Ultrasonographic screening for cystic echinococcosis in sheep in Tunisia

Sheep from the areas of Fondouk-Jeddid, Bir Mchergua and El Fahs, located in the Northeast of Tunisia, were examined by ultrasonography between 2001 and 2004 in order to assess their infection with Echinococcus granulosus, the agent of hydatid disease, and to evaluate this method as an efficient aire for hydatid cysts. A total of 1039 sheep, aged between 1 and 14 years was examined. The highest prevalence was found in sheep aged more than 8 years. The least infected animals were aged between 1 and 2 years. All hydatid cysts detected by ultrasound were located in the liver. In all age-groups, the dead cysts were more numerous than viable cysts. Eighteen positive sheep were autopsied and a comparison between ultrasound and autopsy results was performed. The results showed a prevalence of about 40% for the three areas. Ultrasonography allowed the cysts, deep or superficial to localize in the central or left part in relation to the caudal vena cava of the animals. Consequently, all the cysts were not detected with this technique. This work shows that ultrasonography confirms the importance of ovine hydatid cyst in Tunisia and that its use as a mass screening approach for cystic echinococcosis in sheep could be helpful for the monitoring of this disease in a hydatid control program without great stress for the animals.     

牛羊4种寄生虫病联合诊断技术的研究与应用

疫区牛羊同时寄生有捻转血矛线虫、日本血吸虫、伊氏锥虫和肝片吸虫等多种寄生虫。目前血清学诊断方法对这 4种寄生虫病的检测需 2～ 4次操作。将捻转血矛线虫、日本血吸虫、伊氏锥虫和肝片吸虫抗原分别以 0 1 5 ,0 0 4 ,0 0 6和 0 1 3μg/ μL的最佳浓度依次定点在同一硝酸纤维素膜条上 ,制成 4种寄生虫病联合诊断膜。用黄牛IgG ,水牛IgG和山羊IgG联合免疫兔 ,获得了高效价兔抗黄牛、水牛和山羊 (简称兔抗牛羊 )IgG抗血清。应用兔抗牛羊IgG抗血清连接酶标SPA ,建立了 1份血纸能同时用于检测牛、羊捻转血矛线虫、日本血吸虫、伊氏锥虫和肝片吸虫病抗体技术。经浙江、湖北、四川、安徽等省应用 ,该项技术具有省工、省时、经济、实用等优点。适宜于牛、羊捻转血矛线虫、日本血吸虫、伊氏锥虫和肝片吸虫病流行区的普查或监测     

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.     

Control of cystic echinococcosis: Background and prospects

Cystic echinococcosis (CE), caused by Echinococcus granulosus, is a chronic and debilitating zoonotic larval cestode infection in humans, which is principally transmitted between dogs and domestic livestock, particularly sheep. Human CE occurs in almost all pastoral communities and rangeland areas of the underdeveloped and developed world. Control programmes against CE have been implemented in several endemic countries to reduce or eliminate the disease. New Zealand and Tasmania are examples of some of the first programmes to be undertaken (in insular territories) and which were very successful in the elimination of CE. The advent and proven effectiveness of praziquantel, plus the experience of insular models, produced high expectations for rapid advances in a second generation of control programmes undertaken in continental areas (Argentina, Uruguay and Chile). Nevertheless, only moderate gains in CE control have been made and the impact on prevalence among humans has been slight. A major impediment to the adoption of procedures that were successful in New Zealand and Tasmania has been the requirement to administer praziquantel to dogs in rural areas eight times per year over numerous years. In addition, there have been clear technological improvements made in the diagnosis of canine echinococcosis for surveillance, the genetic characterization of parasite strains and in vaccination against CE infection in livestock. In order to establish new paradigms and appropriate combinations of control strategies, we have carried out a review and discussion of the available control tools and control models. Control strategies must be suitable and sustainable to benefit the Echinococcosis–endemic areas primarily, which at the same time are the poorest regions of the world.     

