%, as determined in 35 dogs naturally infected with this cestode species. The specificity was 98% in 97 randomly selected dogs from Cyprus, but it was reduced to 80% in a group of 50 dogs, infected with Taenia spp. A total of 6551 dogs (mainly of rural origin) was examined, including three large groups (N: 2928, 1761 and 1800) from the Government Control Area (GCA) in southern Cyprus and a small group (N: 62) from the Non-Government Control Area (NonGCA) in the northern part of the island. Among the dogs from the GCA, 184 (2.8%) tested positive for coproantigen; coproantigen prevalences were 2.6, 4.9 and 1.1% in these three groups, and of 62 dogs from the NonGCA 8.1% were positive. The calculated true prevalences of E. granulosus in the dog population of the GCA ranged between 0.0 and 3.58%. The predictive values of the test, based on a 0.2% prevalence, was >99.9% for negative results, but very low (7%) for coproantigen-positive results. However, the relatively small number of coproantigen-positive dogs can be treated with praziquantel or the results can further be confirmed by arecoline purging.     

Specificity of scolex and oncosphere antigens for the serological diagnosis of taeniid cestode infections in dogs

Groups of dogs raised free of helminths were monospecifically infected with the common nematodes Toxocara canis, Ancylostoma caninum and Trichuris vulpis. Serums from these dogs, and a group of dogs of unknown history but infected with Dirofilaria immitis and Dipylidium caninum, had levels of antibody to their homologous nematode antigens readily detectable by ELISA. No cross-reactions were apparent when these serums were tested by ELISA using oncosphere antigens of Taenia hydatigena, T. pisiformis and T. ovis, scolex excretory/secretory antigens of T. hydatigena, T. pisiformis and Echinococcus granulosus or protoscolex antigen of E. granulosus.     

Use of Echinococcus granulosus worm antigens for immunodiagnosis of E. granulosus infection in dogs.

Echinococcus granulosus worm excretory/secretory antigens (WES) were used in ELISA for diagnosis of E. granulosus infection in dogs and compared with protoscolex somatic antigens (PSM). Sera from 224 dogs were tested. There was no correlation between ELISA absorbance values and E. granulosus worm burdens using either antigen. There was a significant linear relationship between absorbance values of sera tested in the ELISA using WES (W-ELISA) and the ELISA using PSM (P-ELISA). However, there was a small but significant difference between the absorbance values of the sera tested against the two antigens. Western blot analysis of WES using sera from E. granulosus-infected and uninfected dogs revealed antigenic components of relative molecular mass (Mr) larger than 94,000, Mr 94,000-68,000 and Mr 43,000-39,000 in worms, and these were specific for E. granulosus and not identified in PSM; these antigenic differences may be responsible for differences in reactivity in ELISA. The sensitivities of W-ELISA and P-ELISA were 80.8% and 75.6%, respectively. The specificities of W-ELISA and P-ELISA were 93.7% and 97.9%, respectively. The reduced specificity in W-ELISA was mainly attributable to increased background reactivity of sera from Taenia hydatigena-infected dogs. Despite the reduction in specificity, both ELISAs are valuable epidemiological tools to determine the prevalence of antibody to E. granulosus in dog populations and to monitor the success of hydatid control campaigns.     

The effect of fospirate on Echinococcus granulosus and Taenia hydatigena infections in dogs.

Trials with fospirate carried out with 170 dogs infected with either Echinococcus granulosus or Taenia hydatigena indicated that a dose rate of 40 mg/kg given on three occasions and 10 mg/kg given on one occasion eliminated each species, respectively. Increasing the dose rat substantially above 40 mg/kg did not reduce the number of treatments required to eliminate all hydatid organisms. Vomiting was observed in some dogs.     

Echinococcus granulosus in Finland

Echinococcus granulosus is shown to occur in eastern Finland in a sylvatic cycle involving wolves (Canis lupus) as the definitive host and reindeer (Rangifer tarandus tarandus) and probably also elk (Alces alces) and the wild forest reindeer (Rangifer tarandus fennicus) as intermediate hosts. Even though the prevalence of E. granulosus in reindeer has increased in recent years, it is still very low (<0.013%). The results suggest, however, that the reindeer is a good sentinel animal to show the contamination of soil with Echinococcus eggs. This is the first report of wolves acting as a definitive host for E. granulosus in northern Europe. The parasite seems to be quite common in the Finnish wolf population, with a prevalence of approximately 30% in both intestinal and faecal samples. The present results and previous ones indicate that E. granulosus infection has not spread to dogs in the reindeer herding area.     

The effect of nitroscanate on Echinococcus granulosus and Taenia hydatigena infections in dogs.

Trials with nitroscanate carried out on 186 dogs infected with either Echinococcus granulosus or Taenia hydatigena indicated that a single treatment at a dose rate of 1000 mg/kg or two treatments at 250 mg/kg eliminated the former, but a single treatment at 64 mg/kg was sufficient to eliminate the latter. At this dosing schedule, vomiting and diarrhoea occurred, as well as a transient 'tranquillising' effect on some dogs.     

Diagnosis of cystic echinococcosis on sheep farms in the south of Argentina: areas with a control program

In 2000 Guarnera et al. proposed using ELISA in canine faeces collected from the ground to detect dogs infected with Echinococcus granulosus, thus determining sheep farms with active transmission. The objective was to evaluate the prevalence of E. granulosus infection in sheep farms of the Patagonia. Sheep farms were randomly selected in the Provinces of Río Negro, Chubut, Neuquén, Santa Cruz and Tierra del Fuego (areas with control programs) and La Pampa (comparison area). From one to three samples of fecal matter were obtained for each sheep farm, which were processed by means of copro-ELISA test with confirmation of positive samples by copro-Western blot. A total of 1042 samples were obtained from 352 sheep farms, 26 (7.3%) proving positive. Of these 5 (6.3%) were from La Pampa, 9 (13.8%) from Neuquén, 4 (4.7%) from Río Negro, 2 (2.9%) from Chubut, 1 (5.9%) from Santa Cruz and 5 (13.9%) from Tierra del Fuego. The identification of parasitized dogs is an essential activity upon which rests the strategy of control and surveillance. Arecoline tests or coproantigen test with fecal matter obtained directly from the dog contribute information on individual prevalence, while the use of coproantigens detected in ground-collected samples transfers the dog unit of observation to units of greater epidemiological value. In the present experience, the technique employed seems promising for its application in systems of epidemiological surveillance of cystic echinococcosis and in drawing a baseline on which to measure the progress of control programs in the Argentine Patagonia in subsequent years.     

Echinococcus multilocularis infections in domestic dogs and cats from Germany and other European countries

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.