首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A survey on the prevalence of Thelazia spp. in the province of Bari (Apulia region, Italy) in slaughtered native horses was conducted from June 20, 1995 to April 3, 1996. Both eyes from 409 ten-month- to 4-year-old native animals were examined. Sixty horses (14.7%) were found parasitized by Thelazia lacrymalis. Three hundred-sixty one parasite specimens (220 females, 99 males and 42 larvae) were collected with a mean count burden of 6.0-5.1 (range 1 to 20) per head. T. lacrymalis specimens were found free in the conjunctiva and behind the nictitancte, in the excretory ducts of the Harderian gland and in the ducts of the lacrimal glands. Thelazia specimens were significantly more common in horses of 3-4 years. Gross examination of all infected animals showed a follicular conjunctivitis. This is the first report of T. lacrymalis horse infection in Italy.  相似文献   

2.
Eyes from 114 (30.3%) of 376 dead horses, examined from 3 April 1975 to 3 April 1976, were naturally infected with adult Thelazia lacrymalis; 1 horse was also infected with 1 male Thelazia skrijabini. Adult T. lacrymalis from dead horses were successfully transferred mechanically to the eyes of 3 of 4 Shetland ponies raised helminth-free. Larvae from gravid female T. lacrymalis underwent development in experimentally infected, laboratory-raised face flies (Musca autumnalis) and third-stage larvae ranging from 1.82 to 2.94 mm in total length were recovered at 12 to 15 days postexposure. A total of 866 naturally occurring face flies were collected from the head region of horses. Twelve of the face flies harbored larval stages of Thelazia spp. One of the larvae resembled third-stage T. lacrymalis that were recovered from the experimentally infected, laboratory-raised face flies. Introduction of 3 third-stage larvae from 1 face fly onto the cornea of a pony raised helminth-free resulted in the recovery of 1 male T. skrjabini 242 days later. In addition to the eyeworm larvae, other parasites recovered from the face flies included Heterotylenchus autumnalis, hypopi of astigmatid mites and a first instar beetle (Coleoptera: Rhipiphoridae). Data from these investigations indicate the likelihood that face flies are an intermediate host for T. lacrymalis and probably other species of Thelazia in this part of the country.  相似文献   

3.
Spirurid nematodes of the genus Thelazia cause ocular infection in several mammals and are transmitted by dipteran flies. Of the 10 described species, T. gulosa, T. rhodesi, T. skrjabini (affecting cattle), T. lacrymalis (affecting horses), and T. callipaeda (affecting carnivores and humans) are the most common. The aim of this study was to characterize the first internal transcribed spacer (ITS1) ribosomal DNA sequences of these 5 species. The length of the ITS1 sequences ranged from 357 bp (T. lacrymalis) to 905 bp (T. callipaeda). Interspecific differences ranged from 35 to 77%. Polymorphic sites were detected in each species. Intraspecific variation varied from 0.3 to 2.5%. The characteristics of the ITS1 of Thelazia spp. show similarities to those of other Spirurida. The findings of this present study show that the ITS1 represent a powerful genetic marker for the molecular identification of eyeworms and a useful tool for developing molecular epidemiological techniques to study Thelazia spp. transmission patterns and prevalence in definitive and intermediate hosts.  相似文献   

4.
The occurrence of Thelazia gulosa and T. skrjabini in cattle in Italy, together with an update of the prevalence of Thelazia spp. in the southern Italy, is reported. On 764 slaughtered native cattle, fifty-five (7.2%) bovines were infected by Thelazia spp: T. rhodesi was found in 44 (80%) animals, T. gulosa was found in 19 (34.5%) cattle and only one (1.8%) cattle harboured T. skrjabini. This is the first report of T. gulosa and T. skrjabini in Southern Europe.  相似文献   