Epidemiological study of the cystic echinococcosis in Morocco

The objectives of this epidemiological study on cystic echinococcosis (CE) in Morocco (2001-2004) were to update the prevalence of CE in different animal species living in the most important areas of the country and to collect protoscoleces and germinal layers for genetic research purposes. The post mortem inspection concerned 2948 sheep, 2337 goats, 618 cattle, 482 camels and 455 equines (325 horses, 60 mules and 70 donkeys) in five different regions: the Rif (Mediterranean coast and high mountains of the Rif), the Loukkos (Atlantic northwest plain), the center (Rabat and Casablanca regions), the Middle Atlas mountains and the south (arid and semi desert areas). The global CE infection prevalence rates obtained were 22.98% in cattle, 10.58% in sheep, 12.03% in camels, 17.80% in equines and 1.88% in goats. The infection rates were especially high in the Middle Atlas in cattle (48.72%) and in the Loukkos in cattle and sheep (37.61 and 31.65%, respectively). The majority of infected cattle (49.6%) and sheep (52.1%) had hydatid cysts in both liver and lungs. Except for cattle, the liver was more infected than lungs in all the other animal species. Animals more than 5 years old were the most infected in all species. The mean CE infection rates of these animals were about 56% in cattle, 40% in sheep, 20% in camels, 17.80% in equines and 7% in goats. These rates were much higher in the Loukkos (85% of cattle and 59% of sheep) and in the Middle Atlas (68% of cattle and 45% of sheep) than in the other regions. Results showed that Echinococcus granulosus is in an endemic steady state with no evidence of protective immunity in the intermediate hosts. The mean numbers of infections per year are 0.099 for cattle, 0.063 for sheep, 0.03 for camels and 0.010 for goats.     

New transtracheal bronchoalveolar lavage technique for the diagnosis of respiratory disease in sheep

A new transtracheal bronchoalveolar lavage technique for the diagnosis of respiratory disease in sheep under field conditions was tested in 76 sheep. The sheep were divided into three groups, normal sheep, sheep with clinical signs of respiratory disease and housed sheep, on the basis of their respiratory disease history and husbandry conditions. The detection of Mannheimia haemolytica and Mycoplasma ovipneumoniae or parainfluenza virus type 3 and bovine respiratory syncytial virus antigen in the lavage samples was closely correlated with clinical disease. The sheep with clinical respiratory disease had a higher mean percentage of neutrophils in the lavage fluid than the sheep in the other two groups.     

Field evaluation of a PCR for the diagnosis of chlamydial abortion in sheep

A total of 94 vaginal swab samples and 195 serum samples collected from aborted ewes in 15 flocks were examined by pcr and a complement fixation test, respectively. In addition, 172 samples of stomach contents from fetuses from different flocks submitted for the diagnosis of abortion during the four lambing periods between 2000 and 2004 were tested by pcr. Chlamydial dna was detected in seven vaginal swabs obtained from five of the 15 flocks and in six samples of fetal stomach contents. The results of pcr and flock serology for Chlamydia were positive in five of the 15 flocks and negative in eight.     

Genetic survey of cystic echinococcosis in farm animals in Oman

Tropical Animal Health and Production - Echinococcus granulosus sensu lato (s.l.) is the causative agent of cystic echinococcosis (CE) in animals and humans with a worldwide distribution affecting...     

Cystic echinococcosis in slaughtered sheep in Sardinia (Italy)

Of 771 regularly slaughtered Sardinian breed sheep, 580 (75%) were found infected with Echinococcus granulosus hydatid cysts. Seventy-nine sheep (10.3%) had at least 1 fertile cyst. The prevalence of sheep infected with purulent/caseous cysts, calcified cysts and sterile cysts was 13, 59 and 28%, respectively. The age of sheep was positively associated with the probability of infection that increased 1.15 fold for each further year of age. Fertile cysts were found in the lungs of 46 sheep (6%) and in the liver of 13 sheep (1.7%), and in the lung and the liver of 20 sheep (2.6%). Most fertile cysts were found in the lungs (314) and most sheep were infected with less than 10 cysts. When analyzed by a mixed-effect logistic model, the probability to find fertile cysts in the lungs was three times higher compared to the liver and it increased with the age of the sheep (rho = 0.70, p < 0.001). Of 4072 collected cysts, 532 were fertile, 178 purulent/caseous, 2339 calcified and 1023 sterile.     

Molecular characterization and prevalence of cystic echinococcosis in slaughtered water buffaloes in Turkey

The present study was carried out between March 2006 and June 2010. During the study nine abattoirs were visited and 166 water buffalo internal organs were examined in Black Sea Region of Turkey. It was found that 10.24% buffaloes were infected with cystic echinococcosis (CE). The rate of CE found as 3.77% in males and 21.66% in females, 37.93% in older and 4.38% in young animals. The degree of prevalence according to age and sex was statistically significant (p<0.05). CE was observed 29.41% only in liver, 47.06% only in lungs and 23.53% in both liver and lungs. Therefore, the lungs were the predominant sites of the CE in buffaloes. Molecular identification on nine isolates, based on mitochondrial cox1 sequencing analyses, revealed that six cysts belonged to G1 genotype (domestic sheep strain) while 3 samples showed variant genotypes of Echinococcus granulosus complex G1-G2-G3. Two of them showed a thymine in position 52, like G2 strain, but the rest of sequences were completely identical to strain G1; also one specimen showed a single nucleotide change compared to strain G1 (C122T).     

Application of PCR technique in diagnosis of small ruminant lentivirus infection in sheep and goats

Detection of small ruminant lentiviruses (SRLVs) in sheep and goats usually relies on serological testing. In this study, we evaluated semi-nested PCR and nested PCR techniques applied as a diagnostic tool for detection of maedi-visna virus (MVV) and caprine arthritis-encephalitis virus (CAEV) in naturally infected sheep and goats, respectively. The examination of 193 ovine and 85 caprine serum samples by the ELISA revealed the presence of specific antibodies in 133 (69%) and 18 (21.2%) animals, respectively. Presence of proviral DNA was manifested in 103 (53.4%) sheep and 12 (14.2%) goats. Despite the relatively lower sensitivity of PCR, the fact of detection of proviral DNA in 19 out of 60 ovine samples and 7 out of 67 caprine samples collected from animals previously negative by ELISA was noteworthy. In conclusion, the data demonstrated that combinations of both ELISA and PCR might afford optimal detection of SRLVs infection.     

Induction of ovarian cystic follicles in sheep

Cystic follicles are a significant cause of infertility in women, dairy cattle and sheep. Sheep were used as a model to identify factors that may elicit formation of cystic follicles. Insulin resistance and elevated LH activity were tested in overweight ewes because of associations among these factors and the formation of cystic follicles. Sheep were synchronized using a progesterone-releasing pessary and insulin resistance was induced during the synchronization period through administration of bovine somatotropin. Following removal of pessaries follicular growth was stimulated by treatment with eCG or eCG and hCG (PG-600). Follicular growth was monitored via daily transrectal ultrasonography and blood samples were collected for hormonal analyses. Six of 18 ewes had a subnormal or absent preovulatory gonadotropin surge and developed cystic follicles. Neither insulin resistance nor elevated LH activity were associated with formation of cystic follicles. Ewes that developed cystic follicles were heavier (93 +/- 4 kg) than ewes that ovulated (81 +/- 3 kg; P = 0.02). Furthermore, following pessary removal and initiation of daily ultrasonography, ewes that developed cystic follicles lost body weight (-3 +/- 1%), while ovulatory ewes continued to gain body weight (1 +/- 1%; P = 0.005). It is speculated that in heavy ewes metabolic factors associated with acute body weight loss inhibit the positive feedback of estradiol and thereby suppress the preovulatory gonadotropin surge leading to formation of cystic follicles.     