5.
The female reproductive system of Thelazia lacrymalis (Nematoda: Thelaziidae) was investigated by light and scanning electron microscopy (SEM) with regard to the developmental stages and the stage deposited by the gravid nematode. Female T. lacrymalis have a didelphic and opisthodelphic type of reproductive system with paired ovaries, oviducts and uteri and a single vagina and vulva. Round and spindle-shaped primary oocytes are documented within the ovaries and oviducts, respectively. The distal part of each uterus provides a fertilization chamber filled with spermatozoa, followed by a sphincter-like part. Further anterior, the uteri broaden gradually containing dividing zygotes, small and large morulae, tadpole-stage embryos and horseshoe-shaped embryos which increase in length and become slimmer forming pretzel-stage embryos and larvae rolled up. The larvae stretch gradually and finally lie straight but still covered with their egg membrane in the vagina. The egg membrane encloses the whole larva and is enlarged at the pointed tail of the larva forming a bulb. At the SEM level, the first-stage larva is shown to have a terminal mouth and three hooks directed posteriorly and a striated cuticle. As morphologically identical larvae were also found in lavages of the conjunctival sac of horses infected with T. lacrymalis, this nematode species can be described as ovoviviparous.  相似文献   

6.
A survey was performed on the occurrence of some internal parasites in 461 horses (1–30 years old) slaughtered from October 1992 to September 1993 at the Linköping abattoir in central Sweden. Macroscopical examination was carried out specifically for parasites of the tear ducts and conjunctival sacs of the eyes, and of selected parts of the alimentary tract and car-dio-vascular system. The following parasites were found in selected parts of the large intestine: encapsulated cyathostome larvae (in 35.6% of the horses), and mature strongyle worms (17.4%); in the stomach: Gasterophilus intestinalis (12.3% during October-June) and Habronema muscae (1.1%); and in the conjunctival sac: Thelazia lacrymalis (3.1%). Significantly more encapsulated cyathostome larvae were found during January to June than during other times of the year, and horses aged 1–5 years harboured significantly more larvae than older horses. Severe damage to the cranial mesenteric artery and its main branches was noticed in 16 (6.1%) out of 263 horses specifically examined. However, the 4th stage larva of Strongylus vulgaris was only recovered in 6 (2.3%) of the horses. Quantitative and qualitative faecal egg counts were done on 412 and 384 of the horses, respectively. Eggs of strongyles, Parascaris equorum and Strongyloides westeri were found in 78.1%, 1.9% and 0.2% of the faecal samples, respectively. Highest prevalence of strongyle eggs was found during July to September. Third stage larvae of the following nematodes were recovered from faecal cultures: subfamily Cyathostomum sensu lato (78.1%) Triodontophorus spp. (6.5%), Strongylus vulgaris (3.6%), Trichostrongylus axei (1.3%), while Gyalocephalus sp., Oesophagodontus sp., Poteriostomum sp. and Strongylus edentatus each comprised less than 0.5%.  相似文献   

7.
A face fly (Musca autumnalis) population near Wetaskiwin, central Alberta, Canada, was sampled 9 times from 26 July to 29 September 1988 for the early larval stages of Thelazia spp. Of 426 female flies examined, 159 (37%) contained Thelazia spp. (almost exclusively T. skrjabini), with an average worm burden of 4.2 larvae per infected fly. Prevalence ranged from 17 to 56% over 9 collections. This is the first report of Thelazia skrjabini in flies from western North America and the highest Thelazia prevalence in face flies yet reported in North America. The face fly population was also parasitized by Heterotylenchus autumnalis, with a prevalence of 5.5%.  相似文献   