Field evaluation of a coproantigen enzyme-linked immunosorbent assay for diagnosis of canine echinococcosis in a rural Andean village in Peru

One hundred and six dogs (61 males and 45 females) were examined for Echinococcus granulosus infection in a farming cooperative in the central highlands of Peru during November 1998. Canine echinococcosis was diagnosed using direct microscopic examinations of purged feces following arecoline purging and a coproantigen-detection enzyme-linked immunosorbent assay (ELISA) for E. granulosus. Mean age was 2 years with a range of 3 months to 9 years. The overall prevalence of canine echinococcosis using the ELISA test was 79% (84/106). Seventy-four dogs were successfully purged with arecoline. The frequency of canine echinococcosis was 82 (61/74) and 34% (25/74) by the coproantigen ELISA test and arecoline purging, respectively. The sensitivity and specificity of the coproantigen ELISA test was 88 and 95%, respectively. We found this assay to be especially advantageous in remote geographical areas. In future control programs against echinococcosis in Peru and other areas where E. granulosus is endemic the coproantigen ELISA should be used for the surveillance of the dog population.     

Molecular update on cystic echinococcosis in cattle and water buffaloes of southern Italy

Cystic echinococcosis (CE)--caused by the larval stage (hydatid cyst) of the cestode Echinococcus granulosus--is one of the most widespread zoonoses of veterinary and medical importance. Molecular techniques have allowed the identification of 10 different genotypes (G1-G10) of the parasite. The present paper is an update regarding the E. granulosus genotypes infecting water buffaloes and cattle bred in the Campania region of southern Italy. The molecular study was performed on 30 hydatid cysts (11 from water buffaloes and 19 from cattle). Two different mitochondrial DNA genes, namely the cytochrome c oxidase subunits 1 and the 12S ribosomal DNA (12S rDNA) were used as genetic markers. Three different genotypes of E. granulosus were unequivocally identified, i.e. the G1 (common sheep), G2 (Tasmanian sheep) and G3 (buffalo) genotypes, as well as some G1 and G2 variants. It should be noted that the present study demonstrated for the first time: (i) the presence of the G2 genotype in water buffaloes from a Mediterranean area; and (ii) the fact that the analysed portion of the 12S rDNA gene can not discriminate between the G2 and G3 genotypes of E. granulosus. The finding of the G1, G2 and G3 genotypes in large ruminants from southern Italy is of epidemiological relevance and immediate public health importance because of their recognized infectivity in humans.     

Prevalence and economic importance of cystic echinococcosis in slaughtered ruminants in Burdur,Turkey

This study was conducted between April 2000 and March 2001, in 12-month period. During the study, local slaughterhouses were visited periodically for 1 year to examine the internal organs (livers, lungs, spleens and hearts) for the presence of cysts and total 1355 cattle, 218 sheep and 104 goats were examined for the cystic echinococcosis (CE). It was found that 13.5% of cattle, 26.6% of sheep and 22.1% of goats were infected with this disease. While cysts in cattle (P < 0.001) and goats (P > 0.05) were found mostly in lungs (88.5 and 82.6%, respectively), but they were mostly found in livers (P > 0.05) in sheep. In addition to this, three spleens and one heart in cattle were infected with CE. In this study, the prevalence of CE and the number of cysts in ruminants were found different when the cattle, sheep and goats examined were stratified based on age. The prevalence and the number of cysts increased with age approaching an asymptotic prevalence of one in the oldest animals (P < 0.05). The number of cysts in cattle, sheep and goats were increasing at a rate of 0.31, 0.63 and 0.42/year, respectively. The economic decrease in the value of the carcasses because of the discarded liver and lung as a result of CE was estimated as 1.1% (7.5 US dollars per cattle) for cattle, 4.37% (3.2 US dollars per sheep) for sheep and 4.26% (2.9 US dollars per goat) for goats. The minimum total loss for all infected animals was determined to be 583 US dollars in infected animals, based on the market prices in the year 2002.