8.
Bovine thelaziasis in Iowa   总被引:1,自引:0,他引:1  
The prevalence of developing Thelazia nematodes in face flies (Musca autumnalis) was studied for 7 yr at a beef farm in central Iowa. Juvenile nematodes were not found among flies in reproductive diapause in autumn, nor among nulliparous, overwintered flies in spring, but only among actively reproducing insects. Thus Thelazia probably do not overwinter in face flies. A mean prevalence of 2.0% infected was recorded among flies in 7 fly breeding seasons. No heterogeneity in Thelazia prevalence was detected within fly breeding seasons. The frequency distribution of Thelazia among face flies by year of occurrence was homogeneous, with a mean of 2.75 larval nematodes per infected fly. Thelazia gulosa and T. skrjabini were recovered in necropsy from the eyes of bovines from central Iowa. Prevalence among fat cattle 18-27 mo old was 15%; among cows 3-15 yr old, prevalence was only 3%. Thelazia skrjabini was found in 29 eyes and T. gulosa in 4 eyes. Infections were randomly distributed among the eyes of subject cattle. The mean worm burden was 2.3 T. skrjabini and 12 T. gulosa per infected eye. Thelaziasis is clearly enzootic in Iowa.  相似文献   

9.
The distribution of Thelazia skrjabini in the eyes of cattle was examined from necropsies on 297 animals. Although the overall prevalence in beef cattle (21.5%) was similar to that in dairy cattle (25.7%), in general worms were more abundant in beef than in dairy animals. The worm prevalence was lowest in the months from March to June and highest in September among beef and dairy animals. Thelazia skrjabini was found in 76 (16.8%) eyes from beef, and 23 (16.4%) eyes from dairy cattle. Infections were not randomly distributed among the eyes of cattle. Significantly more dairy and beef cattle contained T. skrjabini in both eyes than expected based on the observed prevalences. Based on chi-square probabilities, significantly more cattle more than 2 yr of age and less than 10 mo of age were infected with T. skrjabini. Although all age groups were infected, more worms were observed in cattle more than 2 yr of age. More female worms than males were collected from cattle. The male-to-female ratio of 1:2 was consistent regardless of cattle age, season, or type.  相似文献   

10.
The genus Thelazia (Spirurida, Thelaziidae) includes a cosmopolitan group of eyeworm spirurids responsible for ocular infections in domestic and wild animals and transmitted by different species of muscids. Bovine thelaziosis is caused by Thelazia rhodesi Desmarest 1828, Thelazia gulosa Railliet & Henry 1910, and Thelazia skrjabini Erschow 1928, which occur in many countries; T. gulosa and T. skrjabini have been reported mainly in the New World, while T. rhodesi is particularly common in the Old World. In Italy, T. rhodesi was reported in southern regions a long time ago and, recently, T. gulosa and T. skrjabini have been identified in autochthonous cattle first in Apulia and then in Sardinia. Thirteen species of Musca are listed as intermediate hosts of eyeworms, but only Musca autumnalis and Musca larvipara have been demonstrated to act as vectors of Thelazia in the ex-URSS, North America, ex-Czechoslovakia and more recently in Sweden. In Italy, after the reports of T. gulosa and T. skrjabini in southern regions, the intermediate hosts of bovine eyeworms were initially only suspected as the predominant secretophagous Muscidae collected from the periocular region of cattle with thelaziosis were the face flies, M. autumnalis and M. larvipara, followed by Musca osiris, Musca tempestiva and Musca domestica. The well-known constraints in the identification of immature eyeworms to species by fly dissection and also the time-consuming techniques used constitute important obstacles to epidemiological field studies (i.e. vector identification and/or role, prevalence and pattern of infection in flies, etc.). Molecular studies have recently permitted to further investigations into this area. A PCR-RFLP analysis of the ribosomal ITS-1 sequence was developed to differentiate the 3 species of Thelazia (i.e. T. gulosa, T. rhodesi and T. skrjabini) found in Italy, then a molecular epidemiological survey has recently been carried out in field conditions throughout five seasons of fly activity and has identified the role of M. autumnalis, M. larvipara, M. osiris and M. domestica as vectors of T. gulosa and of M. autumnalis and M. larvipara of T. rhodesi. Moreover, M. osiris was described, for the first time, to act as a vector of T. gulosa and M. larvipara of T. gulosa and T. rhodesi. The mean prevalence in the fly population examined was found to be 2.86%. The molecular techniques have opened new perspectives for further research on the ecology and epidemiology not only of Thelazia in cattle but also of other autochthonous species of Thelazia which have been also recorded in Italy, such as Thelazia callipaeda, which is responsible for human and canid ocular infection and Thelazia lacrymalis, the horse eyeworm whose epidemiological molecular studies are in progress.  相似文献   

11.
Thelazia nematodes cause ocular infection in several mammals and are transmitted by dipteran flies. Thelazia callipaeda Railliet and Henry 1910 (Spirurida, Thelaziidae) is common in the Far East, where it causes eyeworm infection in carnivores and humans. In the past few years, it has also been reported in dogs, cats and foxes in Northern and Southern Italy. Although a great deal of work has been carried out in China and other Eastern countries, knowledge of the morphology of T. callipaeda is scanty. Eighty-three nematodes collected from the eyes of naturally infected dogs from the Basilicata region (southern Italy) were examined by light and scanning electron microscopy, and the most important features of the nematodes were described. The morphological characteristics useful for the identification of T. callipaeda are discussed.  相似文献   

12.
The present study is the first report that investigated the seroprevalence of Toxoplasma gondii infection in domestic horses in various prefectures of Japan and analyzed risk factors for seropositivity. We performed a latex agglutination test for riding/racing horses from 11 prefectures in Japan (783 samples) and 4 groups of Japanese native horses (254 samples). The total seroprevalence of anti-T. gondii antibody in horses examined in this study was 4.24% (44/1037). As for riding/racing horses, we did not find a statistically different T. gondii seroprevalence between sampling prefectures. In contrast, seroprevalence of T. gondii in older horses (> 21 years) was significantly higher than that in younger horses (< 5 years and 11–15 years). There was no significant difference in T. gondii seroprevalence between riding/racing horses and Japanese native horses. Logistical regression analysis revealed that age, but not sex and usage, is a significant risk factor of T. gondii infection for domestic horses in Japan. These findings suggest that domesticated horses in Japan can be horizontally infected with T. gondii by ingestion of food or water contaminated with oocysts.  相似文献   

13.
The presence of antibodies to Toxoplasma gondii in livestock and poultry was investigated by latex agglutination tests; samples that agglutinated at dilutions of 1:64 or higher were regarded as positive. Sera were collected from fattening beef cattle (102 Japanese black, 105 crossbreeds and 114 castrated Holstein), culled dairy cattle (101 Holstein), 100 horses, 115 fattening pigs and 235 chickens (163 free-range and 72 broilers) at abattoirs in Gifu Prefecture, Japan, from August 2012 to August 2013. Antibodies to T. gondii were found in 7.3% (31/422) in cattle, 5.2% (8/155) in pigs, but not in horses or chickens. These results suggest that toxoplasmosis may be transmitted to humans via consumption of T. gondii-infected raw beef in Japan.  相似文献   

14.
The development of Thelazia skrjabini Erschow, 1928, was studied in experimentally infected laboratory-reared Musca autumnalis De Geer. Thelazia skrjabini developed to the infective third stage in a minimum of 9 days in M. autumnalis maintained at 27 +/- 2 C. First-stage larvae were not observed postinoculation, but second-stage larvae were first observed 3 days postinoculation. Development was asynchronous. Second- and third-stage larvae occur in capsules, occasionally in the head but primarily in the abdomen attached to fat bodies. First-stage larvae have anteriorly 1 ventral and 2 dorsal hooks, directed posteriorly. Second-stage larvae have 4 submedian cephalic papillae and faint annular striations. Third-stage larvae have 6 labial papillae, 4 submedian cephalic papillae and pronounced annulations. Morphometric studies of each larval stage were performed with specimens in glycerine.  相似文献   

15.
We report 2 cases of Thelazia rhodesii infection in the African buffaloes, Syncerus caffer, in Zambia. African buffalo calves were captured from the livestock and wildlife interface area of the Kafue basin in the dry season of August 2005 for the purpose to translocate to game ranches. At capture, calves (n=48) were examined for the presence of eye infections by gently manipulating the orbital membranes to check for eye-worms in the conjunctival sacs and corneal surfaces. Two (4.3%) were infected and the mean infection burden per infected eye was 5.3 worms (n=3). The mean length of the worms was 16.4 mm (95% CI; 14.7-18.2 mm) and the diameter 0.41 mm (95% CI; 0.38-0.45 mm). The surface cuticle was made of transverse striations which gave the worms a characteristic serrated appearance. Although the calves showed signs of kerato-conjunctivitis, the major pathological change observed was corneal opacity. The calves were kept in quarantine and were examined thrice at 30 days interval. At each interval, they were treated with 200 μg/kg ivermectin, and then translocated to game ranches. Given that the disease has been reported in cattle and Kafue lechwe (Kobus lechwe kafuensis) in the area, there is a need for a comprehensive study which aims at determining the disease dynamics and transmission patterns of thelaziasis between wildlife and livestock in the Kafue basin.  相似文献   

16.
A postmortem survey of 57 horses in tropical northern Queensland revealed 41 (89%) infected with intestinal strongyles. Thirty-five strongyle species (8 large strongyles and 27 small strongyles [Cyathostominae]) were recorded of which 9 species are reported from Australia for the first time. The 14 most prevalent small strongyles were Cyathostomum catinatum (in 76% of horses), Cyathostomum coronatum (65%), Cyathostomum pateratum (33%), Cyathostomum labiatum (30%), Cylicostephanus calicatus (70%), Cylicostephanus longibursatus (67%), Cylicostephanus goldi (43%), Cylicostephanus minutus (26%), Cylicocylus nassatus (67%), Cylicocyclus leptostomus (41%), Cylicocylus insigne (41%), Cylicocyclus radiatus (33%), Cylicocyclus brevicapsulates (22%), and Poteriostomum imperidentum (24%). The remaining cyathostomes were each found in less than 15% of horses. The 4 most common large strongyles were Triodontophorus serratus (30%), Strongylus vulgaris (28%), Strongylus equinus, and Strongylus edentatus (both 22%). The number of species of small strongyles per horse showed a marked variation (mean 10.3, range 2-21) but bore no relationship to either the total number of strongyles per horse, age, sex, and breed of horse, or season. Total number of strongyles per horse (mean 15,890, range 20-165,000) was less than in recent surveys in Europe and the U.S.A. Most horses had low worm burdens, whereas a very small number were heavily infected. Ninety-seven per cent of the total strongyle counts were small strongyles. Strongylus species contributed just over 1%. Small numbers of large strongyles per horse were usual with T. serratus (mean 570), S. vulgaris (mean 330), and S. equinus (mean 330) the most numerous.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

17.
Thelazia callipaeda (Spirurida, Thelaziidae) infects the eyes of humans and rabbits as well of domestic and wild carnivores (i.e., dogs, cats, and foxes). The first three cases of infection by T. callipaeda eyeworms in wolves (Canis lupus) are here described with up to 96 nematodes collected from a single animal. The host competence of wolf was demonstrated by the retrieval of adult worms in the eyes of all examined animals. All nematodes collected were evaluated by morphologic and molecular techniques. Sequence analysis of the partial mitochondrial cytochrome c oxidase subunit 1 gene (cox1) confirmed that only one haplotype of T. callipaeda was present. The competence of wolves as a definitive host for T. callipaeda is discussed in view of the relevance of wild fauna in maintaining and spreading eyeworm infection in humans and domestic animals.  相似文献   

18.
Once a month, from June 1992 to May 1993, collections of tabanids on horse were conducted in the Nhecolandia, Pantanal State of Mato Grosso do Sul, Brazil. Tabanid catches using hand nets were conducted from sunrise to sunset at grassland and cerrad?o (dense savanna) habitats. A total of 3,442 tabanids from 21 species,12 genera, and 3 subfamilies were collected. Although species abundance varied seasonally depending on habitat, no habitat specificity was observed for the most abundant species. In the grassland, 1,625 (47.2%) tabanids belonging to 19 species were collected, while 1,817 (52.8%) tabanids from 17 species were caught in the cerrad?o. The number of tabanid species varied from 7 during winter (July/August) to 15 in the spring (October). Tabanus importunus (56%) was the most abundant species, followed by T. occidentalis (8.2%), and T. claripennis (8.1%). The tabanid peak, in October, coincided with the beginning of the rainy season. The population peak of most species, including those with higher vector potential, suggests that the rainy season can be considered as the period of potentially higher risk of mechanical transmission of pathogens by tabanids to horses in the region.  相似文献   

19.
Distal ileum, caecum and proximal colon of 470 horses were examined for helminths during 1 year at an abattoir in central Sweden. The infection levels of the horse tapeworm Anoplocephala perfoliata, their stage of development, site of attachment and gross pathological lesions caused by the worm were recorded. Faecal samples from 395 of the horses were examined specifically for tapeworm segments and eggs in order to correlate these findings with the numbers in the alimentary canal. In total 65% of the horses were infected with A. perfoliata and the mean intensity of infection was 79 worms per infected horse with a maximum of 912. The level of infection was significantly higher in (1) 3rd and 4th than in 1st and 2nd quarter of the year; (2) older horses than in yearlings; (3) females than in males and geldings; (4) thoroughbreed and cold-blooded horses than in Swedish standardbreeds and ponies. The level of infection was unaffected by the usage of anthelminthics against nematodes. Of the horses examined 51% had 1-100 worms whereas 14% were infected with more than 100 worms. Of the tapeworm positive horses 72% had mixed infections with both adult and juvenile worms, 20% solely juveniles, and 8% solely adults. The severity of intestinal lesions exacerbated by increasing numbers of A. perfoliata. About 11% of the intestines examined had severe lesions, but there was no history of acute abdominal distress in any of the horses included in this study. Although the number of detectable eggs was significantly higher for horses heavily infected with A. perfoliata, the egg recovery among infected horses was only 35%. An additional field survey comprising 218 horses on 88 premises in central and southern parts of Sweden showed that the prevalence of A. perfoliata egg positive horses was the same as found on faecal examination during the abattoir survey.  相似文献   

20.
Knowledge of the effects that Thelazia callipaeda (Spirurida, Thelaziidae) infection has on the survival of its vector Phortica variegata (Drosophilidae, Steganinae) is scarce. The present study aimed to: (a) assess the rate of infection between experimentally infected (EI) and not experimentally infected (NEI) flies and (b) determine how T. callipaeda infection may affect the survival of P. variegata. In addition, fat composition was evaluated in flies that died during overwintering. Molecular analysis showed that T. callipaeda prevalence in flies that died before experimental infection, plus those from the NEI group, is 0.75% (i.e. 11 out of 1462 individuals). The EI group showed a significantly higher positivity to T. callipaeda (i.e. 51 out of 682 individuals; 7.48%) compared with the NEI group (i.e. 9 out of 750 individuals; 1.2%). Thelazia callipaeda DNA was detected until 147 days after experimental infection. This demonstrates that larvae of this eyeworm may survive in the fly for a significant period of the winter. Fat composition analysis showed that flies produced more unsaturated than saturated fatty acids during diapause, probably because unsaturated fatty acids remain in a liquid state at lower temperatures, providing anti-freeze properties to survive winter.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号